Question

1. Which of the following statements about the process of translation is INCORRECT?

a. Translation ends when the ribosome encounters a stop codon.

b. The polypeptide might be attached to a tRNA found either in the “A” site or in the “P” site of the ribosome.

c. Ribosomes and initiation factors begin translation by locating the promoter.

d. An “empty” tRNA (attached neither to an amino acid nor to a polypeptide) might be found either in the “E” or in the “P” site of the ribosome.

2. When a chloroplast is illuminated with visible light, electron transport and proton pumping can raise the pH of the stroma to around 8 and lower the pH of the thylakoid lumen to about 4. This means that the concentration of hydrogen ions (H⁺) in the thylakoid is roughly _____ times that observed in the stroma.

a. 10,000

b. 2

c. 0.5

d. 0.0001

3. In the context of the process of oxygenic photosynthesis, the _____ require(s) the greatest amount of energy while the _____ requires the least amount of energy.

a. light-dependent reactions — fixation of carbon dioxide

b. reduction of 3PG to G3P — regeneration of RuBP

c. reduction of 3PG to G3P — fixation of carbon dioxide

d. fixation of carbon dioxide — regeneration of RuBP

4. During the process of cellular aerobic respiration, which of the following steps gives off the LEAST amount of energy?

a. Chemiosmosis

b. Glycolysis

c. The Citric Acid Cycle

d. Electron Transport

5. A cell cycle checkpoint at the end of the G₁ phase might assess any of the following EXCEPT whether

a. all DNA is duplicated successfully.

b. the cell is large enough to divide successfully.

c. there is any damage to DNA strands.

d. the cell has a sufficient quantity of ribosomes and mitochondria..

6. During the process of DNA replication, each of the following steps proceeds in the 5' —> 3' direction EXCEPT the

a. production of the leading strand in a replication bubble.

b. "reading" of each DNA strand by DNA polymerase.

c. production of the RNA primer by primase.

d. production of the lagging strand in a replication bubble.

Answer 1

1. C) Ribosomes and initiation factors begin translation by locating the promoter.

The above statement is wrong regarding the translation. Promoter region is important for the transcription. Translation starts with the start codon.

2. a) 10,000

pH = - log 10 [H+]. Here, the pH is determined by the hydrogen ion concentration to the base 10. Therefore, each single unit of pH change would be the effect of hydrogen ion concentration in ten fold. To make the 4 pH change, it needs to observe 10000 (104) hydrogen ion from the thylakoid.