Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from 7(i) to 7(v) given below:

The vectors are DNA molecules that can carry a foreign DNA segment and replicate inside the host cell. Vectors may be plasmids, bacteriophages (viruses that attack bacteria), cosmids, yeast artificial chromosomes (YACs), Bacterial artificial chromosomes (BACs) and viruses. The most widely used, versatile, easily manipulated vector pBR 322 is an ideal plasmid vector. Features that are required to facilitate cloning into a vector includes origin of replication (Ori) which is a specific sequence of DNA bases responsible for initiating replication, selectable marker genes and cloning sites

1. Pin pBR 322 denotes that it is a:

1. plasmid
2. prokaryote
3. protist
4. plant cell.

2. Ori is a specific DNA sequence that help in.

1. Attachment of primers.
2. Initiation of replication.
3. Extension of DNA base.
4. Initiation of denaturation.

3. A and B shown in the figure respectively indicates:

1. Pvu II and Cla I.
2. ROP and Sal I.
3. amp^R and tet^R.
4. tet^R and amp^R.

4. Selectable markers in vector,

1. Are responsible for replication.
2. Help in selecting transformants from non-transform ants.
3. Code for proteins involved in the replicating plasmids.
4. Contain unique recognition sites.

5.  Plasmid vectors are:

1. dsDNA molecule
2. Extra-chromosomal
3. Present in bacteria and yeast
4. All of these.

What is sewage? Describe secondary treatment (biological treatment) in Sewage Treatment plant.

Read the following and answer any four questions from 9(i) to 9(v) given below:

Bioreactors are considered as vessels in which raw materials are biologically converted into specific products by microbes, plant and animal cells or their enzymes. They are used for large scale production as they provide optimum growth conditions such as temperature, pH, substrate, vitamins, oxygen and salts for obtaining desired product. Most commonly used bioreactors are of stirring type which include simple stirred tank bioreactor and sparged stirred-tank bioreactor.

1. Bioreactor are useful in:

1. Amplifying a gene.
2. Isolation of genetic material.
3. Processing large volume of culture.
4. Infecting DNA in a cell.

2. Which of the following is essential to obtain desired product in a bioreactor?

1. Size of the bioreactor.
2. Sterile condition.
3. Quantity of the raw material.
4. All of these.

3. Assertion: The stirred-tank is well suited for large scale production of microorganisms under aseptic conditions.

Reason: In sparged stirred tank bioreactor, surface area for oxygen transfer is increased.

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.

4. Growth condition that could affect the quality of obtained product in a bioreactor are:

1. Temperature and pH only.
2. pH and oxygen supply only.
3. Temperature and oxygen supply only.
4. Temperature, pH and oxygen supply.

5. Vessels in which raw materials are biologically converted into specific products are.

1. Bioreactors.
2. Fermentors.
3. Gene guns.
4. Both (a) and (b).

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

The endosperm makes the main source of food for the embryo. Generally the endosperm nucleus divides after the division of the oospore, but in several cases the endosperm is formed to a great extent even before the first division of the oospore. There are three general types of endosperm formation: (a) nuclear type, (b) cellular type and (c) helobial type. The endosperm is usually triploid, but haploid endosperm is also found. Endosperm may either be completely consumed by the developing embryo before seed maturation, or it may persist in the mature seed.

1. Haploid endosperm is found in:

1. Pin us.
2. Cauliflower.
3. Sunflower.
4. Pea.

2. Persistent endosperm is found in:

P. Pea Q. Castor R. Bean S. Coconut T. Groundnut.

1. Q and S.
2. P and T.
3. R, S and T.
4. P, S and T.

3. Milk of tender coconut represents (A) and the surrounding white coconut meal represents (B).

S. No	A	B
(a)	Cellular endosperm	Free- nuclear endosperm
(b)	Free-nuclear endosperm	Cellular endosperm
(c)	Helobial endosperm	Cellular endosperm
(d)	Free-nuclear endosperm	Helobial endosperm

4. If an endosperm cell of a gymnosperm contains 12 chromosomes, the number of chromosomes in each cell of the root will be:

1. 4
2. 24
3. 16
4. 6

5. In angiosperms, normally after fertilization:

1. The zygote divides earlier than the primary endosperm nucleus.
2. The primary endosperm nucleus divides earlier than the zygote.
3. Both the zygote and primary endosperm nucleus divide simultaneously.
4. Both the zygote and primary endosperm nucleus undergo a resting period.

Give an account of energy flow in an ecosystem.

Explain in situ approach for conservation of biodiversity.

Read the following text carefully and answer the questions that follow:
A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. Pathogens are taxonomically widely diverse and comprise viruses and bacteria as well as unicellular and multicellular eukaryotes. The immune system of a person is suppressed. He was found positive for a pathogen in the diagnostic test ELISA.

i. Name the disease, the patient is suffering from. (1)
ii. Which pathogen is identified by ELISA test? (1)
iii. Which cells of the body are attacked by the pathogen? (2)
OR
Suggest preventive measures of the infection. (2)

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.

Read the following and answer any four questions from (i) to (v) given below:
The first menstruation is called menarche, that usually occurs between 12 and 15 years. In human females, menstruation is repeated at an average interval of about 28/29 days and is called menstrual cycle. It is regulated by certain hormones, as pituitary gland is stimulated by releasing factors produced in the hypothalamus. The hormones produced by pituitary gland influence the ovaries. The hormones secreted by the ovaries affect the walls of the uterus.

1. The breakdown of endometrium is characteristic of:

1. Proliferative phase.
2. Luteal phase.
3. Ovulatory phase.
4. Menstrual phase.

2. Which days of the menstrual cycle marks the proliferative phase?

1. 1-5
2. 15-28
3. 6-13
4. 10-14

3. Which of the following occurs during secretory phase?

1. Empty Graafian follicle changes into corpus luteum.
2. Primary follicle changes into Graafian follicle.
3. Endometrium rebuilds and estrogen secretion increases.
4. LH surge, inducing release of an ovum.

4. Identify the hormones that attain peak level during ovulatory phase.

1. FSH.
2. Progesterone.
3. LH.
4. Both (a) and (c).

5. Withdrawal of which hormone causes degeneration of corpus luteum?

1. FSH.
2. LH.
3. Progesterone.
4. Estrogen.

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