Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Exercise Physiology (KPE 264) > Mod 2: Oxidative And Non-oxidative Metabolism During Exercise > Flashcards

Mod 2: Oxidative And Non-oxidative Metabolism During Exercise Flashcards

1
Q

What is the location and fuel storage forms of the major energy systems? Phosphagen, glycolytic, oxidative

A

Phosphagen: cytosol of mitos, no O2, fuel stored as phosphocreatine (PCr) 1. Rxn to produce atp

Glycolytic: cytosol of mitos, no O2, fuel stored as glucose and glycogen. 10 rxns to produce atp

Oxidative: in mitos, needs O2, fuel stored as glucose, glycogen, fatty acids, triglycerides, and amino acids. >10 rxns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Explain the rate vs duration trade-off of atp supply

A

As PCr decreases atp slightly increases then stays high then gets low with the decrease of PCr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Explain the PCr energy system chemical reaction

A

The enzyme creatine kinase(highly regulated by substrate concentration, ex. PCr and ADP available signals creatine kinase activities to increase ) facilitates the reaction: PCr+ ADP <—> ATP + Cr .

ATP: 1 adenosine, 3P
PCr: 1 creatine, 1 P.

PCr splits into 1 creatine and 1P, the P combines with ADP to form ATP with the help of free energy and creatine kinase.

PCr combines with ADP which allows phosphate in creatine to become 3rd phosphate group on ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the strengths and limitations of the PCr energy system?

A

Strengths: only one quick reaction, an instantaneous process to produce atp

Weaknesses: substrate quickly depleted, only 1 unit of ATP formed per unit substrate(PCr)

Supplementing in creatine: weight gain (water weight)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When do we rely heavily on phosphagen stores?

A
  1. Intense exercise (100m sprint)
  2. Rest to work transition (standing up from chair)
  3. Workload transitions in exercise( riding bike, have to go up hill)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the key enzymes, substrates, and products of non-oxidative glycolysis

A

Hexokinase: phosphorylates glucose to G6-P so it can’t leave the cell (have to store it or use it)

GLUT 4 transporter: get glucose into skm

Glycogen phosphorylase: glycogen broken down to —> G1-P (breakdown of glycogen molecule so we can use it )

Phosphofructokinase(PFK): (rate limiting enzyme) regulated by ADP and ATP conc: increase in ADP conc = enhance PKF activity and speed up glycolysis because we need more ATP, lots of ATP available =inhibits PKF

-energy transfer : use atp to make an ADP (net loss at beginning)glucose —> G6p

ATP NET GAIN:

Glucose: 2
Glycogen : 3

Reduction of NAD to NADH + H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the ATP yield from non-oxidative use of glucose and glycogen

A

Glucose: 2 ATP
Glycogen: 3 ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the role of lactate formation in non-oxidative glycolysis

A

When O2 is low, pyruvate from glycolysis can’t turn into acetyl coA —> krebs—> ETC —> produce ATP so it ferments and turns into lactate which is a reduction process.

-facilitated by enzyme lactate dehydrogenase
Pyruvate —-> lactate
-in process NADH oxidized —> NAD+, which is supplied to glycolysis to continue making ATP

Lactic acid —> H + lactate

-immidetely dissociates ph goes low to 6.5 which is problematic in terms of enzyme activity

Decreased muscle pH —> metabolic inhibition —> decreased enzyme activity

Decreased muscle pH —> contractile inhibition —> decreased cross bridge cycling

-H ion accumulation is the problem that lowers pH

  • lactate continues to cori cycle to keep up glycolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the strengths and limitations of the glycolytic energy system?

A

Strength: don’t run out of glycogen

Limitation: substrate availability, enzyme activity, lactate accumulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is non-oxidative glycolysis?

A

When we run out of PCr stores we partially breakdown glucose and glycogen without oxygen.

-quick process but limited by metabolic by-products(don’t run out glucose, gets inhibited by accumulation of byproduct)

-2-3 ATPs formed/unit of substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Glycolysis vs glycogenolysis

A

Glycolysis: breakdown of 1 glucose to form 2 Pyruvate

Glycogenolysis: breakdown of 1 glucose (6C) from glycogen to form glucose-1-phosphate

6C glucose —> glucose-6-phosphate(g-6-p) —> 2xpyruvate (3C)

Glycogen —> glucose-1-phosphate —> g-6-p

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens to pyruvate in non oxidative glycolysis ?

A

In cytosol:
If Oxygen is available turns into —-> acetyl coA, facilitated thru enzyme pyruvate dehydrogenase (in mito). NAD+ —> NADH + H

No oxygen: turns into lactate (lactic acid) thru enzyme lactate dehyogenase . NADH + H—> NAD +

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When do we rely heavily on non oxidative glycolysis

A

Intense exercise
Rest to work transtition
Workload transtition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain the essential steps involved in oxidative metabolism

A

3 essential steps:

  1. Formation of acetyl coA (from CHO,fat,a.a)
  2. Oxidation of acetyl coA (kerbs cycle)
    -coenzymes are reduced
  3. Formation of ATP (electron transport chain)
    -coenzymes are oxidized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Identify the location in the mitochondria where relevant aspects of oxidative metabolism occur

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is oxidative metabolism

A

The complete breakdown of carbs, fats, amino acids, to CO2 and H2O
-requires oxygen but provides sustained energy
-occur in MITO
->30 atps formed per unit of substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is acetyl CoA formed from carbohydrates?
-formula
-enzyme
-location

A

Pyruvate + NAD –> acetyl coA + CO2 + NADH
- facilitated by enzyme pyruvate dehydrogenase (PDH)
-ability to use carb aerobically measured by PDH

-NAD reduced to NADH

-location: inner mitochondrial membrane

18
Q

List the key “outputs” derived from acetyl coA oxidation

A

1 atp
1 fadh2
3 nadh

19
Q

What is the role of co-enzymes in oxidative metabolism?

A

Coenzymes facilitate redox reactions by helping molecules or atoms lose electrons during oxidation and gain electrons during reduction

  • like citrate synthase, cytochrome oxidase, pyruvate dehydrogenase
20
Q

Describe the essential steps of the electron transport chain

-enzymes

A

-series of ox-red reactions
-electrons passed from NADH and FADH2(BOTH OXIDIZED) to O2 which forms H2O via reduction

-MORE ENERGY FROM nadh (2.5 atp) than fadh (1.5 atp)

  • NADH –> NAD+ (ox)
    -FADH2–> FAD(ox)
    -O2–> H2O (red)

-enzymes: cytochrome oxidase
ATP synthase: ADP + Pi –> ATP

21
Q

What’s the ATP yield from aerobic (with oxygen) use of carbohydrate(from 1 glycogen)

A

33 atp

21
Q

what is the enzyme that facilitates the reaction :
acetyl coA (2C) + oxaloacetate(4C) —> citrate (6C)
-in th

A

CITRATE SYNTHASE
-more citrate synthase in muscle =more mitos
ex. athletes have more than sedentary ppl

22
Q

What is the basic structure of a triglyceride?

-2 main TG sources?

A

3 fatty acid chain attached to a glycerol backbone

-main sources of TG:
1. Adipose tissue
2.skeletal muscle

23
Q

Explain the steps involved in triglyceride catabolism to ATP

A
  1. Mobilization :

-TG breakdown : get fatty acid off of glycerol backbone (occur in adipose tissue) —> lipolysis

  1. Transport: fatty acids circulate in blood and get to skm (carried in blood via albumin (protein))
  2. Uptake : (by skm) fatty acid enters muscle cytosol
  3. Activation: fatty acid prepared for breakdown (requires a bit of atp) formation of fatty acyl CoA
  4. Uptake: fatty acid enters MITOS
  5. Beta oxidation: FA broken down IN MITOS (makes acetyl coA and NADH and Fadh, unique to fats)
  6. Mito oxidation: TCA cycle/ ETC activity)
24
Q

Why is carnitine in fat oxidation important?

A

When fatty acyl - CoA is in the cytosol after coming into blood via FA transporter (original form was a, turned into fatty acyl co A), carnitine palmitoyl transferase(CPT)(enzyme) acts as an escort to get it into mito matrix so it can be used for aerobic energy (regulates ability to oxidize FAs)

-use FA stores during exercise when carb stores are low

-popular weight loss supplement because it oxidizes fat to be used for energy ( doesn’t work bc it doesn’t get into skm )

25
Q

What are the key “outputs” of beta oxidation?

A
  • by products : 1 FADH, 1 NADH, —-> go directly to ETC 1 acetyl coA —> goes to krebs TCA cycle (Fatty acyl coA gets 2C shorter to generate the acetyl coA)
  • enzyme: beta HAD

-end with 14C fatty acyl coA from 16(lost 2C), and goes thru cycle again till it goes down to 2 C which immedtely forma acetyl coA

26
Q

What’s the atp yield from oxidation of a fatty acid?

A

Start with 16 C fatty acyl coA

(Total # C/2)-1 = how many cycles of beta oxidation occur
16/2 -1=7 turns

For palmitate (16-C fatty acid)

Each turn of Beta oxidation:
- 1 FADH (1.5 atp)
- 1 NADH (2.5 atp)
- 1 acetyl coA (3 NADH, 1 FADH, 1 ATP = 10 atp)

TOTAL ATP per cycle of beta oxidation :14 ATP x 7 turns = 98 ATP per palimiate molecule

Remaining 2C unit forms 1 acetyl coA = +10 atp

Minus energy for “activation” of FA : -1 atp

TOTAL YIELD: 106 ATP per palmitate molecule

27
Q

Explain the first step of fatty acid catabolism: fatty acid mobilization

A
  • occurs in adipose tissue and skm if tgs are stored there
    -break down tgs into 3 FAs and 1 glycerol (by enzyme HSL) hormone sensitive lipase

-glycerol goes to liver—> convert to glucose

  • FAs go to muscle to be catabolized for energy

-enzymes that regulate lypolysis: HORMONE-SENSITIVE LIPASE(HSL)(in adipose and muscle)—-> breaks down TG into FA and glycerol

28
Q

Explain fatty acid transport, uptake, and activation

A
  • FA from blood enters cytosol of cell via FA transporter and turns into fatty acyl-CoA by adding a CoA to it (FA now activated and can be recognized by mitos now), uses 2 atp
  • fatty acyl-coA enters mito matrix through enzyme carnitine palmitoyl transferase (CPT) that allows the uptake so it can be used for aerobic energy provision

-CPT regulates ability to oxidize fat

29
Q

Explain beta oxidation (step 6)

A

Only occurs for fatty acids in mitos once fatty acyl co A gets in thru CPT transporter enzyme

  • by products : 1 FADH, 1 NADH, 1 acetyl coA (Fatty acyl coA gets 2C shorter to generate the acetyl coA)
  • enzyme: beta HAD
30
Q

Is carbs (glucose) or fat (palmitate) a better fuel source?

A

Glucose: 4 kcal/g, capacity: 2500 kcal, atp generated/1 carbon: 32 atp/ 6 carbon= 5.3 ratio atp/O2 =5.3

Palmitate: 9kcal/g, capacity: unlimited, atp generated / 1 carbon: 106/16=6.6 ratio, atp generated/unit of O2 =4.6

Fat more Efficient in all except atp/O2: (carbs are 10% more O2 efficient

-at rest fat is preferred, in exercise arbs are preferred because oxygen is limiting , permits exercise at a higher
pace

31
Q

When do we rely heavily on oxidative metabolism?

A

-rest
-steady state exercise
Any form of exercise lasting more than 2 mins

32
Q

Describe amino acid catabolism

A
  1. Removal of amino group:

-major site: liver
-minor site: skm (Branched chain amino acids)

  1. Oxidation of remaining “carbon skeleton” (“oxo acid”)

-eventually form pyruvate or acetyl coA

Major AAs in exercise metabolism :
- BCAA ( leucine, isoleucine, valine)
-alkaline, glutamine

-remove nitrogen group to use amino acid as energy
-alkaline and glutamine take nitrogen to liver to convert to urea

33
Q

Describe the process of gluconeogenesis

A

Recycling of metabolic by-products

The formation of new glucose from metabolic intermediates

-metabolic byproduct of anaerobic glycolysis: lactate
—>helps regenerate NAd for glycolysis (in liver)

-amino acids : alkaline and glutamine take nitrogen to liver

-break down TG thru lipolysis : glycerol and 3 FAs
- glycerol —> goes to liver,, reforms glucose, leaves liver

TLDR: glucose, CHO: lactate, AA: alaline , go to liver from skm
Glycerol goes to liver from adipose tissue

34
Q

Key signals for regulation of energy provision

A

ATP/ADP ratio
Calcium levels
Hormones

-activate enzymes

35
Q

What are some branch chain amino acids: liv

A

Valine, isoleucine, leucine

NOT BCAA: glutamine

36
Q

Can we break down amino acids to form acetyl coA?

A

Yes

37
Q

T or F
Metabolic byproducts derived from the catabolism of carb, proteins, and fat can alll be used for gluconeogenesis

A

TRUE

38
Q

how many ATP does 1 unit of glucose produce?
glycogen?

A

glucose: 32 ATP
glycogen: 33 ATP

39
Q

what are the 3 outputs of acetyl coA oxidation?

A

1 ATP
1 FADH2
3 NADH

40
Q

what are the 3 essential steps in oxidative metabolism? FOF

A
  1. formation of acetyl coA
  2. oxidation of acetyl coA (in krebs) COENZYMES REDUCED
  3. formation of ATP (in e.t.c) COENZYMES OXIDIZED
41
Q

what are the 3 outputs of beta oxidation?
enzyme:

A

1 NADH
1 FADH2
1 acetyl coA

enzyme: beta HAD

Exercise Physiology (KPE 264) (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions