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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

16951.

Question : How important is the presence of air bladder in Pisces ?

Answer»

Solution :Gas BLADDER or air bladder is a gas filled sac present in fishes. It helps in MAINTAINING buoyancy. THUS it helps fishes to ASCEND or descend and stay in the water CURRENT.
Discussion
16952.

Question : What is the significance of imbibition ?

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SOLUTION :(i) During germination of SEEDS, imbibition increase the VOLUME of seed enormously and leads to bursting of the seed coat.
(II) It helps in the absorption of water by roots at the initial level.
Discussion
16953.

Question : How imbibition is importantfor plants ?

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Solution :Significanceof IMBIBITION:
(i)During germinationof seeds, imbibition increases the volume of seed enormously and LEADS to BURSTING of the seed COAT.
(ii) It help in the absorption of water by roots at the INITIAL level.
Discussion
16954.

Question : How does recombinant DNA technology help in treating haemophilia patients?

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Solution :(i) Clotting factor VIII ISOLATED from blood of normal human being was used in the treatment of Haemophilia A.
(ii) REQUIREMENT of LARGE quantities of blood for this purpose and the risk of transmission of infections diseases like AIDS is a disadvantage.
(iii) Recombinant DNA technology was used to produce Recombinant Factor VIII in the Chinese Hamster ovary and in the baby Hamster kidney cells.
(iv) Recently a cell LINE of human origin has been used to produce Human blood, clotting factor VIII for the FIRST time.
Discussion
16955.

Question : How Gram positive and Gram negative bacteria react on Gram staining process?

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Solution :The Gram positive BACTERIA RETAIN crystal voilet and appear dark violet, WHEREAS Gram negative type loose the crystal violet and when counterstained by safrenin appear red under a micorscope.
Discussion
16956.

Question : How guttation is affected by root pressure?

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Solution :(i) Guttation increases with DECREASE in root pressure DUE to low absorption of water.
(ii) When root pressure is HIGH, TRANSPIRATION is low. Herbaceous plants loose small quantity of water in the form of DROPS.
Discussion
16957.

Question :How Gibberellins are transported from its site of production?

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Solution : The TRANSPORT of gibberellins in plants is non-polar. Gibberellins are translocated through PHLOEM and also occur in XYLEM due to lateral MOVEMENT between vascular bundles.
Discussion
16958.

Question : How G_(0) cells help in Closing Technology?

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Solution :Since the DNA of cells in `G_(0)`, do not replicate. The researcher are able to fuse the donor cells from a sheep's MAMMARY glands into `G_(0)`, state by culturing in the nutrient free state. The `G_(0)`, donor NUCLEUS SYNCHRONISED with cytoplasm of the recipient egg, which developed into the clone dolly.
Discussion
16959.

Question : How far does Selaginella one of the few living members of Lycopodiales (pteridophytes) fall short of seed habit ?

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Solution :•Seed Habit : DIFFERENT forms of microspores and megaspores and dependency on PARENT sporophyte for nutrition are some of the characteristics of selaginella which is necessary for seed formation fuitially.
•In selaginella, evoulation of heterospories and seed form and following characteristics are its evidence :
(i) Each sporophyte maintains only one active MEGASPORE.
(ii) Development of protective layer and nutritive tissue TAPETUM is present.
(III) Development of Embryo sac in sporangia.
(iv) Maintenance and germination of Megaspore in Megasporangia.
(v) To absorb pollengrain transformation at far end of megasporangium.
(vi) Siphonogamy and Pollination
(vii) Embryo development stops for short period (Dormancy Period)
Discussion
16960.

Question : How fats and protein enter the krebs cycle?

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Solution :When fats are respiratory substrate they are first broken down into glycerol and FATTY acid. Glycerol is converted into DHAP and acetyl CoA. This acetyl CoA enter into the Krebs CYCLE. When proteins are the respiratory sustrate they are degraded into amino acids by proteases. The amino acids after eamination enter into the Krebs cycle through PYRUVIC acid or acetyl CoA and it depends UPON the structure.
Discussion
16961.

Question : How ferment and enzymes differ?

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Solution :Ferment term was coined by Louis PASTER and enzyme term was GIVEN by BUCHNER. There is no basic difference betweenthe TWO TERMS.
Discussion
16962.

Question : How DPD differsin various conditions of a cell ?

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SOLUTION :`*` DPD innormalcell : DPD `=` OP - TP.
`*` DPD in fully TURGID cell : Osmotic is always EQUAL to turgor pressure in a fully turgid cell.
`* OP = TP` or `OP-TP=0`. Hence DPDof fully turgid cell is ZERO.
`*` DPD in flaccid cell : If the cell is in flaccid condition there is no turgorpressure or `TP=0`. Hence `DPD=OP`.
Discussion
16963.

Question : How does thymus gland play a dual role?

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Solution :Thymus gland is partially an endocrine and partially a lymphoid ARGAN
2. It secretes four HORMONES such as thymulin THYMOSIN , thymopoitin and tymic huoral factor (THF)
3. The PRIMARY function of thymus is the production of immuno competent 'T' LYMPHOCYTES which provides cell mediated immunity
Discussion
16964.

Question : How does the trees increase their girth ?

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Solution :In PLANTS, the increase in the thickness (GIRTH) of stem and root is by MEANS of SECONDARY GROWTH or longitudinal growth.
Discussion
16965.

Question : How does the segmentation of an annelid worm differ from the repeating units of the body of a tapeworm ?

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Solution :ANNELIDS are metamerically segmented organisms, the METAMERES are marked externally by grooves and INTERNALLY by SEPTA. However, tapeworms exhibit pseudo SEGMENTATION.
Discussion
16966.

Question : How does the placement of xylem and phloem differ in monocot and dicot roots?

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Solution :MONOCOT roots have xylem extending as rods AROUND the pith while dicot root has xylem forming a SOLID cylinder at the centre.
Discussion
16967.

Question : How does the pairs of homologous chromosomes appear during zygotene phase ?

Answer»

UNIVALENT
TRIVALENT
TETRAVALENT
BIVALENT

ANSWER :D
Discussion
16968.

Question : How does the male frog attracts the female for mating?

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Solution :Male frog has a pair of vocal sacs and a nuptial pad on the ventral side of the FIRST digit of each forelimb. Vocal sacs assist in amplifying the CROAKING SOUND of frog. It makes a characteristic sound and attracts the FEMALE.
Discussion
16969.

Question : How does the eye regulate the amount of light that falls on the retina

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SOLUTION :By controlling the APERTURE of pupil, the EYE regulates the AMOUNT of light FALLING on retina.
Discussion
16970.

Question : Describe fibrous root system.

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Solution :Most of the monocots the primary root of the seedling is SHORT lived and LATERAL roots arise from various regions of the PLANT body. These are bunch of thread-like roots equal in size which are collectively called fibrous root SYSTEM generally FOUND in grasses. Example: Oryza sativa.
Discussion
16971.

Question : How does the cell wall of a bacteria differentiatesfrom a plant cell wall?

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Solution :Bacterial cell wall has contain polysaccharide. with amino and MUREIN is the MAIN COMPOUND whereas in plant cell wall cellulose is the main COMPONENT Hemicellulose and pectin also present.
Discussion
16972.

Question : How does the bacterial flagellum differ from that of a eukaryote?

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SOLUTION :BACTERIAL flagellum is monofibrillar and is formed of flagellin PROTEIN, while eukaryotic flagellum is formed of 11 MICROTUBULES of tubulin protein
Discussion
16973.

Question : How does temperature offers the activity of enzyme ?

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SOLUTION :Enzymes BECOMES temporarily inactive at lower TEMPERATURE and its activity is destroyed at high temperature .
Discussion
16974.

Question : How does snow appear to be red in colour ?

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Solution :Chlamydomonas NIVALIS grow in snow COVERED MOUNTAINS and IMPART red colour to the snow (Red snow) .
Discussion
16975.

Question : How does serum differ from blood plasma ?

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SOLUTION :Serum is BLOOD plasma minus blood CLOTTING proteins like prothrombin and FIBRINOGEN.
Discussion
16976.

Question :How does rigor mortis happen?

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Solution :After the death of an individual, the membrane of muscle cells become more permeable to CALCIUM ions. This happens due to partial contraction of skeletal muscles. The CONTRACTED muscles are UNABLE to relax. This condition is known as rigor MORTIS.
Discussion
16977.

Question : How does regulation of cardiac activity done ?

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Solution :The regulation of cardiac activity is under the control of nerves control and endocrine control.
Normal activities of the heart are regulated intrinsically i.e auto regulated by specialised muscles (nodal tissue).
Nodal tissue possesses qualities of both muscles and nerves. So heart is CALLED myogenic.
A special neutral centre in the medulla OBLONGATA can moderate the cardiac function through autonomic nervous system (ANS).
Neural signals through the sympathetic nerves (part of ANS) can increase the rate of geart beat, the strength of ventricular contraction and THEREBY the cardiac output.
On the order hand, parasympathic neural signals decrease the rate of heart best, speed of CONDUCTION of potential action and thereby the cardiac output.
Adrenal MEDULLARY hormones can also increase the cardiac output.
Discussion
16978.

Question : How does recycling help reduce pollution?

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Solution :Recycling is one of the techniques in waste management. For some other purpose recycling is the process of converting waste materials into new materials and objects.
(i) As it saves energy, it also prevents the emission of many greenhouse gases which helps to TACKLE CLIMATE.
(ii) It reduces the energy required in disposing waste.
(iii) Using recovered material generates less solid waste.
(iv) It reduces all kinds of pollution caused by EXTRACTION and PROCESSING of new raw materials wherein recycled materials can be substituted. i.e. It can prevent the waste of potentially useful material.
(v) It also has a positive economic impact on the users. REFUSE, Reduce, Reuse and Recycle mantra is the best available remedy for plastic waste pollution.
Discussion
16979.

Question : How does pruning help in making the hdge dense?

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it INDUCES the differentiation of NEW shoots from the rootstock
it frees AXILLARY BUDS from apical dominance
it PROMOTES adventitious root growth
it promotes the growth of apiccal buds

Answer :B
Discussion
16980.

Question : How does progressive metamorphosis differ from retrogressive metamorphosis?

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Solution :In PROGRESSIVE metamorphosis (e.g., FROG), a YOUNG changes into an advanced adult, while in retrogressive metamorphosis (e.g., Herdmania), an advanced larva changes into degenerata adult by LOSS of organs.
Discussion
16981.

Question : How does pepsinogen change into its active form?

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Solution :HCL released from the oxyntic cells of gastric GLANDS activates pepsinogen to PEPSIN.
Discussion
16982.

Question : How does nitrogen fixation occurs non-biologically ?

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SOLUTION :Non - BIOLOGICAL NITROGEN fixation :
`**` Nitrogen fixation by chemical process in industry.
`**` Natural electrical DISCHARGE during lightening fixes atmospheric nitrogen.
Discussion
16983.

Question : How does most of the water moves within the root ?

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Solution :Most of the water is transported to ROOT by apoplast PATHWAY. Because cortical cells POSSESS flaccid arrangement so there is no obstruction in transport of water. It is a mass flow.
This mass flow OCCURS due to cohesive FORCE and adhesive force.
More over symplast pathway is also associated in transport of water (e.g. in endodermis of root).
Discussion
16984.

Question : How do molecular markers work to unlock the evolutionary history of organisms?

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Solution :1.Molecular Taxonomy is the branch of phylogeny that analyses hereditary molecular differences, mainlyin DNA SEQUENCES, to gain information and to establish genetic relationship between the members of different taxonomic categories.
2. Different molecular markers like allozymes, mitochondrial DNA, micro satellites, RFLP (Restriction Fragment Length polymoriphic DNA), AFLPs (Amplifed Fragment Lenght Polyorphism),single nucleotide polymorphism-SNP, microchips or arrays are used in analysis.
(a) RFPL (Restriction Fragment Lenght Polymorphism):
RFLPs is molecular method of genetic analysis that ALLOWS identification taxa based on UNIQUE patterns of restriction sites in specific regions of DNA.
Amplified Fragment Length Polymorphism (AFLP):
A restriction enzyme is used to cut DNA into numerous smaller pieces, each of which terminates in a characteristic nucleotide sequence.
AFLP is largely used for POPULATION genetics studies, studies of closely related species etc.
(c) Random Amplified Poymorphic DNA (RAPD):
(i) It is a method to identify genetic markers using a randomly synthesized primer that , will anneal (recombine (DNA) in the double stranded form) to complementary regions located in various locations of isolated DNA.
(ii)If another complementary site is present on the opposing DNA strand at a distance that is not too great (within the limits of (PCR) then the reaction will amplify this region of DNA.
(iii) RAPDs like microsatellites MAY often be successfully employed in phylogenetic studies to address relationships within aspecies or between closely related species.
Discussion
16985.

Question : How does meiosis help in evolution?

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Answer :Meiosis RESULTS in the production of recombinants, and variation is ESSENTIAL for EVOLUTION.
Discussion
16986.

Question : How does leaf structure affect the rate of transpiration?

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Solution :1. Some anatomical features of leaves like sunken stomata the presence of hairs cuticle the presence of hydrophilic substances like gum, mucilage help to reduce the rate of transpiration.
2. In xerophytes the structural modifications are remarkable. To avoid transpiration as in Opuntia the stem is flattened to LOOK like leaves called phylloclade.
3. Cladode or cladophyll in Asparagus is a modified stem capable of limited growth looking like leaves.
4. In some plants the PETIOLES are flattened and widened to become phyllodes example Acacia melanoxylon.
Discussion
16987.

Question : How does Hardy-Weinberg's expression (p^(2)+2pq+q^(2)=1) explain that genetic equilibrium is maintained in population ? List any four factors that can disturb the genetic equilibrium.

Answer»

Solution :(i) Hardy of UK and Weinberg of Germany stated that the allete frequencies in a population are stable and are constant from generation to generation in the absence of gene flow, GENETIC drift, mutation, RECOMBINATION and natural selection.
(ii) Evolution is a change in the allele frequencies in a population over time. Hence population in Hardy Weinberg is not evolving.
(iii) A large population of beetles, appear in two colours dark grey (black) and light grey, and their colour is determined by .A. gene. .A A. and .A a. beetles are dark grey and .a a. beetles are light grey.
(iv) .A. allele has frequency (p) of 0.3 and .a. allele has frequency (q) of 0.7. Then p+q=1.
(v) If a population is in Hardy Weinberg equilibrium, the genotype frequency can be estimated by Hardy Weinberg equiation.
`(p+q)^(2) =p^(2)+2pq+q^(2)`
`p^(2)` =frequency of AA
2pq = frequency of aa
`q^(2)` = frequency of aa
p=0.3, q=0.7 then,
`p^(2)=(0.3)^(2) (0.7) =0.42=42 % A a`
`q^(2) =(0.7)^(2) 0.49 =49% aa`
Hence the beetle population appears to be in Hardy- Weinberg equilibrium.
(vi) Hardy Weinberg.s assumptions include No mutation- No new alleles are generated by mution nor the genes get duplicated or deleted. Random mating - EVERY ORGANISM GETS a chance to mate and the mating is random with each other with no preferences for a particular genotype.
No gene flow - Neither individuals nor their gemetes enter (immigration) or exit (emigration) the population.
Very large population size - The population should be infinite in size.
No matural selection - All alleles are fit to survive and reproduce.
If any one of these assumptions were not met, the population will not be in Hardy- Weinberg equilibrium.
Discussion
16988.

Question : How does gall stones are formed ?

Answer»

Solution :Any ALTERATION in the composition of the BILE can cause the formation of stones in the gall BLADDER. The stones are mostly formed of CRYSTALLIZED cholesterol in the bile. The gall stone causes obstruction in the cystic duct, hepatic duct and also hepato-pancreatic duct causing pain, jaundice and PANCREATITIS.
Discussion
16989.

Question : How does gaseous exchange take place in the alveoli?

Answer»

Solution :The PRIMARY site for the exchange of gases is the alveoli. The UPTAKE of `O_(2)` and the release of `CO_(2)` occur between the blood and tissues by simple diffusion driven by partial pressure gradient of `O_(2)` and `CO_(2)` . Partial pressure is the pressure contributed by an individual gas in a mixture of gases . It is represented as `pO_(2)` for oxygen and `pCO_(2)` for carbon - dioxide . Due to pressure gradients , `O_(2)` from the alveoli enters into the blood and REACHES the tissues . `CO_(2)` enters into the blood from the tissues and reaches alveoli for ELIMINATION . As the solubility of `CO_(2)` is 20-25 times higher than that of `O_(2)` , the partial pressure of `CO_(2)` is much higher than that of `O_(2)` .
Discussion
16990.

Question : How does food move along the human gut? What is this process called?

Answer»

SOLUTION :Food bolus moves BACKWARD in human gut by INVOLUNTARY contraction and relaxation of smooth muscles of intestinal WALL. It is called peristalsis. It also mechanically churns the food and mixes the food and enzymes.
Discussion
16991.

Question : How does forest conservation help to reduce air pollution?

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Solution :(i) The alteration or CHANGES in the composition of the earth.s atmosphere by natural or human activities is called air POLLUTION.
(ii) Increase in carbon dioxide concentration of air is also a form of air pollution. The normal `CO_(2)` concentration in the atmosphere is only about 0.03%. DEFORESTATION is one of the MAJOR contributions for increase in carbon dioxide of the air. Forests act as carbon sink by utilising the atmospheric carbon dioxide for photosynthesis.
(iii) When forests are cut down, the concentration of the atmosphere increases. This leads to global warming or green HOUSE effect which is an effect of air pollution.
(iv) Thus by forest conservation, we can reduce the carbon foot print by increased trapping of atmospheric `CO_(2)` and thereby reducing global warming. This leads to reduced levels of air pollution.
Discussion
16992.

Question : How does fertilization occur in Gymnosperms ?

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SOLUTION :Fertilization is of siphonogamoustype, i.e., the male gametes are carried to the archegonia through POLLEN TUBE in gymnosperms.
Discussion
16993.

Question :Howdoesfaetalhaemoglobinensuresurvivalof foetus insidethe mother'sbody ?

Answer»

Solution :Foetalhaemoglobinhas higher AFFINITY for oxygenthan the MOTHER 'shaemoglobin. Thisenablesthe faetus TOPICK upoxygen at `PO_(2)` lowenough to causethe mothe'shaemoglobin to RELEASE oxygen.
Discussion
16994.

Question : How does facilitated diffusion differ from simple diffusion?

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Solution :Facilitated diffusion occurs in the PRESENCE of CARRIER MOLECULES so is faster than SIMPLE diffusion.
Discussion
16995.

Question : How does exchangeof gases occurs at lung surface .

Answer»

SOLUTION :At the lung surface , OXYGEN diffuses from alveolar air `(P_(o_(2)) = 104` mmHg) intoblood of pulmonaryarterial CAPILLARY`(P_(o_(2)) = 40` mm Hg), While carbon dioxidediffuse from arterial capillary blood (`P_(CO_(2))` = 46 mm Hg) to alveolarair(`P_(CO_(2))` = 40 mm Hg).
Discussion
16996.

Question :How does cytokinesis in plant cells differ from that in animal cells?

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Solution :Due to presence of cell WALL cytoplasmic division differs greatly in plant cell from animal cell.
Instead of producing centracted ring, plant cells produce cell plate in the middle of cell.
Golgi bodies release vesicles having material of cell wall. It produces cell plate on equatorial pole.
In plant cells cytoplasmic division starts from centre and ATTACH to cell wall located INITIALLY towards periphery.
Discussion
16997.

Question : How does cytokineiss take place in plant and animal cells ?

Answer»

SOLUTION :By cell PLATE METHOD in plant cell and by constriction in animal cells.
Discussion
16998.

Question : How does cladistics classify organisms?

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SOLUTION :Represent diagrammatically
1. Monophyletic group. Taxa comprising all the DESCENDANTS of a COMMON ancestor.

2. Paraphyletic group- Taxon that includts an ancestor but not all of the descendants of that ancestor.
3. Polyphyletic group: Taxa that includes members from two DIFFERENT lineages.
Discussion
16999.

Question : How doescockroach survive withouta head ?

Answer»

SOLUTION :A cockroach can livefor a weekwithout its head . Dueto theiripencirculatory system , and the factthat theybreathe through little holes on each of THEIRBODY segments , sincethey are not dependent on the mouthor head to BREATHE . The cockroach DIES laterdueto starvation .
Discussion
17000.

Question : How does chemical processes occur ? Which kind of changes are observed in it ?

Answer»

Solution :Chemical COMPOUNDS undergo two types of changes :
(1) Physical change : Change in shape without breaking of bonds.
In another type of physical change there is a change in a state of matter e.g. ice molts into water or water becomes a vapour. These are physical processes.
(2) Chemical change : When bonds are broken and new bonds are formed during transformation, is called a chemical reaction.
e.g. `Ba(OH)_2 + H_2SO_4 toBaSO_4 + 2H_2O`
Above mentioned reaction is inorganic chemical reaction.
Hydrolysis of starch into glucose is an organic chemical reaction.
RATE of a physical or chemical process refers to the amount of product formed per unit time.
Rate `=(deltap)/(deltat)`
Rate can ALSO be called velocity if the direction is specified.
Rates of physical and chemical processes are influenced by temperature
RULE of thumb is that the rate doubles or decreases by half every 10°C change in either direction.
Catalysed reactions proceed at rates much higher than uncatalysed ones.
e.g. `underset("carbon dioxide")(CO_(2)) + underset("water")(H_(2)O) overset("Carbonic anhydrase") In the absence of any enzyme this reaction is very slow, with about 200 molecules of `H_2CO_3` being formed in an hour. However, in the presence of carbonic anhydrase enzyme, 6 million molecules of `H_2CO_3` formed every second.
The enzyme has accelerated the reaction rate by about 10 million times.
There are thousands of types of enzymes each catalysing a unique chemical or metabolic reaction. A multistep chemical reaction, when each of the steps is catalysed by the same enzyme complex or different enzymes, is called a metabolic pathway.
Glucose `to 2` Pyruvic acid
`C_(6)H_(12)O_(6) to 2C_(3)H_(4)O_(3) + 2H_(2)O`
This is actually metabolic pathway in which glucose becomes pyruvic acid through 10 different enzyme catalysed metabolic reactions. When you study respiration in Chapter 14 you will study these reactions.
This very metabolic pathway with one or two additional reactions gives rise to a variety of metabolic end products.
In skeletal muscle, under anaerobic conditions, pyruvic acid is formed. In yeast, during FERMENTATION, the same pathway leads to the production of ethanol in different conditions different products are formed.
Discussion