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Monday, 30 March 2015

FSc Notes Chemistry Filtration Crystallization Choice of solvent

           FSc Notes Chemistry Filtration Crystallization

Analytical Chemistry: 

The branch of chemistry which provides a complete characterization of a substance. A complete characterization means, the quantitative and qualitative analysis of the substance.

Qualitative analysis: 

The detection and identification of elements in a compound is called qualitative analysis.

Quantitative analysis: 

The determination of amount or percentage of different elements in a compound is called quantitative analysis.
A complete quantitative determination generally consists of four steps:
  • Obtaining a sample for analysis.
  • Separation of desired constituents.
  • Measurement and calculation of the results.
  • Drawing conclusion from that analysis.

Filtration:

The process by which insoluble particles are separated from liquid is called filtration.

Filtrate: 

The liquid which is obtained after passing through the filter medium is called filtrate.

Residue: 

The solid substance which is present at the filter paper during filtration is called residue.

Filter Medium: 

The porous substance used for filtration is called filter medium. Filter paper, Gooch crucible, sintered crucible are different filter mediums.

Crystallization:

Separation of excess solid at low temperature in the from of crystals from a saturated solution prepared at high temperature is called crystallization.
Principle: Solute should be soluble in suitable solvent at high temperature and when solution is cooled down, the excess amount of solute comes out of the solution in the form of crystals.
This technique is used for separation of different substances on the basis of their solubilities. The process of crystallization involves the following steps:

1. Choice of Solvent:

The solvent is chosen on hit and trial basis and it is necessary to try a number of solvents before arriving at a conclusion. An ideal solvent should have following characteristics.
  1. It should dissolve a large amount of the solute at its boiling point and only only a small amount of solute at the room temperature.
  2. It should not react chemically with the solute.
  3. It should either not dissolve the impurities or the impurities should not crystallize from it along with the solute.
  4. On cooling it should deposit well formed crystals of the pure compound.
  5. It should be inexpensive.
  6. It should be safe to use and should be easily removable.
Solvents mostly used for crystallization:
  1. Water
  2. Rectified Spirit (95% ethanol)
  3. Absolute Ethanol (100%)
  4. Diethyl Ether
  5. Acetone
  6. Chloroform
  7. Carbon Tetrachloride
  8. Acetic Acid
  9. Petroleum Ether
If none of the solvents is found suitable for crystallization, then a combination of two or more miscible solvents may be employed. If this solvent is inflammable then precaution should be taken while heating the solution so that it does not catch fire. In such cases, water bath or sand bath is used for heating purpose.

2. Preparation of the Saturated Solution:

After selecting a suitable solvent, the substance is then dissolved in a minimum amount of solvent and is heated directly or on a water bath with constant stirring. Add more solvent to the boiling solution if necessary until all the solutes has dissolved.

3. Filtration:

The insoluble impurities in the saturate solution are then removed by filtering the hot saturated, through a normal or a fluted filter paper. This avoids the premature crystallization of eh solute on the filter paper or in the funnel stem. If necessary, hot water funnel should be used for this purpose.

4. Cooling:

The hot filtered solution is then cooled at a moderate rate so that medium size crystals are formed. In slow cooling bigger crystals are obtained but have considerable amount of solvent carrying impurities in it.

5. Collecting the crystals: 

When the crystallization is complete, the mixture of crystals and the mother liquid is filtered through a filter paper or Gooch crucible using a vacuum pump. The solution remaining after formation of crystals is called mother liquid. Full suction is applied in the order to drain the mother liquor from the crystals as effectively as possible. When the filter cake is rigid enough it is pressed firmly with cork to drain the left over liquid. The crystals are the washed with a small portion of cold solvent and the process is repeated several times. The mother liquid is quite often concentrated by evaporation and cooled to obtained a fresh crop of crystals. The process of crystallization appears to be very simple yet the success of operation lies in the amount or the percentage of crystallized product obtained from the crude substance.

6. Drying of the Crystallized Substance: 

Drying of crystals can be done by three ways:
  1. Pressing it between several folds of filter papers and repeating the process several times dries the crystallized substance. This process has the disadvantage that the crystals are crushed to a fine powder and sometimes the fibers of the filter paper contaminate the product.
  2. Alternatively the crystals are dried in an oven provided the substance does not melt or decompose on heating at 100 C.
  3. A safe and reliable method of drying is through a vacuum desiccators. In this process the crystals are spread over a watch glass and kept in a vacuum desiccators for several hours. The drying agent usually used in a desiccators are CaCl2, silica gel or phosphorous penta oxide P2O5.

7. De-colorization of Undesirable Colors: 

Sometimes during preparation of a crude substance, the coloring matter or resinous products affect the appearance of product and it may appear colored. Such impurities are conveniently removed by boiling the substance in the solvent with the sufficient quantity of finely powdered animal charcoal and then filtering the hot solution. The colored impurities are absorbed by animal charcoal and the pure decolorized substance crystallized out from the filtrate on cooling.

Tuesday, 24 March 2015

FSc Notes Chemistry Molar Volume Stiochimetry Limiting Reactant Yield

FSc Notes Chemistry Molar Volume Stiochimetry Limiting Reactant

Molar Volume: 

One mole of any gas at standard temperature and pressure occupies 22.4114 dm3, which is called molar volume. for exp:
2.016 g of H2 = 1 mole of H2 = 6.02 * 10(23) mole of H2  =  22.414 dm3 of H2 at STP.
16 g of CH4 =  1 mole of CH4 = 6.02 * 10(23) mole of CH4  =  22.414 dm3 of CH4 at STP.
22.414 dm3 of each gas has a different mass but the same number of molecules. The reason is masses and the sizes of the molecules don't affect the volumes. It is known as in the gaseous state the distance between molecules is 300 times greater than their diameter.

Law of Conservation of Mass: 

Mass can neither be created nor destroyed in a chemical reaction. As matter is atomic in nature, so we can also state that: Atoms can neither be created nor destroyed in a chemical reaction.

Law of Definite Proportions: 

The different samples of same compound will contain the number of atoms of different elements in the same fixed ratio by mass.

Stiochiometry: 

The branch of chemistry which deals with the quantitative relationship between reactants and products in a balanced chemical equation is called Stiochiometry.
Assumptions when stiochiometric calculation are performed:
Chemical equation do not tell about the condition and the rate of reaction. Chemical equation can even be written to describe a chemical change that do not occur. So when these calculation are performed we have to assume the following conditions:
  • All reactants are completely converted into the products.
  • No side reactions occurs.
  • While doing calculation, law of conservation of mass and law of definite proportions are obeyed.

Stiochiometric Amounts: 

The amounts of reactants and products in a balanced chemical equations are called Stiochiometric amounts.

Mass-mass relationship: If we are given the mass of the one substance, we can calculate the mass of the other substance.
Mass-mole relationship or mole-mass relationship: If we are given the mass one substance, we can calculate the moles of the other substance and vice versa.
Mass-volume relationship: If we are given the mass of one substance, we can calculate the volume of the other substance and vice versa.

Limiting Reactant: 

The reactant which is consumed earlier during a chemical reaction and gives the least moles of the product is called limiting reactant.

Identification of Limiting Reactant: 

To identify limiting reactant in a chemical reaction following steps are performed:
  • Calculate the number of moles from the given amount of reactant.
  • Find out the number of moles of product with the help of a balanced chemical equation.
  • Identify the reactant which produces the least amount of product as limiting reactant.

Yield: 

The amount of product obtained as a result of chemical reaction is called yield.


Theoretical Yield: 

The amount of product calculated from balanced chemical equation, is called theoretical yield.

Actual Yield: 

The amount of product that is actually obtained experimentally in a chemical reaction is called actual yield.

Why Actual yield is less than Theoretical yield:
Chemical reactions do not produce the amount of products expected theoretically. The reason are:
  • Side reaction produces by products.
  • Reactions are reversible.
  • Mechanical loss of product during separation by filtration, separation by distillation, separation by a separating funnel, washing, drying and crystallization is not properly carried out decrease the yield.

Percent Yield or Efficiency of Reaction: 

Actual Yield divided by the theoretical yield and answer is multiplied by 100 is called percent yield.

Efficiency of Reaction = % yield = (Actual yield / Theoretical yield ) * 100

Written By: Asad Hussain

Monday, 23 March 2015

FSc Notes Chemistry Basic Concepts of Chemistry

                     Basic Concepts of Chemistry:

Chemistry: The branch of science which deals with the study of structure of matter/, composition of matter, properties of matter, changes in matter and laws and principles which govern theses changes is called chemistry.

There are many branches of chemistry:
  • Physical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Biochemistry
  • Analytical Chemistry
  • Industrial Chemistry
Atom: The smallest particle of an element which may or may not exist independently and can take part in chemical reaction is called atom. For exp: He, Ne, O, N, Fe, Al.

Compound: 

A pure substance which is formed by the chemical composition of two of more than two different elements in a fixed ratio by mass is called compound. Compound is always homogeneous. For exp: NH3, H2O, NaOH. There are two types of compounds.

  • Ionic Compounds
  • Molecular Compounds

Molecule: 

The smallest particle of an element or compound which exist independently is called a molecule. Molecules are classified in different ways: on basis of size, number of atoms and nature of atoms:

On the basis size:
Macromolecules: Molecules which have large number of atoms of different elements in it. For exp: haemoglobin (10000 atoms), proteins, lipids.

Micromolecule: Molecules of smaller size and lower molecular mass for exp: H2SO4. H2O.

On basis of nature:
Homoatomic molecules: Those molecules which have same types of atoms are called homoatomic molecules. for exp: H2, O2, Cl2.
Heteroatomic molecules: Those molecules which consist of atoms of different elements are called heteroatomic molecules for exp: CH4, NH3, SO2.

On the basis of number of atoms:
Monoatomic molecules: The molecule which consist of a single atom is called monoatomic molecule for exp: He, Ne, Ar.
Diatomic molecule: The molecule consisting of two atoms is called diatomic molecule for exp: H2, O2, CO.
Polyatomic molecule: Molecule consisting of more than two atoms is called polyatomic molecule for exp: H2O, NH3, CCl4.

Atomicity: The number of atoms present in a molecule is called atomicity. Atomicity of H2SO4 is 7.

Ions: 

The species which carry either positive or negative charge is called ions. There are two types of ions on the basis of charge present on them i.e cations and anions.

On basis of Charge:
Cation: When an atom loses electron. it forms cation. Some energy is required to ionize and atom. It is an endothermic process.
A ------------>  A+  +  e-
A+ is called cation. Charge is based upon the number of electrons which and atom loses. If an atom loses one electron its charge will be +1 if it loses two electrons its charge will be +2. for exp: Na+, Sr 2+.
Anions: When an atom gains one or more electrons anions is formed . Some amount of energy is released when an electron is added to an atom. Foundation of anions is an exothermic process.
B  +  e-  ---------------> B-
For exp atoms gaining one electron have -1 charge on them F-, Cl-. Atom gaining two electron have -2 charge.

On basis of number:
  • Simple ions
  • Complex ions
Simple ion: If only a single atom changes to charge species it is called simple ion for exp: Na+, K+.
Complex ion: If group of atoms have charge on them they are called complex ions. for exp NH4+, CH3+.
Molecular ion: If an electron is removed from a molecule of a substance it is called molecular ion for exp CH4+, CO+. If we remove electron from a molecule it is called molecular ion.

Isotopes: 

The atoms of same element having same atomic number but different atomic masses are called isotopes. Number of protons present in the nucleus of an atom is called atomic number or proton number, The number of protons and neutron present in the nucleus of an atom is called mass number. Mass number is always a whole number. Isotopes of an element have same chemical properties and same position in the periodic table.

Written By: Asad Hussain

Friday, 20 March 2015

FSc Notes Biology Part 1 Chapter 12 Nutrition

              FSc Notes Biology Part 1 Chapter 12 Nutrition


Q 1. What is stomach?
Ans. It is enlargement of the anterior region of the gut. In vertebrates it follows oesophagus and usually has muscular walls which are helpful in crushing the food, and the lining cells secrete pepsin and hydrochloric acid.

Q 2. Write down two function of tongue.
Ans. (1) Manipulation of food.
(2) Holds food in position between the teeth.

Q 3. Define nutrition.
Ans. Nutrition is the sum total of all the processes concerned with growth, repair and maintenance of the living organism as a whole or its constituent parts.

Q 4. What does bolus of food mean?
Ans. As a result of mastication in the oral cavity, the softened, partly digested, slimy food mass is rolled by the tongue into small oval lump called as bolus.

Q 5. Name the bacteria which commonly cause food poisoning?
Ans. These bacteria are Salmonella and Campylobacter.

Q 6. What is the number and nature of sphincters around the areas of man?
Ans. The human anus is surrounded by two sphincters, the internal of smooth and the outer of striped muscles.

Q 7. Name the parts of the large intestine of man.
Ans. These are the colon, caecum and the rectum from in-front backwards.

Q 8. How is Jaundice caused?
Ans. Jaundice is caused by the accumulation of bile pigments in the blood.

Q 9. What is the innermost layer of the human stomach and the other points of the alimentary canal known as?
Ans. It is known as the mucosa.
Q 10. Name two animals which possess a sac like digestive system.
Ans.These animals are Hydra and Pslanaria.

Q 11. How does Amoeba engulf solid food particles?
Ans.  The Amoeba engulfs solid food particles with the help pf pseudopodia.

Q 12. What is most appropriate name for digestive cavity of Hydra?
Ans. It is the coelenteron.

Q 13. Name the opening through which undigested food is ejected in Hydra and the Planaria?
Ans. It is the mouth.

Q 14. Which parts are included in the fore-gut of cockroach?
Ans. These are mouth, cavity, pharynx, crop and gizzard.

Q 15. What is botulism? What is its cause?
Ans.  The severe form of food poisoning is called botulism. Its cause is a bacterium known as Clostridium botulinum.

Q 16. Define obesity.
Ans. The deposition of abnormal amount of fat on the body is termed as obesity.

Q 17. In which machine form is trypsin secreted? How is it activated?
Ans. Trypsin is secreted in the inactive form of trypsinogen which is activated by an enzyme, enterokinase, secreted by the duodenum.

Q 18. Explain heart burn or pyrosis.
Ans. It is a painful burning sensation in the chest usually associated with the back flush of acidic chyme into the oesophagus.

Q 19. How do the farmers replenish the deficiency of nutrient salts?
Ans. The deficiency of nutrient salts is replenished by adding animal manure, sewage sludge or artificial chemical fertilizers to the soil.

Q 20. Explain a predation.
Ans. A predator is an animal which captures and readily kills other animals for its food.

Q 21. Define detritus.
Ans. Detritus is the organic debris derived from the decomposing plants and animals.

Q 22. Why some people develop intestinal gas and diarrhea by consuming milk products?
Ans. Many humans develop intestinal gas and diarrhea by consuming milk products because they lack the enzymes for digesting lactose in milk.

Q 23. Write down the pH of fresh and stale human saliva.
Ans. The pH of the fresh human saliva is about 8 and that of the stale saliva is 6.

Q 24. Define dyspepsia. What are its symptoms?
Ans. Imperfect digestion is called dyspepsia. Its symptoms are abdominal discomfort, flatulence, heartburn, nausea and vomiting.

Q 25. How is constipation caused in man?
Ans. Constipation may be caused due to excessive absorption of water through the large intestine.

Q 26. What are piles or haemonhoids?
Ans. These are masses of dilated, tortuous veins in the anorectal mucosa which bleed during bowl movements.

Q 27. How are gallstones formed in the gall bladder?
Ans. The gallstones are formed in the gall bladder due to the precipitation of cholesterol, secreted by the liver.

Q 28. What are the functions of the enzymes amino-peptidase and erepsin of the intestinal juice?
Ans. The amino-peptidase converts poly-peptidase into dipeptidase whereas the erepsin splits dipeptides into amino acid.

Q 29. What is the emulsification of fats? Which secretion emulsifies fats?
Ans. The breaking down of fats into small globules is called emulsification. It is brought about by the bile.

Written By: Asad Hussain

Thursday, 19 March 2015

FSc Notes Biology Part 1 Chapter 13 Gaseous Exchange

       FSc Notes Biology Part 1 Chapter 13 Gaseous Exchange

Q 1. How much CO2 is present in venous and arterial blood?
Ans. Arterial blood contains 50 ml of carbon dioxide per 100 ml of blood whereas venous blood has 54 ml of carbon dioxide per 100 ml of blood.
Q 2. How much denser is a water medium than air medium for exchange of respiratory gases?
Ans. Water is 8000 times more dense than air.
Q 3. How aquatic plants obtain oxygen?
Ans. Aquatic plants obtain their oxygen by diffusion from dissolved oxygen is water.

Q 4. Define photo-respiration.
Ans. Respiratory activity which occurs in plants during daytime is called photorespiration. Photorespiraiton is a light dependent process during which oxygen is absorbed and carbon dioxide is released. This oxygen is derived from the early reaction of photosynthesis. The pathway in which RuBP (Ribulose Biphosphala) is converted into serine is called photorespiration.

Q 5. Describe briefly as to how gaseous exchange takes place in plants.
Ans. Gaseous Exchange in Plants:
Gaseous exchange is plants takes place through three methods:
Through Stomata: In most cells of mesophyll which are specialized for photosynthesis, there are present large spaces. Theses air spaces are directly involved in gaseous exchange. Stomata are the main sites of exchange of gases in plants. Stomata are largely present in the leaves and in young stem. These stomata lead to intercellular spaces of mesophyll tissue.
Through Lenticels: In older stems, cork tissue is present which is formed of dead cells. The cork tissue has special pores called lenticles which are involved in gaseous exchange.
Through Roots: The roots of the land plants get their oxygen from the air existing in the spaces between the soil particles.

Q 6. How does breathing differ from respiration?
Ans. Respiration: Respiration is one of the most important metabolic activities of all organisms. Cellular respiration is the process where by cell utilizes oxygen, produce carbon dioxide, extract and conserves the energy from food molecules in biologically useful form, such as ATP.
Breathing: Organismic respiration is also known as breathing or ventilation. During which oxygen is taken from atmosphere and carbon dioxide is released. Breathing provides the basis of cellular respiration.

Q 7. How the rate of carbon dioxide fixation is lowered?
Ans. The photorespiration is a process in which ribulose biphosphala carboxylase / oxygenase fixes oxygen instead of carbon dioxide which results in lowering the overall rate of carbon dioxide fixation and plant growth.

Q 8. What is Rubisco?
Ans. Rubisco, the most abundant protein in chloroplasts and probably the most abundant protein in the world. The rubisco is carboxylase as well as oxygenase.

Q 9. How glycolate is produced?
Ans. When RuBP react with oxygen, a two carbon compound glycolate is produced:
                   RuBP +O2 -----------> Glycolate
That glycolate thus produced diffuses into membrane bounded by organelles known as peroxisomes.

Q 10. What is glycine? How it is converted to serine?
Ans. In the peroxisomes the glycolate is converted into glycine, through a series of reactions.
             Glycolate ----------->  Glycine
The glycine is the simplest amino acid which soon after its formation diffuses into the mitochondria where two glycine molecules are converted into serine and a molecule of carbon dioxide is formed.
          2 Glycine ---------->  Serine CO2

Q 11. How does air always remain in the lungs of Human beings?
Ans.  Air always remain in the lungs pf human beings due to difference in the concentration gradient of carbon dioxide and oxygen in the lungs.

Q 12. What is the difference between photosynthesis and photorespiration?
Ans. Photosynthesis:
  1. Photosynthesis is the process by which energy is acquired by inorganic oxidized compounds of carbon and hydrogen are reduced to energy rich carbohydrates using light energy that is absorbed by chlorophyll.
  2. During photosynthesis carbon dioxide is absorbed and oxygen is released.
  3. In this process Rubisco acts as carboxylase.
Photorespiration:
  1. Respiratory activity that occurs during daytime is called photorespiration.
  2. It is a light dependent process during which oxygen is absorbed and carbon dioxide is released.
  3. During this process Rubisco acts as oxygenase and in this way rate of oxygen in atmosphere is lowered.

Q 13. What are the properties of respiratory surfaces?
Ans. The respiratory surfaces in most animals exhibit the following features:
Large Surface and Moisture: The surface area should be large and kept moist as is in lungs and gills.
Thin Epithelium: The distance for diffusion must be short. In animals, the epithelium is only two cells thick which separates blood and air.
Ventilation: Their should be the difference is the gases at two points which bring about diffusion.
Capillary Network: The respiratory site should possess steps diffusion gradient and extensive network of capillaries through which blood should flow all the time at a n adequate speed.

Q 14. Differentiate between inspiration and expiration.
Ans. Inspiration:
  1. Inspiration is the intake of air inside the lungs.
  2. During inspiration the space inside the chest cavity is raised.
  3. Muscles of ribs contract and elevate the rib upwards and forwards.
  4. The muscles of diaphragm contract and become less dome-like. 
  5. Pressure from the lungs is removed and they expand and vacuum is created due to which air rushes inside the lungs.
Expiration:
  1. Expiration is the expulsion of air from the lungs.
  2. During expiration from the sides of chest cavity the space becomes less.
  3. The muscles of ribs and relaxed and ribs move downward and inward.
  4. The muscles of diaphragm relax becoming more dome-like.
  5. The lungs are pressed and the air moves outside the lungs.
Q 15. If photorespiration is inhibited chemically, the plant can still grow. Then why does photorespiration exist?
Ans.  The active site of rubisco is evolved to bind both carbon dioxide and oxygen together. Originally it was not a problem as there was little oxygen in the atmosphere and the carbon dioxide binding activity was the only one used . The photorespiration started when the quantity of oxygen became more.

Q 16. What are respiratory surfaces?
Ans.  Respiratory surfaces in animals are the sites where gaseous exchange takes place.

Q 17. What are respiratory surfaces in hydra?
Ans. Hydra has no specialized organs for respiration. Exchange of gases i.e., intake of oxygen and removal of carbon dioxide, occurs through entire general surface in contact with water.

Q 18. How skin is kept moist in earthworm?
Ans. Skin is richly supplied with blood capillaries and is always kept moist by the secretion of epidermal mucous gland cells and also by coelomic fluid exuding out through the dorsal pores. Oxygen dissolved on the wet surfaces passes through the cuticle and epidermal cells into the blood.

Q 19. What are spiracles?
Ans. The main tracheal trunk communicates with exterior by 10 pairs of apertures called spiracles.

Q 20. What are tracheoles?
Ans. The main tracheae divide and subdivide forming very fine thin walled tubules called tracheoles.

Q 21. What happens when abdominal muscles of cockroach expand?
Ans. When abdomen muscles expands, the first four pairs of spiracles open, air rushes in through these spiracles into tracheoles.

Q 22. What happens when abdominal muscles of cockroach contract?
Ans. When abdomen muscles contracts, the anterior four pairs of spiracle close and posterior six pairs of spiracle open.

Q 23. What are gills?
Ans. Fish respires through the gills which are paired structures present on either side of the body almost at the junction of head and trunk. Gills are most effective and highly modified for gaseous exchange in aquatic animals. They are in four to five pairs which may open through gill slits and are visible on the surface of pharynx or are placed in bronchial cavities which are covered by operculum. Gills have great surface area for gaseous exchange. The gill surface is all the time ventilated by constant flow of water.

Q 24. What is cutaneous respiration?
Ans. The gaseous exchange through skin is known as cutaneous respiration.

Q 25. What is pulmonary respiration?
Ans. The gaseous exchange through gills or lungs is called pulmonary respiration.

Q 26. What are parabronchi?
Ans. In the lungs of birds, tiny thin walled ducts called parabronchi are present instead of alveoli. These parabronchi are open at both ends and the air is constantly ventilated. The walls of parabronchi are chief sites of gaseous exchange.

Q 27. Why respiration in birds is specialized than any other animal?
Ans. Respiratory system in birds is the most efficient and elaborate. The birds are very active animals with high metabolic rates, and thus need large amount of oxygen. The respiratory system in the birds is so arranged there is one way flow of air through the lungs and the air is renewed after inspiration.

Q 28. What are air sacs?
Ans. The lungs have developed several extensions known as air sacs which reach all parts of the body and even penetrate some of the bones. In most birds, air sacs are nine in number which become inflated by air at atmospheric pressure when the rib articulation are rotated forward and upward. The inflated air sacs act as bellows and send air into the parabronchi for gaseous exchange.

Q 29. What air passage consist of?
Ans. Air passage ways consist of nostrils, nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles and alveolar ducts which ultimately lead into alveolar sacs.

Q 30. What is the function of mucous membrane?
Ans. Air enters the nasal cavity through nostril and the larger dust particles are trapped by the hair and mucus in the nostrils. Air, while passing through the nasal cavity, becomes moist, warm and filtered of smaller foreign particles by mucous membrane.

Q 31. What is pharynx?
Ans. The pharynx is a muscular passage lined with mucous membrane. The air is channelized from the pharynx into the larynx.

Q 32. What is larynx?
Ans. The larynx or voice box is a complex cartilaginous structure surrounding the upper end of the trachea.

Q 33. What is glottis?
Ans. The opening of larynx is called glottis is also lined with mucous membrane.

Q 34. What are vocal cords? What is their purpose?
Ans. In the glottis, the mucous membrane is stretched across into two thin edged fibrous bands called vocal cords, which help in voice production, when vibrated by air.

Q 35. How food is prevented from going into respiratory track?
Ans. One of the cartilages, the epiglottis has a muscularly controlled, hinge-like action and serves as a lid which automatically covers the opening of the larynx during the act of swallowing so as to prevent the entry of food or liquids into the larynx.

Q 36. What is trachea?
Ans. The trachea or wind pipe is a tubular structure lying ventral to the oesophagus and extends to the chest cavity or thorax where it is divided into right and left bronchi.

Q 37. What is the function of cartilage rings in trachea?
Ans. In the wall of trachea there are series of C shaped cartilage rings which prevent the trachea from collapsing and keep the passage of air open.

Q 38. What is functional unit of lungs?
Ans. Air sacs is the functional unit of lungs.

Q 39. What is the difference between bronchi and bronchioles?
Ans. Bronchi:
Each bronchus on entering the lung divides and subdivides progressively into smaller and smaller bronchi. Bronchi have the same cartilage rings as the trachea, but the rings are progressively replaced by irregularly distributes cartilage plates.
Bronchioles:
When the smaller bronchi attain a diameter of one mm or less, then they are called bronchioles. Bronchioles totally lack cartilages. Bronchioles are made up of mainly circular smooth muscles.

Q 40. What are alveoli?
Ans. Each air sac consists of several microscopic single structures called alveoli.

Q 41. What is diaphragm?
Ans. The floor of the chest is called diaphragm. Diaphragm is a sheet of skeletal muscles.

Q 42. What us pleura?
Ans. Lungs are covered with double layered thin membranous sacs called pleura.

Q 43. What are three aspects related to lungs and associated structures?
Ans. The three aspects related to lungs and associated structures are:
  1. Lungs are spongy in nature. The lungs themselves neither pull air in nor can they push it out. During inspiration passive expansion of elastic lungs occurs and expiration is due to a passive contraction of lungs.
  2. The floor of the chest cavity is diaphragm, which is a muscular sheet. The shape of the diaphragm is more domelike when its muscles are relaxed. On the other hand when the muscles of diaphragm contract its shape becomes less domelike.
  3. Walls of chest cavity are composed of ribs and intercostal muscles. When muscles between ribs contract, the ribs are elevated and when muscles between ribs are relaxed the ribs settle down.

Q 44. Explain respiratory distress syndrome in premature infant.
Ans. In premature infant, respiratory distress syndrome is common, especially for infant with a gestation age of less than 7 months. This occurs because enough infant surfactant is not produced to reduce the tendency of the lungs to collapse.

Q 45. On which factors transport of gases depend?
Ans. Intake of oxygen ans release of carbon dioxide by blood passing through capillaries of alveoli is brought by the following factors:
Diffusion of oxygen in and carbon dioxide out occurs because of difference in partial pressure of these gases.
Within the rich network of capillaries surrounding the alveoli, blood is distributed in extremely thin layers and, therefore, exposed to large alveolar surface.
Blood in the large is separated from the alveolar air by extremely thin membranes of the capillaries and alveoli.

Q 46. What is Myoglobin? What is its function?
Ans. Myoglobin is hemoglobin like iron containing protein pigment occurring in muscle fibers. Myoglobin is also known as muscle hemoglobin.
It serves as an intermediate compound for the transfer of oxygen from hemoglobin to aerobic metabolic processes of the muscle cells. It can also store oxygen. Myoglobin consists of just one peptide chain associated with an iron containing ring structure which can bind with one molecule of oxygen. The affinity of myoglobins to combine with oxygen is much higher as compared to haemoglobin.

Q 47. How haemoglobin acts as an efficient oxygen carrier?
Ans. In human beings the respiratory pigment is haemoglobin. It is contained in the red blood corpuscles. Haemoglobin readily combines with oxygen to form bright red oxyhaemoglobin and oxygen in the conditions of low oxygen concentration and less pressure. Carbonic anhydrase enzyme in R.B.C facilitates this activity. In this way haemoglobin acts as an efficient oxygen carrier.

Q 48. What is the maximum amount of oxygen gas which normal human blood absorbs and carries at sea level?
Ans. Normal human blood absorbs and carries oxygen at sea level is about 20 ml / 100 ml of blood.

Q 49. What adaptations a diver adopt when he descends in the sea?
Ans. As a scuba diver descends in the sea, the pressure of the water on his body prevents normal expansion of the lungs. To compensate, the diver breaths pressurized air from air cylinders, which has a greater pressure than sea level air pressure.

Q 50. What are important factors which affect capacity of haemoglobin to combine with oxygen gas?
Ans. There are three factors which affect the capacity of haemoglobin to combine with oxygen.
  1. Carbon Dioxide: When carbon dioxide pressure increases, the oxygen tension decreases, the capacity of haemoglobin to hold oxygen becomes less. In this way increased carbon dioxide tension favors the greater liberation of oxygen from the blood to the tissue.
  2. Temperature: Rise in temperature also causes a decrease in the oxygen carrying capacity of blood. e.g., in the increased muscular activity.
  3. pH: As the pH of the blood declines, the amount of oxygen bound to haemoglobin also declines. This occurs because of decreased pH results from an increase in hydrogen ions, and the hydrogen ions combine with the protein part of the haemoglobin molecules, causing a decrease in the ability of haemoglobin to bind oxygen, Conversely, an increase in blood pH results in an increased ability of haemoglobin to bind oxygen.
Q 51. What is carboxyhaemoglobin?
Ans. Carboxyhaemoglobin is formed when carbon dioxide combines with amino group of haemoglobin.

Q 52. How much percentage of carbon dioxide is carried as carboxyhaemoglobin?
Ans. About 20% of the carbon dioxide is carried as carboxyhaemoglobin.

Q 53. How much percentage of carbon dioxide is carried by plasma proteins?
Ans. Plasma proteins carry about 5% carbon dioxide form the body fluids to the capillaries of lungs.
Q 54. How carbon dioxide is carried as bicarbonate ion?
Ans. About 70% carbon dioxide is carried as bicarbonate ion with sodium in plasma. As carbon dioxide from tissue fluid enters the capillaries it combines to form carbonic acid.
                          Carbonic anhydrase
CO2  +  H2O ------------------------> H2CO3
The carbonic acid spits quickly and ionized to produce hydrogen ions and bicarbonate ions.
H2CO3 ------------------> H+  +  (HCO3)-
When blood leaves the capillary bed most of the carbon dioxide is in the form of bicarbonate ions. In the lungs bicarbonate ions combine with hydrogen ions to form carbonic acid which splits into water and carbon dioxide. It is this carbon dioxide which diffuses out from the capillaries of the lungs into the space of alveolar sac.

Q 55. What is metastasis?
Ans. Metastasis is a process that involves the spread of a tumor or cancer to different parts of the body from its original site.

Q 56. What is malignant tumor?
Ans. Malignant tumour is a tumour in which cancerous cells transport by means of circulatory system.

Q 57. What is cancer?
Ans. Cancer or carcinoma is basically malignant tumour of potentially unlimited growth that expands locally by invasion and systematically by metastasis.

Q 58. What is tuberculosis? How it is caused?
Ans. Tuberculosis is a disorder of respiratory system, In fact, it is the general name of a group of diseases caused by Mycobacterium tuberculosis. Pulmonary tuberculosis is a diseases of lungs in which inside of the lung is damaged resulting in cough and fever. It is more common in poor people. Malnutrition and poor living conditions facilitate Mycobacterium to grow. The disease is curable with proper medical attention. It is a contagious disease.

Q 59. What is asthma?
Ans. Asthma is a serious respiratory disease associated with severe paroxysm of difficult breathing, usually followed by a period of complete relief, with recurrence of attack at more or less frequent intervals. It is an allergic reaction to pollen, spores, cold, humidity, pollution etc., which manifests itself by spasmodic contraction of small bronchiole tubes. Asthma results in the release of inflammatory chemicals such as histamines into circulatory system that cause severe contraction of the bronchiole.

Q 60. Why there is an increased rate and depth of breathing during exercise?
Ans. At rest we inhale and exhale 15 - 20 times per minute. During exercise breathing rate may rise to 30 times per minute. The increased rate and depth of breathing during exercise allows more oxygen to dissolve in blood and be supplied to the active muscles. The extra carbon dioxide which the muscles put into the blood is removed by deep and fast breathing
.
Q 61. What is the total capacity of lungs?
Ans. The total inside capacity of lungs is about 5 liters.

Q 62. What is the volume of air expelled from the lungs during exercise?
Ans. The volume of air taken inside the lungs and expelled during exercise is about 3.5 liters.

Q 63. What is the residual volume of lungs?
Ans. Residual volumes of lungs is 1.5 liters which cannot be expelled even during exercise.

Q 64. How diving mammals differ from the other animals?
Ans. Diving mammals have almost twice the volume of blood in relation to their body weight as compared to non divers. Most of the diving mammals have high concentration of myoglobin in their muscles. Myoglobin binds extra oxygen and store it.

Q 65. How diving reflex is activated in mammals?
Ans. When mammals dives to its limit the diving reflex is activated. The breathing stops, the rate of heart slows down to one tenth of the normal rate, the consumption of oxygen and energy is reduced. The blood is redistributed but most of the blood goes to the brain and heart which can least withstand anoxia. Skin muscles and digestive organs and other internal organs receive very little blood while an animal is submerged because these areas can survive with less oxygen, Muscles shift from aerobic to anaerobic respiration.

Q 66. What is emphysema?
Ans. Emphysema is a break down of alveoli. This respiratory problem is more common among smokers. The substances present in the smoke of tobacco weaken the alveoli wall. The irritant substances of smoke generally cause bursting of weakened of alveoli. In the result of constant coughing the absorbing surface of the lung is greatly reduced. The person suffering from emphysema cannot oxygenate his blood properly and least exertion makes him breathers and exhausted. Emphysema produces increased airway resistance because the bronchioles are abstracted as a result and inflammation and because damaged bronchioles collapse during expiration, trapping air within alveolar sacs.

Q 67. Why the amount of oxygen increase in the blood of birds during gaseous exchange?
Ans.The direction of the blood flow in capillaries around the lungs is opposite to that of the airflow through the parabronchi. This counter current exchange increases the amount of oxygen which enters the blood.

Written By: Asad Hussain

Monday, 16 March 2015

FSc Notes Biology Part 1 Chapter 14 Transport

            FSc Notes Biology Part 1 Chapter 14 Transport

Q 1. What do you know about active transport?
Ans. Transfer of substances from region where its concentration is low to where it is high especially through a membrane accomplished by means of expenditure of energy from metabolism. Probably all cells can do this.

Q 2. How much of the total surface area of the root is provided by the root hairs?
Ans. Root hairs provide 67% of the total area of the root.

Q 3. Which two factors determine the water potential in plant cells?
Ans. These factors are solute potential and the pressure potential.

Q 4. What is pericardial sinus in cockroach?
Ans. It is the cavity in which lies 13-chambered heart of cockroach.

Q 5. Write down the kinds of agranulocytes.
Ans. These are monocytes and lymphocytes.

Q 6. Which veins bring blood from the legs?
Ans.  The iliac veins bring blood from the legs.

Q 7. What us haemorrhage?
Ans. The discharges of the blood from the blood vessels is called haemorrhage.

 Q 8. What us an antiserum?
Ans. The antiserum is serum, containing antibodies.

Q 9. What are blood vessels?
Ans. The vessels in which blood flows are called blood vessels. There are three types of blood vessels.
  1. Arteries
  2. Veins
  3. Capillaries
Q 10. Define osmotic or solute potential.
Ans. It is the component of water potential that takes into account the concentration of solutes in the cell. It is represented by Ψs and is always negative.

Q 11. Where are the old and worn out red blood cells destroyed?
Ans. The old and worn out red blood cells are destroyed in the spleen and liver.

Q 12. What is the condition of high blood pressure in man known as?
Ans. It is known as hypertension.

Q 13. What is thrombus?
Ans. A solid mass or plug of blood clot in a blood vessel is called thrombus.

Q 14. Why is thalassemia also called Cooley's anaemia?
Ans. It is named after an American Pediatrician, Thomas B Cooley who investigated on it.

Q 15. How much water is found in human blood plasma?
Ans. The human blood contains about 90% of water.

Q 16. Who proposed "pressure flow theory" and when?
Ans. Ernest Munch proposed ""pressure flow theory' in 1930.

Q 17. Which parts of the root serve to absorb water and salts from the soil?
Ans. These parts are the root hairs.

Q 18. Name the components of the cell wall which can imbibe water.
Ans. These are the cellulose pectin and lignin etc.

Q 19. Define transpiration.
Ans. The loss of water from the surface of the plant in the form of water vapors is known as transpiration.

Q 20. How does the rise of temperature affect the rate of transpiration in plants?
Ans. The rate of transpiration doubles for every temperature rise of about 10C within certain limits.

Q 21. Name the three main blood vessels of Earth-worm.
Ans. These are the dorsal vessel, the ventral vessel and the sub natural vessel.

Q 22. What is the average life of red blood cell of man?
Ans. The average life of a red blood cell of a man is about 120 days (4 months).

Q 23. Write a short note on heart attack.
Ans. Blockage of blood vessel in the heart by an embolus causes necrosis or damage to portion of heart muscles, a condition known as heart attack or technically myocardial infarction. Heart attack is due to disruption of control system of the heart with accompanying arrhythmia, especially ventricular fibrillation.

Q 24. Name the chambers of the human heart.
Ans. These are right and left atria and the right and left ventricles.

Q 25. Which is the chief blood distributing vessel in man?
Ans. Aorta is the chief blood distributing vessel in man.

Q 26. Define immunity.
Ans. The ability of the living organisms to withstand harmful, foreign infective agents and toxins is called immunity.

Q 27. What are lacteals?
Ans. The branches of lymph capillaries within the villi of the intestine are called lacteals.

Q 28. Define arteriosclerosis.
Ans. It is a degenerative arterial change associated with advancing age.

Q 29. What is the significance of valves in the heart of man?
Ans. The valves allow the blood to flow only in one direction.

Q 30. How much time does a heartbeat of man take?
Ans. It takes about 0.8 second.

Written By: Asad Hussain

Sunday, 15 March 2015

FSc Notes Biology Part 1 Chapter 7 The Kingdom Protista or Protoctista

FSc Notes Biology Part 1 Chapter 7 The Kingdom Protista or Protoctista

Q 1. Write characteristics of protists.
Ans. The protists are unicellular, colonial or simple multicellular organisms that posses a eukaryotic cell organization. e.g., Algae, Protozoa.

Q 2. What are the major groups of eukaryotic organisms of kingdom protista?
Ans. The kingdom protista contain four major groups i.e.
  1. Single cell protozoans.
  2. Unicellular algae.
  3. Multicellular algae.
  4. Slime molds and Oomycotes.
Q 3. Who proposed kingdom protista?
Ans. John Hogg proposed kingdom protista for microscopic organisms.

Q 4. In which respects during course of evolutionary history, organisms in kingdom protists have evolved diversity?
Ans.
  1. Size and structure.
  2. Means of locomotion.
  3. Ways of obtaining nutrients.
  4. Interactions with other organisms.
  5. Habitat.
  6. Modes of reproduction.
Q 5. Write two characteristics of protozoans.
Ans. Characteristics of Protozoans:
  1. All protozoans are unicellular.
  2. Most ingest their food by endocytosis.
Q 6. How zoo-flagellates obtain their food?
Ans. They obtain food either by ingesting living or dead organisms e.g., Euglena, Amoeba or by decomposing organic matter. e.g., Slime Algae.

Q 7. What is the habitat of zoo-flagellates?
Ans. Zooflagellates are free living, parasite, or symbionts.

Q 8. What is trypanosoma?
Ans. Trypanosoma is a human parasite causing African sleeping sickness. It is transmitted by the bite of infected tsetse fly.

Q 9. What is the habitat of choanoflagellates?
Ans. Choanoflagellates are sessile marine or freshwater flagellates which are attached by a stalk.

Q 10. Define pellicle.
Ans. Pellicle is a flexible outer covering of cilliates that gives them definite but changeable shape.

Q 11. In which way cillates differ from other protozoans.
Ans. Cilliates differ from other protozoans in having two kinds of nuclei large is meganucleus and small is micronucleus.

Q 12. From what tests of forminifera and of actinopods are made of?
Ans. Tests of forminifera all made of calcium where as those of actinopode are made of silica.

Q 13. Write two characteristics of Apicomplexans.
Ans. Characteristics of Apicomplexans:
  1. Apicomplexans are unicellular.
  2. They are non-motile.
Q 14. Write the name of apicomplexans that cause malaria.
Ans.  Plasmodium, the apicomplexans that cause malaria enters human body by the bite of infected female anopheles mosquito.

Q 15. What kind of body algae possessed?
Ans. The plant body of algae is thallus i.e., not differentiated into true roots, stems and leave and lack vascular bundles.

Q 16. Write two characteristics of dinoflagellates.
Ans. Characteristics of dinoflagellates:
  1. Most dinoflagellates are unicellular.
  2. Their cells are often covered with shells of interlocking cellulose plates impregnated with silicates.
Q 17. What stage is called plasmodium in slime molds?
Ans. The feeding stage of a slime mold is a multinucleate mass of cytoplasm that can grow to 30cm (1 foot) in diameter. This stage is called plasmodium.

Q 18. What are the similarities between fungus like protists and fungi?
Ans. Some protists resemble fungi in that they are not photosynthetic and some have bodies formed of thread like structure called hyphae.

Q 19. What causes late blight of potatoes?
Ans. Late blight of potatoes is caused by a water mold called phytopthora infestans.

Q 20. Why Euglena is placed in kingdom protists? 
Ans. They are placed in kingdom protista because they have chlorophyll and are photosynthetic but at the same time it had cell wall and is motile.

Q 21. What stage of material parasite causes chill and fever?
Ans. The simultaneous bursting of red blood cells cause the symptoms of malaria, chill, followed by high fever.

Q 22. What is conjugation?
Ans. Conjugation is a sexual process of cilliates during which two individuals come together and exchange genetic material.

Q 23. What is phylum of red algae?
Ans. The phylum of red algae is Rhodophyta.

Q 24. Name the pigments present in diatoms.
Ans. Chlorophyll a, chlorophyll c caroteins and fucoxanthin are pigments present in diatoms.

Q 25. What cause red tides?
Ans. Dinoflagellates are known to have occasional population explosions or blooms. These blooms color the water orange, red or brown and are called red tides.

Q 26. What are kelps?
Ans. The largest brown algae, which are tough and leathery in appearance. Whose leaf like structure called blade, stem like called stipes and root like structure called hold fast.

Q 27. Do slime moulds have definite cellular organization?
Ans. No, they do not have definite cellular organization.

Q 28. What is the causes of Irish potato?
Ans. Phytophthora is the cause of Irish potato.

Q 29. Do red algae has flagellated cells?
Ans. No, they does not have flagellated cells.

Q 30. What is the role of diatoms in ecosystem?
Ans. They are major producers in the aquatic ecosystem because of their extremely large numbers.

Q 31. What is common in Eukaryotic Red algae and Blue Green algae?
Ans. They do not have flagellated cells.

Q 32. What is sporangia?
Ans. During unfavorable condition, slime mold forms resistant haploid spore by meiosis with in stalked structure called sporangia.

Q 33. Write two characteristics of slime molds.
Ans. Characteristics of slime molds.
  1. The feeding stage of a slime mold is a multinucleate mass of cytoplasm.
  2. The plasmodium streams over damp, decaying logs and leaf litter. It often forms a network of channels that covers a large surface area.
Q 34. Write two differences between algae and plants.
Ans. Algae:
  1. Sex organs are unicellular.
  2. The parent body does not protect the zygote.
Plants:
  1. A plant zygote grows into a multicellular embryo.
  2. Zygote is protected by parental tissue.
Q 35. Write two characteristics of Oomycotes.
Ans. Characteristics of Oomycotes.
  1. Their cell walls contain cellulose, not chitin.
  2. Their hyphae are aseptate (without cross walls).
Q 36. How are protists important to humans? What is their ecological importance?

Ans. Importance of Protists:

1. Disease:

  • The intestinal parasite, Entamoeba Histolytica that causes amoebic dysentery, germinates from resistant cysts with the digestive tracts of their mammalian hosts including humans.
  • Trypansoma is a human parasite causing African sleeping sickness. It is transmitted by the bite of infected tsetse fly.
  • Some Apicomplexans such as Plasmodium cause serious diseases such as malaria in humans.
  • Phytophthora Infestans have played infamous roles in human history as they were the cause of Irish potato famine of the 19th century. It causes a disease commonly known as late blight of potatoes. Because of several rainy, cool summers in Ireland in the 1840's, the water mold multiplied unchecked, causing potato tubers to rot in the fields. Since potatoes were the staple of Irish peasant's diet, many people (250,000 to more than 1 million) starved to death. The famine prompted a mass migration out of Ireland to such countries as the United States.

2. Chalk Formation:

  • Dead foraminiferans sink to the bottom of the oceans where their shells form a grey mud that is gradually transformed into chalk. Foraminiferans of the past have created vast limestone deposits.

3. As Food:

  • Some algae such as kelps are edible and may be used to overcome shortage of food in the world.
  • Larvae of some aquatic insects feed on aquatic protozoans. While these larvae are taken as food by clam, prawn and young fishes which are the ultimate source of food of man.

4. Useful Substances:

  • Marine algae are also source of many useful substance like algin, agar, carrageenan and antiseptics.

5. Produces:

  • Algae are major producers of the aquatic ecosystem, thus they play a basic role in food chains, providing food and oxygen to other organisms.
  • Ecologically, diatoms and dinoflagellates are the most important groups of producers in marine ecosystem.

6. Symbiotic Organism:

  • Trichonymophas are complex, specialized flagellates with many flagella which lives as symbionts in the guts of termites and help in the digestion of dry wood.

7. Helpful in the Study of Biological Processes:

  • The plasmodial slime mod Physarum Polycephalum is a model organisms that has been used to study many fundamental biological processes, such as growth and differentiation, cytoplasmic streaming, and the function of cytoskeleton.

8. Helpful in Sanitation:

  • Some protozoans play an important role in the sanitary betterment and improvement of the modern civilization in keeping water safe for drinking purpose. The protozoans living in polluted water feed upon waste organic substances and thus purify it. Some bacteria feed on the bacteria and purify the water indirectly.

9. Building Coral Reefs:

  • Some red algae incorporate calcium carbonate in their cell walls from the ocean and take part in building coral reefs along with coral animals.

Q 37. What are three major groups of protists?
Ans. Major groups of protists:
  • Protozoa                                        Animal-like protists.
  • Algae                                             Plant-like protists.
  • Slime molds and Oomycotes        Fungi-like protists.

Q 38. Give at least two examples of each group of protists.
Ans. Examples of groups of protists:
  • Protozoa:                                         Plasmodium, Amoeba.
  • Algae:                                              Euglena, Spirogyra.
  • Slime molds and Oomycotes          Phytophthora infestans, Physarum polycephalum.

Q 39. Green algae are considered ancestral organisms of green land plants. Discuss.
Ans. Due to the presence of starch and cellulose cell wall, it is generally accepted that plants arose from ancestral green algae. Evidence from RNA sequencing also indicates that green algae and the plants from a monophyletic lineage.

Q 40. What features distinguish Oomycotes from Fungi?
Ans. Features that distinguish Oomycotes from Fungi.
  1. They are regarded as more ancient group.
  2. Their cell walls contain cellulose, not chitin.

Written By: Asad Hussain

Saturday, 14 March 2015

FSc Notes Biology Part 1 Chapter 6 Kingdom Prokaryotae (Monera)

  FSc Notes Biology Part 1 Chapter 6 Kingdom Prokaryotae (Monera)

Q 1. Differentiate between eubacteria and archacobacteria.
Ans. Eubacteria: Eubacteria (Greek of "true bacteria") and a much smaller division. Cell wall is of peptidoglycan or murein. for e.g E.Coli.
Archacobacteria: The archacobacteria (Greek for "ancient bacteria"). Cell wall is of protein, Glycoprotein. polysaccharide. for e.g Methanogenic bacteria.

Q 2. Who was the first scientist who discovered bacteria?
Ans. A dutch scientist "Antone Van Leeuwenhoek" (1673) was the first to report th microbes such as bacteria and protozoa.

Q 3. Leeuwenhoek observed bacteria in which substances?
Ans. He firstly observed small creatures in rainwater, then confirmed these in saliva, vinegar, infusions and other substances.

Q 4. Who formulated the germ theory of disease?
Ans. Robert Koch formulated the "germ theory of disease".

Q 5. Give the postulates of germ theory of disease.
Ans. The postulates of germ theory of disease are:
  1. A specific organism can always be found in association with a given disease.
  2. The organism can be isolated and grown in pure culture in laboratory.
  3. The pure culture will produce the disease when inoculated into susceptible animal.
  4. It is possible to recover the organism in pure culture from experimentally infected animals.

Q 6. What is flagella? What are the important functions performed by flagella?
Ans. Flagella: These are extremely thin, hair like appendages. They come out through cell wall and originate from basal body, structure just beneath the cell membrane in the cytoplasm. They are made up of protein flagellin.
Functions: Primary function of flagella is to help in motility. With the help of flagella, flagellate bacteria can also detect and move in response to chemical signals which is a type of behavior called as chemotaxis.

Q 7. Give classification on the basis of presence of flagella.
Ans. On basis of presence of flagella, pattern pf attachment of flagella and the number of flagella present bacteria are classified into different taxonomic groups:
Atrichous:
Atrichous means bacteria are without any flagella.
Monotrichous:
When single polar flagellum is present then condition is known as monotrichous.
Lophotrichous:
If tuft of flagella is present only at one pole of bacteria then these are lophotrichous flagella.
Amphitrichous:
Amphitrichous is a condition when tuft of flagella at each of two poles is present.
Peritrichous:
In peritrichous form, flagella surround the whole cell.

Q 8. What is pilli? Describe its functions.
Ans.  Pilli: These are hollow, non-helical, filamentous appendages. Pilli are smaller than flagella and are not involved in motility. True pili are only present in gram-negative bacteria. They are made up of special protein called pilin.
Function:
  1. They are primarily involved in a mating process between cells called conjugation process.
  2. Some pili function as a means of attachment of bacteria to various surfaces.
Q 9. Who developed the technique of gram stain?
Ans. Christian Gram developed the technique of gram stain.

Q 10. Define cell envelope.
Ans. Collectively complexes of layer external to the cell protoplasm are called a cell envelope.

Q 11. Differentiate between capsule and slime.
Ans.
Capsule:
Bacteria produce capsule, which is made up of repeating polysaccharides units, and of protein, or both, capsule is tightly bound to the cell. It has a thicker, gummy nature that gives sticky characters to colonies of encapsulated bacteria.
Slime:
Some bacteria are covered with loose, soluble shield of macromolecules which is called as slime capsule and slime provides greater pathogenicity to bacteria and protects them against phagocytosis.

Q 12. Describe the function of cell wall.
Ans. It is a rigid structure. It determines the shape of bacterium. Cell wall also protects the cells from osmotic lysis.

Q 13. What is protoplast?
Ans. The plasma membrane and every thing present within it is known as protoplast.

Q 14. Differentiate between Gram-positive ans Gram-negative bacteria.
Ans. Characteristics          Gram-positive                       Gram-negative
         Staining                    It is stained purple                 It is stained pink
         No. of major layers           1                                            2
         Chemical make up    Peptidoglycan Techoic acid    Lipopolysaccharides
                                         Lipotechoic acid                    Lipoproteins peptidoglycan
                                         Lipids (1 - 4%)                      Lipids (11 - 12%)
         Overall thickness      20 - 80 nm                             8 - 11 nm
         Outer membrane       No                                        Yes
         Periplasmic space      Present in some                     Present in all
         Permeability              More permeable                    Less permeable

Q 15. List function that the cell membrane performs in bacteria.
Ans. The functions performed by cell membrane in bacteria are:
  1. Cell membrane performed regulates the transport of proteins, nutrients, sugar and electrons or other metabolites.
  2. The plasma membranes of bacteria also contain enzymes for respiratory metabolism.
Q 16. What are mesosomes? And what are some of their possible functions?
Ans. Mesosomes: The cell membrane, invaginates into the cytoplasm forming structure called as mesosomes. Mesosomes are in the form of vesicles, tubules or lamellae.
Functions: Mesosomes are involved in DNA replication and cell division where as some mesosomes are also involved in export of exocellular enzyme. Respiratory enzyme are also present on the mesosomes.

Q 17. Name a bacterium that has no cell wall?
Ans. Cell wall is only absent in mycoplasma.

Q 18. What is unique about the structure of bacterial ribosomes?
Ans. Ribosomes are composed of RNA and proteins. Some may also be loosely attached to plasma membranes. They are protein factories. There are thousands of ribosomes in each healthy growing cell. They are smaller then eukaryotic ribosomes. They are 70S, small unit of 30S and large of 50S.

Q 19. What are plasmids? What is the role played by the plasmids?
Ans. Many bacteria contains plasmid in addition to chromosomes. These are the circular, double stranded DNA molecules. They are self-replicating and are not essential for bacterial growth and metabolism. They often contain drug resistant, heavy metals, disease and insect resistant genes on them, Plasmids are important vectors, in modern engineering techniques.

Q 20. Name the substances that bacteria store.
Ans. Bacteria store glycogen, sulphur, fat and phosphate.

Q 21. Name the common waste materials of bacteria.
Ans. Common waste materials are alcohol lactic acid and acetic acid.

Q 22. Differentiate between autotrophic and heterotrophic bacteria.
Ans. Autotrophic Bacteria: Some kinds of bacteria are autotrophic i.e., they can synthesize compounds which are necessary for their survival from inorganic substances.
Heterotrophic Bacteria: Most bacteria are heterotrophic i.e., they cannot synthesize their organic compounds from simple inorganic compounds.

Q 23. Differentiate between saprophytic and parasitic bacteria.
Ans.  Saprophytic Bacteria: Saprophytic bacteria get their food from dead organic matter.
Parasitic Bacteria: Parasitic bacteria for their nutrition are fully dependent on their host.

Q 24. Differentiate between photosynthetic and chemo-synthetic bacteria.
Ans.  Photosynthetic Bacteria: Photosynthetic bacteria possess chlorophyll which differs from the chlorophyll of green plants.
 Chemo-synthetic bacteria: Nitrifying bacteria are chemo-synthetic. Chemosynthetic bacteria oxidize inorganic compounds like ammonia, nitrate, nitrite, sulphur on ferrous iron and trap energy thus released for their synthetic reaction.

Q 25. Differentiate between aerobic, anaerobic, facultative and microaerophillic bacteria.
Ans. Aerobic Bacteria: Bacteria, which are able to grow in the presence of oxygen, are called aerobic bacteria. Exp: Pseudomonas is an aerobic bacterium.
Anaerobic Bacteria: Bacteria, which can grow in the absence of oxygen are known as anaerobic bacteria. Exp: Spirochete is an anaerobic bacterium.
Facultative Bacteria: Facultative bacteria grow either in the presence or absence of oxygen. Exp: E.Coli is a facultative anaerobic bacterium.
Microaerophilic Bacteria: Some bacteria require a low concentration of oxygen for growth and are known as microaerophilic. Exp: Campylobacter is a microaerophilic bacteria.

Q 26. What is the type of asexual reproduction in bacteria?
Ans. Bacteria increase in number by an asexual means of reproduction, called binary fission. In binary fission parent cell enlarges, its chromosomes duplicates, and plasma membrane pinches inward at the center of the cell. When nuclear material has been evenly distributed, the cell wall grows inward to separate cell into two.

Q 27. Define generation time.
Ans. The interval of time until the completion of next division is known as generation time.

Q 28. Describe the four distinct phases recognized in bacterial growth curve.
Ans. Four distinct phases are recognized in bacterial growth curve:
Lag Phase:
It is the phase of no growth. Bacteria prepare themselves for division.
Log Phase:
It is the phase of rapid growth. Bacteria divide at exponential rate.
Stationary Phase:
Bacterial death rate is equal to bacterial rate of reproduction and multiplication.
Death/Decline Phase:
Bacteria start dying. Here the death rate is more than reproduction rate.

Q 29. What is the ecological importance of bacteria?
Ans. Bacteria are ecologically very important. They are highly adaptable as a group and are found nearly everywhere. They are able to decompose organic matter and play a significant role in the completion of cycles of nitrogen, phosphorous, sulphur and carbon.

Q 30. How many species of bacteria cause disease in human?
Ans. Approximately 200 species are known to cause disease in humans.

Q 31. What is the sterilization process?
Ans. The process in which we use physical agents to control bacteria/microorganisms is known as sterilization process. Sterilization is deduction of all life forms.

Q 32. How dry and moist heat are effective in killing bacteria?
Ans. Both dry and moist heat are effective. Moist heat cause coagulation of proteins and kills the microbes. Dry heat cause of oxidation of chemical constituents of microbes and kills them.

Q 33. How electromagnetic radiations are effective in killing bacteria?
Ans. Certain electromagnetic radiations below 300 nm are effective in killing of microorganisms. Gamma rays are in general used for sterilization process.

Q 34. How heat sensitive compounds are sterilized?
Ans. Heat sensitive compounds like antibiotics, sears, hormones etc., can be sterilized by means of membrane filters.

Q 35. Differentiate between antiseptic, disinfectants and chemotherapeutic agents?
Ans. Antiseptics: Chemical substances used on living tissues that inhibits the growth of microorganisms are called antiseptics.

Disinfectants: The important chemical agents used for disinfection are oxidizing and reducing agents. For example halogen and phenols, hydrogen peroxide, Potassium permanganate, alcohol and formaldehyde etc. inhibit the growth of vegetative cells and are used on non-living materials.

Chemotherapeutic Agents: Chemotherapeutic agents and antibodies work with natural defense and stop the growth of bacteria and other microbes. These are sulfonamides, tetracycline, penicillin, etc. They destroy or inhibit the growth of microorganisms in living tissues.

Q 36. Differentiate between microbicidal and microbistatic effect.
Ans. Microbicidal Effect: Microbicidal effect is one that kills the microbes immediately.
Microbistatic Effect: Microbistatic effect inhibits the reproductive capacities of the cells and maintains the microbial population at constant.

Q 37. Define antibodies.
Ans. Antibodies, substances that protect the host against infection sue to subsequent exposure to the virulent organism.

Q 38. What is hydrophobia?
Ans. Hydrophobia, or rabies, a disease transmitted to people by bites from rabid dogs, cats and other animals.

Q 39. What are antibodies?
Ans. Antibodies is a Greek word ANTI, against and BIOS, life. Antibodies are the chemotherapeutic chemical substances which are used in treatment of infectious diseases. Antibodies are synthesized and secreted by certain bacteria, antinomycetes and fungi.

Q 40. How misuse of antibodies effect human health?
Ans. Misuse of antibodies such as penicillin can cause allergic reactions. Streptomycin can affect auditory nerve thus causing deafness. Tetracycline and its related compounds cause permanent discoloration of teeth in young children.

Q 41. What are cyanobacteria?
Ans. The cyanobacteria are the largest and most diverse group pf photosynthetic bacteria which was previously known as "blue green algae". Cyanobacteria are true prokaryotes.

Q 42. What is the size of cyanobacteria?
Ans. They range in diameter from about 1 - 10 micro meter.

Q 43. How cyanobacteria exist in nature?
Ans. They may be unicellular, exist as colonies of many shapes, or form filaments consisting of trichomes surrounded by mucilaginous sheath.

Q 44. Describe locomotion in cyanobacteria?
Ans. They lack flagella and often use gas vesicles to move in the water, and many filamentous species have gliding motility.

Q 45. How the photosynthetic system of cyanobacteria resembles that of eukaryote?
Ans. Their photosynthetic system closely resembles that of eukaryotes because they have chlorophyll and photo-system II. They carry out oxygenic photosynthesis i.e. they use water as an electron donor and generate oxygen during photosynthesis.

Q 46. Differentiate between phycobilins and phycobilisomes.
Ans. Phycobilins: Cyanobacteria use phycobilins as necessary pigment.
Phycobilisomes: Photosynthetic pigments and electron transport chain components are located in thylakoid membranes linked with particles called phycobilisomes.

Q 47. What is phycocyanin?
Ans. Phycocyanin is a pigment-protein complex from the light-harvesting phycobiliprotein family. It is an accessory pigment to chlorophyll..

Q 48. How cyanobacteria reproduce?
Ans. Cyanobacteria reproduce by binary fission, fragmentation.
Q 49. What is the reserve food material in cyanobacteria?
Ans. The reserve food material in cyanobacteria is glycogen.
Q 50. What is the hormogonia?
Ans. Hormogonia are motile filaments of cells formed by some cyanobacteria in the order Nostocales and Stigonematales.
Q 51. Differentiate between heterocyst and akinetes.
Ans. Heterocyst: All cells in trichome are mostly similar in structure but at slightly large, round, light yellowish thick walled cells called as heterocyst.
Akinetes: Akinetes are thick walled, enlarged vegetative cells which accumulate food and become resting cells. On arrival of favorable conditions they form normal vegetative cells.

Q 52. What is super blue green algae?
Ans. Super blue green algae are basically expensive pond scum, in which cyanobacterium is a single called organism that produces its own food through photosynthesis. It serves as a "complete whole food" which contains 60% protein with all essential amino acids in perfect balance.
Q 53. What is nucleoid?
Ans. The nuclear material or DNA in bacterial cells occupies  position near to the center of the cell. This material is a single circular and double stranded DNA molecule. It aggregates as an irregular shaped dense area called nucleoid. This chromatin body is actually an extremely long molecule of DNA that is tightly folded so as to fit inside the cell component.

Q 54. How nucleoid is visible in light microscope?
Ans. It is visible in the light microscope after staining with Feulagen stain.

Q 55. What is the size of E.Coli chromosome?
Ans. Escherichia coil closed circle chromosome measures approximately 14,000 micro meter.

Q 56. Give the economic importance of cyanobacteria. 

Ans. Advantages of Cyanobacteria:

Reclamation of Alkaline Soils:
They help in the reclamation of alkaline soils.
Fixation of Nitrogen:
They have heterocysts which are helpful in the fixation of atmospheric nitrogen.
Photosynthetic Activity:
They release oxygen gas in environment due to their photosynthetic activity.
Pollution Indicator:
Oscillation and few other cyanobacteria can be used as pollution indicator.
Symbiotic Associations:
They have symbiotic relationships with protozoa, fungi and nitrogen fixing species from associations with angiosperms. They are photosynthetic partner in most of lichen association.

Disadvantage of Cyanobacteria:

Water Blooms:
Many species form water blooms where they often impart unpleasant smell and due to large amount of suspended organic matter water becomes unfit for consumption.

Q 57. Differentiate between spores and cyst.
Ans. Spores: Spores are metabolically dormant bodies, produced at a large stage of cell growth. They are resistant to change in light, pH,high temperature, dessication. They form vegetative cells.
Cyst: Cyst are thick walled, dormant dessication resistant forms and develop during differentiation of vegetative cells which can germinate. They are not heat resistant.

Q 58. What is the difference between photosynthesis in plants and photosynthesis in bacteria?
Ans. During photosynthesis the autotrophic bacteria utilize hydrogen sulphide instead of water as in plants as a hydrogen source ans liberate sulphur instead of oxygen.
In Bacteria:
                              Light
CO2  +  2H2S ----------------> (CH2O)n  +  H2O  +  2S
                          Chlorophyll
In Plants:
                                       Light
6CO2  +  12H2O  ------------------> C6H12O6  +6O2   +  Energy
                                  Chlorophyll
Q 59. How cell wall of archeobacteria differ from other bacteria or eubacteria?
Ans. The cell walls of most bacteria have a unique macromolecules called peptidoglycan. It also contains sugar molecules, techoic acid, lipoproteins and lipopolysaccharides which are linked to peptidoglycan. Whereas cell wall of archeobacteria do not contain peptidoglycan. Their cell walls are composed of proteins, glycoproteins and polysaccharides.

Q 60. Write shapes and plane of division of different bacterium?
Ans. Shapes of Bacteria:
  • Bacteria may be Cocci (Spherical or oval in shape), Bacilli (Rod shaped) and Spiral (curved/ spring shaped).
  • Some have characteristic shapes: others are pleomorphic (variable shape)
Type                         Shape                               Division
Coccus                      Spherical                           No
Diplococcus              Two cocci                          Single plane of division
Streptococcus           Cocci in chain                    Single plane of division
Staphylococcus         Irregular arrangement         Random planes
Tetrad                       Group of four                     Two planes of division
Sarcina                      Group of eight                   Three planes of division
Bacillus                      Rod shaped                       No
Diplobacillus              Two bacilli                         Single planes of division
Streplobacillus           Chain of bacilli                   Single planes of division
Spirals                       Spirally coiled                     No
Vibrio                        Comma shaped                  No
Spirillum                     Thick, rigid spiral               No
Spirochete                  Thin, flexible spiral             No
Q 61. Write down the range of different sizes of bacterium?
Ans. Size of Bacteria:
  Type:                                             Size:
Range                                               0.1 - 600 micro meter
Mycoplasma (smallest)                      100 - 200 nano meter
Escherichia coli                                  1.1 - 1.5 micro meter (width), 2.0 - 2.6 micro meter (length)
Spirochete                                         500 micro meter
Staphylococci and Streptococci          0.75 - 1.25 micro meter

Q 62. Name a bacterium that has no cell wall.
Ans. Mycoplasmas

Q 63. A gram stain of discharge from an abscess shows cocci in irregular, grape like clusters. What is the most likely genus of this bacterium?
Ans. Streptococci

Q 64. State the diameter of an average sized coccus shaped bacterium.
Ans. An average sized coccus bacterium has a diameter from 0.5 - 1.0 micro meter.

Q 65. Name several general characteristics that could be used to define the prokaryotes.
Ans. Characteristics of Prokaryotes:
  1. Organisms possessing prokaryotic cells are called prokaryotes e.g., bacteria and cyanobacteria.
  2. They lack many of the membranes bound structures e.g., mitochondria, endoplasmic reticulum, Golgi bodies and chloroplasts etc.
  3. Nuclear membrane is absent, therefore prokaryotic cell has no distinct nucleus.
  4. Prokaryotes have small sized ribosomes i.e., 70S.
  5. Mitosis is missing and cell divides by fission.
  6. The cell wall of prokaryotic cell is composed of polysaccharide chains bounded covalently to shorter chains of amino acids forming peptidoglycan or murein. The entire cell wall is often regarded as a single huge molecule or molecule complex called murein.
Q 66. Do any other microbial groups besides bacteria have prokaryotic cell?
Ans. Yes, Cyanobacteria.
Q 67. In what habitats are bacteria found? Give some general means by which bacteria derive nutrients.
Ans. "Bacteria are ubiquitous" it means that they are found everywhere in air, land, lakes , oceans, oil deposits, still ponds, ditches, running streams, rivers, in food, rubbish and manure heaps, decaying organic matter, plant roots, body surface and cavities, as well in intestinal tracts of man and animals.

General means of nutrition in Bacteria:

Photosynthetic Autotrophs: They utilize sunlight as a source of energy. They have chlorophyll like pigment which is dispersed in the cytoplasm. During photosynthesis they use hydrogen sulphide instead of water as hydrogen source and liberate sulphur instead of oxygen.
                              Light
CO2  +  2H2S --------------> (CH2O)  +  H2O  +  2S
                          Chlorophyll
Chemosynthetic Autotrophs: They obtain energy from oxidation of some inorganic substances like ammonia, nitrogen, sulphur or iron.
Saprophytes: Saprophytic bacteria are those which get their food from dead organic matter.
Parasites: Parasitic bacteria are fully dependent in their host for their nutrition.

Q 68. List five functions that the cell membrane performs in bacteria.
Ans. Functions that cell membrane perform in bacteria:
  1. Give shape to bacteria.
  2. It protects bacteria.
  3. Homeostasis.
  4. Exocytosis.
  5. Endocytosis.
Q 69. What are mesosomes and some of their possible functions?
Ans. Mesosomes: The cell membrane invaginates into the cytoplasm forming a structure called mesosomes. Mesosomes are in the form of vesicles, tubules or lamellae, which may be central or peripheral in position. Central mesosomes are involved in DNA replication and cell division where as peripheral mesosomes are involved in export of exocellular enzyme.

Q 70. What is unique about the structure of bacterial ribosomes?
Ans. They are 70S smaller than eukaryotic ribosomes.

Written By: Asad Hussain