Control and Co-ordination — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
Each testicular globule of testis contains one to three highly coiled seminiferous tubules. Wall of each seminiferous tubule is formed of single layered germinal epithelium. Majority of cells in this epithelium are cuboidal, called male germ cells. Study the transverse section of part of seminiferous tubule and answer the following questions.

1. What is the characteristic of K?

1. K is spermatogonium which grows into primary spermatocyte.
2. K is Sertoli cell which provides nutrition to spermatids.
3. K is secondary spermatocyte which undergo meiosis II to form spermatid.
4. K is spermatid being converted into sperm.

2. Which of the following cell undergo reduction division to form secondary spermatocyte?

1. J
2. M
3. L
4. K

3. How many among the following have 46 chromosomes?

1. 2
2. 4
3. 5
4. 3

4. Select an option that correctly identifies different labels.

1. L- Primary spermatocyte, N - Spermatozoa, M - Secondary spermatocyte.
2. J - Spermatogonium, K - Sertoli cell, O - Spermatozoa.
3. L- Primary spermatocyte, M - Secondary spermatocyte, N - Spermatozoa.
4. J - Spermatogonium, K - Primary spermatocyte, N - Spermatid.

5. Which hormone initiates spermatogenesis at puberty?

1. FSH
2. ICSH
3. ABP
4. GnRH

Read the following and answer any four questions from (i) to (v) given below:
RNA or ribonucleic acid is a single chain polyribonucleotide which functions as carrier of coded genetic or hereditary information from DNA to cytoplasm for taking part in protein and enzyme synthesis. Six types of RNAs are ribosomal, transfer, messenger, genomic, small nuclear and small cytoplasmic RNA. Out of these, rRNA, mRNA and tRNA are major classes of RNAs that are involved in gene expression.

1. Which one is referred to a soluble RNA?

1. mRNA
2. tRNA
3. rRNA
4. hnRNA

2. The RNA that picks up specific amino acid from amino acid pool in the cytoplasm to ribosome during protein synthesis is?

1. rRNA
2. hnRNA
3. mRNA
4. tRNA

3. Which of the following is found in both DNA and messenger RNA?

1. Double helix structure
2. Ribose
3. Sugar-phosphate chain
4. Thymine

4. Which of the following statements regarding RNA is correct?

1. Messenger RN As carries coded information for synthesis of polypeptide.
2. Ribosomal RNAs bind with tRNA to catalyse the formation of phosphodiester bonds.
3. Genomic RNA is always single stranded.
4. Synthesis of rRNA occurs in cytoplasm by RNA polymerase III

5. In studying a virus, you find the following proportions of nitrogenous bases present: adenine 23%, guanine 37%, cytosine 23% uracil 17%. Which of the following statement(s) regarding this virus is/are correct?

1. It probably uses RNA as its genetic material.
2. The genetic material of this virus is probably single stranded.
3. Base pairing rules in virus in this virus include adenine: cytosine.

1. I only
2. I and II only
3. II and III only
4. All of these.

Distinguish between: m-RNA, t-RNA and r-RNA.

Read the following and answer any four questions from (i) to (v) given below:
Excessive exploitation of species, whether a plant or animal reduces the size of its population so it becomes vulnerable to extinction. Such as Dodo and passenger pigeon have become extinct due to over exploitation by humans. Thus the world is facing accelerated rates of species extinctions, largely due to human interference.

1. Which of the following cause of biodiversity loss is not included in evil quartet?

1. Coextinction.
2. Pollution.
3. Alien species invasion.
4. Habitat loss and fragmentation.

2. Identify the species that have become extinct due to over exploitation.

1. Stellar sea cow.
2. Yucca moth.
3. Blatta orientalis.
4. Nile Perch.

3. Factors which make species susceptible to extinction are:

1. Large population size.
2. Lack of genetic variability.
3. Ower status of trophic level.
4. Ability to switch over to ahem ate foods.

4. Assertion: Pollution reduces species biodiversity.

Reason: Spill over of oil in sea causes death of several marine animals.

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.

5. ________ is the first major cause of species extinction.

1. Coextinction.
2. Over exploitation.
3. Habitat destruction.
4. Alien species invasion.

Distinguish between: Vasa efferentia and Vasa deferentia.

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.