W1-L3: Energy Metabolism

Question 1

What is Phosphocreatine? (PcR)

Answer 1

• A high-energy phosphate compound
• Cells store approximately 4-6x more PCr than ATP
• Free energy releases when the bond cleaves between PCr’s creatine and phosphate molecule

Question 2

PCR Enzymes

Answer 2

Question 3

PCr and ATP during SPRINT exercise

Answer 3

explain

Question 4

Can physical training increase the muscles’ quantity of high-energy phosphates?

Answer 4

yes do interval of maximal movement training to increase storage

Question 5

Cellular oxidation: Electron Transport

Answer 5

slide 35

Question 6

3 ATP for every NADH + H+…but really 2.5.. Why?
2 ATP for every FADH2 … but really 1.5… Why?

https://www.youtube.com/watch?v=zJNx1DDqIVo

Answer 6

uses ATP

Question 7

What are the 3 requirements for an uninterrupted electron transport chain?

Answer 7

1. Tissue availability of the reducing agent NADH or FADH2
2. Presence of the oxidizing agent oxygen in the tissues
3. Sufficient concentration of enzymes and mitochondria to ensure that energy transfer reactions proceed at their appropriate rate

Question 8

What are the 3 Stages of Energy release form Macronutrients?

Answer 8

Stage 1: digestion, absorption and assimilation of large food macromolecules into smaller subunits for use in cellular metabolism

Stage 2: degrade amino acid, glucose, fatty acid and glycerol units within the cytosol into acetyl-coenzyme A, with limited ATP and NADH production

Stage 3: within the mitochondrion, acetyl-coenzyme A degrades to CO2 and H2O with considerable ATP production

Question 9

What is Aerobic or slow Glycolysis?

Answer 9

• Slow process
• Substantial ATP formation
• pyruvate become the end product. Will go through other processes to further breakdown in the citric acid cycle and electron transport production of ATP

Question 10

What is Anaerobic or rapid Glycolysis?

Answer 10

• Rapid process
• Limited ATP production
• Lactate is formed from pyruvate and is the end produc

Question 11

Energy Release from Carbohydrate

Answer 11

1:1 Ratio

Question 12

What is Rapid Glycolysis, where does it take place?

Answer 12

• Occurs outside of the mitochondria
• Important for maximum effort physical activity for up to about 90s

Question 13

What is Glycogenesis?

Answer 13

glycogen synthesis

Question 14

What is Glycogenolysis?

Answer 14

glycogen breakdown
- the glycogen reacts with a phosphate and become G6P
- When this occurs, we get a net gain of 3 ATP instead of 2 ATP

Question 15

What is the starting substrate of Glycolosis?
What is the Net Gain of ATP?
What if the starting Substrate is Glycogen?

Answer 15

Glucose

The net gain of ATP in glycolysis is 2 ATP molecules per glucose molecule.

we get a net gain of 3 ATP instead of 2 ATP

Question 16

Answer 16

Glucose to G6P uses 1 ATP (not glycogen)
make 2 ATP
use 2 ATP
make 2 ATP
Net Gain of 2

research more on when each ATP is used

Question 17

What Three factors regulate glycolysis?

Need to know specific enzymes (rate-limiting Enzymes)

Answer 17

1. Concentration of the four key glycolytic enzymes: hexokinase, phosphorylase, phosphofructokinase and pyruvate kinase
2. Levels of the substrate fructose 1-6-diphosphate
3. Oxygen, which in abundance inhibits glycolysis

Question 18

What is Lactate?

Answer 18

“steady rate” exists when hydrogen oxidizes at about
the same rate it becomes available

Question 19

Lactate

What is the Cori Cycle?

Answer 19

Cori cycle removes lactate released from active muscles and uses it to replenish glycogen reserves depleted from intense physical activity

Question 20

What is Lactate shuttling?

Answer 20

Lactate shuttling is a process whereby lactate produced in one muscle fiber will circulate to another, convert to pyruvate then to acetyl CoA and enter the citric acid cycle

Question 21

What happens if energy demand exceeds O2 supply or its rate of use?

Answer 21

need to make lactate to replinish NAD+
check that

Question 22

The Citric Acid Cycle (also Krebs Cycle)

Answer 22

Question 23

A more in depth look at the citric acid cycle

Answer 23

Question 24

NET ATP GAIN

Answer 24

Question 25

Anaerobic Versus Aerobic Glycolysis

Answer 25

Anaerobic Versus Aerobic Glycolysis

• Two forms of carbohydrate breakdown:

1. Anaerobic (rapid) glycolysis results in pyruvate-to- lactate formation with the release of about 5% of energy within the original glucose molecule -Rapid, but less ATP
2. Aerobic (slow) glycolysis results in pyruvate-to- acetyl-CoA-to-citric acid cycle and electron transport of the remaining energy within the original glucose molecule - Slower, but more ATP (Efficient)

Question 26

Net ATP Gain from glycolosis and Krebs

Answer 26

Question 27

Energy Release from Fat

Answer 27

Fuel reserves from fat come from 2 main sources:
1. 60,000-100,000 kcal form triacylglycerol in fat cells
2. 3000 kcal from intramuscular triacylglycerol
Perspective: Carbohydrates energy reserves generally amount to less than 2000 kcal

Question 28

Fat Catabolism comes from what?

Answer 28

1. Triacylglycerols stored directly within the muscle fiber in close proximity to the mitochondria
2. Circulating Triacylglycerols in lipoprotein complexes that become hydrolyzed on the surface of a tissue’s capillary endothelium
3. Circulating free fatty acids mobilized from Triacylglycerols in adipose tissue

Question 29

Answer 29

Question 30

What is Beta oxidation?
What does it produce?

Answer 30

removal of 2- carbon units by oxidation at the fatty acyl-CoA molecule

Each round of B-oxidation produces one mole of NADH, one mole of FADH2 and one mole of acetyl-CoA

Question 31

What is the Total energy transfer from fat catabolism?

Answer 31

• For each 18-carbon fatty acid molecule, 147 ATP are formed
  during B-oxidation and citric acid cycle metabolism X3 = 441 ATP
• 19 ATP are formed during glycerol breakdown