Biotechnology: Principles and Processes — BIOLOGY STD 12 Science — Question

Explain incomplete dominance in dog flower (snapdragon or Antirrhinum sp.) with the help of a chart.###During monohybrid experiment, in F 2 generation, the ratio of phenotype & genotype remains same - explain by giving suitable example (chart is necessary).

Explain innate immunity in detail

Read the following and answer any four questions from (i) to (v) given below:
IUCN maintains a Red Data Book or Red List which is a catalogue of taxa facing risk of extinction. The IUCN Red List (2004) documents the extinction of 784 species in the last 500 years. Some examples of recent extinctions include the dodo, quagga, thylacine and Steller's sea cow. The last twenty years alone have witnessed the disappearance of 27 species. Red List has eight categories of species.

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.

	(i)	(ii)	(iii)	(iv)
(a)	Threatened	Extinct	Endangered	Rare
(b)	Endangered	Extinct	Threatened	Rare
(c)	Extinct	Rare	Threatened	Endangered
(d)	Threatened	Extinct	Rare	Endangered

Read the following and answer any four questions from (i) to (v) given below:
Embryo develops at the micropylar end of the embryo sac, where the zygote is situated. Most zygotes divided only after certain amount of endosperm is formed. The early stages of embryo development are similar in both monocotyledons and dicotyledons. The zygote gives rise to the proembryo and subsequently to the globular heart-shaped and mature embryo. A typical dicotyledonous embryo consists of an embryonal axis and two cotyledons. Embryo of monocotyledons possess only one cotyledon.

1. True embryo develops as a result of fusion of:

1. Two polar nuclei of embryo sac.
2. An egg cell and a male gamete.
3. Synergid and male gamete.
4. A male gamete and antipodals.

2. Refer to the given diagram of the embryo of an angiospermous plant with parts labelled P, Q and R. Select the correct statement(s) regarding this.

1. Part 'P' supplies nutrition to the developing embryo.
2. Part 'Q' is the protective sheath of radicle and root cap.
3. Part 'R' is the protective sheath of shoot apex and leaf primordia.
4. The embryo shown in the diagram is present in members of Family Poaceae.

1. (IV) only.
2. (II) and (III) only.
3. (I) and (IV) only.
4. (I), (II), (III) and (IV).

3. Which of the given statements are true?

1. During the development of a dicot embryo, heart-shaped embryo is followed by globular embryo.
2. The part of embryonal axis above the level of cotyledons is epicotyl, while the part below the level of cotyledons is hypocotyl.
3. Monocot seeds possess a single cotyledon, represented by scutellum.

1. (I) and (II).
2. (II) and (III).
3. (I) and (III).
4. (I), (II) and (III).

4. Consider the following parts of an embryonal axis of a dicot seed.

1. Hypocotyl.
2. Epicotyl.
3. Radicle.
4. Plumule.

In which of the following the above parts are correctly arranged from top to base?

1. (III) → (I) → (II) → (IV).
2. (II) → (I) → (III) → (IV).
3. (IV) → (II) → (I) → (III).
4. (III) → (IV) → (II) → (I).

5. In grass family, the cotyledon, is called:

1. Epiblast.
2. Plumule.
3. Scutellum.
4. Perisperm.

Read the following and answer any four questions from (i) to (v) given below:
In testis, the immature male germ cells produce sperms by spermatogenesis that begins at puberty. It occurs in the seminiferous tubules of the testes. Seminiferous tubules are lined by germinal epithelium. Study the schematic representation of spermatogenesis and answer the following questions.

1. Which cell division occurs during multiplication phase?

1. Mitosis.
2. Meiosis I.
3. Meiosis II.
4. Both (b) and (c).

2. How many chromosomes are present in secondary spermatocyte and spermatid, respectively?

1. 46, 23
2. 46, 46
3. 23, 23
4. 23, XY

3. Transformation of L into M is known as:

1. Spermiation.
2. Spermateliosis.
3. Spermatogenesis.
4. None of these.

4. Select the correct option.

1. Type A spermatogonia grows to larger primary spermatocyte.
2. One spermatogonium forms two spermatids.
3. Spenniation is the release of sperms from seminiferous tubules.
4. Primary spermatocyte undergoes mitosis to form secondary spermatocytes.

5. Which hormone acts on spermatogonia to stimulate sperm production?

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

Read the following text carefully and answer the questions that follow:
Cancer refers to any one of a large number of diseases characterized by the development of abnormal cells that divide uncontrollably and have the ability to infiltrate and destroy normal body tissue. Cancer often has the ability to spread throughout your body. Cancer is the second-leading cause of death in the world.

i. How does a cancerous cell differ from a normal cell? (1)
ii. Benign tumor is less dangerous than malignant tumor. Why? (1)
iii. Describe causes of cancer. (2)
OR
Mention two methods of treatment of the disease. (2)

Read the following and answer any four questions from (i) to (v) given below:
The anther is a four-sided structure consisting of four microsporangia located at the corners, two in each lobe. TI1e microsporangia develop further and become pollen sacs. In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers-the epidermis, endothecium, middle layers and the tapetum.

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

Select the option that correctly fills the blanks.

S. No	A	B
(a)	Four	Two
(b)	Two	One
(c)	Two	Two
(d)	Four	One

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

(a)	A-Middle layer	B-Endothecium	C-Tapetum
(b)	A-Endothecium	B-Tapetum	C- Middle layer
(c)	A-Endothecium	B-Middle layer	C-Tapetum
(d)	A-Tapetum	B-Middle layer	C-Endothecium

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.

Read the following and answer any four questions from (i) to (v) given below:
A woman unable to conceive after many years of regular unprotected coitus went to specialised infertility clinic. On complete examination, woman was found to be normal, while male partner was diagnosed with infertility. Male partner is unable to copulate the female. Couple was advised to opt for assisted reproductive technology (ART).

1. Which ART could have been useful for this couple?

1. ZIFT
2. IUT
3. AI
4. GIFT

2. In which of the following infertility issues could this technique be used?

1. Anovulation.
2. Oligospermia.
3. Low fructose content in seminal fluid.
4. All of these.

3. Which among the following techniques is useful to conceive when there is very low sperm count?

1. GIFT
2. Test-tube baby
3. IUT
4. JCSI

4. Assertion: Artificial insemination (AI) is intra-uterine insemination.

Reason: In Al, sperms collected from donor are introduced into the uterus.

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. Success rate of artificial insemination technique is:

1. 20-40%
2. 60-70%
3. 40-50%
4. 5-7%