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GCET Mock - 5 (Bio)

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Which of the following statements is true about complementary DNA (cDNA)?

  1. It is the “other strand” of a DNA.

  2. It does not need any template for its synthesis.

  3. It is the base sequence of the vector DNA.

  4. It is produced by reverse transcription.


Correct Option: D
Explanation:

Complementary DNA (cDNA) is produced by reverse transcription.

Which of the following is an example of Monoecious plant?

  1. Date palm

  2. Tomato

  3. Rose

  4. Cucumber


Correct Option: D
Explanation:

Cucumber is an example of Monoecious plant. Cucumber is an example of Monoecious plant.

Assertion (A) : The rate of DNA replication is much faster in E. coli than in eukaryotes.

Reason (R) : The length of Okazaki fragments that result from DNA Polymerase I activity are much shorter in prokaryotes than in eukaryotes.

  1. Both A and R are individually true and R is the correct explanation of A.

  2. Both A and R are individually true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.


Correct Option: B
Explanation:

It is true that the rate of DNA replication is much faster in E. coli than in eukaryotes. It is also true that the length of Okazaki fragments that result from DNA Polymerase I activity are much shorter in prokaryotes than in eukaryotes. But R is not the correct explanation of A. 

Chemically the female sex hormones estradiol and progesterone are ____________.

  1. proteins

  2. carbohydrates

  3. aminoacids

  4. steroids

  5. none of these


Correct Option: D
Explanation:

Chemically the female sex hormones estradiol and progesterone are steroids.

Before ejaculation in mammals, the spermatozoa are stored in which of the following?

  1. Testis

  2. Vas deferens

  3. Epididymis

  4. Seminal vesicle

  5. Cowper's glands


Correct Option: C
Explanation:

Before ejaculation in mammals the spermatozoa are stored in epididymis.

Which of the following is not a whorl of flower?

  1. Calyx

  2. Androecium

  3. Corolla

  4. Scion


Correct Option: D
Explanation:

Scion is a cutting of young stem used for grafting.

Which of the following structures is not present in Androecium?

  1. Filament

  2. Stamen

  3. Anther

  4. Micropyle


Correct Option: D
Explanation:

Micropyle is an opening at the lower end of the ovule.

Match the following items given

Column-I Column-II
1. Parasitism A. Advantageous for both A and B
2. Commensalism B. Harmful for both A and B
3. Predation C. Advantageous for A but harmful for B
4. Mutualism D. Advantageous for A but inhibitory for B
5. Competition E. Advantageous for A and has no effects on B
  1. 1 - A, 2 - B, 3 - C, 4 - D, 5 - E

  2. 1 - D, 2 - B, 3 - A, 4 - D, 5 - C

  3. 1 - C, 2 - E, 3 - D, 4 - A, 5 - B

  4. 1 - B, 2 - C, 3 - A, 4 - E, 5 - D

  5. 1 - E, 2 - A, 3 - B, 4 - C, 5 - D


Correct Option: C
Explanation:

Parasitism is more difficult to describe. However a parasite defines an organism which is in continues intimate association with other organism called host upon which it is metabolically dependent directly or indirectly. Commensalism considered as a loose association in which two animals of different species lived together without being either metabolically dependent on one or both organisms may receive some benefits from the association. Predation is a type of symbiotic association between two different organisms where one acts as predator that seizes & feeds on other organism which acts as prey. Mutualism is an association between two organisms of two different species where both organisms are benefited from the relationship. Competition is an association between organisms for resources like food, shelter and so on where both may causes harm to each other.

Which of the following statements is/are correct?

  1. Green plants or primary consumers make up the first trophic level of the food chain.
  2. At the fourth level of the food chain are the decomposers, that is the organisms that break down dead or dying matter into nutrients.
  1. Only 1

  2. Only 2

  3. Both of these

  4. Neither of these


Correct Option: D
Explanation:

The trophic level of an organism is the position it occupies in the food chain. Green plants make up the first trophic level and are known as primary producers. Plants are able to convert energy from the sun into food through a process known as photosynthesis. In the second trophic level, the primary consumers - known as herbivores - are animals and insects that obtain their energy solely by eating the green plants. The third trophic level is composed of the secondary consumers, flesh-eating or carnivorous animals that feed on herbivores. At the fourth level are the tertiary consumers, carnivores that feed on other carnivores. Finally, the fifth trophic level consists of the decomposers, organisms such as fungi and bacteria that break down dead or dying matter into nutrients that can be used again.

Which of the following vegetative propagules in angiosperms is incorrectly matched?

  1. Eyes : potato

  2. Rhizome : ginger

  3. Bulbil : Agave

  4. Offset : banana


Correct Option: D
Explanation:

Offset of water hyacinth, Rhizome of ginger and banana. Offset of water hyacinth, Rhizome of ginger and banana.

Genes for antibiotic resistance are located in the

  1. chromosome

  2. plasmid

  3. cell wall

  4. nucleus


Correct Option: B
Explanation:

Genes for antibiotic resistance are located in the plasmid.

The vector for transfer of DNA to plants is

  1. T1 plasmid

  2. pBR322

  3. YAC

  4. M13


Correct Option: A
Explanation:

Correct. T1 plasmid is used as cloning vector,it is used to deliver to genes of interest into plants. IT is produced by Agrobacterium Tumifaciens.

With which of the following did the linking of antibiotic resistance gene with the plasmid vector became possible?

  1. Exonucleases

  2. DNA ligase

  3. Endouncleases

  4. DNA polymerase


Correct Option: B
Explanation:

Restriction endonucleases act as molecular scissors but DNA ligases help in linking foreign DNA to plasmid.

The enzyme which is highly useful in polymerase chain reaction (PCR) is

  1. RNA polymerase

  2. DNA polymerase

  3. restriction endonuclease

  4. reverse transcriptase


Correct Option: B
Explanation:

DNA polymerase is used in PCR. It is used to produce double stranded DNA from single stranded DNA.

Main objective of production/use of herbicide resistant GM crops is to

  1. reduce herbicide accumulation in food articles for health safety

  2. eliminate weeds from the field without the use of manual labour

  3. eliminate weeds from the field without the use of herbicides

  4. encourage eco-friendly herbicides


Correct Option: B
Explanation:

Herbicide resistant GM crops will remain unaffected to the herbicide used, therefore the weeds will be killed.

Golden rice is rich in

  1. vitamin A

  2. vitamin B

  3. vitamin C

  4. vitamin D


Correct Option: A
Explanation:

It is a variety of Oryza sativa  produced by genetic engineering to synthesize beta carotene, a precursor of vitamin A. This option is correct.

Amino acid sequence in protein synthesis is decided by the sequence of

  1. tRNA

  2. mRNA

  3. cDNA

  4. rRNA


Correct Option: B
Explanation:

Amino acid sequence in protein synthesis is decided by the sequence of mRNA. 

What is antisense technology?

  1. RNA polymerase producing DNA.

  2. A cell displaying a foreign antigen used for synthesis of antibodies.

  3. Production of somaclonal variants in tissue cultures.

  4. When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene


Correct Option: D
Explanation:

Antisense technology is the translational control of protein synthesis which involves use of RNA which is complementry to m-RNA, inhibiting the expression of genes.

An active immune system recruits many cells to the affected tissue to kill off the disease-causing microbes. What is this recruitment process known as?

  1. Inflammation

  2. Infection

  3. Immunization

  4. Vaccination


Correct Option: A
Explanation:

This recruitment process is known as inflammation.

Linkage between a pair of genes is indicated when their recombination frequency is

  1. less than 25%

  2. less than 50%

  3. less than 60%

  4. more than 60%


Correct Option: C
Explanation:

Less than 60%

What is Darwin's explanation of the way in which evolution occurs?

  1. God determines which species should evolve.

  2. Adaptations enable one species to produce more offspring by natural selection.

  3. Certain species undergo mutations.

  4. The traits used most often persist longer.


Correct Option: B
Explanation:

Darwin stated that adaptations enable one species to produce more offspring by natural selection. 

Which of the following are the examples of analogous organs?

  1. Wings of bird and bat

  2. Forelimbs of man and bat

  3. Forelimbs of man and bird

  4. Forelimbs of frog and lizard


Correct Option: A
Explanation:

Analogous organs are the organs which have the same function but are of different origin. Wings of birds and bats are analogous organs.

HIV that causes AIDS, first starts destroying which of the following?

  1. B-lymphocytes

  2. Leucocytes

  3. Thrombocytes

  4. Helper T-lymphocytes


Correct Option: D
Explanation:

 HIV that causes AIDS, first starts destroying helper T-lymphocytes.

All of the following are disease-causing pathogens in plants, except

  1. bacteria

  2. viruses

  3. fungi

  4. algae


Correct Option: D
Explanation:

Algae do not cause diseases in plants.

Cross breeding is the crossing of two different pure breeds or populations, as a result of mixing the genetic contributions of its parents the offspring exhibit the characters of both the parents. What is this condition referred to as?

  1. Co-dominace

  2. Dominant epistasis

  3. Heterosis

  4. Duplicate Dominant Interaction


Correct Option: C
Explanation:

Heterosis is the improved or increased function of any biological quality in a hybrid offspring. An offspring exhibits heterosis if its traits are enhanced as a result of mixing the genetic contributions of its parents.

Cells of which of the following tissues possess totipotency?

  1. Meristem

  2. Cambium

  3. Phloem

  4. Cork


Correct Option: A
Explanation:

Cells of meristematic tissue are totipotent as they composed of immature and undifferentiated cells which are either in a continuous state of division or retain the power of division.

Which two plants reproduce by the means of spore?

  1. Rose and lotus

  2. Moss and ferns

  3. Mint and cacti

  4. Bryon phylum and dahlia


Correct Option: B
Explanation:

The spores are the means of reproduction in many fungi like mosses and ferns. The growth of fungus can also be observed on moist bread surface kept undisturbed for some time.

Which of the following statements is/are correct?

A. It is advantageous to use microbial enzymes in organic synthesis than mammalian enzymes. R. Microorganisms can be made available, if needed, in much higher amounts than the animals.

  1. Both A and R correct and R is the correct explanation of A.

  2. Both A and R are incorrect.

  3. A is correct and R is incorrect.

  4. Both A and R are correct and R is not the explanation of A.


Correct Option: A
Explanation:

It is advantageous to use microbial enzymes in organic synthesis than mammalian enzymes. This is because microorganisms can be made available, if needed, in much higher amounts than the animals. 

Which of the following combinations are incorrect? I. Asthma - Lung II. Influenza - Respiratory tract III. Rickets - Pancreas IV. Malaria - Brain

  1. I and II

  2. I and III

  3. II and IV

  4. III and IV


Correct Option: D
Explanation:

Rickets affects bones and malaria affects blood cells which may in turn damage spleen or liver.

Endosymbiosis is useful for

  1. only host

  2. only endosymbiont

  3. both host and endosymbiont

  4. none of these


Correct Option: C
Explanation:

Symbiosis is useful for both host and endosymbiont. 

Which fuel does not cause pollution on burning?

  1. Wood

  2. Petrol

  3. LPG

  4. Kerosene


Correct Option: C
Explanation:

LPG does not cause pollution on burning.

In maize, hybrid vigour is exploited by

  1. bombarding the protoplast with DNA

  2. crossing of two inbreed parental lines

  3. harvesting seeds from the most productive plants

  4. inducing mutations


Correct Option: B
Explanation:

In maize, hybrid vigour is exploited by crossing of two inbreed parental lines. 

High growth at the time of exponential phase of human population growth curve is due to

  1. high birth and low death rates

  2. high birth and death rates

  3. low birth and high death rates

  4. low birth and death rates


Correct Option: A
Explanation:

In S-shaped or sigmoid curve, the growth rate is very high. The birth and death rates are two major determinants of population growth. Growth rate will be high when birth rate exceeds the death rate. 

Which of the following statements is/are true regarding the food chain given below? Grass → rabbits → snakes → hawks

  1. Each predator population has a greater biomass than its prey population.

  2. Each prey population has a greater biomass than its predator population.

  3. Each population is omnivorous.

  4. Both (1) and (3) are correct.


Correct Option: B
Explanation:

Each prey population has a greater biomass than its predator population in all food chains except in pond ecosystem. 

Which of the following is an in situ method for biodiversity conservation?

  1. Zoological park

  2. Seed bank

  3. Cryopreservation

  4. National park


Correct Option: D
Explanation:

National park is an in situ method for biodiversity conservation. In situ conservation is on the site conservation method ex-situ conservation means conservation away from natural habitat.

Keystone species deserve protection because these

  1. are capable of surviving in harsh environmental conditions

  2. indicate the presence of certain minerals in the soil

  3. have become rare due to over exploitation

  4. play an important role in supporting other species


Correct Option: D
Explanation:

A keystone species is a species whose very presence contributes to a diversity of life and whose extinction would consequently lead to the extinction of other forms of life. Keystone species help to support the ecosystem (entire community of life) of which they are a part. 

Among the following environmental pollutants, which one leads to the occurrence of acid rain?

  1. Carbon dioxide

  2. Hydrogen peroxide

  3. Carbon monoxide

  4. Sulphur dioxide


Correct Option: D
Explanation:

Sulphur dioxide causes acid rain.

What is the name given to the global ecosystem?

  1. Lithosphere

  2. Biosphere

  3. Atmosphere

  4. Hydrosphere


Correct Option: B
Explanation:

The global ecosystem is known as biosphere.

Withdrawal of which of the following hormones is the immediate cause of menstruation?

  1. Estrogen

  2. FSH

  3. FSH-RH

  4. Progesterone


Correct Option: D
Explanation:

Withdrawal of progesterone leads to menstruation.

The reproduction in phanerogams occurs by

  1. flowers

  2. fruits

  3. seeds

  4. spores


Correct Option: C
Explanation:

The reproduction in phanerogams occurs by seeds. 

Match the following:

 
I II
A. Biosphere Reserve 1. Areas reserved for wildlife where it can freely use habitats and natural resources
B. Wildlife Sanctuary 2. Large areas of protected land for conservation of wildlife, plant and animal resources and traditional life of tribals living in the area
C. National Park 3. An establishment that maintains wild animals in a park to study, conserve and display
4. Areas where animals are protected from any disturbance to them and their habitat
  1. A – 2, B – 4, C – 1

  2. A – 2, B – 1, C – 3

  3. A – 3, B – 4, C – 1

  4. A – 1, B – 3, C – 2


Correct Option: A
Explanation:

Biosphere Reserve: Large areas of protected land for conservation of wildlife, plant and animal resources and traditional life of tribals living in the area.  Wildlife Sanctuary: Areas where animals are protected from any disturbance to them and their habitat. National Park: Areas reserved for wildlife where it can freely use habitats and natural resources.

Which of the following statements are correct?

I. Greenhouse gases are responsible for global warming. They should be eliminated to save the planet. II CO2 is the most dangerous of the greenhouse gases. Reduction in the release of CO2 would surely bring down the temperature. III The greenhouse effect could be traced back to the industrial revolution. But the current development and the patterns of life have enhanced their emissions. IV. Deforestation has been one of the biggest factors contributing to the emission of greenhouse gases.

  1. I and III

  2. II and III

  3. II, III and IV

  4. III and IV


Correct Option: D
Explanation:

Greenhouse gases are responsible for global warming. But they cannot be eliminated as one of them is CO2 , which is essential for plants to synthesise food. CO2 is not the most dangerous gas, it is said so just because it is present in highest concentration in the atmosphere. Otherwise, on per molecule basis, the most dangerous greenhouse gas is methane.

J-shaped chromosomes are called

  1. acrocentric

  2. telocentric

  3. metacentric

  4. sub-metacentric


Correct Option: A
Explanation:

J-shaped chromosomes are called acrocentric. 

How many polar bodies are formed at the end of 1 cycle of oogenesis?

  1. 1

  2. 2

  3. 3

  4. 4

  5. 5


Correct Option: C
Explanation:

2 polar bodies are formed and the 2nd polar body divides again to form 2 more polar bodies , hence in the end there are 3 polar bodies .

Which phase of menstrual cycle is the longest phase?

  1. Menstrual Phase

  2. Follicular Phase

  3. Proliferative Phase

  4. All are equal

  5. None of the above


Correct Option: B
Explanation:

It is about 14 days long .

In angiosperms, there is double fertilization, which means fusion of _____.

  1. egg nucleus with two male nuclei

  2. two egg nuclei by two male nuclei

  3. two egg nuclei by a single male nucleus

  4. one male nucleus with egg nucleus and other male nucleus with polar nuclei


Correct Option: D
Explanation:

Double fertilization means fusion of one male nucleus with egg nucleus and other male nucleus with polar nuclei. 

Placenta in mammalian embryo is formed by

  1. amnion

  2. yolk sac

  3. chorion

  4. all of these


Correct Option: C
Explanation:

Placenta in mammalian embryo is formed by chorion. 

Which of the following is an example of hypoploidy?

  1. Down's syndrome

  2. Patau's syndrome

  3. Edward's syndrome

  4. Turner's syndrome

  5. Klinefelter syndrome


Correct Option: D
Explanation:

Turner's syndrome, 45,X, encompasses several conditions in human females, of which monosomy X (absence of an entire sex chromosome, the Barr body) is most common. It is an example of hypoploidy.

Match the following. ||| |---|---| | List I| List II| | (a) Vulnerable species | (i) Nicobar pigeon | | (b) Rare species | (ii) Pink head duck | | (c) Endemic species | (iii) Indian wild ass | | (d) Extinct species | (iv) Blue sheep | | (e) Endangered species | (v) Horn bill |

  1. (a) – (iv), (b) – (v), (c) – (i), (d) – (ii), (e) – (iii)

  2. (a) – (v), (b) – (iv), (c) – (ii), (d) – (i), (e) – (iii)

  3. (a) – (iv), (b) – (v), (c) – (i), (d) – (iii), (e) – (ii)

  4. (a) – (iii), (b) – (iv), (c) – (ii), (d) – (i), (e) – (v)


Correct Option: A
Explanation:

  ||| |---|---| | List I| List II| |

(a) Vulnerable species
|
(iv) Blue sheep 
| |
(b) Rare species
|
(v) Horn bill 
| |
(c) Endemic species
|
(i) Nicobar pigeon
| |
(d) Extinct species
|
(ii) Pink head duck
| |
(e) Endangered species
|
(iii) Indian wild ass
|  

In angiosperms, embryosac is developed from

  1. megaspore mother cell

  2. secondary nucleus

  3. endothecium

  4. microspore mother cell


Correct Option: A
Explanation:

Megaspore mother cell undergoes meiosis. On the basis of participation of megaspore nuclei, the development of embryosac may be monosporic, bisporic of tetrasporic.

Consider the following statements: (a) Endometrium is the innermost layer of uterus which is highly vascularized and rich in glands. (b) Gametogenesis is the process of formation of gametes in sexual reproduction. (c) Golgi provide energy for the movement of sperm. Which of the above statements are correct?

  1. Only (a) and (c)

  2. Only (a) and (b)

  3. Only (b) and (c)

  4. All of the above


Correct Option: B
Explanation:

Statement (a) is correct. Endometrium is the innermost layer of uterus which is highly vascularized and rich in glands. Statement (b) is correct. Gametogenesis is the process of formation of gametes in sexual reproduction. Statement (c) is incorrect. Mitochondria provides energy for the movement of sperm.

How many parent cell divisions are necessary to produce two hundred pollen grains?

  1. 100

  2. 199

  3. 50

  4. 200


Correct Option: C
Explanation:

50 parent cell divisions are necessary to produce two hundred pollen grains. 

In which of the following techniques do eggs and sperm are collected and injected directly into the upper regions of the oviducts, where fertilization normally takes place?

  1. Gamete intrafallopian transfer (GIFT)

  2. Intracytoplasmic sperm injection (ICSI)

  3. Zygote intrafallopian transfer (ZIFT)

  4. Embryo transfer


Correct Option: A
Explanation:

In gamete intrafallopian transfer (GIFT)eggs and sperm are collected and injected directly into the upper regions of the oviducts, where fertilization normally takes place.

Which of the following hormones is secreted by sertoli cells which exerts negative feedback on the production of FSH by cells in the anterior pituitary?

  1. Testosterone

  2. Inhibin

  3. Progesterone

  4. Luteinizing hormone


Correct Option: B
Explanation:

Inhibin is secreted by sertoli cells. It exerts negative feedback on the production of FSH by cells in the anterior pituitary.

In Mirabilis jalapa, red flowering plant is crossed with white flowering plant. What will be the F2 phenotypic ratio?

  1. 1:1:1:1

  2. 3:1

  3. 1:2:1

  4. 9:3:3:1


Correct Option: B
Explanation:

In Mirabilis, red flower crossed with white flower parent, F1 is pink due to codominance of both the alleles and in F2 one red two pink and one white will be produced.

Syphilis can spread through

  1. air

  2. water

  3. sexual contact

  4. all of the above


Correct Option: C
Explanation:

Syphilis is a bacterial infection that's typically spread through sexual contact.It most commonly begins as a painless sore, usually in the area of your genitals, rectum, or mouth.The infection spreads from person to person through contact with these sores by the skin or mucous membranes.

How many gametes will be produced by a plant which is heterozygous for 3 traits assorting independently?

  1. 4 Types of gametes

  2. 6 Types of gametes

  3. 8 Types of gametes

  4. 12 Types of gametes


Correct Option: C
Explanation:

Probability of number of gametes produced is 2n. When n = 3, then 2 X 2 X 2 = 8 types of gametes. 

What is the amount of DNA of the parent cell as compared to daughter cells formed after cell division?

  1. Four times

  2. Two times

  3. Remains same

  4. One-fourth


Correct Option: B
Explanation:

During S phase, cell will undergo DNA replication.

Which of the following shows codominance pattern of inheritance?

  1. Flower colour in garden pea

  2. Flower colour in snapdragon

  3. ABO blood group

  4. Both 2 and 3


Correct Option: D
Explanation:

Snapdragon flower color: FRallele is for red flower colour and FWallele for white flower and in when both FRFW condition it will be pink due to codominance and in ABO blood group A and B alleles are codominant to each other. 

A fruit fly heterozygous for sex linked genes is mated with a normal female fruit fly. The male specified chromosome is likely to enter egg cells in the proportion of

  1. 1:1

  2. 1:2

  3. 3:1

  4. 7:1


Correct Option: A
Explanation:

A fruit fly heterozygous for sex linked genes is mated with a normal female fruit fly. The male specified chromosome is likely to enter egg cells in the proportion of 1:1. 

Semi-conservative model of DNA replication was experimentally proved by

  1. Jacob and Monad

  2. Meselson and Stahl

  3. Beadle and Tatum

  4. Watson and Crick


Correct Option: B
Explanation:

Semi-conservative model of DNA replication was experimentally proved by Meselson and Stahl.

Consider the following statements:

(1) A river with high BOD (Biological Oxygen Demand) is comparatively less polluted. (2) Eutrophication leads to the decrease in concentration of CO2 in water bodies.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2


Correct Option: D
Explanation:

Statement 1 is incorrect. BOD - Standard method for indirect measurement of the amount of organic pollution in a sample of water. Thus, high BOD means high pollution. Statement 2 is also incorrect.             Eutrophication - The process by which a water body acquires high concentration of nutrients, especially phosphates and nitrates. It promotes growth of algae and the decomposing organisms deplete the available oxygen in water. Thus, there is a decrease in concentration of oxygen and increase in concentration of carbon dioxide.

RNA retroviruses have special enzyme that

  1. transcribes viral RNA to DNA

  2. disintegrates host DNA

  3. translates host DNA

  4. polymerises host DNA


Correct Option: A
Explanation:

RNA retroviruses have special enzyme that transcribes viral RNA to DNA. 

The enzyme which helps to remove nucleotide from the end of DNA is

  1. endonuclease

  2. exonuclease

  3. DNA ligase

  4. primase


Correct Option: B
Explanation:

The enzyme which helps to remove nucleotide from the end of DNA is exonuclease.

Which type of covalent bonds link the amino acids in a protein?

  1. Peptide bonds

  2. Hydrogen bonds

  3. Ionic bonds

  4. Glycosidic bonds


Correct Option: A
Explanation:

A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O).

During protein synthesis in prokaryotes, the initiation of polypeptide chain is induced by

  1. serine

  2. lysine

  3. methionine

  4. leucine


Correct Option: C
Explanation:

In protein synthesis of prokaryotes, the initiation of polypeptide chain is always brought about by an amino acid, methionine, which is coded by AUG.

What is the mode of gene regulation in lac-operon?

  1. Induction

  2. Inhibition

  3. Repression

  4. Either 1 or 3


Correct Option: A
Explanation:

Genes required for lactose metabolism will be transcribed when inducer is present.

One turn of the helix in a B-form DNA is approximately

  1. 20 nm

  2. 0.34 nm

  3. 3.4 nm

  4. 2 nm


Correct Option: C
Explanation:

One turn of the helix in a B-form DNA is approximately 3.4 nm. 

Chromosomal theory of inheritance was based on

  1. segregation of genes

  2. diploidy and haploidy

  3. sex linkage

  4. presence of sex chromosomes


Correct Option: A
Explanation:

The behaviour of homologous chromosomes during meiosis (their segregation) and independent assortment) and their reunion in fertilisation confirmed that the genetic material occurs in the chromosomes and formed the basis of chromosomal theory of inheritance. Which is propounded independentaly by Sutton and Boveri in 1902. A karyotype composed of two identical sets of dissimilar chromosomes is called diploid set and of single set of chromosomes is called haploid set.

If the gene encoding the trp repressor is mutated, such that it can no longer bind tryptophan, then will the transcription of the trp operon occur?

  1. Yes, because the trp repressor can only bind the trp operon and block transcriptional initiation when it is bound to tryptophan.

  2. No, because this mutation does not affect the part of the repressor that can bind the operator.

  3. No, because the trp operon is repressed only when tryptophan levels are high.

  4. Yes, because the trp operon can allosterically regulate the enzymes needed to synthesize the amino acid tryptophan.


Correct Option: A
Explanation:

If the repressor can no longer bind tryptophan, then it cannot bind the operator and transcription of the trp operon will always be on, whether tryptophan levels in the cell are high or low.

Which one of the following pairs is correctly matched?

  1. Frederick Griffith – Discovered the phenomenon of transformation

  2. Linus Pauling – Isolated DNA for the first time

  3. Francis Crick – Proposed one gene-one polypeptide hypothesis

  4. George Beadle – Proposed the concept of inborn erros


Correct Option: A
Explanation:

Only option 1 gives the correct match of the scientist name with its discovery.

Mongolism is also known as

  1. Turner's syndrome

  2. Hypothalmic syndrome

  3. Klinefelter's syndrome

  4. Down's syndrome


Correct Option: D
Explanation:

Down's syndrome or mongolism or mongolian idiocy is caused by the trisomy on chromosome number 21. Thus, the egg possesses 24 chromosomes instead of 23 and the offspring has 47 chromosomes (45 + XY in male, 45 + XX in female). 

Which of the following cells are associated with immune system of human body?

  1. Neutrophils

  2. Macrophages

  3. Lymphocytes

  4. All of these


Correct Option: D
Explanation:

Neutrophils, macrophages, lymphocytes, eosinophils and basophils are the kinds of WBCs which take part in immune system. 

Identify the type of sex determination seen in humans and drosophilas.

  1. XX-XO

  2. ZZ-ZW

  3. ZZ-ZO

  4. XX-XY

  5. XX-ZW


Correct Option: D
Explanation:

In humans and drosophilas, the sex determination is of XX-XY type.

Match List I and List II and identify the correct answer.

List – I List – II
(A) Hybrid DNA (a) Vector
(B) Molecular cloning (b) Tissue culture
(C) Replicon (c) r–DNA
(D) Totipotency (d) Gene cloning
  1. (A) – (c), (B) – (d), (C) – (a), (D) – (b)

  2. (A) – (d), (B) – (c), (C) – (b), (D) – (a)

  3. (A) – (b), (B) – (d), (C) – (d), (D) – (a)

  4. (A) – (c), (B) – (a), (C) – (d), (D) – (a)


Correct Option: A
Explanation:

 

List – I| List – II| |
(A) Hybrid DNA
|
(c) r–DNA
| |
(B) Molecular cloning
|
(d)Gene cloning
| |
(C) Replicon
|
(a) Vector
| |
(D) Totipotency
|
(b) Tissue culture
|
 

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