All Free Biology MCQs with Answers
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19844 questions · page 525 of 1985
5241. The reason plants are considered totipotent is:
- A. Each cell has full genetic potential of the organism
- B. A single cell could become a complete plant
- C. Because they have lesser potential for tissue culturing
- D. Both A and B
Explanation: Each cell has the full genetic potential of the organism, and a single cell could become a complete plant. The term "totipotent" means that a single cell has the ability to regenerate an entire plant. This is possible because each plant cell contains the full genetic potential of the organism. This means that under the right conditions, a single cell can be stimulated to divide and differentiate into all of the different cell types that make up the plant.
Correct answer: Both A and B5242. Source of Taq polymerase:
- A. Thermus aquaticus
- B. Thermus floral
- C. Floral aquaticus
- D. Taq aquaticus
Explanation: Taq polymerase is a heat-stable DNA polymerase that is used in the polymerase chain reaction (PCR) to amplify DNA. It was originally isolated from the bacterium Thermus aquaticus, which is found in hot springs and other high-temperature environments. Taq polymerase is able to withstand the high temperatures required for the denaturation of double-stranded DNA during PCR, making it a valuable tool for molecular biology.
Correct answer: Thermus aquaticus5243. The technique is used to determine the growth of bacteria, rate of photosynthesis, and minute quantity of DNA:
- A. Electrophoresis
- B. Micrometry
- C. Microscopy
- D. Chromatography
- E. Spectrophotometry
Explanation: Spectrophotometry is a quantitative analytical technique used to measure the absorbance or transmittance of light by a substance. It relies on the principle that different substances absorb light at specific wavelengths, allowing for identification and quantification.
Correct answer: Spectrophotometry5244. A technique used for correcting defective genes responsible for disease development:
- A. Gene therapy
- B. Cloning
- C. Tissue culture
- D. Gene sequencing
Explanation: Gene therapy is a technique that uses a gene(s) to treat, prevent or cure a disease or medical disorder.
Correct answer: Gene therapy5245. The deficiency of which of the following causes severe combined immunodeficiency?
- A. Hypoxanthine-guanine transferase
- B. Xanthine oxidase
- C. PRPP synthetase
- D. Adenosine deaminase
Explanation: ADA deficiency leads to SCID, a group of rare, inherited disorders characterized by a severe impairment of both the T and B lymphocytes of the immune system. Adenosine deaminase is involved in the breakdown of purines, and its deficiency results in the accumulation of toxic metabolites. that are particularly harmful to developing immune cells.
Correct answer: Adenosine deaminase5246. To clean up environmental pollutants, increase the fertility of the soil and kill insect pests, genetically engineered:
- A. Animals have been used
- B. Bacteria have been used
- C. Plants have been used
- D. Viruses have been used
Explanation: Genetically engineerad bacteria are used to remove environmental pollutants through bioremediation. Thay also help increase soil fertility and can be modified to control insect pests.
Correct answer: Bacteria have been used5247. The use of natural biological system to produce a product or to achieve an end desired by humans is called:
- A. Biotechnology
- B. Bioenergetics
- C. Genetic engineering
- D. Gene therapy
Explanation: The use of natural biological system to produce a product or to achieve rend desired by humans is called biotechnology.
Correct answer: Biotechnology5248. In case of cystic fibrosis, the solution containing gene coated liposomes is sprayed into patients:
- A. Oral cavity
- B. Nostrils
- C. Thoracic cavity
- D. Mouth
Explanation: For treatment of cystic fibrosis, a solution containing gene coated liposomes is sprayed into patient's nostrils.
Correct answer: Nostrils5249. To cure Parkinson's disease, dopamine producing cells, could be grafted directly into the brain as a:
- A. Gene therapy
- B. Transplant therapy
- C. Chemotherapy
- D. Radiation therapy
Explanation: In Parkinson's disease, dopamine-producing cells can be directly transplanted into brain to restore dopamine levels, which is known as transplant therapy.
Correct answer: Transplant therapy5250. Microscopic vesicles that spontaneously form when lipoproteins are put into a solution, are called:
- A. Liposomes
- B. Lysosomes
- C. Nucleosomes
- D. Peroxisomes
Explanation: Liposomes are spherical vesicles of of phospholipid bilayer which are used as a vehicle for administration of nutrients and pharmaceutical drugs and for insertion of desired genes. into cells or tissues.
Correct answer: Liposomes