Biotechnology and its Applications — BIOLOGY STD 12 Science — Question

Explain parasitism as population interaction with examples.

Read the following and answer any four questions from (i) to (v) given below:
Regular change in temperature that occurs at specific intervals of time is called thennoperiodicity. It is of two types-diurnal and seasonal thermoperiodicity. Diumal periodicity refers to temperatures of day and night. It determines periods ofannual activity. In season periodicity different temperature prevails in different seasons of the year. 'Tiley favour different aspects of plant and animal life termed as phenology. For example in wheat, leaf growth requires a temperature of 10º-25ºC. Apple requires temperature below 7ºC for a period of 800 hrs before flowering and fruiting can occur. Low temperature is required for germination of some seeds as well as flowering in some plants. It also determines growth, reproduction, colour and morphology of animals. Both low and high temperature cause stress in organisms which is overcome by particular adaptations.

1. Some plants require low temperature treatment for flowering. This phenomenon is known as:

1. Photoperiodism.
2. Vemalisation.
3. Thermoperiodism.
4. None of these.

2. Animals found in arctic zones are called.

1. microtherms
2. Megatherms
3. Mesotherms
4. Hekistotherms

3. Which of the following parts of wheat plant grows maximum in temperature around 10º-25ºC?

1. Root
2. Seeds
3. Leaf
4. Stem

4. "Different temperatures prevail in different seasons of the year." It represents:

1. Diurnal thermoperiodicity.
2. Seasonal periodicity.
3. Homeostasis.
4. Thermoregulation.

5. Assertion: Low and high temperature causes stress in organisms.

Reasons: Organisms show specific adaptations to overcome stressful condition.

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.

Explain exponential growth equation with well labeled diagram.###Explain exponential growth.

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)

Explain: Acquired Immunity.

Read the following and answer any four questions from (i) to (v) given below: The mature ovum or a female gamete is spherical in shape. The human ovum is almost free of yolk and is said to be alecithal. Human ovum loses its ability to be fertilised about 24 hours after ovulation. Refer to the given structure of ovum and answer the following questions.

1. Thick cellular layer formed of radially elongated follicular cells is:

1. Zona pellucida.
2. Plasma membrane.
3. Perivitelline membrane.
4. Corona radiata.

2. In humans, at which stage does ovum get released from ovary?

1. Secondary oocyte.
2. Oogonium.
3. Primary oocyte.
4. First polar body.

3. Cytoplasm of an ovum is enveloped by _____.

1. Zona pellucida.
2. Corona radiata.
3. Cell membrane.
4. Perivitelline space.

4. Select the correct option:

S. No	V	W	X
(a)	Cytoplasm	Zona pellucida	Plasma membrane
(b)	Cortical granules	Corona radiata	Zona pellucida
(c)	Cortical granules	Plasma membrane	Corona radiata
(d)	Cytoplasm	Corona radiata	Zona pellucida

5. Which of the following is not a characteristic of an ovum?

1. Nucleus of an ovum has prominent nucleolus.
2. Only one ovum formed from one oogonium.
3. It lacks centrioles.
4. It has very small amount of ooplasm.

Describe: Genetic engineered insulin

Write a short note on pollination by wind.

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.

Read the following and answer any four questions from (i) to (v) given below:
The pollen grains or microspores are the male reproductive bodies of a flower and are contained in the pollen sac or microsporangia. Each pollen grain consists of a single microscopic cell, possessing two coats: the exine and the in tine. The exine of a pollen grain is made of chemically stable material. Because of this, pollen grains are often very well preserved for thousands of years in soil and sediments.

1. One of the most resistant biological material present in the exine of pollen grain is:

1. Pectocellulose.
2. Sporopollenin.
3. Suberin.
4. Cellulose.

2. The exine possesses one or more thin places known as:

1. Raphe.
2. Germ pores.
3. Hilum.
4. Endothecium.

3. What is the function of germ pore?

1. Emergence of radicle.
2. Absorption of water for seed germination.
3. Initiation of pollen tube.
4. All of these.

4. What is the key advantage to the plant for having such strong pollen grain walls?

1. It protects the vital genetic material in the pollen grain.
2. It allows pollen to serve as a valuable fossil record for the study of ancient plants.
3. It prevents the pollen tube from growing out before the pollen grain reaches the stigma of a compatible species.
4. It gives weight to the pollen grain, allowing it to cling better to the body surfaces of insect pollinators.

5. The number of germ pores in dicots and monocots respectively are:

1. One and three.
2. Three and two.
3. Two and three.
4. Three and one.