Respiration and Circulation — BIOLOGY STD 12 Science — Question

Diffusion and Osmosis.

Read the following and answer any four questions from (i) to (v) given below:
The foundations of recombinant DNA (rDNA) were laid by the discovery of restriction enzymes. These enzymes are present in many bacterias where they function as a part of their defense mechanism called the Restriction Modification system (RM system). Molecular basis of this system was explained first by Werner Arber in 1962. The Restriction Modification system consists of two components:

• A restriction enzyme (called restriction endonuclease) identifies the introduced foreign DNA and cuts it into pieces.
• The second component is a modification enzyme (methylase) that adds a methyl group to DNA at specific site to protect it from the restriction enzyme cleavage.

1. Restriction endonucleases are enzymes present in ________ where they function as a part of _______ mechanism.

1. (i) bacteria (ii) digestive
2. (i) protists (ii) transcription
3. (i) plant cells (ii) replication
4. (i) prokaryotes (ii) defence

2. Which of the following statements regarding modification enzyme is correct?

1. It adds methyl group to one or two bases usually within the host DNA sequence to protect it from the restriction enzyme.
2. It adds ethyl group to one or two bases usually within the sequence recognised by the restriction enzymes.
3. It adds methyl group to only one of bases within the foreign DNA sequence that is recognised by the restriction enzymes.
4. None of these.

3. Which of the following is a type II restriction enzyme?

1. Alu I
2. EcoR I
3. BamH I
4. All of these.

4. Which of the following is the first discovered restriction endonuclease?

1. Sal I
2. EcoR I
3. Hind II
4. EcoR II

5. Components of Restriction Modification System include?

1. Restriction enzyme.
2. Modification enzyme.
3. Lysing enzyme.
4. Both (a) and (b).

Distinguish between : Eosinophils and Basophils.

Read the following and answer any four questions from (i) to (v) given below:
Saurin, a M.Sc student, get an assignment on sewage treatment plant (STP) to study the microbial load. After visiting such plant in his locality, he makes a simplified diagram of the STP for his project. Study the diagram given below and answer the following questions.

1. In the diagram 'A' denotes:

1. Aeration tank.
2. Primary settling tank.
3. Secondary settling tank.
4. Sludge digester.

2. Which of the following is incorrect regarding the sludge released from A?

1. It is formed after primary treatment.
2. It does not require aeration.
3. It possesses floes of decomposer microbes.
4. It is used in landfills.

3. A large number of aerobic heterotrophic microbes grow in:

1. A
2. B
3. C
4. Both (a) and (b).

4. What is denoted by 'D' in the given diagram?

1. Primary sludge.
2. Primary effluent.
3. Activated sludge.
4. Secondary effluent.

5. Assertion: The colloided and finely suspended matter of sewage form aggregates which are called floes.

Reason: Floes contain masses of bacteria, slime and fungal filaments.

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:
DNA fingerprinting is a technique of determining nucleotide sequences of certain areas of DNA which are unique to each individual. Each person has a unique DNA fingerprint. Each fingerprint is the same for every cell, tissue and organ of a person. DNA fingerprinting is the basis of paternity testing in case of disputes.

1. The technique developed to identify a person with the help of DNA restriction analysis is known as.

1. DNA profiting
2. DNA fingerprinting
3. RFLP
4. Both (a) and (b).

2. For DNA fingerprinting, DNA is obtained from.

1. Blood
2. Hair root cells
3. Semen
4. All of these

3. During DNA fingerprinting, the radioactive probes.

1. Hybridise with DNA sample to form double stranded structure
2. Egrade the DNA
3. Create positive charge on DNA
4. Cut the DNA sample at various sites.

4. In India, DNA fingerprinting technique was developed by?

1. Dr. Lalji Singh
2. Alec Jeffreys
3. Dr. Khorana
4. None of these.

5. Which of the following is true about DNA fingerprinting?

1. VNTR is used as probe.
2. DNA samples are loaded on agarose gel electrophoresis.
3. It is based on identification of nucleotide sequence present on the DNA molecule.
4. All of these

Distinguish between: Graafian follicle and Corpus luteum.

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