MODEL PAPER 3 BIOLOGY - MODEL PAPER 3

Among the ecosystem mentioned below, where can one find maximum biodiversity?

The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C.

The phenomenon involved in the formation of female gametophyte is known as:

Which of the following is true for a Plasmid -

DNA replication takes place during:

The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:
i. Bacteria
ii. Banyan
iii. Deer
iv. Fish

Why cannot a population live alone by itself in nature?

Antibiotics are sold in combination with Lactobacillus (reason)

Name the labels A, B, C, D, E and F in the diagram of seminiferous tubule.

(A) bacterial cell is shown in the figure given below. Label the part (A) and (B). Also mention the use of part 'A' in rDNA technology.

Draw the diagram of a microsporangium and label its wall layers. Write briefly on the role of the endothecium.

i. Why is tender coconut considered as a healthy source of nutrition?
ii. How are pea seeds different from castor seeds with respect to endosperm?

i. Name an ideal pyramid existing in an ecosystem. Construct it up to its three trophic levels along with their
names.
ii. The sun provides 1,000,000 J of sunlight (solar energy) to an ecosystem. Write the amount of energy that is available to the first and third trophic levels, respectively.

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8 mg/L and 400 mg/L respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Why is Saheli considered an effective contraceptive for women to space children?

What is the Pulse Polio Programme of Government of India? What is OPV? Why is it that India is yet to eradicate Polio?

i. What is the chemical name of smack? Why is the consumption of smack considered as an abuse?
ii. Name the source plant and one effect of the following drugs on the human body:
1. Marijuana
2. Cocaine
3. Morphine

A patient is suffering from ADA deficiency. Can the patient be cured? How?

Describe the various evidences from palaeontology which support organic evolution.

i. Describe the phenomenon of adaptive radiation as explained by Darwin.
ii. Is human evolution an example of adaptive radiation? Give reason in support of your answer.

Assertion (A): Siblings are monoparental in origin.
Reason (R): Monoparental progenies are exact copies of the parent.

Assertion (A): Escherichia coli, Shigella sp., and Salmonella sp. are all responsible for diarrhoeal diseases.
Reason (R): Dehydration is common to all types of diarrhoeal diseases and an adequate supply of fluids and electrolytes should be ensured.

Assertion (A): DNA fingerprinting is a very quick way to distinguish any two individuals.
Reason (R): Any two individuals in the world except identical twins have not similar VNTR.

Assertion (A): Appetency is the formation of new structural or habit of the organism according to its need.
Reason (R): It is also called Lamarckian doctrine.

Read the following text carefully and answer the questions that follow:
Transgenic animals can serve as factories that in some cases, may produce large amounts of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing a large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cows or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenes can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.
i. In transgenic animals, i.e. cow and sheep proteins of pharmaceutical value are produced in large quantities in which gland. (1)
ii. Why is mouse the most preferred animal for studies on gene transfer? (1)
iii. Why does the production of transgenic animals take place? (2)
OR
Assertion (A): Transgenic mice have been engineered to express human antibodies. (2)
Reason (R): Large segments of human DNA encoding human immunoglobulin have been transferred to mice.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.

Read the following text carefully and answer the questions that follow:
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 gene regulation, 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.

i. Regulation of gene expression occurs at which the level? (1)
ii. What is complementary to an mRNA molecule transcribed from the lac operon contains nucleotide sequences? (1)
iii. Describes the control of transcription of the genes involved in the breakdown of lactose in Escherichia coli?
(2)
OR
What is the function of catabolic activator protein in lac operon? (2)