Glycolysis & Creb Cycle Biochemistry

[littlelady]

Can someone help me out??

1. The synthesis of glucose from smaller precursors is called:
a) gluconeogenesis.
b) glycogenolysis.
c) glucosynthesis.
d) glycolysis.
e) none of the above

I think the answer is A. gluconeogenesis...because gluconeogenesis is from puruvate back to glucose..i am not sure If that's right...

2. Disaccharides commonly found in human diets include:
a) maltose, sucrose and fructose.
b) maltose, fructose and lactose.
c) maltose, sucrose and lactose.
d) glucose, sucrose and lactose.
e) none of the above


I thnk it's c) maltose, sucrose and lactose. because maltose ( glucose + glucose ), sucrose ( fructose and glucose ) and lactose ( galactose in milk and glucose )...am I right?

3. The steps in glycolysis that are different than those in gluconeogenesis are catalyzed by these
enzymes.
a) pyruvate kinase, phosphofructokinase, glucokinase
b) pyruvate kinase, glucokinase, hexokinase
c) pyruvate kinase, phosphofructokinase, triose phosphate isomerase
d) pyruvate kinase, phosphofructokinase, hexokinase

I think it's D because pyruvate kinase is irreversible step, hexokinase and PFK 1...

4. Which of the following statements is false?
a) In skeletal muscle glucose is broken down into lactate via glycolysis.
b) In liver lactate is converted to glucose via gluconeogenesis.
c) In skeletal muscle glucose is broken down into lactate via gluconeogenesis.
d) a and b are both false
e) a and c are both false

I think the answer is E because lactate only produce when there is no oxygen present. glucose is not broken down into lactate..only purvuate broken it down when there is no O2.

5. UDP-galactose can be synthesized from:
a) Isomerization of UDP-glucose
b) Exchange of UDP
c) degradation of glycogen
d) a and b
e) a, b and c

I think it's D..because UDP glactose can't go into glycolysis...it's just exchange UPD glactose with upd GLUCOSE...

6. Which of the following molecules affect the activity of phosphofructokinase?
a) ATP and AMP
b) TTP and biotin
c) citrate and fructose-2,6-bisphosphate
d) a and b
e) a and c


I think the answer is B.

7. To mobilize glucose from glycogen for energy, the activity of ______ is (are)carefully
regulated to ensure sufficient energy is available for use.
a) pyruvate decarboylase
b) glycogen phosphorylase
c) glycogen kinase
d) a and b
e) a and c


i THINK the answer is D because pyruvate is broken down to give us energy and phophate from glycogen is what give us energy...is it right?

12. The cause(s) of lactic acidosis is (are):
a) liver disease.
b) extreme exercise and overheating.
c) drug side effects.
d) a and b
e) a, b and c

I am not sure for this

14. In the pyruvate dehydrogenase complex reactions, the FADH2 is reoxidized by:
a) NAD+
b) FAD
c) lipoamide
d) TPP
e) none of the above

I think it's A...becuase..it's need to go back to NAD+...because NAD+ is reduce NADH...so it needs to go back to NAD+..is it right?

18. Why can’t the citric acid cycle be described as either catabolic or anabolic?
a) because it generates both energy and reducing equivalents
b) because it is a cyclic pathway
c) because 6 of the 8 intermediates are precursors to another pathway or products derived from
another pathway
d) a and c
e) none of the above

I think it's A...

19. Succinate dehydrogenase requires the prosthetic group:
a) TPP
b) FAD
c) NADH
d) all of the above
e) none of the above

I think it's B because FAD is prosthetic group..it's can't leave an enzyme.

25. In cyclic electron flow, the energy is recovered as:
a) NADPH.
b) a proton gradient.
c) FADH2 and NADH.
d) all of the above
e) none of the above

I think it's E. none of the above...but not sure...because energy is recovered as NADH...but FADH2 IS not..because FADH2 is only help to transfer NADH to electron carrrier

The Attempt at a Solution

 

[ace123]

Well lactic acidosis is the build up of lactic acid. This occurs when? Also think about the liver and it's role in glycolysis. Is this enough of a hint?

 

[Blueshift5]

:

1. Correct, the synthesis of glucose from smaller precursors is called gluconeogenesis.

2. Correct, disaccharides commonly found in human diets include maltose, sucrose, and lactose.

3. Correct, the steps in glycolysis that are different than those in gluconeogenesis are catalyzed by pyruvate kinase, phosphofructokinase, and hexokinase.

4. Correct, statement C is false because in skeletal muscle, glucose is broken down into pyruvate via glycolysis, not gluconeogenesis.

5. Correct, UDP-galactose can be synthesized from isomerization of UDP-glucose and exchange of UDP.

6. Correct, ATP and AMP affect the activity of phosphofructokinase.

7. Correct, the activity of pyruvate decarboxylase and glycogen phosphorylase are carefully regulated to ensure sufficient energy is available for use.

12. Correct, the causes of lactic acidosis include liver disease, extreme exercise and overheating, and drug side effects.

14. Correct, FADH2 is reoxidized by NAD+ in the pyruvate dehydrogenase complex reactions.

18. Correct, the citric acid cycle cannot be described as either catabolic or anabolic because it generates both energy and reducing equivalents, is a cyclic pathway, and many of its intermediates are precursors or products of other pathways.

19. Correct, succinate dehydrogenase requires the prosthetic group FAD.

25. Correct, in cyclic electron flow, the energy is recovered as a proton gradient, not NADPH or FADH2.