Respiration and Circulation — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
ln many species of fig trees, there is a tight one-to-one relationship with the pollinator species of wasp. It means that a given fig species can be pollinated only by its 'partner' wasp species and no other species. The wasp pollinates the fig inflorescence while looking for suitable egg-laying sites. ln return for the favour of pollination, the fig offers the wasp some of its developing seeds as food for the developing wasp larvae.

1. The interaction between fig trees and wasp is an example of:

1. Mutualism
2. Commensalism
3. Amensalism
4. Parasitism

2. AD the given interactions are similar to interaction between fig trees and wasp, except.

1. Plant and animal relation for pollination.
2. Association of algae and fungi in lichens.
3. Association of cattle egret and grazing cattle.
4. Association of fungi and roots of higher plants in mycorrhiza.

3. In which of the following interactions both partners are adversely affected?

1. Parasitism
2. Mutualism
3. Competition
4. Predation

4. ln relationship between fig and wasp:

1. One benefitted other harmed.
2. Both are benefitted.
3. One benefitted other unaffected.
4. One inhibited, other unaffected.

5. Assertion: Fig and wasp cannot complete their life cycle without each other.

Reason: They show mutualistic relationship.

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.

Distinguish between: Phase of cell division and Phase of cell enlargement

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.

Read the following and answer any four questions from (i) to (v) given below:
Turner's syndrome is an example of monosomy. It is formed by the union of an allosome free egg and a normal 'X' containing sperm or a normal egg and an allosome free sperm. 'The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, under developed breasts, small uterus, short stature, webbed neck and abnormal intelligence. 'They may not menstruate or ovulate. This disorder can be treated by giving female sex hormone to the women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.

1. Number of barr body present in a female with Turner's syndrome is?

1. 0
2. 1
3. 2
4. < 2.

2. Turner's syndrome is an example of?

1. Aneuploidy.
2. Euploidy.
3. Polyploidy.
4. Autosomal abnormality.

3. Turner's syndrome is a/an.

1. Autosomal recessive Mendelian disorder.
2. Autosomal dominant Mendelian disorder
3. Sex linked Mendelian disorder.
4. Chromosomal disorder.

4. Which of the following statements regarding Turner's syndrome is incorrect?

1. It is a case of monosomy of chromosomes.
2. The suffering individual is a sterile female, having one 'X' chromosome missing in the cells.
3. The problem is due to an extra chromosome.
4. The individual are of short stature.

5. Assertion: Turner's syndrome is caused due to absence of any one of the X and Y sex chromosome.

Reason: Individuals suffering from Turner's syndrome show masculine as well as feminine development

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 front (i) to (v) given below:
Gene regulation is the mechanism of switching off and switching on of the genes depending upon the requirement of cells and the state of development. Gene regulation is of two types : negative and positive. In negative generegulation the genes continue expressing their effect till their activity is suppressed. Positive gene regulation is the one in which the genes remain non-expressed unless and until they are induced to do it. Operon model is a co-ordinated group of genes such as structural gene, operator gene, promoter gene, regulator gene which function together and regulate a metabolic pathway as a unit, e.g., lac operon, trp operon, ara operon, etc.

1. Regulation of gene expression occurs at the level of.

1. Transcription
2. Processing/splicing
3. Translation
4. All of these.

2. Inducible operon system usually occurs in A pathways. Nutrient molecules serve as B to stimulate production of the enzymes necessary for their breakdown. Genes for inducible operon are usually switched C and the repressor is synthesised in an D form.

S.no	A	B	C	D
(a)	anabolic	corepressor	on	inactive
(b)	anabolic	inducer	off	active
(c)	catabolic	inducer	off	active
(d)	catabolic	corepressor	on	inactive

3. An mRNA molecule transcribed from the lac operon contains nucleotide sequences complementary to.

1. Structural genes coding for the enzymes.
2. the operator region
3. the promotor region
4. the repressor gene.

4. Which statement correctly describes the control of transcription of the genes involved in the breakdown of lactose in Estherichia coli?

1. A repressor protein binds to the operator and the genes are switched on.
2. A repressor protein binds to the operator and the genes are switched off.
3. A transcription factor binds to the promoter and the genes are switched on.
4. A transcription factor binds to the promoter and the genes are switched off.

5. Function of catabolic activator protein in lac operon is.

1. To form mRNA
2. Help to bind RNA polymerase
3. Code for repressor
4. To activates lac gene when glucose is absent.

Read the following and answer any four questions from (i) to (v) given below:
Non-native or alien species are often introduced in advertently for their economic and other uses. They often become invasive and drive away the local species. Exotic species have proved harmful to both aquatic and terrestrial ecosystems. For example, water hyacinth (Eichhornia crassipes) was introduced in Indian waters to reduce pollution. It was clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.

1. Island water ecosystem are the most vulnerable due to:

1. Small size.
2. Small number of species.
3. Increases reproductive capacity.
4. Both (a) and (b).

2. Which of the following is not an alien species?

1. Lantana camara.
2. Periplaneta americana.
3. Nile Perch.
4. Yucca moth.

3. Second major cause of species extinction is:

1. Habitat loss and fragmentation.
2. Over exploitation.
3. Alien species invasion.
4. Co-extinction.

4. Assertion: Eichhomia crassipes drains off oxygen from water and can be seen growing in standing water.

Reason: Eichhornia crassipes is an indigenous species of India.

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. The population of species Pin a certain conununity was constant until a population species Q from a distant land was subsequently introduced into that community. The interaction between the two populations is reflected in the graph below.

What could be the possible reason for the decrease in the population of species P over a number of days?

1. Species Q is a predator of species P.
2. Species Q is a prey species which wiped out the population of species P.
3. Species P and Q compete for space but feeds on different food.
4. None of these.

Distinguish between: DNA and RNA

Distinguish between: Zona pellucida and Corona radiata.

Eurythermal and stenothermal.

Outcrossing and Crossbreeding.