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Exsc 463 Final > Chapter 25 > Flashcards

Chapter 25 Flashcards

1
Q

What is the primary energy molecule? Why is it called that?

A

ATP

-the breakdown of ATP is the only energy that can be directly used for muscle contraction and other cellular processes

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2
Q

Why does ATP produce so much energy?

A

it has three phosphate groups linked with high energy phosphate bonds which release energy when split

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3
Q

Hydrolysis?

A

rxns that use water to break chemical bonds

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4
Q

What is the result of the hydrolysis of ATP?

A

high energy bonds linking gamma and beta phosphate are broken which leaves adenosine diphosphate (ADP) and an inorganic phosphate (Pi) HOPO3^2- (H2O becomes part of the Pi)

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5
Q

What catalyzes the rxn to break down ATP?

A

ATP is stable in water so the enzyme ATPase helps break the molecule down

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6
Q

How much energy is released per mole of ATP?

A
  1. 3 kcal of free energy (delta G’)

- some energy is released as heat so it is closer to 12 kcal

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7
Q

GTP?

A
  • Guanosine Triphosphate
  • formed in the Krebs Cycle
  • similar high energy compound like ATP
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8
Q

How much ATP is stored in metabolically active organs such as skeletal muscle?

A
  • very little, only enough is stored to support about 4 to 6 seconds of maximal intensity exercise so ATP must be continuously resynthesized at the rate equivalent to rate of use
  • 4 to 8 mmol of ATP per kg of wet muscle (2-4 g ATP/kg)
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9
Q

Where does ATP come from to be used by each individual cell?

A

ATP is unable to cross the cell membrane so ATP for each cell must come from within each cell

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10
Q

What rxn uses adenylate kinase or myokinase to catalyze the synthesis of ATP? (Myokinase rxn)

A

ADP + ADP -> ATP + AMP

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11
Q

What is the ATPase rxn to resynthesize ATP?

A

ADP + Pi -> water + ATP

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12
Q

What is the most rapid way to resynthesize ATP?

A

ATP-PC system (phosphocreatine)

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13
Q

What is the coupled rxn of ATP-PC?

A

CrP(creatine phosphate) -> C(creatine) + Pi + energy (exergonic)

Energy + ADP + Pi -> ATP (endergonic)

Net rxn: ADP + CrP -> ATP + C

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14
Q

What is a coupled rxn?

A

energy released from the first rxn (exergonic) is used in the second rxn (endergonic) to resynthesize ATP

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15
Q

Where does the Pi needed to bind to creatine (C) to resynthesize CrP come from? creatine phosphate shuttle?

A

comes from ATP from the mitochondria, Pi is shuttled across the mitochondrial membrane where it binds to creatine on the outer membrane (creatine phosphate shuttle)

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16
Q

What happens with creatine after exercise?

A
  • since C requires ATP to be resynthesized, most of it is resynthesized during the recovery period following exercise when ATP is not needed for muscle contraction anymore
  • all of it is resynthesized within 5 minutes
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17
Q

How does the muscle stores of CrP compare to ATP? Greater one?

A

CrP is 2-6 times greater than ATP

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18
Q

What type of muscle fibers have more creatine?

A

fast twitch

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19
Q

How long can CrP in skeletal muscle support maximal intensity exercise?

A

15 seconds

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20
Q

Why is the ATP-PC system important?

A

it can rapidly resynthesize ATP b/c two rxns take place in the cytoplasm without the use of oxygen

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21
Q

How much CrP is stored in skeletal muscle?

A
  • 30 mmol C/kg wet muscle

- 4 g C/kg

22
Q

What kinds of food is CrP found in?

A
  • beef and fish

- some degrades during cooking

23
Q

What is the average daily consumption of creatine?

A

1 g/day

24
Q

Where else is creatine synthesized besides muscle?

A

liver, kidneys, pancreas from dietary amino acids, arginine, and glycine

25
Q

In an average 70 kg adult, how much total creatine do they have? How much is stored in skeletal muscle?

A

120g

90% in muscle (most is stored as CrP, 30-40% as C)

26
Q

How much creatine is excreted from the body as urine each day?

A

2g/day as creatinine (restored from diet or endogenous synthesis)

27
Q

What is the premise of creatine supplementation benefit?

A

if greater amounts of CrP are stored in muscle, more ATP can be resynthesized to improve performance during short durations

28
Q

What is the recommended loading dose of creatine monohydrate per day? Recommended maintenance dose?

A
  • 20g/day over a 5 day loading period increases CrP stores by 25% (like carb loading to increase glycogen stores for endurance runners)
  • more than this is pointless b/c the muscle has a storage limit
  • maintain: 2-3g/day
29
Q

Responders vs non-responders?

A
  • a lot of variability in the response to supplementation
  • responders- show 25% or greater increase in CrP
  • nonresponders- little increase in CrP
30
Q

What is the strongest determinant of how much creatine will be taken up by the muscle by supplementation?

A
  • the initial content of CrP in the muscle

- those with high CrP content before supplementation wil experience less of an increase in muscle stores

31
Q

What is the relative loading dose for creatine? maintenance dose?

A

0.3 g/kg/day

.03 g/kg/day

32
Q

When should creatine supplements be taken?

A
  • during a training cycle to improve quality of training and optimize adaptations to allow time for the athlete to notice any side effects, not recommended for the first time prior to competition
  • high intensity, short duration (less than 30 secs)
33
Q

Why is there inconsistency in the research to support creatine supplementation?

A

differences in creatine dosing and the type and intensity of exercise, inconclusive results

34
Q

Ergogenic aid?

A

anything that improves performance (CrP)

35
Q

What are some side effects of creatine supplements?

A

nausea, muscle cramps, dehydration, gastrointestinal distress

36
Q

What is a possible risk of taking creatine?

A

it may establish habits of supplementation to improve performance which may lead to illegal supplements

37
Q

What increases the absorption of creatine monohydrate?

A

dissolving the powder in hot beverages

38
Q

What is the effect of caffeine? with creatine?

A

-caffeine acts as a sympothomimetic agent by elevating circulating catecholamines, could abolish the effects of creatine

39
Q

Cellular respiration definition?

A

metabolic process that uses energy released from the breakdown of energy substrates to resynthesize ATP within the cell

40
Q

What are the 4 metabolic pathways of cell respiration?

A
  1. Anaerobic Glycolysis
  2. Aerobic Glycolysis
  3. Beta Oxidation
  4. Degration of proteins
41
Q

What are energy substrates for respiration?

A

carbs, fats, proteins

42
Q

Anaerobic Glycolysis?

A
  • incomplete breakdown of glucose or glycogen to lactate resulting in the net resynthesis of 2-3 ATP
  • occurs in cytoplasm of cell and does not require oxygen
43
Q

Aerobic Glycolysis?

A

complete breakdown of glucose or glycogen to water, CO2, and 36-37 net ATP, require oxygen in the final stage

44
Q

Beta Oxidation?

A

oxidative phosphorylation of fatty acids in the complete breakdown of fatty acids in the mitochondria, yielding large quantities of ATP aerobically (depends on number of carbons)

45
Q

Degradation of proteins?

A

breaks down amino acids into smaller molecules which then enter the metabolic pathways at different locations

46
Q

Why is it necessary to have different metabolic pathways that resynthesize ATP?

A
  • resynthesize different amounts of ATP at different rates
  • use different energy substrates
  • either aerobically or anaerobically
  • engage in different activities
47
Q

How are carbs metabolized?

A

aerobically and anaerobically

48
Q

How are fatty acids and amino acids metabolized?

A

aerobically

49
Q

Aerobic metabolism takes place where? anaerobic?

A
  • aerobic- require oxygen, takes place in mitochondria

- anaero- takes place in cytoplasm

50
Q

Enzyme to breakdown CrP?

A

Creatine kinase or creatine phosphokinase

Exsc 463 Final (4 decks)

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