Reproductive Health — BIOLOGY STD 12 Science — Question

1. It is difficult for DNA to pass through the membrane as

1. It is a hydrophilic molecule.
2. It is a hydrophobic molecule.
3. It is a circular molecule.
4. It changes its shape when it comes in contact with host cell.

2. What type of ions are used for DNA mediated gene transfers?

1. Divalent anions.
2. Divalent cations.
3. Monovalent cations.
4. Monovalent anions.

3. rDNA stands for,

1. reduced DNA
2. red DNA
3. recombinant DNA
4. related DNA.

4. Which of the following statements with regard to DNA is correct?

1. DNA is a positively charged molecule having two polynucleotide chains.
2. Nitrogen bases of two polynucleotide chain form complementary pairs, i.e., A opposite G and T opposite C.
3. Backbone of DNA chain is built up of alternate deoxyribose sugar and phosphate group.
4. Both (a) and (c)

5. Assertion: Competent host is essential for transformation with rDNA.

Reason: Transfer of DNA in a prokaryotic cell is called transfection.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

1. A dithecous another consists of (A) microsporangia, (B) in each lobe.

Select the option that correctly fills the blanks.

2. The given diagram shows microsporangium of a mature anther. Identify A, B and C.

3. The function of labelled part X is:

1. Dehiscence.
2. Mechanical.
3. Nutrition.
4. Protection.

4. Select the incorrect statement.

1. Microsporangium is generally surrounded by four wall layers-epidermis, endothecium, middle layers and tapetum.
2. Outer three layers perform functions of protection and dehiscence of anthers.
3. Cells of tapetum possess dense cytoplasm and generally have more than one nucleus.
4. Cells of tapetum undergo meiosis and produce microspore tetrads.

5. Which function oftapetum is correct?

1. Helps in pollen wall formation.
2. Transportation of nutrients to inner side of another.
3. Synthesis of callase enzyme for separation of microspore tetrads.
4. All of these.

1. Which of the following parts of gynoecium determines the compatible nature of pollen?

1. Stigma.
2. Style.
3. Ovary.
4. Thalamus.

2. In Triforium, which type of self-incompatibility is found?

1. Gametophytic self-incompatibility (GSI).
2. Sporophytic self-incompatibility (SSI).
3.  Both GSI and SSI.
4. None of these.

3. Select the incorrect statement.

1. In Asteraceae, incompatibility is due to the genotype of the sporophytic stigmatic tissues.
2. In members of Brassicaceae, incompatibility is due to the genotype of the pollen.
3. Nature has imposed self-incompatibility to avoid highly homozygous individuals, which have a very low survival value.
4. None of these.

4. Which of the following are examples of self incompatibility?

1. Tobacco.
2. Potato.
3. Crucifers.
4. All of these.

5. Given figures show the pollen-stigma interaction, where pollen wall proteins are released onto the pellicle of stigmatic papillae, where a recognition reaction occurs.

Which of the following statements drawn from given figures is incorrect?

1. P indicates compatible reaction in which the pollen tube penetrates the cuticle and grows down the papilla.
2. Development of callose plug between the plasma membrane and pectocellulosic layer of stigmatic papillae results in the incompatibility reaction in Q.
3. A callose plug, which appears at the tip of pollen in Q, is dissolved by callase enzyme secreted by stigma resulting in compatibility reaction.
4. Deposition of callose can be employed as a reliable bioassay to detect compatibility or incompatibility reactions of pollen and stigma.

1. The source of sample 'C' is:

1. River water.
2. Primary effluent.
3. Secondary effluent.
4. Untreated sewage water.

2. If sewage in untreated condition is disposed off in a freshwater body then.

1. BOD and dissolved oxygen both will increase.
2. BOD will increase and dissolved oxygen will decreas.
3. BOD will decrease and dissolved oxygen will increase.
4. BOD and dissolved oxygen both will decrease.

3. A large number of pathogenic microbes can be present in water sample of:

1. C
2. A
3. D
4. Both (a) and (c).

4. High value of BOD in sample O is due to:

1. High amount of organic wastes and aerobic microbes.
2. High amount of inorganic wastes and anaerobic microbes.
3. High amount of organic wastes and anaerobic microbes.
4. High amount of inorganic wastes and aerobic microbes.

5. River water is represented by the sample.

1. A
2. B
3. C
4. D

1. Agent for production of dairy products.
2. Source of industrial enzyme.
3. Indicator of water pollution.
4. Insecticide.

1. Which of the following is an example of natural Iysing activity in a human body?

1. Lysozyme present in tears dissolve the bacterial cell wall.
2. Conversion of starch to maltose in the buccal cavity
3. Absorption of digested food into the intestinal cells.
4. Conversion of protein molecules into amino acids in the stomach.

2. Which of the following depicts exonuclease activity?

4. All of these

3. Cloning vectors are the DNA molecules that.

1. Carry foreign DNA segment but do not replicate inside the host cell.
2. Carry foreign DNA segment and replicate inside the host cell.
3. Transfer nuclear DNA form nucleus to the cytoplasm of the same cells.
4. Help in sealing gaps in DNA segments.

4. Transfer of DNA into a eucaryotic cell is called:

1. Transformation.
2. Transduction.
3. Transfection.
4. Electroporation.

5. Assertion: Type I restriction enzymes are not used in rDNA technology.

Reason: Biotechnology mostly involves cutting and pasting of desired DNA fragments.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

1. Haploid endosperm is found in:

1. Pin us.
2. Cauliflower.
3. Sunflower.
4. Pea.

2. Persistent endosperm is found in:

P. Pea Q. Castor R. Bean S. Coconut T. Groundnut.

1. Q and S.
2. P and T.
3. R, S and T.
4. P, S and T.

3. Milk of tender coconut represents (A) and the surrounding white coconut meal represents (B).

4. If an endosperm cell of a gymnosperm contains 12 chromosomes, the number of chromosomes in each cell of the root will be:

1. 4
2. 24
3. 16
4. 6

5. In angiosperms, normally after fertilization:

1. The zygote divides earlier than the primary endosperm nucleus.
2. The primary endosperm nucleus divides earlier than the zygote.
3. Both the zygote and primary endosperm nucleus divide simultaneously.
4. Both the zygote and primary endosperm nucleus undergo a resting period.

1. Dodo, an extinct taxon, belongs to which country?

1. Mauritius
2. Africa
3. Australia
4. Russia

2. To which of the following categories of IUCN, Berberis nilghiriensis belongs?

1. Extinct.
2. Extinct in wild.
3. Endangered.
4. Critically endangered.

3. Steller's sea cow and passenger pigeon became extinct due to:

1. Alien species invasion.
2. Over-exploitation.
3. Coextinctions.
4. Intensive agriculture.

4. Bali, Javan and Caspian are:

1. Species of tiger.
2. Species of cheetah.
3. Subspecies of cheetah.
4. Subspecies of tiger.

5. Select the correct term for the following definitions (i, ii, iii, iv).

• The taxon is liable to become extinct if not allowed to realise its full biotic potential by providing protection from exotic species/ human exploitation/habitat deterioration/depletion of food.
• The taxon has been completely eliminated or died out from earth, e.g., Dodo.
• The taxon is facing a high risk of extinction in the wild in the near future due to decrease in its habitat, excessive predation or poaching.
• They are species with naturally small populations, either localised or thinly scattered, which are always at risk from pests/ pathogens/ predators/ exotic species.