Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

Read the following text carefully and answer the questions that follow:
The following is the illustration of the sequence of ovarian events (a-i) in a human female.

i. Identify the figure that illustrates ovulation and mentions the stage of oogenesis it represents. (1)
ii. Name the ovarian hormone and the pituitary hormone that have caused the above-mentioned event. (1)
iii. Explain changes that occur in the uterus simultaneously in anticipation. (2)
OR
Draw a labelled sketch of the structure of a human ovum prior to fertilization. (2)

Read the following and answer any four questions from (i) to (v) given below:
In recombinant DNA technology, the fragments of DNA generated after cutting the DNA by restriction enzymes are separated according to their size or length by gel electrophoresis. Gel electrophoresis is performed in a gel matrix so that molecules of similar electric charges can be separated on the basis of size. Most commonly used matrix in gel electrophoresis is agarose. The fragments are separated under the influence of electric field. The separated DNA fragments can be seen only after staining the DNA with compound known as ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange band.

1. Gel electrophoresis is used for the separation of

1. DNA only.
2. DNA and RNA only.
3. DNA and proteins only.
4. DNA, RNA and proteins.

2. Most commonly used matrix is _____ which is a ______ extracted from _______.

1. (i) agarose (ii) polysaccharide (iii) sea weed
2. (i) agarose (ii) protein (iii) sea weed
3. (i) EtBr (ii) polysaccharide (iii) sea weed
4. (i) EtBr (ii) protein (iii) bacteria

3. A DNA molecule was treated with a restriction endonuclease and three fragments of size (i) 426kb, (ii) 129kb and (iii) 46kb were obtained. Identify the order in which these bands will arrange themselves in the gel plate after gel electrophoresis is completed. (Assuming that negative part of electrode is towards the well)

1. (iii) → (ii) → (i)
2. (i) → (ii) → (iii)
3. (i) → (iii) → (ii)
4. (iii) → (i) → (ii)

4. Which of the following statements regarding gel electrophoresis is incorrect?

1. Separated DNA fragments can be seen only after staining DNA with EtBr.
2. DNA fragments are separated according to their size.
3. Under the influence of electric field, positively charged molecules move towards the anode and negatively charged molecules move towards the cathode.
4. None of these.

5. The factor that will not affect the rate of DNA migration in gel electrophoresis is:

1. Size of DNA molecule.
2. Concentration of DNA.
3. Voltage supplied.
4. Concentration of the gel.

Read the following and answer any four questions from (i) to (v) given below:

ln many species of fig trees, there is a tight one-to-one relationship with the pollinator species of wasp. It means that a given fig species can be pollinated only by its 'partner' wasp species and no other species. The wasp pollinates the fig inflorescence while looking for suitable egg-laying sites. ln return for the favour of pollination, the fig offers the wasp some of its developing seeds as food for the developing wasp larvae.

1. The interaction between fig trees and wasp is an example of:

1. Mutualism
2. Commensalism
3. Amensalism
4. Parasitism

2. AD the given interactions are similar to interaction between fig trees and wasp, except.

1. Plant and animal relation for pollination.
2. Association of algae and fungi in lichens.
3. Association of cattle egret and grazing cattle.
4. Association of fungi and roots of higher plants in mycorrhiza.

3. In which of the following interactions both partners are adversely affected?

1. Parasitism
2. Mutualism
3. Competition
4. Predation

4. ln relationship between fig and wasp:

1. One benefitted other harmed.
2. Both are benefitted.
3. One benefitted other unaffected.
4. One inhibited, other unaffected.

5. Assertion: Fig and wasp cannot complete their life cycle without each other.

Reason: They show mutualistic relationship.

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.

Read the following and answer any four questions from (i) to (v) given below:
The DNA, which is transferred from one organism into another by joining it with the vehicle DNA is called passenger or foreign DNA. Generally three types of passenger DNAs are used. These are complementary DNA (cDNA), synthetic DNA (sDNA) and random DNA. Complementary DNA (cDNA) is synthesized on RNA template (usually mRNA) with the help of reverse transcriptase. Synthetic DNA (sDNA) is synthesized on DNA template or without a template. Random DNA are small fragments fanned by breaking a chromosome of an organism in the presence of restriction endonucleases.

1. Reverse transcriptase enzyme was discovered by:

1. Temin and Baltimore.
2. Cohen and Boyer.
3. Arber and Nathan.
4. Paul Berg.

2. During cDNA formation, what would happen if DNA formed by reverse transcriptase is not treated with the alkali?

1. cDNA will not be digested.
2. mRNA will not be digested.
3. Hydrogen bonds will not form between base pairs.
4. rnRNA will not be formed.

3. Enzyme that helps in the formation of double stranded cDNA is:

1. DNA synthetase
2. Ligase
3. DNA polymerase
4. Helicase.

4. DNA polymerase can be obtained form:

1. Retrovirus.
2. Agrobacteriurn.
3. Tobacco mosaic virus.
4. Thermus aquaticus.

5. DNA synthesised without a template is referred to as:

1. Complementary DNA.
2. Random DNA.
3. Synthetic DNA.
4. Z-DNA..

Explain population attributes.

Give an account of energy flow in an ecosystem.

Suggest some methods to assist infertile couples to have children.

Read the following and answer any four questions from (i) to (v) given below:

Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources. Each biosphere reserve has three zones-core, buffer and transition zone.

1. Which of the following is similar to biosphere reserve in terms of conservation?

1. Gene banks.
2. Offsite collection.
3. Orchards.
4. Hotspots.

2. Refer to the given figure representing different zones of a biosphere reserve and select the correct option regarding it.

1. A-Limited human activity is allowed such as for research and education.
2. B-An active co-operation occurs between reserve management and local people for activities like cropping, settlements, etc.
3. C-No human activity is allowed.
4. None of these.

3. Refer to the given diagrammatic representation of a biosphere reserve.

Select the incorrect statement regarding X, Y and Z.

1. X is devoted to strict protection of wildlife and no human activity is allowed in this zone.
2. In Y, only limited human activity (compatible with conservation) is allowed.
3. In Z, commercial exploitation of natural resources is allowed.
4. Tourism is allowed in Z zone only.
5. Zone Y helps to maintain the lifestyle of the tribal people living in the area.

1. (iii), (iv) and (v) only
2. (ii), (iii) and (v) only
3. (i), (iii) and (iv) only
4. (ii), (iii) and (iv) only

4. Biosphere reserves differ from national parks and wildlife sanctuaries because in the former.

1. Human beings are not allowed to enter
2. People are an integral part of the system
3. Plants are paid greater attention than the animals
4. Living organisms are brought from all over the world and preserved for posterity.

5. MAB Programme means.

1. Man and biosphere programme.
2. Man and biodiversity conservation programme.
3. Manually aided biosphere conservation programme.
4. None of these.

Explain any two X-linked recessive disorder?

Read the following and answer any four questions from (i) to (v) given below:

Ginkgo tree has been saved from extinction by selective breeding followed by channeling into trade of nature lovers. This is an ex-situ conservation, where endangered species are protected from all adverse factors. Offspring produced in captive breeding are released in natural habitat for acclimatisation.

1. What is the significance of offsite collections?

1. Restock depleted populations.
2. Protection of endangered species.
3. Reintroduce species in wild.
4. All of these.

2. Which of the following is not an ex-situ conservation?

1. Wetlands
2. Orchards
3. Aquaria
4. Botanical gardens.

3. Select the incorrect statements for ex-situ conservation.

1. It is conservation of species outside their natural habitats.
2. Endangered species are kept under human supervision and provided all the essentials.
3. The species population recovers in natural environment.
4. Both (b) and (c).

4. Conditions maintained in seed banks for orthodox seeds are:

1. Low moisture content.
2. Anaerobic conditions.
3. Low temperature.
4. All of these.

5. Assertion: Animal species which have become extinct in wild continue to be maintained in zoological parks.

Reason: Captive breeding is the conservation of those cases where these is no realistic chance of in-situ survival.

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.