MODEL PAPER 8 BIOLOGY - MODEL PAPER 8

Select the option that gives the correct description of the process of Natural Selection with respect to the length of the neck of giraffe.

Which of the following sexually transmitted disease is not caused by a virus?

A chemical substance derived from a living source and has the capacity to inhibit the growth or destroy the microbes is called:

Bacteria present in rumen of a cattle digest cellulose to produce

The source organism of Taq polymerase is:

Treatment of wastewater is done in a sewage treatment plant to make it less polluting. Explain the following with reference to this treatment process:
a. Primary sludge
b. Activated sludge
c. Anaerobic sludge digesters

a. A patient had suffered myocardial infarction and clots were found in his blood vessels. Name a clot buster that can be used to dissolve the clots and the micro-organism from which it is obtained.
b. A woman had just undergone a kidney transplant. A bioactive molecular drug is administered to oppose kidney rejection by the body. What is the bioactive molecule? Name the microbe from which this is extracted.
c. What do doctors prescribe to lower the blood cholesterol level in patients with high blood cholesterol? Name the source organism from which this drug can be obtained.

Study the sectional view of human testis showing seminiferous tubules given below.

i. Identify A, B and C.
ii. Write the function of A and D.

Majority of angiosperms have hermaphrodite flowers, but self-pollination is discouraged by them. Explain any three outbreeding devices that they have developed to achieve this.

Some of the microbes used as biofertilizers are prokaryotes. Name the taxonomic group they come under. With the help of an example, mention how they act as biofertilizers.

Study the table showing the population interaction between species Z and Y respectively. Assign the appropriate +/– signs for A,B,D,E and respective interactions for C and F.

i. Explain the concept of endemism.
ii. Name four regions in and around our country that are considered hot-spots.

A child is born with ADA-deficiency.
a. Suggest and explain a procedure for possible life-long (permanent) cure.
b. Name any other possible treatment for this disease.

Who put forward the theory of natural selection? Explain the concept of differential reproduction as a major component of the theory of natural selection.

The image below eleborates enzyme-replacement therapy.

i. Explain enzyme-replacement therapy to treat adenosine deaminase deficiency.
ii. Mention two disadvantages of this procedure.

If a desired gene is identified in an organism for some experiments, explain the process of the following:
i. Cutting this desired gene at specific location.
ii. Synthesis of multiple copies of this desired gene.

a. Describe the process of double fertilisation in angiosperms.
b. Trace the development of polyploidal cell that is formed after double fertilisation in a non-albuminous seed and albuminous seed.

a. Draw the embryo sac of a flowering plant and label the following:
i. Central cell
ii. Chalazal end
iii. Synergids
b. Name the cell and explain the process it undergoes to develop into an embryo sac.
c. Explain the development of endosperm in coconut.

Explain the relationship of ribosomes, 1-RNA and m-RNA during the process of translation in Prokaryotes.

A gene was identified in a fungus by a research worker in a lab which was considered to be of a great importance in the field of agriculture. As a student of biotechnology, write the steps you would suggest to (i) Isolate this gene of interest from the fungus and (ii) amplify this gene for further experimentation and research.

Assertion (A): Generally, a woman does not conceive during the lactation period.
Reason (R): The hormone prolactin initiates and maintains lactation in a woman.

Assertion (A): Griseofulvin extracted from P. griseofulvum is used for ringworm treatment.
Reason (R): Trichophyton, Epidermophyton, etc. cannot grow well in presence of Penicillium griseofulvum.

Assertion (A): Most evolutionary trees place information about pattern of relationship on horizontal axis and time on vertical axis.
Reason (R): An evolutionary tree depicts pattern of relationship among parents and offsprings.

Assertion (A): Autotrophs are also called as transducers.
Reason (R): They change one form of energy into another.

Read the following text carefully and answer the questions that follow:
A lymphocyte isa type of white blood cell. Enlarge. Blood cells. Blood contains many types of cells: white blood cells (monocytes, lymphocytes, neutrophils, eosinophils, basophils, and macrophages), red blood cells (erythrocytes), and platelets. Blood circulates through the body in the arteries and veins.

i. Why are the antigens called antibody-generating chemicals? (1)
ii. Which two types of lymphocytes are involved in immunity? (1)
iii. Give the common site of formation of two types of lymphocytes. (2)
OR
What is the site of differentiation of two types of lymphocytes? (2)

Read the following text carefully and answer the questions that follow:
The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. A schematic representation of Oogenesis is shown below study the flow chart carefully.

i. How is a primary oocyte different from a secondary oocyte? (1)
i. Mention the changes taking place during the transition of a secondary follicle to Graafian follicle in the oogonia. (1)
iii. How many primary follicles are left in each ovary in a human female at puberty? (2)
OR
What happen to graafuan follicle after ovulation? (2)