Principles of Inheritance and Variation — 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:

Riya studies in 11 standard in a government school. She belongs to a backward family and her parents did not get her properly vaccinated according to immunisation programme. Once while playing in school playground she fell down due to weakness and developed high fever, headache and stiffness in her neck. identify the illness she could be suffering from and answer the following questions.

1. The microbe responsible for Riya's illness could be.

1. Vibrio cholerae
2. Enterovirus
3. Plasmodium
4. Mycobacteriurn.

2. Which vaccine, if administered earlier, would have saved Riya from the illness she unfortunately contracted?

1. Salk vaccine
2. MMR vaccine
3. BCG vaccine
4. Varicella vaccine

3. The disease that Riya has contracted spreads through.

1. Bite of an infected mosquito
2. Bite of an infected dog
3. Faecal oral route
4. Direct contact with the infected person.

4. Riya can spread her illness to other children through.

1. Her faeces
2. Direct contact
3. Coughing and sneezing in open
4. Vectors.

5. Assertion: Polio produces inflammation of the nervous system.

Reason : Stiffness of the neck, paralysis of particular skeletal muscle, is an important symptom of polio.

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.

With labeled diagrams describe the mechanism of Pollen-pistil Interaction.

What is spermatogenesis? Briefly describe the process of spermatogenesis.###Explain the process of spermatogenesis. (Diagram is not required)###According to spermatogenesis (i) Development of sperm from primary spermatocytes. Explain it. (ii) Role of hormones which secreting from pituitary gland (iii) Structure of sperm (Diagram is not necessary)

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

A typical angiospermic ovule is a small structure attached to the placenta by means of a stalk called funicle. The body of the ovule fuses with funicle in the region called hilum. Each ovule has one or two protective envelopes called integuments. Integuments encircle the nucellus except at the tip where a small opening called the micropyle is formed. Mature ovules are classified on the basis of funiculus. It can be orthotropous, anadromous, hernitropous, campylotropous, etc.

1. The body of the ovule consists of a mass of parenchymatous cells called:

1. Integuments.
2. Nucellus.
3. Hilum.
4. Funiculus.

2. Refer to the given figure and select the correct statement regarding it.

1. This type of ovule is found in cactus.
2. The micropyle comes to lie close to the funiculus due to unilateral growth of ovule.
3. It is most common type of ovule found in the members of Chenopodiaceae.
4. It is half inverted ovule.

3. Identify the parts labelled as A, B, C and D in the given figure and select the correct option.

S. No	A	B	C	D
(a)	Chalaza	Female gametophyte	Embryo sac	Micropyle
(b)	Chalaza	NuceIIus	Embryo sac	Micropyle
(c)	Micropyle	Egg	Embryo sac	Chalaza
(d)	Micropyle	Nucellus	Embryo sac	Chalaza

4. Mature ovules are classified on the basis of funiculus. If micropyle lie close to the funiculus, the ovule is termed as:

1. Orthotropous.
2. Anatropous.
3. Hemitropous.
4. Campylotropous.

5. In Asphodel us, ovule is:

1. Unitegmic.
2. Tritegmic.
3. Bitegmic.
4. Ategmic.

Give information about primary and secondary lymphoid organ ### Explain lymphatic organs of human lymphatic system. (Diagram is not required)

Explain in situ approach for conservation of biodiversity.

Explain: separation and isolation of DNA fragments.###How will you make separation and isolation of DNA fragments by using gel electrophoresis?

Highlight five areas where biotechnology has influenced our lives.