Origin and Evolution of Life — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
Tools used in the formation of recombinant DNA are of three types. These are enzymes, cloning vectors and competent host. lysing enzymes are used to extract DNA for experimental purpose from the cells. Cleaving enzymes break the DNA molecules. TI1ey are of three types : exonucleases, endonucleases and restriction endonucleases. A competent host is required for transformation with recombinant DNA and cloning vectors help to propagate DNA.

1. Which of the following is an example of natural Iysing activity in a human body?

1. Lysozyme present in tears dissolve the bacterial cell wall.
2. Conversion of starch to maltose in the buccal cavity
3. Absorption of digested food into the intestinal cells.
4. Conversion of protein molecules into amino acids in the stomach.

2. Which of the following depicts exonuclease activity?

1.  

2.  

3.  

4. All of these

3. Cloning vectors are the DNA molecules that.

1. Carry foreign DNA segment but do not replicate inside the host cell.
2. Carry foreign DNA segment and replicate inside the host cell.
3. Transfer nuclear DNA form nucleus to the cytoplasm of the same cells.
4. Help in sealing gaps in DNA segments.

4. Transfer of DNA into a eucaryotic cell is called:

1. Transformation.
2. Transduction.
3. Transfection.
4. Electroporation.

5. Assertion: Type I restriction enzymes are not used in rDNA technology.

Reason: Biotechnology mostly involves cutting and pasting of desired DNA fragments.

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: Blastula and Gastrula ### Give two differences between blastula and gastrula.

Read the following and answer any four questions from (i) to (v) given below:
The given graphs show fluctuations in blood sugar of person X and Y during a 24 hour time period.

Based on the above information, answer the following questions.

1. Which of the following holds true for person X?

1. Person X is suffering from type I diabetes.
2. Person X shows severe insulin deficiency and beta cell depletion.
3. Person X is normal and shows good control of blood sugar level.
4. Person X is subjected to excessive urination and abnormal thrust.

2. The given graph indicates that person Y is suffering from.

1. Diabetes
2. Hypertension
3. Atherosclerosis
4. Rheumatic heart disease.

3. Which of the following conditions are common in person Y?

1. Excretion of glucose in urine and excessive urination.
2. Polydipsia and mild beta cell depletion.
3. Progressive erosion of articular cartilage at synovial joint.
4. Both (a) and (b).

4. A person suffering from diabetes mellitus becomes weak because.

1. The cells are unable to utilise glucose and other carbohydrates for energy production.
2. Degradation of fat increases production of toxic ketone bodies.
3. Cells utilise proteins for obtaining energy
4. All of these.

5. Assertion: Type I diabetes involves failure of insulin to facilitate the movement of glucose into cells.

Reason: Type II diabetes is caused by failure of beta cells to produce adequate amount of insulin due to beta cell depletion.

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.

Germ line gene therapy and somatic cell gene therapy.

Read the following and answer any four questions from (i) to (v) given below:
When it comes to biopesticides, one of the most widely used fungi is Beauveria bassiana. It infects a range of insects like, pecan weevil, Colorado potato beetle, kudzu bug, etc. It causes a disease known as the white muscardine. Even after an insect is killed, the white mold continues to produce millions of new infective spores that are released into the environment. It is commercially formulated as products including Naturalis L, Mycotrol, BotaniGard, etc. Some other widely used molds are Trichoderma, Metarhizium, etc. Some of them release enzymes that dissolve potential pathogens, others form barriers around plant roots and make it impossible for harmful bacteria and pathogens to pass through.

1. The key benefits of the biopesticides are that they are:

1. Highly effective.
2. Target specific.
3. Reduced environmental risks.
4. all of these.

2. Naturalis-L is a conunercial formulation containing:

1. Bacterial biopesticide.
2. Fungal biopesticide.
3. Fungal biofertiliser.
4. Chemical pesticide.

3. Which of the following is used as an effective bacterial biopesticide?

1. Trichoderma.
2. Beauveria.
3. Bacillus thuringiensis.
4. All of these.

4. Baeuveria causes a disease called:

1. White muscardine.
2. Aspergillosis
3. Green muscardine.
4. Powdary mildews.

5. Assertion: Trichoderma, found in root ecosystem, exerts biological control over several plant pathogens.

Reason: Trichoderma release enzyme which inhibits growth of several disease causing pathogens.

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: Primary sex organs and Secondary sex organs.

Distinguish between: Vasa efferentia and Vasa deferentia.

Distinguish between : External respiration and Internal respiration.

Distinguish between: Asexual reproduction and Sexual reproduction.