Question

1. One could say that the Calvin cycle is a
   1. reducing cycle
   2. oxidizing cycle
   3. neutral cycle (no net oxidation or reduction)
   4. hydrating cycle (water is introduced)

2. Succinate is produced in the glyoxylate cycle by the action of the enzyme
   1. citrate synthase                       c. aconitase
   2. isocitrate lyase                        d. malate synthase

3. The fatty acid most commonly made by animal cells is    
   1. myristic                                             c. stearic
   2. lauric                                       d. palmitic

4. The number of enzymes used in the synthesis of fatty acids is
   1. 1                      b. 2                  c. 5                  d. 7

Answer 1

• Calvin cycle is a

a. reducing cycle

Explanation-

Calvin cycle reduces a total of nine molecule of ATP and six molecules of NADPH. ATP and NADPH are used to convert the 3-PGA molecules into molecules of a three-carbon sugar, glyceraldehyde-3-phosphate (GA3P). NADPH donates electrons to, or reduces, a three-carbon intermediate to make GA3P.

• Succinate is produced in the glyoxylate cycle by the action of the enzyme

b. Isocitrate lyase

Isocitrate lyase enzyme in the glyoxylate cycle catalyzes the cleavage of isocitrate to succinate and glyoxylate. Glyoxylate is converted to malate by malate synthase. These two steps bypasses the two decarboxylation steps of the tricarboxylic acid cycle (TCA cycle) .This cycle is used by bacteria, fungi, and plants.

• The fatty acid most commly made by the animal cell is-

d. Palmitic acid

Palmitic acid is the most common saturated fatty acid accounting for 20–30% of total fatty acids in the animal body. Animal cells can itself synthesize palmitic fatty acid and its n-9 derivatives.

• The number of enzymes used in the synthesis of fatty acids is-

a. 2

Explanation-

Acetyl-CoA carboxylase and fatty acid synthase are the two enzymes required in fatty acid. Acetyl-CoA catalyzes synthesis of malonyl-CoA. Fatty acid synthase catalyzes all the reaction steps in the conversion of acetyl-CoA and malonyl-CoA to palmitate.