Biochem Exam 3 QUESTIONS and WELL-VERIFIED ANSWER
2026
Which of the following pathways use intermediates of the citric acid cycle?
I. glucogenesis
II. amino acid biosynthesis
III. fatty acid oxidation
IV. glycolysis
A. I, II
B. I, III
C. II, IV
D. III, IV
E. I, IV - ANSWER✔✔🌹-A. I, II
Which of the monosaccharides seen below are L sugars?
A) C and D
B) A and C
C) A and B
D) A, B, and C
E) B and C - ANSWER✔✔🌹-A) C and D
,At equilibrium in solution, D- Glucose consists of a mixture of its anomers. Which statement most
accurately describes the solution?
A) Consists of approximately equal amounts of the a-and B-anomers
B) the a-anomer is more stable and is slightly preferred over the B-anomer
C) the B-anomer predominates over the a-anomer by a ratio of approximately 2:1
D) Straight chain form is present in high concentration
E) None of the above - ANSWER✔✔🌹-C) the B-anomer predominates over the a-anomer by a ratio of
approximately 2:1
The structure below shows a Fischer projection of D-idose. Which of the structures below represents B-
D-idopyranose?
A) A
B) B
C) C
D) D
E) E - ANSWER✔✔🌹-E) E
In the following structure, which carbon is the anomeric carbon?
A) A
B) B
C) C
D) D
,E) E - ANSWER✔✔🌹-E
The configuration around which carbon atom shown in the figure determines whether this is a D or an L
sugar?
A) A
B) B
C) C
D) D
E) E - ANSWER✔✔🌹-A) A
Which structures shown in the picture below represent reducing sugars?
A) A
B) D
C) C and D
D) A, B, C, and D
E) A, B, and C - ANSWER✔✔🌹-E) A, B, and C
To be a reducing sugar, you need a free aldehyde or ketone group (aka last in the chain), A, B, and C
have free ketones on the top part of their chain. *(Remember this note for the exam there's question
asking which is not a reducing sugar)*
Amylopectin contains primarily ___ glycosidic bonds with ____ glycosidic bonds as branch points
A) B (1->4); a (1->6)
B) a (1->4); B (1->6)
C) B (1->4); a (1->4)
, D) a (1->4); a (1->2)
E) a (1->4); a (1->6) - ANSWER✔✔🌹-E) a (1->4); a (1->6)
In which of the following metabolic conversions is ATP required during glycolysis?
I. fructose-6-phosphate -> fructose-1,6-bisphosphate
II. glucose -> glucose-6-phosphate
III. fructose-1,6-bisphosphate -> dihydroxyacetone phosphate + glyceraldehyde-3-phosphate
IV. glucose-6-phosphate -> fructose-6-phosphate
A) I only
B) II only
C) I, II
D) I, III
E) I, IV - ANSWER✔✔🌹-C) I, II
- catalyzed by phosphofructokinase in (i), catalyzed by hexokinase in (II), both need ATP (memorize
these they might be individually on the exam)
Which of the following is a potent activator of phosphofructokinase in mammals?
A) fructose-1,6-bisphosphate
B) fructose-6-phosphate
C) glucose-6-phosphate
D) glyceraldehyde-3-phosphate
E) fructose-2,6-bisphosphate - ANSWER✔✔🌹-E) fructose-2,6-bisphosphate
2026
Which of the following pathways use intermediates of the citric acid cycle?
I. glucogenesis
II. amino acid biosynthesis
III. fatty acid oxidation
IV. glycolysis
A. I, II
B. I, III
C. II, IV
D. III, IV
E. I, IV - ANSWER✔✔🌹-A. I, II
Which of the monosaccharides seen below are L sugars?
A) C and D
B) A and C
C) A and B
D) A, B, and C
E) B and C - ANSWER✔✔🌹-A) C and D
,At equilibrium in solution, D- Glucose consists of a mixture of its anomers. Which statement most
accurately describes the solution?
A) Consists of approximately equal amounts of the a-and B-anomers
B) the a-anomer is more stable and is slightly preferred over the B-anomer
C) the B-anomer predominates over the a-anomer by a ratio of approximately 2:1
D) Straight chain form is present in high concentration
E) None of the above - ANSWER✔✔🌹-C) the B-anomer predominates over the a-anomer by a ratio of
approximately 2:1
The structure below shows a Fischer projection of D-idose. Which of the structures below represents B-
D-idopyranose?
A) A
B) B
C) C
D) D
E) E - ANSWER✔✔🌹-E) E
In the following structure, which carbon is the anomeric carbon?
A) A
B) B
C) C
D) D
,E) E - ANSWER✔✔🌹-E
The configuration around which carbon atom shown in the figure determines whether this is a D or an L
sugar?
A) A
B) B
C) C
D) D
E) E - ANSWER✔✔🌹-A) A
Which structures shown in the picture below represent reducing sugars?
A) A
B) D
C) C and D
D) A, B, C, and D
E) A, B, and C - ANSWER✔✔🌹-E) A, B, and C
To be a reducing sugar, you need a free aldehyde or ketone group (aka last in the chain), A, B, and C
have free ketones on the top part of their chain. *(Remember this note for the exam there's question
asking which is not a reducing sugar)*
Amylopectin contains primarily ___ glycosidic bonds with ____ glycosidic bonds as branch points
A) B (1->4); a (1->6)
B) a (1->4); B (1->6)
C) B (1->4); a (1->4)
, D) a (1->4); a (1->2)
E) a (1->4); a (1->6) - ANSWER✔✔🌹-E) a (1->4); a (1->6)
In which of the following metabolic conversions is ATP required during glycolysis?
I. fructose-6-phosphate -> fructose-1,6-bisphosphate
II. glucose -> glucose-6-phosphate
III. fructose-1,6-bisphosphate -> dihydroxyacetone phosphate + glyceraldehyde-3-phosphate
IV. glucose-6-phosphate -> fructose-6-phosphate
A) I only
B) II only
C) I, II
D) I, III
E) I, IV - ANSWER✔✔🌹-C) I, II
- catalyzed by phosphofructokinase in (i), catalyzed by hexokinase in (II), both need ATP (memorize
these they might be individually on the exam)
Which of the following is a potent activator of phosphofructokinase in mammals?
A) fructose-1,6-bisphosphate
B) fructose-6-phosphate
C) glucose-6-phosphate
D) glyceraldehyde-3-phosphate
E) fructose-2,6-bisphosphate - ANSWER✔✔🌹-E) fructose-2,6-bisphosphate
