Assignment:
Introduction to Biochemistry
In this class, we discussed gluconeogenesis, glycogen metabolism, and the pentose phosphate pathway and their roles in glucose metabolism. Based on the topics discussed in Lecture #5, please answer each of the following questions.
1. Which enzyme-catalyzed reactions are shared between the gluconeogenesis and glycolysis pathways? (Note: just provide the name of the enzyme that catalyzes each of the shared reactions).
2. Why are some enzymes needed only in the gluconeogenesis pathway and not in the glycolysis pathway?
3. Which one of the following reactions only occurs during gluconeogenesis (i.e., not during glycolysis)?
a. 1,3-bisphosphglycerate into 3-phosphoglycerate
b. Glucose 6-phosphate into fructose 6-phosphate
c. Oxaloacetate into Phosphoenolpyruvate
d. Phosphoenolpyruvate into Pyruvate
4. An increase in glucagon levels can __________.
a. Promote the degradation of glycogen (i.e., glycogenolysis)
b. Occurs during the fasting state (starvation)
c. Promotes the synthesis of glycogen
d. A and B
5. A high school girl who is self-conscious about her appearance has been fasting for several days to fit into a dress she intentionally bought a size too small for a school dance. Which of her organs/tissues is producing the glucose that is being synthesized through gluconeogenesis?
a. Red blood cells
b. Muscles
c. Liver
d. Brain
6. Why do only some tissues (e.g., liver) contain the enzyme glucose-6- phosphatase?
7. What are the main products of the pentose phosphate pathway, and how does the cell use them?
8. How many molecules of ATP are produced during the metabolism of one (1) molecule of glucose through the pentose phosphate pathway?
9. Which two (2) molecules are produced during the pentose phosphate pathway that are also produced during glycolysis?
10. Describe two (2) specific things that make NADH and NADPH different from each other (Note: consider the structural and biological properties of the two molecules).
Discussion: (Artificial Sweetners, Glucose, and Self-Control)
Article: Sugar on the Brain
Video: The Science on Low-Calorie Sweeteners
We discussed glucose and how it is metabolized in our body to produce the energy (i.e., ATP) needed to perform biological activities that keep us alive. This article, published in The New Yorker, discusses the conclusions of a study that suggests there is a link between our blood glucose levels and irritability and self-control. Based on the topics we've covered in class regarding glucose, what are your thoughts on the different points of view discussed in this article? Do you disagree with any of the statements made in the article? If so, discuss why you disagree. Can any of the times you have experienced a lack of self-control or irritability be associated with you having low blood glucose levels? After viewing the video on the science of low-calorie (non-nutritive) sweeteners, did your opinion change regarding these products? If so, discuss how it changed. Since many of you are working toward a career in medical/health professions, would you recommend low-calorie (non-nutritive) sweeteners to your patients as a part of a weight management program?
You should contribute one (1) comment (at least 300 words) to this discussion. In your post, you should provide a detailed explanation to support your views (include references, if needed). You may use the questions I asked above or discuss another aspect of the article and video that caught your attention.
Readings:
Gluconeogenesis
By Dr. Omari J. Bandele