All Free Biology MCQs with Answers
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19844 questions · page 505 of 1985
5041. Amino acid leucine is coded by how many codons:
- A. 1
- B. 2
- C. 4
- D. 6
Explanation: Amino acid leucine is coded by 6 codons UUA, UUG, CUU, CUC, CUA, and CUG.
Correct answer: 65042. During the formation of addition polymers, which smaller molecules you think are eliminated:
- A. H2O
- B. HCl
- C. NH3
- D. No one is eliminated
Explanation: In polymer chemistry, an additional polymer is a polymer that forms by simple linking of monomers without the co-generation of other products. Addition polymerization differs from condensation polymerization, which does co-generate a product, usually water.In addition, polymerization monomers simply react to form polymers without the formation of by products.
Correct answer: No one is eliminated5043. Which one of the following is addition polymer:
- A. Nylon
- B. PVC
- C. Polythene
- D. Both PVC and Polythene
Explanation: In addition polymerization (sometimes called chain-growth polymerization), a chain reaction adds new monomer units to the growing polymer molecule one at a time through double or triple bonds in the monomerOn the other hand, condensation polymerization is a process that involves repeated condensation reactions between tri-functional or bi-functional monomers with elimination of small molecules.
Correct answer: Both PVC and Polythene5044. If the primer annealing temperature is increased to 94°C . What will happen ?
- A. Annealing
- B. Extension
- C. No Annealing
- D. Primer-dimer formation
Explanation: Primer annealing is a critical step in polymerase chain reaction or PCR. In this step, the primers bind to flanking sequences of the target DNA for amplification. If the primer annealing temperature is increased to 94°C non annealing occurs. At high temperature Non annealing occurs and the whole process is disturbed.
Correct answer: No Annealing5045. Which one of the following is called animal starch?
- A. Amylose
- B. Cellulose
- C. Glycogen
- D. Glycine
Explanation: Glycogen Is known as animal starch. The animals have polymerized glucose stored in the form of glycogen. Glycogen is stored in the hepatic cells in the liver. Starch obtained from plants to the animals is stored in the animal body in the form of glycogen.
Correct answer: Glycogen5046. Enzymes are _that catalyze chemical reactions in living organisms and are very specific in their action:
- A. Proteins
- B. Vitamins
- C. Lipids
- D. Minerals
Explanation: Enzymes are proteins that help speed up metabolism, or the chemical reactions in our bodies.
Correct answer: Proteins5047. In RNA, which of the bases is replaced by uracil?
- A. Cytosine
- B. Adenine
- C. Guanine
- D. Thymine
Explanation: Uracil forms a nucleoside with only ribose sugar while thymine forms the same with only deoxyribose sugar. Other nitrogen bases (i.e. adenine, guanine, cytosine) produce nucleosides with both sugars.
Correct answer: Thymine5048. Chlorophyll is a naturally occurring macromolecule that contains:
- A. Mg2+
- B. Al3+
- C. Fe3+
- D. B3+
Explanation: In chlorophyll, the central ion is magnesium, and the large organic molecule is a porphyrin.
Correct answer: Mg2+5049. Which of the following is necessary for the normal development of leaves and bark of the plants?
- A. Sodium
- B. Aluminium
- C. Calcium
- D. Beryllium
Explanation: Calcium plays an important role in producing plant tissues and it enables plants to grow better.
Correct answer: Calcium5050. Which one is a polymer substance?
- A. Glass
- B. Iron
- C. Plastic
- D. copper
Explanation: A polymer is a substance made of many repeating units called monomers. Plastics are formed by many identical repeating monomers thus are polymers.
Correct answer: Plastic