Metabolism

Question 1

Immediate sources of energy don’t require ___?

Answer 1

oxygen

Question 2

What are immediate sources of energy?

Answer 2

• anaerobic hydrolysis of ATP in cytosol
• phosphocreatine system
• adenylate kinase/myokinase system

Question 3

What are nonoxidatve/glycolytic sources of energy?

Answer 3

-catabolism of glucose/glycogen in cytosol with lactic acid accumulation

Question 4

How long can glycolytic energy sustain muscular activity?

Answer 4

rapid, high intensity for 15-30s

Question 5

What are oxidative sources of energy?

Answer 5

catabolism of carbs, fats, and proteins in mitochondria

Question 6

What is the primary energy source for long duration muscular contraction?

Answer 6

oxidative energy sources

Question 7

What is glycolysis?

Answer 7

aerobic or anaerobic breakdown of glucose

Question 8

What is glycogenesis?

Answer 8

synthesis of glycogen from glucose for storage in liver and muscle

Question 9

What is glycogenolysis?

Answer 9

glycogen is broken into glucose-1 phosphate for use by muscles

Question 10

What is gluconeogenesis?

Answer 10

synthesis of glucose from pyruvate or lactate; occurs in liver and kidneys

Question 11

What is the rate limiting step in glycolysis?

Answer 11

PFK

Question 12

Summary of Glycolysis:

Answer 12

• 1 molecule of 6-carbon glucose is broken down into 2 molecules pyruvate (pyruvic acid)
• glucose used=consumes 2 ATP and yields 4 ATP
• glycogen used= 1 ATP consumed and 4 ATP produced
• 2 NADH produced

Question 13

Under aerobic conditions during glycolysis, what happens to pyruvate and NADH and what cycles are they a part of?

Answer 13

transported to mitochondria

• pyruvate->acetyl-CoA=TCA cycle
• NADH=ETC

Question 14

Under anaerobic conditions during glycolysis, what happens to NADH and pyruvate?

Answer 14

• NADH is oxidized to NAD+

- pyruvate is reduced to lactate

Question 15

During glycolysis, what does an accumulation of pyruvate result in?

Answer 15

inhibition of ATP re-synthesis

Question 16

What is lactate oxidized to in working muscle?

Answer 16

pyruvate

Question 17

What is the preferred fuel for heart and red skeletal muscle?

Answer 17

pyruvate

Question 18

Lactate and pyruvate build up as a result of anaerobic glycolysis, but why is that not always bad?

Answer 18

both can be moved to other cells/organs and mitochondria for energy source or to the liver for gluconeogenesis

Question 19

What are facts about lactate?

Answer 19

1. Links aerobic and anaerobic metabolism
2. Shuttles NADH and electrons to the mitochondria
3. Helps regulate glucose levels
4. Stimulates mitochondrial biogenesis

Question 20

Is the oxidative system a slow or fast source of energy?

Answer 20

slow

Question 21

Where does the oxidative system come into play in relation to glycolysis?

Answer 21

after pyruvate and NADH produced (aerobic glycolysis)

Question 22

What is the rate limiting step in the oxidative system?

Answer 22

PDH–pyruvate dehydrogenase

Question 23

What is the ETC?

Answer 23

utilization of NADH from aerobic glycolysis and the TCA cycle

Question 24

What are the end products of ETC?

Answer 24

CO2 and O2

Question 25

What product goes to the TCA cycle after its conversion?

Answer 25

acetyl-CoA

Question 26

What is esterification?

Answer 26

attachment of FFAs to 3-carbon (glycerol) backbone = triglyceride

Question 27

Where does esterification occur?

Answer 27

in liver

Question 28

What is lipolysis?

Answer 28

process of triglyceride dissolution

Question 29

What is a lipoprotein?

Answer 29

mixture of triglycerides and phospholipids encapsulated by protein and cholesterol -transport for lipids

Question 30

Lipid metabolism can only occur in the presence of ___?

Answer 30

oxygen

Question 31

What are key events of lipid metabolism?

Answer 31

- Mobilization - Circulation - Uptake - Activation - Translocation - β-oxidation * TCA / Krebs Cycle * Electron Transport

Question 32

What is a FFA esterified to in the cytosol during lipid metabolism?

Answer 32

acyl coA

Question 33

Where does lipid metabolism take place?

Answer 33

in mitochondria

Question 34

What is beta-oxidation?

Answer 34

carbon atoms cleaved from fatty acyl coA producing acetyl CoA, NADH, and FADH->TCA and ETC

Question 35

Relate lipid oxidation to CHO oxidation in terms of O2 requirements and energy generation.

Answer 35

lipid requires more O2, but generates more energy than CHO

Question 36

What is RER?

Answer 36

ratio of CO2 production to O2 consumption

Question 37

RER .7 fuel source:

Answer 37

lipid

Question 38

RER .85 fuel source:

Answer 38

lipid-->CHO

Question 39

RER > 1.0 fuel source:

Answer 39

CHO

Question 40

Ketone bodies are produced where and as a result of what?

Answer 40

in liver | -low CHO intake, prolonged exercise, uncontrolled diabetes

Question 41

What are ketone bodies?

Answer 41

by-product of gluconeogenesis (FFAs converted to glucose)

Question 42

What can ketone bodies be re-converted into?

Answer 42

acetyl-CoA for energy source in nervous system, kidneys, or muscles

Question 43

What is ketosis?

Answer 43

when ketone synthesis by liver exceeds utilization by other tissues -fruity breath

Question 44

What is ketoacidosis?

Answer 44

low insulin levels and high glucagon concentration induces high glucose production by liver, which lowers pH and induces renal excretion of acid that can result in dehydration

Question 45

How are proteins metabolized?

Answer 45

catabolized into amino acids thru proteolysis

Question 46

Can proteins and amino acids be stored?

Answer 46

no

Question 47

What is the amino acid pool?

Answer 47

total amino acids available from dietary sources or degradation of existing protein

Question 48

What is a product of protein metabolism?

Answer 48

ammonia

Question 49

How is ammonia excreted?

Answer 49

converted to urea and excreted as sweat or urine

Question 50

Once proteins are deaminated, what do AAs appear as?

Answer 50

pyruvate and TCA cycle intermediates