Which of the following activates ribulose1 5bisphosphate car

Which of the following activates ribulose-1, 5-bisphosphate carboxylase (RuBisCO)? A. Phosphorylation of ribulose-1, 5-bispbosphate carboxylase B. High pH in the stroma C. Absence of light D. Low level of magnesium in the stroma E. Low concentration of ribululse-1, 5-bisphosphate What is the main goal of phase 3 of the Calvin Cycle? A. To produce glucose. B. To produce 3-phophoglycerate. C. To produce glyceraldehyde 3-phosphate. D. To produce ribulose-1, 5-bisphosphate. E. To produce ATP and NADPH. How many molecules of CO2 must be fixed to produce one molecule of glucose? A. One B. Two C. Three D. Six E. Twelve Which organ is the primary regulator of blood glucose levels? A. Pancreas B. Liver C. Skeletal muscle D. Adipose tissue E. Intestines Insulin: A. activates glycogen phosphorylase. B. activates glycogen synthase. C. activates protein kinase A and phosphorylase kinase. D. inhibits glycogen synthesis. E. activates gluconeogenesis. Which enzyme catalyzes the removal of the trans double bond during beta oxidation? (see figure inside of cover page) A. Acyl-CoA-dehydrogenase B. Enoyl-CoA hydratase C Hydroxyacyl CoA dehydrogenase D. B-ketothiolase E. Glycerol kinase

Solution

1. RubisCO activates itself by an enzyme called rubisCO activase. RubisCO activase itself is activated by increased concentrations of ATP in the stroma caused by its phosphorylation. It also needs magnesium ions for its activation.

Therefore, option 1(phosphorylation of RubisCO) is correct.

2. Production of ATP and NADPH during the light reaction of photosynthesis.

G-3-P and glucose molecules are produced during the reduction phase of Calvin cycle.

Regeneration of RuBP is during the third phase of Calvin cycle.

Therefore, option D (production of RuBP) is correct. The main goal of phase 3 of Calvin cycle is the production of RuBP.

3. For the formation of one G-3-P molecule, three CO2 molecules are required.

Therefore, for the formation of one glucose molecule, which is a six carbon compound, six CO2 molecules have to be fixed.

Therefore, option D (six) is correct.

4. The primary regulator of blood glucose levels is pancreas.

When blood sugar level rises, pancreas immediately secretes insulin.

Therefore, option A (pancreas) is correct.

5. Insulin activates the enzymes which are required for glycogen synthesis.

Insulin inhibits glycogenolysis and gluconeogenesis.

Therefore, option B is correct. It activates glycogen synthase.

6. In beta oxidation, the removal of trans double bond occurs during the hydration reaction.

Trans- Enoyl CoA is hydrated to beta hydroxyl CoA. This hydration reaction is catalyzed by an enzyme Enoyl- CoA hydratase.

Therefore, option B (Enoyl-coA hydratase) is correct.