Lecture 18: Energy Balance and Metabolism II

Question 1

How it ATP generated?

Answer 1

Combustion of carbohydrates, fatty acids, proteins

Question 2

How is phosphocreatine used as a storage depot for energy?

Answer 2

Can be directly interchanged with ATP, used as storage since ATP cannot be stored

Question 3

How is phosphocreatine used as an ATP buffer?

Answer 3

Keeps the concentration of ATP high in the presence of phosphocreatine

Question 4

Essential Amino Acids

Answer 4

Cannot be synthesized by the body; MUST be obtained from diet

Question 5

Non-essential Amino Acids

Answer 5

Formation depends on alpha-keto acid precursors; can be synthesized in the body

Question 6

What enzyme is required to synthesize alanine from pyruvic acid?

Answer 6

Transaminase

Question 7

What is a peptide linkage?

Answer 7

A bond formed between N-CO that connects amino acids, where H2O is released by condensation

Question 8

How many high-energy phosphate bonds are needed to form one peptide linkage?

Answer 8

4 phosphate bonds

Question 9

What are the resulting products of deamination?

Answer 9

Energy release and ammonia

Question 10

Which of the following occurs in the mitochondria during the Ornithine/Urea cycle?

A. Arginine –> Urea + Ornithine
B. Citrulline + aspartate –> argininosuccinate
C. Ammonia + CO2 –> carbamoyl phosphate
D. Fumarate enters TCA cycle

Answer 10

C. Ammonia + CO2 –> carbamoyl phosphate

Question 11

What are the 2 determinants of the chemical reaction rate?

Answer 11

1. Concentration of enzyme

2. Concentration of substrate

Question 12

How is the reaction rate influenced by high substrate concentration?

Answer 12

Reaction rate will be determined almost entirely by concentration of enzyme

Question 13

How is the reaction rate influenced by high enzyme concentration?

Answer 13

Reaction rate will be directly proportional to concentration of substrate and enzyme

Question 14

What is the major rate-limiting factor for almost all energy metabolism in the body?

Answer 14

ADP

Question 15

Energy equivalent of oxygen

Answer 15

Energy liberated per liter of oxygen with average diet = 4.825 Cal

Question 16

Basal Metabolic Rate

Answer 16

Minimum level of energy required for a person to “exist”; avg 70 kg male lying in bed all day uses 1650 Cal/day

Question 17

How does thyroxine influence BMR?

Answer 17

Increases BMR by increasing reaction rates in cells

Question 18

How does testosterone influence BMR?

Answer 18

Testosterone influences BMR 10-15%; related to increase in skeletal muscle mass

Question 19

How does malnutrition influence BMR?

Answer 19

Results in marked reduction in metabolic rate

Question 20

How does aging influence BMR?

Answer 20

BMR declines, related to loss of muscle mass/gain of adipose tissue

Question 21

How does BMR differ between gender?

Answer 21

Male BMR slightly higher than female BMR; related to skeletal muscle mass

Question 22

Glycogenolysis

Answer 22

Breakdown of glycogen to form glucose molecules

Question 23

Gluconeogenesis

Answer 23

Formation of glucose