KVPY Interview Important Questions Biology Part 2

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Q: 21. What is the difference between a bacterium and a virus?

Sol. Bacteria are unicellular prokaryotic living organisms and viruses are nucleoprotein particles devoid of cellular organization and metabolism. Viruses are obligate intracellular parasites and hence are neither living nor dead.

Q: 22. What is AIDS and which micro-organism causes it?

Sol. The word AIDS stands for Acquired Immunodeficiency Syndrome. AIDS is caused by the Human Immunodeficiency Virus (HIV) , a type of retrovirus.

Q: 23. Why a cure for AIDS hasn՚t been found yet and how does it affect our body?

Sol. Due to high mutation rate of HIV, vaccination hasn՚t been possible. It causes immunodeficiency due to destruction of CD4 + receptor cells or helper T cells.

Q: 24. What are the different types of extinctions?

Sol. Extinction occurs when the last existing member of a given species dies. It is a scientific certainty when there are no surviving individuals are left to reproduce.

Functional extinction occurs when only a handful of individuals are left, and the chances of reproduction are poor Coextinction the loss of one species leads to the loss of another in a chain effect. A small impact in the beginning of an extinction can have an overall larger effect. Coextinction could be a result of a predator losing its food source or key species becoming extinct leading to the ecosystem becoming off balance.

Mass extinction- It is also known as an extinction event that destroys many species at once. It is characterized by a sharp decrease in the number of species on earth in a short period of time.

Planned extinction- Human controlled extinction were through to be helpful for the human population but generally ended in the spread of deadly viruses e. g. smallpox-extinct in the wild, polio-nearly extinct but can be found in some parts of the world.

Q: 25. What do you think about Lamarckism and list out a few examples to disprove Lamarckism from daily life?

Sol. Lamarckism suggests that variations among organisms originate because of response to the needs of the environment. Moreover, this ability to respond in a particular direction guides a trait՚s adaption. His theory is often called the theory of inheritance of acquired characters or the theory of use and disuse of organ. The following examples can be cited to disprove Lamarckism.

1. The eyes of a voracious reader do not increase in size and power with increasing age.

2. The constantly beating heart maintains a constant size through generations.

3. The piercing of various body parts such as external ear pinnae is not transmitted to the progeny.

Q: 26. How does paracetamol act?

Sol. Paracetamol contains acetaminophen and is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, enzymes involved in prostaglandin (PG) synthesis. Unlike NSAIDS (Non-Steroidal Anti-Inflammatory Drugs) , paracetamol or acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, thus, has no peripheral anti-inflammatory effects.

Q: 27. what՚s hyperbaric oxygen therapy?

Sol. It is treatment involving the use of high partial pressure oxygen. It is employed in cases of carbon monoxide poisoning.

Q: 28. What is a cell biology?

Sol. Cell biology is that discipline of science, which deals with the study of structure, biochemistry, functions, reproduction, behaviour, genetics, and evolution of cell.

Q: 29. What are unicellular organisms?

Sol. Each unicellular organism consists of highly specialized cell capable of performing different activities of life and capable of independent survival e. g. Amoeba, Paramoecium, and Euglena.

Q: 30. What is cancer?

Sol. Cancer is defined as uncontrolled mitotic proliferation of cells due to loss of contact inhibition. It leads to the formation of abnormal growth (of a body part) which may be benign or malignant. The cancer cells are undifferentiated and actively dividing cells.

Q: 31. Can unicellular organisms get cancer?

Sol. No, as the only cell representing the unicellular organism must be fully differentiated while for cancer causation at least one cell must be undifferentiated to undergo uncontrolled mitotic proliferation. Thus, it is possible only in multicellular organisms.

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