Lecture 2 (Exam 2)

Question 1

Hydrolysis

Answer 1

the chemical breakdown of a compound due to reaction with water

Question 2

Phosphorylation

Answer 2

the addition of a phosphate group (PO4) to a molecule

Question 3

Phosphocreatine

Answer 3

an energy-rich compound that plays a critical role in providing energy for muscle action by maintaining ATP concentration

Question 4

Oxidation

Answer 4

removing an electron

Question 5

Reduction

Answer 5

addition of an electron

Question 6

Redox potential

Answer 6

the ratio of NAD+ to NADH

-continues glycolysis

Question 7

Oxidative Phosphorylation

Answer 7

mitochondrial process that uses oxygen and high-energy electrons to produce ATP and water
-ATP is generated from oxidation of NADH, FADH2, and subsequent transfer of electrons and pumping of protons (generates electrochemical gradient required to power ATP synthase)

Question 8

Cori cycle

Answer 8

1. Lactate is transferred back to the liver

2. In the liver, lactate is reconverted into pyruvate (pyruvic acid) then into glucose through glycogenesis

Question 9

3 phases of Oxidative Phosphorylation

Answer 9

1. Everything funnels to Acetyl-CoA
2. Isocitrate Dehydrogenase: important enzyme in Krebs
3. More NADH and FADH2 are produced BUT not used in Krebs used later in the ETC

Question 10

Alanine Cycle

Answer 10

liver converts alanine into pyruvate

Question 11

Beta-Oxidation

Answer 11

FFA’s travel through the blood to muscle fiber and are broken down by enzymes in the mitochondria into acetic acid, which is converted to acetyl CoA

Question 12

3 ATP synthesis pathways and where they are performed within skeletal muscle

Answer 12

1) ATP-PCr system (anaerobic, cytoplasm)
2) Glycolytic system (anaerobic, cytoplasm)
3) Oxidative system (aerobic, mitochondria)

Question 13

How does the Phosphagen System operate? (ATP-PCr system)

Answer 13

• short-term anaerobic energy system that maintains ATP levels
• can prevent energy depletion by quickly regenerating ATP from ADP
• Pi donation from PCr to ADP to form ATP

(energy system used during an all-out sprint for 10 seconds)

Question 14

Phosphagen System’s Formula (products, substrates, and enzymes)

Answer 14

PCr + ADP ————Creatine Kinase———-> ATP + Cr

Question 15

How does Creatine Kinase (CK) control rate of ATP production?

Answer 15

-Negative feedback system
When ATP levels decrease (ADP increase), CK activity increases
When ATP levels increase, CK activity decreases

Question 16

Phosphofructokinase (PFK) and its effect on it’s energy pathway

Answer 16

rate-limiting enzyme in the glycolytic pathway

• as ATP decreases (ADP and Pi increase), PFK increases; which speeds up glycolysis
• as ATP increases, PFK decreases; which slows glycolysis

Question 17

Creatine Kinase (CK) and its effect on it’s energy pathway

Answer 17

• enzyme that releases energy from PCr, which acts on PCr to separate Pi form creatine
• the energy released can then be used to add a Pi molecule to an ADP molecule, forming ATP

When ATP levels decreases (ADP increases), CK activity increases
When ATP levels increase, CK activity decrease

Question 18

Hydrogen Carriers

Answer 18

NAD: Nicotinamide adenine dinucleotide
FAD: Flavin adenine dinucleotide

Question 19

Hydrogen carriers purposes

Answer 19

Transfer of hydrogens and associated electrons to:

• the mitochondria to generate ATP (aerobic)
• convert pyruvic acid into lactate acid (anaerobic)

Question 20

Purpose of Electron Transport Chain (ETC)

Answer 20

to convert the hydrogen ion generated by glycolysis and the Krebs cycle into water and produce energy for oxidative phosphorylation

Question 21

2 sources of fat utilized for energy relase

Answer 21

Triacylglycerol in fat cells (adipocytes)
Intramuscular triacylglycerol (triglyceride)

Question 22

Pathway of fat metabolism

Answer 22

oxidative pathway

Question 23

How is lactate utilized by the body? (3)

Answer 23

1. Lactate produced in the cytoplasm can be taken up by the mitochondria of the same muscle fiber and oxidized
2. Lactate can be transported via MCT transport proteins to another cell and oxidized there (lactate shuttle).
3. Lactate can recirculate back to the liver, reconverted to pyruvate and then to glucose through gluconeogenesis. (Cori Cycle)

Question 24

Relation between the 3 energy systems

Answer 24

they interact for all activities

• although one system might be dominant, the other two provide a small portion of the energy needed
• e.g. ATP-PCr system is dominant during a 10s sprint with a small amount of help from glycolytic and oxidative systems. Vis versa, oxidative is dominant during a 30min 10k, but both ATP-PCr and glycolysis contribute some energy

Question 25

Energy Systems (3)

Answer 25

ATP-PCr
Glycolytic (Glycolysis)
Oxidative (from carbs or from fat)

Question 26

Products, Substrate, and Major Regulators of Glycolysis Phase 1 & 2

Answer 26

Products: NADH, NAD+, pyruvic acid, lactic acid
Substrate: Carbs
Regulators: Phosphofructosekinase and Pyruvate Kinase

Question 27

Products, Substrate, and Major Regulators of the Krebs Cycle

Answer 27

Products: 3 NADH, 1 FADH2
Substrate: Carbs and Fats
Regulators: ATP, NADH, ADP (???????)

Question 28

Products, Substrate, and Major Regulators of Electron Transport Chain (ETC)

Answer 28

Products: 2.5 ATP’s per NADH, 1.5 ATP’s per FADH2
Substrate: Protein
Regulators: ADP, ATP

Question 29

3 Steps of breaking down glucose

Answer 29

1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain