Advanced Final

1. During fasting conditions, glucagon induces phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase as a means to increase gluconeogenesis in the muscles. In the liver, muscle doesn’t have glucose-6-phosphatase 

1. True 

Would be true if it said the liver/kidneys 

2. False 

Gluconeogenesis is not done in the muscles.  

2. All tissues prefer glucose first, and then fatty acids, to meet their energy needs. The brain uses glucose first then ketone bodies. Red blood cells cannot use fatty acids as a fuel source since they do not have a mitochondria.  

1. True 

The brain and red blood cells can only use glucose.  

2. False 

Some tissues use fatty acids first.  

3. The Cori cycle would be active during the fed state. Cori cycle is the exchange of lactate and pyruvate in the liver and muscle. Lactate from the muscle to the liver to make energy and goes back to the liver.  

1. True 

Cori cycle is not active when during the fed state since there is glucose that can be used.  

2. False  

The Cori cycle is active during the fasting state and when you are working out.  

4. In the fasting state, the muscles meet their glucose needs by first using their glycogen stores, and then converting amino acids into glucose. Gluconeogenesis (production of glucose from non glucose things). Done in liver and in kidneys during starvation, not in muscles.  

1. True 

The liver converts amino acids into glucose.  

2. False 

Muscles use fatty acids and ketone bodies.  

5. During very prolonged starvation, nearing death, the body shifts from using protein for energy to using fat stores. Textbook doesn’t have information, not on exam  

1. True 

Body uses fat stores than protein.  

2. False 

The body uses fat stores than protein broken down from muscle.  

6. Glucagon and insulin control metabolic pathways that reflect a fasting and fed state, respectively; the primary signal to initiate this hormonal control is the glucose concentration in the blood.  

1. True 

Glucagon regulates hypoglycemia and insulin regulates hyperglycemia.  

2. False 

Glucagon and insulin are used to regulate blood sugar levels.  

7. Protein synthesis is active in the fasting state. During the fed state 

3. True 

Protein synthesis is active during the fed state.  

4. False  

During fasting the body does not make protein, but breaks it down for energy.  

8. Gluconeogenesis occurs only in the liver. Also in the kidneys during starvation 

1. True 
   It mainly occurs in the liver.  

2. False 

During fasting gluconeogenesis can also occur in the liver.  

9. The liver and muscles are important for regulating blood glucose, especially when blood glucose is low. Kidneys are more helpful than the muscles. Muscles have stored glycogen and glucose from glycogen stores are only kept within the muscle. High BG muscles take up glucose. Not when low since muscles do not have glucose six phosphate. Muscles use GLUT4 to the cells. Insulin can lower BG level through increased muscle and adipose tissue uptake and GLUT4 and glucokinase in the liver. More glucokinase = free glucose -> glucose 6-phosphate.  

1. True  

The liver and kidneys are important for regulating blood glucose.  

2. False 

The muscles are not super helpful for regulating blood glucose.  

Multiple choice questions  

10. Insulin insensitivity can result in ______________________. Not on exam 

a. Hyperinsulinemia 

Increased insulin levels 

b. Hyperglycemia 

Increased glucose levels 

c. Hyperlipidemia 

Increased lipid levels 

d. All of the above 

Insulin insensitivity can lead to high blood glucose, insulin levels, and lipid levels. Insulin insensitivity/resistance is common in obesity.  

e.   None of the above 

All of the above are correct.  

11. What is the preferred source of energy used by the brain during prolonged starvation? 

1. Ketones 

Ketone bodies are made in the liver.  

2. Glucose 

Glucose is used during the fed state.  

3. Fatty acids 

Major fuel for muscle.  

4. Amino acids 

Can be used to make glucose in gluconeogenesis.  

12. Which of the following is the action of insulin during the fed state? 

1. It increases the number of GLUT 4 in the plasma membrane of the muscle cells.  

GLUT4 is a glucose transporter, so insulin increases glucose uptake.  

2. It inhibits the activity of anabolic enzymes. stimulates 

Insulin increases anabolic enzymes and has an anabolic effect.  

3. It stimulates the synthesis of catabolic enzymes. inhibits 

Decreases synthesis of catabolic enzymes (has anabolic effect instead) 

4. It increases the number of GLUT 2 in the plasma membrane of the liver cells. GLUT4 

GLUT2 is not insulin dependent.  

13. Which of the following is NOT transported by the vascular system? Not on exam 

1. Hormones from the endocrine system 

In the bloodstream (vascular system) 

2. Oxygen from the respiratory system 

In the bloodstream (vascular system) 

3. Regulatory neural messages from the nervous system 

Related to nerves, not in the blood.  

4. Organic nutrients and minerals from the digestive system 

In the bloodstream (vascular system) 

14. Which amino acid plays an important role in controlling toxicity from ammonia released during amino acid catabolism? Glutamine can transport to the liver.  

1. Glutamine  

Removes ammonia (toxic waste product in the body) 

2. Glycine 

Non-essential AA, not related to ammonia 

3. Serine 

Non-essential AA, not related to ammonia 

4. Valine 

Essential AA, not related to ammonia 

15. Which amino acid produced by the transamination of pyruvate with glutamate provides a disposal route for nitrogen produced from the catabolism of muscle amino acids? Alanine-glucose cycle 

1. Histidine 

Non essential AA, not linked to nitrogen 

2. Tyrosine 

Essential AA, not linked to nitrogen 

3. Tryptophan 

Essential AA, not linked to nitrogen 

4. Alanine 

Seen in the alanine glucose cycle 

16. Amino acids used primarily by muscle for synthesis of dispensable amino acids and for protein synthesis are: Not on exam 

1. branched-chain amino acids. 

Valine, leucine, isoleucine are the branched chain AAs  

2. aromatic amino acids. 

Have aromatic ring; include phenylalanine, tyrosine, and tryptophan 

3. basic amino acids. 

Have a basic amino group, not linked to protein synthesis 

4. acidic amino acids. 

Have an acidic amino group, not linked to protein synthesis 

17. The brain cannot use fatty acids for energy because ____________________________.  

1. The brain cells lack mitochondria. 

The brain has mitochondria. Red blood cells do not have mitochondria.  

2. Fatty acids cannot cross the blood-brain barrier. 

The blood-brain barrier is selective.  

3. All of the above. 

The brain does have mitochondria in it’s cells.  

4. None of the above. 

The blood-brain barrier is selective and doesn’t allow fatty acids.  

18. Amino acids from muscle breakdown provide the primary substrate for which metabolic process? Gluconeogenesis if sent to the liver since the muscle cannot do gluconeogenesis.  

1. Glycolysis 

Breaking down of stored glycogen to glucose for energy.  

2. Gluconeogenesis 

Formation of glucose from non-glucose products (lactate, pyruvate, glycerol, certain AAs) 

3. Glycogenesis 

Formation of new glycogen from glucose in a fed state.  

4. pentose phosphate pathway 

Metabolizes glucose-6-phosphate to pentose phosphate making NADPH 

19. Because muscle does not have the enzyme, _________________, the muscle cannot help regulating blood glucose levels during the fasting state?  

a. glucose-6-phosphatase 

Glucose-6-phosphatase converts glucose-6-phosphate into free glucose and is not in the muscle.  

b. phosphofructokinase  

Used in glycolysis 

c. Hexokinase 

Catabolizes glucose -> glucose-6-phosphate  

d. Glucokinase 

Used in glucose phosphorylation.  

20. What is the final common catabolic pathway for the metabolism of carbohydrates, proteins, and fats to generate energy?  

a. Pyruvate, acetyl-CoA 

Acetyl-CoA goes into the Krebs cycle 

b. Glycolysis 

Breakdown of stored glycogen 

c. Krebs cycle; electron transport 

Krebs cycle/citric acid cycle and electron transport chain make energy.  

d. lipolysis, β-oxidation 

Seen in breakdown of fats 

e.   All of the above 

Some are only seen in certain macronutrients.  

21. ________________ stimulates __________ in the liver during the fed state and ________________ stimulates _____________in the liver during the fasting state.  

1. Insulin, glycogenesis; Glucagon, gluconeogenesis 

Insulin -> creation of glycogen (storage form of glucose), glucagon -> creation of glucose form non-glucose substances (lactate, pyruvate, glycerol, certain AAs) 

2. Insulin, glycogenolysis; Glucagon, glycolysis 

Glucagon does not trigger the breakdown of glycogen.  

3. Glucagon, gluconeogenesis; Insulin, glycogenesis 

Glucagon is not overly active in the fed state.  

4. Glucagon, glycolysis; Insulin, glycogenolysis 

Glucagon is not overly active in the fed state.  

More notes: Glucose is taken up by hepatocyte by facilitated diffusion? T/F: True, GLUT2 (all GLUTs are facilitated) know the transporter and whether it is facilitated. GLUT2 is used in enterocyte glucose, galactose, fructose (monosaccharides).  

Which of the following is incorrect about glycolysis? Glycolysis occurs in RBC T, Most ATP synthesis is made in glycolysis F (most is made in electron transport chain or beta oxidation),  

Uncontrolled type 2 diabetes: Lack of proper insulin function – regulation of glucose uptake to the brain is not abnormal since GLUT4 is not found in the brain.