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Thursday, 31 March 2016

FSc Notes Biology Part 2 Chapter 21 Cell Cycle Short Questions

FSc Notes Biology Part 2 Chapter 21 Cell Cycle Short Questions


Q 1. Define cell cycle?
Ans.
The cell under goes a sequence of changes, which involve period of growth, replication of DNA followed by cell division. This sequence of changes is called cell cycle.

Q 2. How much time is required for cell cycle in case of human?
Ans.
In the case of human cell, average cell cycle is about 24 hours.

Q 3. What does you know about chromatin?
Ans.
Chromatin is a network of very fine threads which can be visualized but using histologic stains of DNA.

Q 4. In higher plants instead of visible centriole what is present?
Ans.
Higher plants lack visible centrioles, instead they have its analogous region from which the spindle microtubules radiate.

Q 5. What is metastasis?
Ans.
The cell composing a malignant tumor or cancer, divide more rapidly, mostly invade surrounding tissues, get into the body circulatory system, and set up areas of proliferation, away from their site of original appearance. This spread of tumor cells and establishment of secondary areas of growth is called metastasis.

Q 6. When in plants and animals the meiosis takes place?
Ans.
Meiosis takes place in diploid cells only, in animals at the time of gamete formation, while in plants when spores are produced.

Q 7. Define crossing over?
Ans.
It is the exchange of segments between non-sister chromatids of homologous chromosomes due to chiasmata formation.

Q 8. What are the two significant happenings of meiosis?
Ans.
Crossing over and random assortment of chromosomes are two significant happening of meiosis.

Q 9. How many chromosomes do occur in male affected by Klinefelter's syndrome?
Ans.
Males with 48 chromosomes (44 autosomes + XXXY), with 49 chromosomes (44 autosomes + XXXXY) and male with 47 chromosomes (44 autosomes + XYY) are also observed.

Q 10. What are symptoms of Turner's syndrome?
Ans.
The affected individuals have one missing X chromosome with only 45 chromosomes (44 autosomes + Y). Individuals have female appearance with short stature, webbed neck, without ovaries and complete absence of germ cells.

Q 11. What is apoptosis?
Ans.
Internal programme of events and sequence of morphological changes by which cell commits suicide is collectively called apoptosis (Greek word that means dropping off or falling off).

Q 12. Name the different stages of interphase?
Ans.
Interphase can further e divided into G1-phase, S-phase and G2-phase.

Q 13. What is G1-phase?
Ans.
G1 (Gap 1) is the period of extensive metabolic activity, in which cell normally grows in size, specific enzymes, are synthesized and DNA base units are accumulated for the DNA synthesis.

Q 14. What is G0?
Ans.
Post-mitotic cell can exit the cell cycle during G1 entering phase called G0, and remain for days, weeks, or in some cases even the life time of the organism without proliferation further.

Q 15. What is S-phase of cell cycle?
Ans.
Following the G1 is the S-phase (synthesis phase) during which the DNA is synthesized and chromosomes number doubled.

Q 16. What happens in G2-phase (pre-mitotic phase)?
Ans.
In G2 phase (pre-mitotic phase) the cell prepares for division i.e., energy storage for chromosome movements, mitosis specific proteins, RNA and microtubule subunits (for spindle fibres) synthesis are accomplished.

Q 17. Define mitosis?
Ans.
It is the type of cell division, which ensures the same number of chromosomes in the  daughter cells as that in the parent cells.

Q 18. What are two conventional phases of Mitosis?
Ans.
Conventional phases of Mitosis
  1. Karyokinesis, which involves the division of nucleus.
  2. Cytokinesis that refers to the division of the whole cell.

Q 19. What is Mitotic apparatus?
Ans.
The specialized micro-tubule structure including aster and spindle is called mitotic apparatus.

Q 20. Name the microtubules which originate from centrioles?
Ans.
Three sets of microtubules (fibres) originate from each pair of centrioles ie.e, astral microtubules, kinetochore microtubules and polar microtubules.

Q 21. What events occur in Prophase of mitosis?
Ans.
Each chromosome is visible having two sister chromatids, attached at centromere. Towards the end of prophase nuclear envelope disappears and nuclear material is released in the cytoplasm, nucleoli disappear. Mitotic apparatus is organized. Cytoplasm becomes more viscous.

Q 22. What is kinetochore?
Ans.
The centromere has special area the kinetochore, with specific base arrangement and special proteins where kinetochore fibres of mitotic apparatus attach.

Q 23. What happens in Telophase of mitosis?
Ans.
The chromosomes decondense, due to unfolding, ultimately disappear as chromatin. Mitotic apparatus disorganize, nuclear membrane and nucleoli reorganize, forming two nuclei  at two poles of the cell.

Q 24. What is Phragmoplast?
Ans.
At cytokinesis, in plants, a membrane structure called phragmoplast is formed from vesicles of Golgi complex. These vesicles line up in the centre of the dividing cell, where they fuse to form phragmoplast at the end of telophase.

Q 25. Define cancer?
Ans.
Any malignant growth or tumour from an abnormal and uncontrolled division of body cells is known as cancer.

Q 26. What is Tumour?
Ans.
When such cells produce new cells which continue to proliferation in uncontrolled fashion, an unwanted clone of cells, called Tumour is formed, which can expand un-definitely.

Q 27. What are two basic types of tumour?
Ans.
Basic types of tumour
  • Benign tumours.
  • Malignant tumours.

Q 28. What is benign tumours?
Ans.
Benign tumours are of small size and localized (not transferred to other parts) called Benign. The cells in this type usually behave like the normal cells and have little deleterious (harmful) effects.

Q 29. What is malignant tumour?
Ans.
The cells composing a malignant tumour or cancer, divide more rapidly, mostly invade surrounding tissues, get into the body's circulatory system, and set up areas of proliferation, away from their site of original appearance.

Q 30. How can you distinguish cancer cells from normal cells?
Ans.
Cancer cells can be distinguished from normal cells because they are less differentiated than normal cells, exhibit the characteristics of rapidly growing cells, that is, high nucleus to cytoplasm ratio, prominent nucleoli and many mitosis.

Q 31. What main causes of cancer?
Ans.
Cancer is caused mainly by mutations in somatic cells. The cancer results from the accumulation of as few as three to as many as twenty mutations, in genes that regulate cell division.

Q 32. Define meiosis?
Ans.
Meiosis is the special type of cell division in which the number of chromosomes in daughter cells reduces to half, as compared to the parent cell.

Q 33. How prophase of meiosis differs from that of mitosis?
Ans.
This is very prolonged phase, and differs from the prophase of mitosis, because in this chromosomes behave as homologous pairs. Each diploid cell has two chromosomes of each type, one member from each parent.

Q 34. What are homologous chromosomes?
Ans.
The chromosomes which are similar but not necessarily identical are called as homologous chromosomes.

Q 35. Name the sub-stages of prophase I of meiosis?
Ans.
Leptotene, zygotene, diplotene and diakinesis.

Q 36. What is synapsis?
Ans. The pairing of homologous chromosomes during zygotene stage is called synapsis.

Q 37. What is bivalent or tetard?
Ans.
Each paired but not fused, complex structure of homologous chromosomes is called as bivalent or tetard.

Q 38. What is the duration of Pachytene, leptotene and zygotene?
Ans.
Pachytene may lasts for days, weeks or even years, whereas leptotene and zygotene can last only for few hours.

Q 39. What is chiasmata?
Ans.
The paired homologous chromosomes repel each other and begin to separate but still remain united by their point of interchange which is called chiasmata.

Q 40. What happens in Diakinesis?
Ans.
The condensation of chromosomes reaches to its maximum. At the same time separation of the homologous chromosomes is completed, but still they are united at one point, more oftenly at ends, Nucleoli disappear.

Q 41. What events occur in metaphase I of meiosis?
Ans.
Nuclear membrane disorganize at the beginning of this phase. Spindle fibres originate and the kinetochore fibres attached to the kinetochore o homologous chromosome from each pole and arrange bivalents at the equator.

Q 42. How does anaphase I of meiosis differs from that of mitosis?
Ans.
In anaphase I of meiosis the sister chromatids are not separated, only homologous chromosomes get separated. while anaphase of mitosis the sister chromatids are separated.

Q 43. How meiosis maintains chromosome number constant generation after generation?
Ans. Meiosis usually takes place at the time of sexual cells (gamete) formation, (spore formation in plants) thus reducing the number of chromosomes to half in each, which is restored after fertilization and maintains chromosome number constant generation after generation.

Q 44. Define non-disjunction?
Ans.
In non-disjunction chromosomes fail to segregate during Anaphase and Telophase and do not finish with equal distribution of chromosome among all the daughter nuclei. This results either increase (or decrease) in the number of chromosomes, causing serious physical, social and mental disorders.

Q 45. What is autosomal non-disjunction?
Ans.
The non-disjunction in which autosomal chromosomes fail to segregate is called autosomal non-disjunction.

Q 46. What is Downs Syndrome (Mongolism)?
Ans.
It occurs, in man, during which 21st chromosome fails to segregate, resulting gamete with 24 chromosomes. This gamete fertilizes normal gamete the new individual will have 47 (2n + 1) chromosomes.

Q 47. Does Downs syndrome is related to the age of mother?
Ans.
Yes, the chances of teenage mother having downs syndrome child is one in many thousands, forty years old mother one in hundred chance and by forty-five the risk is three times greater.

Q 48. What are apparent symptoms or effects of Downs syndrome?
Ans.
The affected individuals have flat, broad face, squint eyes with the skin fold in the inner corner, and protruding tongue, mental retardation and defective development of central nervous system.

Q 49. What is sex chromosomal non-disjunction?
Ans.
The non-disjunction in which sex chromosomes fails to segregate is called sex chromosomal non-disjunction.

Q 50. What is Necrosis?
Ans.
The cell death due to tissue damage is called necrosis, during which the typical cell swells and bursts, releasing the intracellular contents, which can damage neighboring cells and cause inflammation.

Written by: Usman Rashid & Asad Hussain

Wednesday, 30 March 2016

FSc Notes Part 1 Biology Pairing For Board Examination

FSc Notes Part 1 Biology Pairing For Board Examination


Objective Portion


Multiple Choice Questions: (17)

One MCQ from every chapter from Chapter 1 to 9 + 12 + 13
Two MCQ from Chapter 10 + 11 + 14

Subjective Portion


Section No 1 Short Question: (22 out of 33)

Question No 2:  (8 out of 12)
                          Chapter 1 (2) Two Short Questions
                          Chapter 2 (1) One Short Questions
                          Chapter 3 (3) Three Short Questions
                          Chapter 7 (4) Four Short Questions
                          Chapter 8 (2) Two Short Questions

Question No 3:  (8 out of 12)
                          Chapter 4 (2) Two Short Questions
                          Chapter 10 (4) Four Short Questions
                          Chapter 11 (2) Two Short Questions
                          Chapter 13 (4) Four 4 Short Questions
                         
Question No 4:  (6 out of 9)
                          Chapter 5 (1) One Short Questions
                          Chapter 6 (1) One Short Questions
                          Chapter 9 (2) Two Short Questions
                          Chapter 12 (3) Three Short Questions
                          Chapter 14 (2) Two Short Questions

 

Section No 2 Long Question: (3 out of 5)

Question No 5: Chapter 1 + 9
Question No 6: Chapter 2 +12
Question No 7: Chapter 4 + 8
Question No 8: Chapter 5 + 11
Question No 9: Chapter 6 + 14

Written by: Asad Hussain

FSc Notes Biology Part 2 Chapter 20 Chromosomes and DNA Short Questions

FSc Notes Biology Part 2 Chapter 20 Chromosomes and DNA Short Questions


Q 1. Who first observe the chromosomes?
Ans. The German embryologist Walther Fleming first observed them in 1882, when he was examining the rapidly dividing cells of salamander larvae.

Q 2. What is euchromatin?
Ans. The portion of the chromosome except heterochromatin is called euchromatin. It is condensed only during cell division, when compact packaging facilitates the movement of the chromosomes. At all other times, euchromatin is present in an open configuration and its genes can by expressed.

Q 3. What is transformation?
Ans. Transformation is the transfer of genetic material from one cell, to another and can alter the genetic up of the recipient cell.

Q 4. What is nuclein?
Ans. Miescher extracted a white substance from the nuclei of human cells and fish sperm. He called substance "Nuclein" because it seemed to be specifically associated with the nucleus.

Q 5. What is semi-conservative replication?
Ans. In this form of DNA replication, the daughter DNAs have one of the original strands and the other strand is newly synthesized from complementary nucleotides.

Q 6. How DNA polymerase III can initiate synthesis of DNA?
Ans. DNA polymerase can initiate synthesis of DNA only if another enzyme, primase, constructs an RNA primer. DNA polymerase III recognizes the primer and adds DNA nucleotides to it to construct the DNA strands. The RNA nucleotides in the primers are then replaced by DNA nucleotides.

Q 7. What are Okazaki frangments?
Ans. The lagging strand, which elongates away from the replication fork, in synthesized discontinuously as a series of short segments that are later connected. These segments are called Okazaki frangments.

Q 8. What is the length of Okazaki frangments?
Ans. They are about 100-200 nucleotides long in eukaryotes and 1000-2000 nucleotides long in prokaryotes.

Q 9. What "one gene / one polypeptide"?
Ans. Many enzymes contain multiple protein or polypeptide subunits, each encoded by a separate gene, this relationship is referred to as "one gene / one polypeptide".

Q 10. What is transcription?
Ans. The first step of central dogma is the transfer of information from DNA to RNA, which occurs when an mRNA copy of gene is produced. The process is called transcription.

Q 11. Which codons are called stop codons and nonsense condon and why?
Ans. Out of 64 codons, three codons UAA, UAG and UGA do not code for any amino acid and hence are known as nonsense condon. These codons are usually present at the end of the gene and hence are also called stop codons.

Q 12. What is initiation condon?
Ans. Every gene starts with initiation condon AUG, which encodes the amino acid methionine.

Q 13. How long DNA would stretch, if the DNA all of the cells of an adult human were lined up end to end?
Ans. if the DNA in all of the cells of an adult human were lined up end to end, it would stretch nearly 100 billion kilometer - 60 times the distance from Earth to Jupiter.

Q 14. What is primer?
Ans. The primer is a sequence of about 10 RNA nucleotides complementary to the parent DNA template. It is synthesized by enzyme primase.

Q 15. What are the three major classes of RNA?
Ans. mRNA, tRNA and rRNA.

Q 16. What is the function of RNA polymerase in transcription?
Ans. Transcription is initiated when the enzyme RNA polymerase binds to a particular binding site called a promoter located at the beginning of the gene.

Q 17.  What is triplet code?
Ans. The genetic code for specifying amino acids does consists of 3 bases. This is called triplet code.

Q 18. What is anticondon?
Ans. A sequence of three nucleotides in tRNA that is complementary to mRNA is called anticondon.

Q 19. What are chromosomes?
Ans. Chromosomes are thread like structures that appear inside the nucleus at the time of cell division. They were first observed by Walther Fleming in 1882, when he was examining the rapidly' dividing cells of salamander larvae.

Q 20. What is the number of chromosomes in Penicillium and ferns?
Ans. Penicillium, a fungus, has only one pair of chromosomes, while some ferns have more than 500 pairs.

Q 21. What a typical chromosome is made up of?
Ans. Typically a chromosome is made of chromatids, centromere (primary constriction) and a secondary constriction.

Q 22. What is Karyotype?
Ans. The particular array of chromosomes that an individual possesses is called its Karyotype. They vary in size, staining properties, the location of centromere, he relative length of the two arms on either side of centromere, and the position of constricted regions along the arms.

Q 23. What are different types of Chromosomes depending upon location of centromere?
Ans. The Chromosomes are called Telocentric, acrocentric sub metacentric and metaccentric depending upon the location of centromere between the middle and tip of the chromosomes.

Q 24. What are different shapes of chromosomes?
Ans. The usual shapes of chromosomes are i, j and v.

Q 25. What is the composition of chromosomes?
Ans. Chromosomes are composed of DNA and protein. Most are about 40% DNA and 60% protein.

Q 26. How many nucleotides are contained in a typical human chromosome?
Ans. A typical human chromosome contains about 140 million (14 * 10(8)) nucleotides in its DNA.

Q 27. How much information is contained in one chromosome?
Ans. The amount of information one chromosome contains would fill about 280 printed books of 1000 pages each, if each nucleotide corresponds to a word and each page had about 500 words on it.

Q 28. What is the length of a strand of DNA from a single chromosome?
Ans. If the strand of DNA from a single chromosome were laid out in a straight line, it would be about 5 centimeter long.

Q 29. What is nucleosomes?
Ans. Every 200 nucleotides, the DNA duplex is coiled around a core of eight histone proteins forming a complex known as a nucleosome.

Q 30. Why histones are positively charged?
Ans. Histones are positively charged due to an abundance of the basic amino acids, arginine and lysine. They are thus strongly attracted to the negatively charged phosphate groups of the DNA.

Q 31. What are supercoils of DNA?
Ans. The histone cores act as magnetic forms that promote and guide the coiling of the DNA. Further coiling occurs when the string of nucleosomes wraps up into higher order coils called supercoils.

Q 32. What are heterochromatin?
Ans. Highly condensed portions of the chromatin are called hetero-chromatin. Their DNA is never exposed.

Q 33. Define the chromosome theory of inheritance?
Ans. According to this theory, the genes are physical units located on the chromosome. It means that one member of gene pair is located on one homologous chromosome and the other member of a gene pair is located on the other homologous chromosome.

Q 34. What is a sex linked trait?
Ans. A trait determined by a gene on the X chromosome is said to be sex linked.

Q 35.Who repeated the experiments of Griffith?
Ans. In 1944, in a classic series of experiments Oswald Avery along with Colin Macleod and Maclyn McCarty repeated Griffith's experiments and characterized what they referred to as the Transforming principle.

Q 36. Why Hershey and Chase are famous for?
Ans. In 1952 by Alfred Hershey and Martha Chase experimented with bacteriophages T2 and provided additional evidence supporting Avery's conclusion.

Q 37. What are the main components of DNA?
Ans. Main components of DNA:
  • Phosphate (PO4) groups,
  • Five carbon sugars, and
  • nitrogen containing bases called purines (adenine, A, and guanine, G) and pyrimidines (thymine, T and cytosine, C, RNA contains uracil, U instead of T).

Q 38. What is the structure of a typical nucleotide?
Ans. In a typical nucleotide, nitrogen base is attached to carbon number 1 of a pentose sugar and phosphate group is attached to carbon number 5 of the sugar. In addition a free hydroxyl (-OH) group is attached to the 3 carbon atom.

Q 39. What is phosphodiester bond or linkage?
Ans. In a polynucleotides chain the linkage between two groups is called a phosphodiester bond because the phosphate group is now linked to the two sugars by means of a pair of ester (P-O-C) bonds.

Q 40. What is the work of Chargaff?
Ans. Erwin Chargaff showed that the amount of adenine in DNA always equals the amount of thymine, and the amount of guanine always equals the amount of Cytosine.

Q 41. What is X-ray diffraction?
Ans. In this analysis a molecule is bombarded with a beam of X-rays. When individual rays encounter atoms their path is bent or diffracted and the diffraction pattern is recorded on the photographic film. When carefully analyzed this pattern gives three dimensional structure of a molecule.

Q 42. Who prepared the X-ray diffraction of DNA?
Ans. Rosalind Franklin prepared this X-ray diffraction pattern of DNA in the laboratory of British Biochemist Maurice Wilkins, who prepared DNA fibres.

Q 43. What does X-ray diffraction of DNA suggest?
Ans. The diffraction pattern prepared suggested that the DNA molecule had a shape of a helix with a diameter of 2nm and a complete helical turn every 3.4 nm.

Q 44. Who proposed the double helical structure of DNA?
Ans. In 1953, James Watson and Francis Crick, proposed structure of the DNA molecule.

Q 45. Define replication?
Ans. The process by which DNA of a living organism gives rise to a copy of itself is called DNA replication.

Q 46. What is Semi-conservative replication of DNA?
Ans. In semi conservative replication, the two strands of the duplex separate out each acting as a model or mold, along which new nucleotides are arranged thus giving rise to two new duplexes.

Q 47. Define Conservative Replication of DNA?
Ans. The conservative model stated that the parental double helix would remain intact and generate DNA copies consisting of entirely new molecules.

Q 48. What is Dispersive Replication of DNA?
Ans. The dispersive model predicted that parental DNA would become dispersed throughout the new copy so that each strand of all the daughter molecules would a mixture of old and new DNA.

Q 49. What was work of Meselson - Stahl?
Ans. The three hypothesis of DNA replication were evaluated by Mathew Meselson and Franklin Stahl of the California Institute of Technology in 1958.

Q 50. What is the role of DNA polymerase I?
Ans. DNA polymerase I is a relatively small enzyme that plays a supporting role in DNA replication.

Q 51. What is the role of DNA polymerase II?
Ans. DNA polymerase II play a role in DNA repair.

Q 52. What is the role of DNA polymerase III?
Ans. This enzyme is a dimmer and catalyzes replication of one DNA strand. Polymerase III progressively threads the DNA through the enzyme complex moving it at a rapid rate of some 1000 nucleotides / second.

Q 53. What is the direction of replication on growing DNA strand?
Ans. Replication always proceeds 5 -> 3 direction on a growing DNA strand because DNA polymerase III can add nucleotides only to the 3 end of a DNA strand.

Q 54. What is the role of DNA ligase?
Ans. DNA ligase, attaches the repaired fragments of the lagging strand.

Q 55. What is Alkaptonuria?
Ans. It is disorder in which the patients produced urine that contained homogentisic acid. This substance oxidized rapidly when exposed to air, turning the urine black. In normal individuals, homogentisic acid is broken down into simpler substances.

Q 56. Why Beadle and Tatum are famous for?
Ans. Beadle and Tatum performed experiment on Neurospora, fungus, and concluded that each gene encodes the structure of one enzyme. This is also called one gene one enzyme hypothesis.

Q 57. Why Sanger was famous for?
Ans.  In 1953, Frederick Sanger, described the complete sequence of amino acids of insulin. Sanger's achievement was significant, as it was demonstrated for the first time that proteins consisted of definable sequences of amino acids.

Q 58. Why Vernon Ingram is famous for?
Ans. Vernon Ingram in 1956 discovered the molecular basis of sickle cell anaemia. He showed that sickle cell anaemia is caused by a change from glautamic acid to valine at position 6 in one chain of haemoglobin.

Q 59. What is Promotor?
Ans. Transcription is initiated when the enzyme RNA polymerase binds to a particular binding site called a promoter located at the beginning of the gene.

Q 60. What is translation.
Ans. The process by which the nucleotide sequence of the mRNA is translate into an amino acid sequence in the polypeptide is called translation.

Q 61. What is codon?
Ans. A sequence of 3 nucleotides along strand of mRNA is called codon.

Q 62. What are template and coding strands of DNA?
Ans. Only one of the two strands of DNA are transcribed. This strand is called template strand or the anti-sense strand. The opposite strand is called coding or the sense strand.

Q 63. What is the role of RNA polymerase?
Ans. The RNA polymerase enzymes synthesize RNA from 5 - 3 direction.

Q 64. What is core enzyme?
Ans. When sigma subunit is detached from other subunits of RNA polymerase then enzyme is called core enzyme.

Q 65. How many binding sites are found in in promoter of prokaryote and eukaryote?
Ans. In prokaryote within promoter there are two binding sites TTGACA also called -35 sequence and TATAAT also called -10 sequence, which have affinity for the RNA polymerase. In Eukaryotes these sites are at -25 and -70 sites.

Q 66. What is the stop signal for transcription?
Ans. The simplest stop signal is a series of GC base pair followed by a series of AT base pairs. The RNA forms a GC hairpin followed by four or more U ribonuleotides. The hairpin causes RNA polymerase to stop synthesis.

Q 67. Why a cap and a tail is added to mRNA?
Ans. A cap and a tail is added to mRNA so that the molecule may remain stable during long journey to ribosome.

Q 68. What is genetic code?
Ans. Genetic code is a combination of 3 nulceotides in DNA, which specify a particular amino acid.

Q 69. What is Chromosomal aberrations?
Ans. The change in number or structure of chromosomes is called chromosomal abberation.

Q 70. What are Point mutations?
Ans. Point mutations are mutational changes which affect the message itself, producing alterations in the sequence of DNA molecule. If alterations involve only one or a few base pairs in the coding sequence they are called point mutation.

Q 71. Give examples of point mutations?
Ans. Sickle cell anaemia and phenylketonuria are very well known examples of point mutations.

Q 72. What is Sickle cell anaemia?
Ans. In Sickle cell anaemia a point mutation leads to the change of amino acid glutamic acid into valine at position 6 from N terminal end in haemoglobin B chain. This reduces its ability to carry oxygen.

Q 73. What is Phenlyketonuria?
Ans. In phenlyketonuria, phenylalanine is not degraded because of defective enzyme phenylalanine hydroxylase. Phenylalanine consequently accumulates in the cells leading to mental retardation as the brain fails to develop in infancy.

Written by: Usman Rashid & Asad Hussain

FSc Notes Biology Part 2 Chapter 19 Growth and Development Short Questions

FSc Notes Biology Part 2 Chapter 19 Growth and Development Short Questions


Q 1. What are growing points?
Ans. In higher plants, growth is limited o certain regions known as growing points e.g., shoot apex and root tip.

Q 2. What is secondary growth?
Ans. The growth of secondary tissues i.e., secondary xylem and phloem, by the intercalary or vascular cambium leading to increase in thickness is called secondary growth.

Q 3. Name the factors by which rate of growth is influenced?
Ans. The growth rate is influenced by number of factors both external and internal. External factor are temperature, light, oxygen, carbon dioxide, etc. While internal factors are hormones, water, vitamins etc.

Q 4. What is correlation?
Ans. The development of a plant is usually correlated with its growth and different organs grow at different rates in different directions and the development of different parts takes place, such reciprocal relationship is known as correlation.

Q 5. What is embryology?
Ans. Embryology is the study of growth and differentiation undergone by an organism in the course of its development from a single fertilized egg into highly complex and an independent living being like his parents.

Q 6. What is discoidal cleavage?
Ans. In bird's egg the process of cell division is confined to the small disc of protoplasm lying on the surface of the yolk at the animal pole. This type of cleavage is referred to as discoidal cleavage.

Q 7. What is the role of cytokinins in apical dominance?
Ans. Cytokinins play important role in apical dominance and in many cases if cytokinins is applied directly on the inhibited bud, it allows lateral buds to be released from apical dominance.

Q 8. Which process is defined as negative physiological changes?
Ans. Aging can be defined as negative physiological changes in our body.

Q 9. Due to what factors normal process of development is disturbed?
Ans. The normal process of development is disturbed by abnormalities inherited from parents, abnormalities due to chromosomes or genes, environmental factors or metabolic defects.

Q 10. Define embryonic induction?
Ans. The influence of notochordal cells on he ectodermal cells to become nervous system was called embryonic induction by Spemann.

Q 11. Differentiate between growth and development?
Ans. Growth is the permanent and irreversible increase in size that occurs as an organism matures. While the progressive changes which are undergone before an organism become adult, constitute embryonic development.

Q 12. What is meristem?
Ans. Meristems are young tissues or population of cells that retain the potential to divide.

Q 13. What is open growth?
Ans. A plant has a growth pattern called open growth because throughout life, the plant adds new organs, such as branches, leaves and roots, enlarging from the tips of roots and shoots.

Q 14. What is Apical Meristem?
Ans. The apical meristems are found at the tips of roots and shoot and are primarily concerned with the extension of plant body. These are perpetual growth zones found at the apices of roots and stems. They play important role in primary growth.

Q 15. What are Intercalary Meristems?
Ans. These are the parts of apical meristem which get separated from apex by permanent tissues. They are situated at the bases of internodes in many plants. they play important role in the production of leaves and flower. These are of temporary nature.

Q 16. What are Lateral meristems?
Ans. Lateral Meristems are cylinders of dividing cells present in dicots and gymnosperms. Vascular and cork cambium are the examples of lateral meristems. They play an important role in he increases in diameter of stem and root and are involved in secondary growth.

Q 17. Define differentiation?
Ans. Differentiation is the formation of specialized tissues.

Q 18. What was the work of Thimann and Skoog?
Ans. Thimann and Skoog in 1934 performed experiments and showed that apical dominance was caused by auxin diffusing from the apical bud.

Q 19. Differentiate between inhabitory and compensatory effects?
Ans. Auxin released from apical bud inhibited the growth of lateral shoots or buds and it is called inhibitory effect. While the removal of apex releases the lateral buds from apical dominance. It is called compensatory effect.

Q 20. What is the temperature for incubation for chick egg?
Ans. In incubating eggs artificially, the incubators are usually regulated at temperature between 36-38 degree centigrade. At this temperature, the chick completes development and is hatched on the twenty first day.

Q 21. Define Cleavage?
Ans. The egg undergoes a series of mitotic divisions, called cleavage.

Q 22. What is Morula?
Ans. Cleavage results in the formation of a rounded closely packed mass of blastomeres. This is morula.

Q 23. What is Blastula?
Ans. The morula stage is short lived and soon changes into blastula and is characterized by the presence of a segmentation cavity or blastocoele.

Q 24. what is blastoderm?
Ans. The discoidal cap of cells above the blastocoele is called blastoderm.

Q 25. What is zone of junction in developing chick embryo?
Ans. The marginal area of the blastoderm in which the cells remain undetached from the yolk and closely adherent (supporting) to it, is called the zone of junction.

Q 26. Define Gastrulation?
Ans. It is characterized by the movement and rearrangement of cells in the embryo.

Q 27.Which two layers are formed from blastoderm during gastrulation?
Ans. During gastrulation the blastoderm splits into two layers: an upper layer of cells called epiblast, and a lower layer of cells called hypoblast.

Q 28. What is area pellucida?
Ans. The central cells of blastoderm can be separated from the yolk, under these central cells a pool of fluid develops, raising them off the yolk and giving the area a translucent appearance - the area pellucida.

Q 29. What is area opaca?
Ans. The peripheral part of the blastoderm where the cells lie unseparated from the yolk is termed as area opaca.

Q 30. What is Primitive streak?
Ans. In the chick the mesodermal cells migrate medially and caudally from both sides create a mid line thickening called primitive streak. The primitive streak represents the dorsal and both lateral lips of blastopore.

Q 31. What is primitive node?
Ans. The anterior end of the primitive streak is occupied by an aggregation - the primitive node or notochordal cells while res of cells are mesodermal cells.

Q 32. What is Hensen's node?
Ans. At the cephalic end of primitive streak, closely packed cells form a local thickening known as Hensen's node.

Q 33. What is Germ wall?
Ans. In sections of embryo incubated from 18-20 hours, it is seen that ectoderm has spread and become organized into a coherent layer of cells merging peripherally with the yolk and the marginal area where the expanding germ layers merge with the under lying yolk is known as germ wall.

Q 34. What is gastrocoele?
Ans. The cavity of the gastrula is called gastrocoele.

Q 35. How many layers, the lateral plate mesoderm is split-ted into?
Ans. The lateral plate mesoderm is split-ted into two sheet like layers viz Somatic mesoderm and Splanchnic mesoderm with a space between them.

Q 36. What is coelom?
Ans. The cavity formed between somatic and splanchnic mesoderm is coelom.

Q 37. What is Neurula?
Ans. The whole process of formation of nervous system is called neurulation.

Q 38. How neural plate is formed?
Ans. On the dorsal surface of gastrula, over the notohchord, presumptive neural ectoderm is present in the form of a band. As gastrula elongates, the band thickens to form a neural plate.

Q 39. What is Neurula?
Ans. In 24 hour chick embryos, the folding of neural plate is clearly visible. The embryo is now termed as neurula.

Q 40. How neural tube is formed in chick embryo?
Ans. The neural plate sinks and the neural folds grow toward one anther and meat in the mid-dorsal line, fuse and convert the neural groove into neural tube.

Q 41. What are neuropores?
Ans. At each end of neural tube, a small opening called anterior and posterior neuropores are also seen, which close later on.

Q 42. What is neurocoel?
Ans. With the formation of neural tube, there is formation of central nervous system and the cavity enclosed is known as neurocoel.

Q 43. What was work of Dietrich?
Ans. In 1892, Hans Dietrich, took sea urchin egg at two-cell stage, shook it apart and separated it into two cells. Later on, it was seen that both half embryos developed into normal larvae.

Q 44. What is Acetabularia?
Ans. It is multicellular alga. It consists of rhizoid, which is attached to the grounds, from which arises a long talk with an umbrella shaped cap at its top. Two species of Acetabularia have been identified; Acetabularia mediterranea and A. crenulata.

Q 45. What is primary induction?
Ans. Spemann designated the dorsal lip area the primary organizer because it was the only tissue capable of inducing development of secondary embryo in the host. This was called primary induction.

Q 46. Define regeneration?
Ans. The ability to regain or recover the lost or injured part of the body is called regeneration.

Q 47. What are neoblasts?
Ans. In flatworms, and Planaria the unspecialized cells, called, neoblasts, are always present in the body of adult and are mobilized and migrate to the site of amputation (cut off), where they differentiate into specialized cell types.

Q 48. Define abnormal development?
Ans. Sometimes, under unfavourable conditions, some parts of the body do not develop normally and this is called abnormal development.

Q 49. Define Teratology?
Ans. Teratology is the branch of biology, which  deals with these abnormal development and causes for such developments.

Q 50. How normal process of development is disturbed?
Ans. How normal process of development is disturbed:
  • abnormalities Inherited from parents,
  • abnormalities due to chromosomes or genes,
  • environmental factors,
  • metabolic defects.

Q 51. What are Teratogens?
Ans. Environmental factors causing or contributing to abnormal development are grouped together as teratogens e.g., ionizing radiations such as X rays.

Q 52. What is Microcephaly?
Ans. It is a defect in which the Individuals are born with small skull.

Q 53. What is Cleft palate?
Ans. It is an abnormality in which individuals have their upper lips folded or the individual has harelip.

Written by: Usman Rashid & Asad Hussain

Tuesday, 29 March 2016

FSc Notes Biology Part 2 Chapter 17 Coordination and Control Short Questions

FSc Notes Biology Part 2 Chapter 17 Coordination and Control Short Questions


Q 1. Define coordination?
Ans. All the aspects such as organization, regulation, integration and control in the constitution and work of the complex multicellular animals come under the fold of the term coordination.

Q 2. Why Chlorosis arises?
Ans. Chlorosis usually arises from short supplies of mineral nutrients in the soil.

Q 3. In higher animals how coordination is brought about?
Ans. It is brought about in higher animals by nervous coordination and chemical coordination.

Q 4. What are photoreceptors?
Ans. Photoreceptors are electromagnetic receptors. These respond to stimuli of light for example in eyes, rods and cones.

Q 5. What is Neuroglia?
Ans. The chief structural and functional unit of the nervous system is neurons, but there are other cells, in higher animals, and in humans called Neuroglia, which make up as much as half of the nervous system.

Q 6. What are cranial nerves?
Ans. In human, there are 12 pairs of nerves, which arises from the brain, or lead to the brain these are called cerebral or cranial nerves.

Q 7. What is the effect of nicotine on coordination?
Ans. Nicotine affects postsynaptic membrane in CNS and PNS. It minimizes the action of acetylcholine on nicotine receptors, so it is stimulant of nerve impulse. It increases the heart beat rate, blood pressure and digestive tract mobility, Nicotine may induce vomiting and diarrhea and even may cause water retention relation by kidneys.

Q 8. What ethologists think about animal’s response?
Ans. The early ethologists (Uexkull 1935, Lorenz 1935) thought that animals sometimes respond instinctively to specific though often complex stimuli such stimuli came to be called “sign stimuli”.

Q 9. Define learning behavior?
Ans. Thrope defined learning as that process which manifests itself by adaptive changes in individual behavior as a result of experience.

Q 10. Who has demonstrated and studied operant conditioning or conditioned reflex type II?
Ans. This type of learning has been demonstrated and studied by Thorndike and B.F Skinner a Harvard psychologist.

Q 11. How neuron fibres and cell bodies can be exited?
Ans. The neuron fibres and cell bodies can be excited by small electric shocks, mechanical, chemical, light and temperature stimuli.

Q 12. How plants respond to the stimuli?
Ans. Plants respond by.
  • Regulating their growth and development in appropriate ways.
  • Controlling their body functions through plant hormones or growth hormones.

Q 13. Which type of plants are said to etiolated?
Ans. If plants are grown without light, they become extremely long and they fail to form chlorophyll. They are said to be etiolated.

Q 14. What is Chlorosis?
Ans. Many plants take on a yellowish hue when they fails to form chlorophyll in sufficient amounts. This condition is known as Chlorosis.

Q 15. What are Calluses?
Ans. If plants are wounded, they often develop masses of amorphous (formless or shapeless) material with very poor differentiation known as calluses.

Q 16. What are galls?
Ans. Galls are growths on a plant that are induced by parasites and usually, highly organized growth galls are tumors induced by the bacteria. They are usually less differentiated the other types of galls.

Q 17. Define biorhythms or biological rhythms?
Ans. In living things he behavioral activities occur at regulars intervals which are called biorhythms or biological rhythms.

Q 18. What are diurnal rhythms?
Ans. Biorhythms may occur showing periodicity of about 24-hours. These are called circadian which means about one day, so they are also called diurnal rhythms.

Q 19. What is Circaannual?
Ans. If the biorhythms are less than or about 365 days, these rhythms in activity are called Circaannual.

Q 20. What are plant hormones?
Ans. The special substances produced by the plants which influence the growth and plants responses to various stimuli are called plant hormones.

Q 21. Name different plant hormones?
Ans. Auxins, giberrellins, cytokinins, abscisic acid and ethane.

Q 22. Give two functions of giberrellins?
Ans. Functions of giberrellins
  • Promote cell enlargement in presence of Auxins.
  • Promote leaf growth and fruit growth.

Q 23. What is use of GA3?
Ans. GA3 is used in the brewing industry to stimulate amylase production in barely and this promotes malting.

Q 24. Give two functions of Cytokinins?
Ans. Functions of cytokinins
  • Promote stern growth by cell division in apical meristerm and cambium.
  • Promote bud initiation.

Q 25. What is commercial application?
Ans. Cytokinins delay the aging of fresh leaf crops, such as cabbage and lettuce (delay of senescence) as well as keeping flowers fresh. They can also be used to break dormancy of some seeds.

Q 26. Give two functions of Abscisic acid?
Ans. Functions of Abscisic acid
  • Inhibits stern growth notably during physiological stress, e.g., drought, water-logging.
  • Promotes bud dormancy.

Q 27. What is commercial application of abscisic acid?
Ans. Abscisic acid can be sprayed on tree crops to regulate fruit drops the end of the season. This removes the need for picking over a large time-span.

Q 28. What is commercial application of ethane?
Ans. Ethane induces flowering in pineapple. It stimulates ripening of tomatoes and citrus fruit. It stimulates flow of latex in rubber plants.

Q 29. What is nervous coordination?
Ans. This type of coordination involves specialized cells or neurons linked together directly or via the central nervous system, to form network that connect the cell or organs which receive stimuli (receptors) and those which carry out actions or responses (effectors).

Q 30. What are elements of nervous system?
Ans. The elements of nervous system which help in co-ordination are.
  1. Receptors
  2. Neurons
  3. Effectors.

Q 31. What are Receptors?
Ans. Receptors detect changes in the external and internal environment of the animal. The receptor may be a cell, or neuron ending or a receptor organ.

Q 32. What are chemoreceptors?
Ans. The receptors which are stimulated by the chemicals are called chemoreceptors. These are for smell, taste and for blood CO2 oxygen, blood glucose, amino acids and fatty acids.

Q 33. What are Mechanoreceptors?
Ans. The receptors which detect stimuli of touch, pressure and hearing and equilibrium are called mechanoreceptors.

Q 34. What are thermo-receptors?
Ans. The receptors which respond to cold and warmth are called thermo-receptors.

Q 35. What are nociceptors?
Ans. These are undifferentiated nerve endings which produce the sensation of pain.

Q 36. What is modality of sensation?
Ans. Each type of principle type of sensation that we can experience e.g., pain, touch, sight, sound and so forth is called a modality of sensation.

Q 37. What are Meissner's corpuscles?
Ans. These are encapsulated nerve endings which is lie in papillae which extend into the ridges of the fingertips. The corpuscle consists of spiral and much twisted endings, each of which ends in a knob. These are touch receptors.

Q 38. What are Pacinian corpuscles?
Ans. Pacinian corpuscles are situated quite deep in the body. These are encapsulated neuron endings and receive deep pressure stimulus. Those located in the limbs probably form a basis for vibration sense.

Q 39. What is Dendron or are dendrites?
Ans. The cytoplasmic process which carries impulse towards cell body is called Dendron, if it is a single fibre but if smaller fibres they are called dendrites.

Q 40. What are Axons?
Ans. The processes conducting impulses away from cell body are termed axons. These may be more than a meter long in some neurons.

Q 41. What are Nissl's granules?
Ans. Nissl's granules are groups of ribosomes associated with rough endoplasmic reticulum and protein synthesis and Golgi apparatus and are present in the cell body.

Q 42. What is Cell body or soma?
Ans. The cell body or soma is the main nutritional part of the nerve cell and is conserved with the biosynthesis of materials necessary for the growth and maintenance of the neuron.

Q 43. Name different types of neurons?
Ans. There are three functional types of neurons in mammals i.e., the sensory, associative (intermediate / relay) and motor neurons.

Q 44. What are Sensory Neurons?
Ans. These are the neurons which carry nerve impulses from receptors to brain or spinal cord. They have a single, elongated Dendron and shorter axon.

Q 45. What are Motor Neurons?
Ans. These are the neurons which carry nerve impulses from brain and spinal cord to the effectors in all parts of the body. They have a long axon and number of small dendrites.

Q 46. What are Associative Neurons?
Ans. These are the neurons which occur exclusively in the spinal cord and brain. They serve as intermediate links between numerous sensory and motor neurons.

Q 47. What are Effectors?
Ans. These are the structures which respond when they are stimulated by impulse coming via motor neuron. The principal effectors are glands, which respond by secreting; and muscles which respond by contracting.

Q 48. What is reflex arc?
Ans. Reflex arc is the path way of passage of impulse during a reflex action. Reflex action is a type of involuntary action. The direction of stimulus is form receptors to sensory neurons to associative neuron and then through motor neuron to the effectors.

Q 49. Define nerve impulse?
Ans. Nerve impulse is a wave of electrochemical changes, which travel along the length of the neuron involving chemical reactions and movement of ions across the cell-membrane.

Q 50. Define electrical potential and membrane potential?
Ans. Electrical potential is a measure of the capacity to do electrical work. The electrical potential that exists, across a cell membrane is known as membrane potential.

Q 51. What is resting membrane potential?
Ans. A typical neuron at rest is more positive electrically outside than inside the cell membrane. This net difference in characteristics between the inner and outer surface of a non-conducing neuron is called the resting membrane potential.

Q 52. What is active membrane potential?
Ans. After initiation of nerve impulse the resting membrane potential disappears for a brief instant and is replaced by a new potential called active membrane potential which is in the form of impulse.


Q 53. What is salutatory impulse?
Ans. It may be added that in myelinated neurons the impulse jumps from node to node (node or Ranvier). This is called salutatory impulse.

Q 54. What is synapse?
Ans. There is no cytoplasmic connection between the two neurons and microscopic gaps are left between them .Each of these contact points is known as synapse.

Q 55. How does nerve impulse pass from one neuron to other through the synapse?
Ans. A nerve impulse is passed from one neuron to the other through the synapse with the help of chemical messenger, called neurotransmitters.

Q 56. What are neurotransmitters? Give their various types?
Ans. Neurotransmitters are chemicals which are released at the axon ending of the neurons, at synapse. Acetylcholine, adrenaline, nor epinephrine, serotonin and dopamine are some neurotransmitters.

Q 57. What is Acetylcholine?
Ans. Acetylcholine is the main neurotransmitter for synapses that lie outside the central nervous system.

Q 58. What are different designs of nervous systems in the animal kingdom?
Ans. Designs of nervous system in animal kingdom
  • Diffused nervous system It is found in Cnidarians (Hydra, jelly fish and their relatives).
  • Centralized nervous system It is found to varying degrees in more complex organisms, from Platyhelminthes to choradates including humans.

Q 59. What are the main parts of nervous system of man?
Ans. Main parts of nervous system of man
  • Central Nervous System.
  • Peripheral Nervous System.

Q 60. Name the two parts of central nervous system?
Ans. Parts of Central Nervous System
  • Brain
  • Spinal Cord.

Q 61. What is Cranium?
Ans. Cranium is part of skull which protects the brain and neural arches of vertebrae.

Q 62. What are Meninges?
Ans. Beneath the cranium, the brain and spinal cord are protected by triple layer of Meninges.

Q 63. What is Cerebrospinal fluid (CSF)?
Ans. Between the layers of Meninges, the cerebrospinal fluid (CSF), is present which bathes the neurons of brain and spinal cord and cushions against the bumps and jolts.

Q 64. Name different parts of brain?
Ans. The brain can be divided into forebrain, mid brain and hind brain.

Q 65. Name various parts of forebrain?
Ans. Forebrain is divided into three functional parts.
  1. The thalamus
  2. The limbic system
  3. The cerebrum.

Q 66. What is the function of Thalamus?
Ans. Thalamus carries sensory information to the limbic system and cerebrum. The information includes sensory input from auditory and visual pathways from the skin and from within the body.

Q 67. How does limbic system work?
Ans. Limbic system work together to produce our most basic and primitive emotions, drives, the behaviors, including fear, rage, tranquility (calmness, peace of mind), hunger, thirst, pleasure and sexual responses.

Q 68. What are various parts of limbic system?
Ans. The limbic system consists of hypothalamus, the amygdala, and hippocampus, as well as nearby regions of cerebrum.

Q 69. What is role of Hypothalamus?
Ans. The hypothalamus acts as a major co-ordinating centre controlling body temperature, hunger, the menstrual cycle, water balance and the sleep-wake cycle.

Q 70. What is role of Amygdala?
Ans. In the amygdala, the cluster of neurons produces sensation of pleasure, punishment or sexual arousal when stimulated. It is also involved in the feelings of fear and rage.

Q 71. What is the function of Hippocampus?
Ans. Hippocampus plays an important role in the formation of long term memory, and thus is required for learning.

Q 72. What are cerebral hemispheres?
Ans. Cerebrum is the largest part of the brain and is divided into two halves, called cerebral hemispheres. The left cerebral hemisphere controls the right side of the body, and right cerebral hemisphere controls the left side of the body.

Q 73. What is corpus callosum?
Ans. The two cerebral hemispheres communicated with each other by means of a large band of axons, called corpus callosum.

Q 74. What is cerebral cortex?
Ans. It is the outer region of the cerebrum. It forms folds called convolutions, which greatly increase its surface area.

Q 75. What is reticular formation?
Ans. Midbrain contains reticular formation, which is a relay centre connecting hindbrain with the forebrain. It is very important in screening the input information, before they reach higher brain centers.

Q 76. Name different parts of Hindbrain?
Ans. Hindbrain includes the medulla, pons and cerebellum.

Q 77. What is the function of Medulla?
Ans. Medulla controls several automatic functions, such as breathing, heart rate, blood pressure and swallowing.

Q 78. What is the role of Pons?
Ans. Certain neurons in pons, located above the medulla, appear to influence transitions between sleep and wakefulness, and the rate and pattern of breathing.

Q 79. What is the role of cerebellum?
Ans. The cerebellum is important in co-ordinating movements of the body. The cerebellum guides, smooth and accurate motions and body position. The cerebellum is also involved in the learning and memory storage of behaviors.

Q 80. What is spinal cord?
Ans. Medulla oblongata narrows down into an oval shaped hollow cylinder, the spinal cord, running through the vertebral column. It is made up of a very large number of neurons, the cell-fibres and bodies of which are arranged in a definite pattern.

Q 81. What is grey matter?
Ans. In cross section, the spinal cord shows an inner butterfly shaped grey matter, containing a central canal. It consists of cell bodies and non-myelinated nerve fibres or tracts.

Q 82. What is white matter?
Ans. The outer portion of spinal cord is composed of white matter. It s made up of myelinated nerve fibres or tracts.

Q 83. What is the composition of peripheral nervous system (PNS)?
Ans. It comprises sensory neurons and motor neurons, which may form ganglia and the nerves.

Q 84. Ganglia are the concentrations of cell bodies of neurons?
Ans. Ganglia are the concentrations of cell bodies of neurons.

Q 85. What are Nerves?
Ans. The nerves are the bundles of axons or dendrites, bounded by connective tissue. They may be sensory, mixed or motor nerves depending upon the direction of impulse they conduct.

Q 86. What is chemical coordination?
Ans.
The coordination brought about by the chemicals is called Chemical coordination.

Q 87. What are spinal nerves?
Ans.
From the spinal cord 31 pairs of spinal nerves arise or lead to spinal cord. All these nerves are mixed i.e., having fibres sensory and motor neurons.

Q 88. What is Somatic nervous system?
Ans.
Motor neurons form somatic nervous system, which controls voluntary movements, which are under the conscious control of the boyd, involving skeletal muscles.

Q 89. Name different parts of autonomic nervous system?
Ans.
The autonomic nervous system is further divided into sympathetic nervous system and parasympathetic nervous system.

Q 90. What is the role of Sympathetic nervous system?
Ans.
This system is important during emergency situations and is associated with "fight or flight". This system accelerates the heart beat and dilates and inhabits the digestive tract.

Q 91. What is Parasympathetic nervous system?
Ans.
A few cranial nerves including the vagus nerve together with fibres from the bottom portion of spinal cord, form the parasympathetic nervous system. It promotes all the internal responses i.e., contracts of the pupils, promotes digestion of food, retards heart beat.

Q 92. Name a few nervous disorders.
Ans.
Parkinson's disease, Addison's disease, Epilepsy and Alzheimer's disease.

Q 93. What is Parkinson's disease (paralysis agitans)?
Ans.
It is a nervous disorder, characterized by involuntary tremors, diminishing motor power and rigidity. The mental faculties are not affected. The disease is believed to be caused by cell death in a brain area that produces dopamine.

Q 94. What is Epilepsy?
Ans.
It is one of the convulsive disorders of nerves which are characterized by abrupt transient symptoms of motor, sensory psychic or autonomic nature, frequently associated with changes in consciousness. The onset of epilepsy is usually before age 30.

Q 95. What is Alzheimer's disease?
Ans.
Alzheimer's disease was first described by Alois Alzheimer in 1907. It characterized by the decline in brain function. It tends to run in families. There is also evidence that high levels of aluminum may contribute to the onset of disease.

Q 96. What are hormones?
Ans.
The endocrine or ductless glands are with a few exceptions, discrete groups of cells, which make specific chemicals compounds called hormones Endocrine system consists of some 20 endocrine glands / tissues lying in different parts of the body.

Q 97. Give two characteristics of Hormones?
Ans.
Characteristics of Hormones
  • They are poured directly into the blood stream.
  • They are transported to respective target tissues by the blood.

Q 98. What is Hypothalamus?
Ans.
It is parts of the fore brain. It is here that many of the sensory stimuli of nervous system are converted into hormonal responses.

Q 99. What is Pituitary Gland?
Ans.
In man the pituitary gland or hypophysis cerebri is an ovoid structure about 0.5 gm in the adult and is connected to brain through a short stalk (the infundibulum). It has three lobes viz, anterior, median and posterior.

Q 100. Why pituitary gland is called Master gland?
Ans.
The anterior lobe of pituitary is often referred toas the master gland, because in addition to producing primary hormones it produces the trophic hormones which control the secretion of hormones in many of the other endocrine glands.

Q 101. Name different hormones released by anterior lobe of pituitary gland?
Ans.
Anterior lobe of pituitary secretes the following hormones:
  • Somtotrophin.
  • Thyroid stimulating hormone.
  • Adenocorticotrophic hormone.
  • Gonadotrophic hormones. i) FSH and LH/ICSH. ii) Prolactin.

Q 102. Name the hormones released by median lobe of pituitary gland?
Ans.
Median lobe secretes the following hormones:
  • Melanophore stimulating hormone.

Q 103. Name the hormones released by posterior lobe of pituitary gland?
Ans.
Hormones released by Posterior lobe of pituitary gland
  • Anti-diuretic hormone (ADH: also called vasorpressin).
  • Oxytocin.

Q 104. Give one function of thyroxine and tri-iodothyronine?
Ans.
Thyroxine and tri-iodothyronine act on the basal metabolic rate by stimulating the breakdown of glucose and release of heat and generation of ATP.

Q 105. What is the effect of over-secretion of thyroxine?
Ans.
Excess thyroxine produced a condition called Graves' disease, with exophthalmic goiter and increase in the basla metabolic rate. This can lead to cardiac failure if prolonged.

Q 106. What is cretinism?
Ans.
In infants, the deficiency of thyroxine causes a dwarfed condition called cretinism. The individual are small, have coarse scanty hair, thick yellowish scaly skin and mentally retarded.

Q 107. What is myxedema?
Ans.
Deficiency of thyroxine in adults, perhaps due to iodine shortage in diet, produces a swelling o the neck (goiter) and may lead to laying down of excess fat and weight is increased. The condition is known as myxedema.

Q 108. What is calcitonin?
Ans.
It is hormone released by thyroid gland in response to high Ca2+ concentration in the blood. Excess or deficiency leads to a disturbance of calcium metabolism with its associated effects on nerve, skeleton, muscle, blood etc.

Q 109. What is action of glucagon?
Ans.
Glucagon causes an increase in blood glucose levels. It does this mainly by promoting breakdown of glycogen to glucose in the liver and muscles. It also increases the rate of breakdown of fats.

Q 110. Name the hormones released by adrenal gland?
Ans.
The medulla produces the hormones adrenaline and nor-adrenaline. The adrenal cortex secretes aldosterone and androgenic hormones.

Q 111. What is the function of aldosterone?
Ans.
Aldosterone is a mineralcortioid which conserves the level of Na+ ions in the body by preventing their loss from the kidney tubules.

Q 112. What is the function of Cortisol?
Ans.
Cortisol brings about an increase in blood glucose level mainly by its production from protein and by antagonizing the action of insulin.

Q 113. What is the function of Corticosterone?
Ans.
Corticosterone is bot a glucorticoid and  mineralocorticioid, it increases blood glucose levels and regulates mineral ion balance.

Q 114. What is Cushing's disease?
Ans.
In chushing's disease too much cortical hormone is produced. Symptoms are an excessive protein breakdown resulting muscular and bone weakness. The high blood sugar disturbs the metabolism as in diabetes.

Q 115. What are Androgens?
Ans.
Androgens cause development of the secondary male characters. Very small amounts of androgens are secreted in both male and female adrenal glands.

Q 116. What is gastrin?
Ans.
Gastrin is the hormones produced by mucosa of the pyloric region of the stomach. It stimulates the secretin of gastric juice, It is produced under the influence of protein food in the stomach after it is partially digested.

Q 117. What is Secretin?
Ans.
It is produced from the duodenum when acid food touches its lining. It affects the pancreas to produce and release pancreatic juice and also affects the rate of bile production, in the liver.

Q 118. Where oestrognes and progesterone are produced?
Ans.
Oestrognes are secreted by ripening follicles whose development has been initiated by FSH from the pituitary.
Progesterone is produced by the ruptured follicle in response to LH from the pituitary.

Q 119. What are seminiferous tubules and interstitial cells?
Ans.
The testes consists of many coiled seminiferious tubules where the spermatozoa develop and, between the tubules, regions of interstitial cells which produced gonadal hormones called Testosterone and 17 B-hydroxytestosterone.

Q 120. Define feedback mechanism?
Ans.
It is a type of interaction in which a controlling mechanism itself controlled by the products of reactions it i controlling.

Q 121. What is behaviour?
Ans.
Behaviour is defined as a change in response to stimulus. In other words animal behaviour is the sum of every thing that animals do, i.e flying, walking, sitting, sleeping, eating, mating, rearing young ones, etc.

Q 122. what is the Innate Behaviour?
Ans.
It is a collection of responses that are predetermined by the inheritance of specific nerve or cytoplasmic pathways in multicelluar or unicellular (acellular) organisms. All plant behvaiour is innate.

Q 123. What are Kineses?
Ans.
It is a behaviour in which an organism changes the speed of random movements which help them to survive in the environment e.g., this type of behaviour enables pillpugs to reach the moist area which is required for their life.

Q 124. What are Taxes?
Ans.
A taxis (plural: taxes) is a directed movement either towards (positive taxis) or away from (negative taxis) a stimulus.

Q 125. What are instincts?
Ans.
According to Darwin, instincts are complex reflexes made up of units compatible with the mechanisms of inheritance, and thus a product of natural selection, that had evolved together with the other aspects of life.

Q 126. Define Learning?
Ans.
Learning depends on the experiences in one's own life. Or Thrope defined learning as that process which manifests itself by adaptive changes in individual behaviour as a result of experience.

Q 127. What is innate releasing mechanism (IRM)?
Ans.
The selective responses to stimuli suggested that there must be some built-in mechanism by which sign stimuli were recognized. This mechanism came to be called the innate releasing mechanism.

Q 128. What is Imprinting?
Ans.
Brief exposure of a organism to the stimulus with long lasting effect is called imprinting. It is best known in birds such as geese, ducks and chickens.

Q 129. Define Habituation?
Ans.
Habituation is the simplest form of learning and involves modification of behaviour through a diminution (reduction) of response to repeated stimuli.

Q 130. Define conditioning or conditioned reflex type I?
Ans.
Conditioning or conditioned reflex type I involves the pairing of an irrelevant stimulus within a natural primary stimulus that elicits an automatic response.

Q 131. Define Operant conditioning or conditioned reflex type II?
Ans.
Under natural conditions the achievement of a particular goal is the reward that directs random activities into a hevaoural pattern, Trial and error repetitions, step by step, lead to final achievement.

Q 132. What is Latent learning?
Ans.
Thrope defined latent learning as the association of indifferent stimuli or situations without patent (clear or observable) reward.

Q 133. What is insight learning?
Ans.
Insight learning is an extreme case of behavioural modification involving the application of insight (nearby or within reach) or reasoning to a novel (new or unusal) situation.

Written by: Usman Rashid  &  Asad Hussain

FSc ICS Notes Part 2 Physics Pairing For Board Examination

FSc ICS Notes Part 2 Physics Pairing For Board Examination


Objective Portion


Multiple Choice Questions: (17)

One MCQ from every Chapter 13 + 17 + 20
Two MCQ from every Chapter 12 + 14 + 15 + 16 + 18 + 19 + 21

Subjective Portion


Section No 1 Short Question: (22 out of 33)

Question No 2: (8 out of 12) Chapter 12 + 14 + 15 (Four from every chapter)
Question No 3: (8 out of 12) Chapter 13+ 16 + 17 + 18 (Three from every chapter)
Question No 4: (6 out of 9) Chapter 19(3 sq) + 20(2 sq) + 21(4 sq)

Section No 2 Long Question: (3 out of 5)

Question No 5: Chapter 12 +13
Question No 6: Chapter 14 + 15
Question No 7: Chapter 16 + 17
Question No 8: Chapter 18 + 19
Question No 9: Chapter 20 + 21

Section No 3 Practicals:

Question 10:
a: Short Questions
b: Procedure
c: Graph related

Written by: Asad Hussain

 

FSc Notes Part 2 Chemistry Pairing For Board Examination

FSc Notes Part 2 Chemistry Pairing For Board Examination


Objective Portion


Multiple Choice Questions: (17)

One MCQ from every chapter from Chapter 1 to 15
Two MCQ from Chapter 16

Subjective Portion


Section No 1 Short Question: (22 out of 33)

Question No 2:(8 out of 12) Chapter 1 to Chapter 6 (Two from every chapter)
Question No 3:(8 out of 12) Chapter 7 to Chapter 11 + 16 (Two from every chapter)
Question No 4:(6 out of 9) Chapter 12 + 13 + 15 ( Two from each chapter) Chapter 14 ( Three )

Section No 2 Long Question: (3 out of 5)

Question No 5: Chapter 1 + 2
Question No 6: Chapter 3 + 5
Question No 7: Chapter 7 + 10
Question No 8: Chapter 8 + 12
Question No 9: Chapter 9 + 11

Section No 3 Practicals:

Question 10:
a: Basic Radicals (Pb, Al, An, Fe, Cr)
b: (Ca, Ba, Na, K, NH4)
c: (CO3, HCO3, Cl, NO3, CH3COO)
d: Group (Aldehyde, Carboxylic acid, Phenol)
e: Preparation: Idoform + Aspirin + Copper amine complex.

Written by: Asad Hussain

Monday, 28 March 2016

FSc Notes Biology Part 2 Chapter 26 Some Major Ecosystems Short Questions

FSc Notes Biology Part 2 Chapter 26 Some Major Ecosystems Short Questions


Q 1. Can you differentiate between altitude and latitude?
Ans. The angular distance on a meridian(circle passing through poles) north or south of the equator, expressed in degrees and minutes is called latitude. While height in relation to equator is called altitude.

Q 2. How many regions open water area is divided into?
Ans. The open water area is divided into two regions:
  1. The upper Limnetic zone
  2. The lower Profundal zone.

Q 3. What is hydrospheric or aquatic ecosystem?
Ans. Hydrospheric ecosystem is a system in water where living and non-living components exchange material and transfer of energy also takes place within water.

Q 4. What are plankton?
Ans. Living among the anchored plants are microscopic organism called plankton. These can be divided into two groups:
  1. Phytoplankton: Greek meaning "drifting plants". They include photosynthetic protista, bacteria and algae.
  2. Zooplankton: Greek meaning "drifting animals". Such as protozoa and tiny crustaceans.

Q 5. What types of organisms are present in profundal zone of lake?
Ans. Decomposers and detritus feeders such as snails and certain insect larvae, bacteria, fungi and fishes are present in it.

Q 6. Name the sub-divisions of forest ecosystem.
Ans. Forest ecosystem is further sub-divided into:
  1. Tropical Rain Forests
  2. Temperate Deciduous Forest
  3. Coniferous Alpine and Boreal Forest.

Q 7. What type of animals are present in temperate decicuous forest.
Ans. Some very common animals are Macaca mulatta (Rhesus Monkey), Solenorotos tibitanus (black bear), Felis bengalensis (leopard cat), deer, and wolves with various types of micro-organisms to convert the litter into organic matter such as bacteria, fungi and earthworm.

Q 8. What is the location of coniferous alpine and boreal forests?
Ans. In Pakistan these forest are in upper Kaghan, Dir and Chilas, Malam Jaba in Swat valley. In world they stretch across Eurasia (Europe + Asia) and North America, Canada just south of the Tundra.

Q 9. Name some grasslands of Pakistan.
Ans. Grassland ecosystems are found in Gilgit, Kashmir, Waziristan, lower Chitral and North Kallat.

Q 10. What is layering in ecosystem?
Ans. Layering is the characteristics of grassland. Tall grasses from the first layer, mid high grasses from the second layer and third layer is formed by short grasses and forbs and warfare species with mosses and lichens.

Q 11. Define productivity of an ecosystem.
Ans. Productivity can be defined as the rate of production of new biomass during the period under consideration. Productivity is generally expressed in terms of grams or kilo-calories per sq. meter or hector per sq. meter per year.

Q 12.Name three zones in lake ecosystem.
Ans. Three zones in lake ecosystem are as under:
  1. Littoral zone: Shallow water area.
  2. Limnetic zone: Open water area with light penetration.
  3. Profundal zone: Deep, dark water area without light penetration.

Q 13. How many biomes are present in the world, name only five of them.
Ans. 10 biomes are present in the world e.g., Tropical rain forest, Tropical deciduous forest, Tropical scrub forest, Savanna, Temperate grassland, Temperate deciduous forest, Desert, Taiga, Tundra and Chaparral.

Q 14. Give the names of some major ecosystem on land in Pakistan.
Ans. Major ecosystems in Pakistan:
  1. Temperate Deciduous forest
  2. Coniferous Alpine and Boreal Forests
  3. Grass land Ecosystem
  4. Desert Ecosystem
  5. Tundra Ecosystem

Q 15. What are the four major requirements for life?
Ans. Major requirement for life are:
  1. Light
  2. Nutrient
  3. Water
  4. Temperature
  5. Air

Q 16. Differentiate between weather and climate.
Ans. Weather refers to short term fluctuations in temperature, humidity, cloud cover, wind and precipitation over periods of hours or days. Climate in contrast refers to overall patterns of weather that prevail from year to year even century to century in a particular region,

Q 17. What are the characteristics of littoral zone?
Ans. In this zone the water is shallow, and plants find abundant light, anchorage and adequate nutrients from the bottom sediments.

Q 18. What is the location temperate deciduous forests in Pakistan and rest of the world.
Ans. In Pakistan temperate moist conditions are present in Neelam valley and Shogran. These forests originally covered India, Southeast Asia, Eastern North America, Europe, China, Australia, Japan, North and South America.

Q 19. What is the range of rainfall and temperature in temperate deciduous forest?
Ans. The average rainfall is between 750-1500 mm. Moderate temperature ranges from 4 degree Celsius to 30 degree Celsius.

Q 20. Name the plants of temperate deciduous forest?
Ans. Some dominant trees are: Taxus baccata, Pinus wallichiana, Berberis lyceum usually with height 8 to 30 meters.

Q 21. What is taiga?
Ans. Northern coniferous forests are also called taiga.

Q 22. Differentiate between alpine and boreal forests.

Ans. Coniferous forests located at high altitude are called alpine while coniferous forests located at high latitude are called boreal forests.

Q 23. What do you know about the animal life of coniferous alpine and boreal forests?

Ans. Large mammals, bison, wolf, black bear, deer, Marco polo sheep and smaller animals such as small Kashmir flying squirrel, snowshoe hare, wolverine, crossbills are present.

Q 24. Name the plants of coniferous alpine and boreal forests?

Ans. Plants like Pinus wallichiana, Pinus roxburgii, Abies pindrow, Picea smithiana, Cederous deodara are present.

Q 25. What are prairies?

Ans. Grasslands present in temperate climates are called Prairies,such as Prairies of North America, pampas of Argentina. These grasslands do not have woody plants so they are known as prairies.

Q 26. What is Savanna?

Ans. The grasslands in tropic climates have woody trees and are called Savanna.

Q 27. What is the annual rain fall in grasslands?

Ans. Annual rainfall is about 250 to 750 mm. The grasslands usually face severe rains, which in tropical and subtropical grasslands, reaches about 1500 mm.

Q 28. Name some predators of grassland.

Ans. The predators are reptiles, amphibians and mammals, such as Lizards, toads and turtles prey on insects. Foxes and wolves among mammals are very common.

Q 29. What is the productivity of grassland ecosystem?

Ans. In temperate grasslands the rate of primary production is about 700-1500 g/cm2 annually. In sub humid tropical grasslands it is more than 4000 g/cm2.

Q 30. What is the location of deserts in Pakistan?

Ans. In Pakistan the desert ecosystems are found in western Punjab where it is known as Thal. In southern Punjab, areas like Fort Abbas. Bahawal Nagar, Yazman Bahawal Pur, Khan pur and Rahim yar khan also have deserts. In Sindh this desert ecosystem is called Thar.

Q 31. What is desertification?

Ans. While human activities are reducing the extent of many biomes, they are causing the spread of deserts, a process called desertification.

Q 32. What is tundra?

Ans. It is used to describe types of vegetation in treeless high latitudes between taiga and polar ice caps, and at high altitude across the mountain above timberline such as mountain of Karokaram and Koh Hindukush in Pakistan.

Q 33. What types of plant life is found in tundra?

Ans. The ground is carpeted with small perennial flowers and dwarf willows no more than a few centimeters tall often with large lichen called rein deer moss.

Q 34. What type of animal life if present in tundra?

Ans. The standing pools provide superb mosquito habitat. The mosquitoes and other insects provide food fore numerous birds. The tundra vegetation supports lemmings, which are eaten by wolves, snowy owls, arctic foxes and even grizzly bears.

Written by: Asad Hussain

Sunday, 27 March 2016

FSc Notes Biology Part 2 Chapter 24 Evolution Short Questions

FSc Notes Biology Part 2 Chapter 24 Evolution Short Questions


Q 1. What are the sources of hydrogen for reducing CO2 in first photosynthetic organism?
Ans. The first photosynthetic organism probably used hydrogen sulphide as a source of hydrogen for reducing carbon dioxide to sugars.

Q 2. Which idea is known as endosymbiont hypothesis?
Ans. The eukaryotic cell might have evolved when a large anaerobic amoeboid prokaryotic ingested small aerobic bacteria and stabilized them instead of digesting them. This is known as endosymbiont hypothesis.

Q 3. What was the second idea of Lamarck called?
Ans. The second idea of Lamarck adopted, was called the inheritance of acquired characteristics. In this concept of heredity, the modifications an organism acquires during its lifetime can be passed along to its offspring e.g., the long neck of the giraffe.

Q 4. What is the important turning point for evolutionary theory?
Ans. The origin of species convinced most biologists that species are products of evolution. An important turning point for evolutionary theory was the birth of population genetics, which emphasizes the extensive genetic variation within populations and recognizes the importance of quantitative characters.

Q 5. How natural selection occurs?
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population.

Q 6. What was the statement or theorem of Hardy-Weinberg?
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.

Q 7. Which mating is called non-random mating?
Ans. Individuals with certain genotypes sometimes  mate with one another more commonly than would be expected on a random basis. This is called non-random mating.

Q 8. On what evidence Darwin's theory of evolution was mainly based.
Ans. Darwin's theory of evolution was mainly was mainly based on evidence from the geographical distribution of species and from the fossil record.

Q 9. Who was Darwin's predecessor who developed a comprehensive model that attempted to explain how life evolves?
Ans. Jean Baptiste Lamarck (1744-1829).

Q 10. What is spirochete?
Ans. A helical bacterium which is flexible and has periplasmic flagella is called spirochete.

Q 11. Define bio-geography.
Ans. The study of geographical distribution of life on earth. Bio-geographers attempt to explain the factors that influence where species of plants and animals live on earth.

Q 12. What are fossils?
Ans. Any remain, impressions or traces of organisms of a formal geological age.

Q 13. Define embryology.
Ans. Study of animal development from fertilized egg to formation of all major organs.

Q 14. What is molecular biology?
Ans. The study of biochemical structures and function of organisms at molecular level.

Q 15. What does evolution refer?
Ans. Evolution refers to the processes that have transformed life on earth from its earliest forms to the vast diversity that is observed today.

Q 16. What is the concept of special creation?
Ans. According to the theory of special creation all living things came into existence in their present forms especially and specifically created by nature. Among the scientists who believed in divine creation was Carolus Linnaeus.

Q 17. What is the concept of Evolution.
Ans. The idea that organisms might evolve through time, with one type of organism giving rise to another type of organism is called evolution.

Q 18. What Darwin said about Finches of Galapagos?
Ans. Among the birds Darwin collected 13 types of finches that, although quite similar, seemed to be different species. Some were unique to individual islands, while other species were distributed on two or more islands that were close together.

Q 19. What did Lamarck said about the use and disuse of organs?
Ans. Lamarck argued that those parts of the body used extensively to cope with the environment become larger and stronger, while those that are not used deteriorate.

Q 20. What was Darwin's idea of Origin of Species?
Ans. A new species would arise from an ancestral form by the gradual accumulation for adaptations to different environment, separated from original habitat by geographical barriers. Over many generations, the two population could become dissimilar enough to be designated separate species.

Q 21. What was the contribution of Wallace in the development of theory of natural selection?
Ans. Alfred Wallace developed a theory of natural selection essentially identical to Darwin's. Wallace's paper, along with extracts from Darwin's unpublished 1844 essay, were presented to the Linnaean society of London on July 1, 1858.

Q 22. Define the theory of natural selection.
Ans. Nature will select the organism whose inherited characteristics fit them best to their environment and eliminate others.

Q 23. What is Neodarwinism?
Ans. According to neodarwinism the new species evolve due to extensive genetic variation within populations and natural selection.

Q 24. What does indicate that prokaryotes are ancestors of all life?
Ans. Evidence from biochemistry, molecular biology, and cell biology places prokaryotes as the ancestors of all life, and predicts that bacteria should precede all eukaryotic life in the fossil record.

Q 25. What are homologous structures?
Ans. Similarity in characteristics resulting from common ancestry is known as homology, and such anatomical signs of evolution are called homologous structures. For example: the forelegs(cat etc.), wings(bat), flippers(whale), and arms(man).

Q 26. What are vestigial organs?
Ans. Vestigial organs are historical remnants of structures that had important functions in ancestors but are no longer essential. For instance: vermiform appendix in carnivores and man.

Q 27. Name some vestigial structures in man.
Ans. Ear muscles, nictitating membrane, vermiform appendix and coccyx in man are vestigial structures.

Q 28. Differentiate between homologous and analogous organs.
Ans. Homologous organs are functionally different but structurally alike e.g., forelimbs of man, bat, horse, whale, etc., are example of divergent evolution. Analogous organs are functionally alike but structurally different e.g., wings of bat, birds and insects are examples of convergent evolution.

Q 29. Differentiate between natural selection and artificial selection.
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population, while the selective breeding of domesticated plants and animals by man is called artificial selection.

Q 30. What is population?
Ans. Population is a group of inter-breeding individuals belonging to a particular species and sharing a common geographic area or a population is a localized group of individuals belongings to the same species.

Q 31. Define species.
Ans. A species is a group of individuals that have the potential to interbreed in nature.

Q 32. What is gene pool?
Ans. The total aggregate of genes in a population at one time is called the population's gene pool. It consists of all alleles at all gene loci in all individuals of the population.

Q 33. Define the Hardy-Weinberg theorem.
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.

Q 34. What is Hardy-Weinberg equation used for?
Ans. A general formula, called the Hardy-Weinberg equation is used for calculating the frequencies of alleles and genotypes in populations at equilibrium.

Q 35. What factors affect the gene frequency?
Ans. Factors that affect that gene frequency:
  • Mutation
  • Migration
  • Genetic drift
  • Non-random mating
  • Selection
 

Q 36. Differentiate between endangered and threatened species.
Ans. A species which is in imminent danger of extinction throughout its range is called endangered species. A threatened species is likely to become endangered in the near future.

Q 37. What are hydrothermal vents?
Ans. Hydrothermal vents are hot springs deep in the oceans, in underwater where life may have begun.

Q 38. Name any five species, declared extinct in Pakistan.
Ans. Cheetah, Tiger, Asian lion, Indian rhino, Crocodile, Cheer pheasant.

Written by: Asad Hussain