Human Health and Diseases — BIOLOGY STD 12 Science — Question

With the help of suitable diagram describe the logistic population growth curve.

Given below is a list of autotrophs and heterotrophs. With your knowledge about food chain, establish various linkages between the organisms on the principle of 'eating and being eaten'. What is this inter-linkage established known as? Algae, Hydrilla, grasshopper, rat, squirrel, crow, maize plant, deer, rabbit, lizard, wolf, snake, peacock, phytoplankton, crustaceans, whale, tiger, lion, sparrow, duck, crane, cockroach, spider, toad, fish, leopard, elephant, goat, Nymphaea, Spirogyra.

1. Why should we conserve biodiversity? How can we do it?
2. Explain the importance of biodiversity hot-spots and sacred groves.

Raj was a known sportsman in his school. While returning home he found some unknown miscreants beating a young fellow. He tried to drive them off, but by that time the fellow died of injury. The police arrested Raj and he was put on trial. The judge being convinced by Raj's plea, ordered for DNA fingerprinting reports.

1. What is the basis of DNA fingerprinting?
2. Explain the steps in DNA fingerprinting.
3. Write the applications of DNA fingerprinting.
4. Raj's fingerprints on the dead body were sufficient to convict him but the judge asked for authentic proof. What values can be observed by the judge?

Read the following and answer any four questions from (i) to (v) given below:
Gene therapy is the technique of genetic engineering to replace a faulty gene by a normal healthy functional gene. It is a way of treating genetic disease by introducing a piece of DNA into the cells of an affected individual. Liposomes can be used for gene therapy as they target the cells affected by a genetic disease.

1. A patient suffers from adenosine deaminase (ADA) deficiency, an autosomal recessive immune deficiency in which bone marrow lymphoblasts cannot replicate to generate immuno-competent lymphocytes. The treatment option that would cure the patient is:

1. Germ-line gene therapy to replace one ADA gene copy.
2. Germ-line gene therapy to replace both ADA gene copies.
3. Somatic cell gene therapy to replace both ADA gene copies in circulating lymphocytes.
4. Somatic cell gene therapy to replace one ADA gene copy in bone marrow lymphoblasts.

2. Which type of gene therapy is least effective in transferring DNA to the nucleus?

1. Adenoviruses.
2. DNA attached to a ligand.
3. Liposomes.
4. Retroviruses.

3. Liposomes can be used for gene therapy as they target the cells affected by a genetic disease. The diagram shows the structure of a liposome.

What feature of a cell surface membrane allows the liposome to target cells affected by a genetic disease?

1. Carrier molecules.
2. Phosphate groups.
3. Protein channels.
4. Receptor molecules.

4. Which of the following disorders would gene therapy be least effective?

1. Cystic fibrosis.
2. Huntington's disease.
3. Sickle cell anaemia.
4. Type II diabetes.

5. Following are some reasons explaining why gene therapy is not yet fully an effective treatment for genetic diseases.

1. Lack of knowledge of DNA sequences.
2. Lack of efficient and safe gene delivery system.
3. Cost of the technology.
4. Some diseases involve multiple genes.
5. Problems with appropriate gene regulation.

Select the correct option.

1. I, III and V only
2. II, IV and V only
3. Ill, IV and V only
4. I, III and IV only

For question 1-4, use this key:Key-

1. Ecology.
2. Population.
3. Community.
4. Ecosystem.

1. A community plus its physical environment.
2. Study of the interactions of organisms with each other and with the physical environment.
3. All populations that are found in a particular area.
4. All members of the same species that inhabit a particular area.

Mutualism

Write a brief account of Klinefelter’s syndrome.

Define receptors. Enlist different types of receptors.

1. Label the three tiers 1, 2, 3 given in the above age pyramid.
2. What type of population growth is represented by the above age pyramid?