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Physiology II > Energy Balance and Metabolism II (Lec 13) > Flashcards

Energy Balance and Metabolism II (Lec 13) Flashcards

1
Q

ATP is generated by the combustion of what 3 things?

A

carbs, FAs, and proteins

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2
Q

Synthesis of cellular components, muscle contraction, active transport across membranes, glandular secretion, and nerve conduction are all energized by what?

A

ATP

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3
Q

What does phosphocreatine function as?

A

an accessory storage depot for energy and as an “ATP buffer”

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4
Q

Phosphocreatine has a high energy ___ bond (13,000 cal)

A

phosphate

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5
Q

True or false?

Phosphocreatine is 3X more abundant than ATP

A

true

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6
Q

True or false?

Phosphocreatine can participate directly in energy transfer

A

false; can’t participate directly

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7
Q

Can phosphocreatine transfer energy interchangeably with ATP?

A

yes

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8
Q

___ equilibrium occurs among tissue proteins, plasma proteins, and plasma amino acids

A

reverse

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9
Q

Synthesis of alanine from pyruvic acid occurs by ___

A

transamination

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10
Q

What is the name of the enzyme used in synthesis of alanine from pyruvic acid?

A

transaminase

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11
Q

What type of bonds are formed between successive amino acids?

A

peptide

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12
Q

What are essential amino acids?

A

amino acids not made by the body which is why they must come from food

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13
Q

What are nonessential amino acids?

A

amino acids required for normal health and can be synthesized by the body

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14
Q

In regards to protein synthesis, formation of ___ ___ is among the most important of intracellular processes that require energy

A

peptide linkages

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15
Q

Different peptide linkages require anywhere from ___ to ___ calories per mole

A

500 to 5000

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16
Q

What are four ways that a peptide bond can be formed?

A

AA + ATP -> AA-AMP + 2Pi

AA-AMP + tRNA -> AA-tRNA +AMP

Attachment of tRNA to mRNA via codon-anticodon pairing

Formation of peptide bond with second AA using peptidyl transferase + GTP

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17
Q

How many high energy phosphate bonds are needed to form one peptide linkage?

A

4

note: peptide linkage = 48,000 cal, but each peptide bond only stores 500-5000 cal

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18
Q

What happens to excess AAs in the body fluids?

A

degraded and used for energy

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19
Q

What is the first step of AA degradation? What does it involve?

A

deamination; generally involves transamination and one of the end products is ammonia

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20
Q

Two molecules of ammonia + one molecule of carbon dioxide are combined in the ___ to form ___

A

liver; urea

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21
Q

Production of urea occurs in what cycle?

A

urea (ornithine) cycle

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22
Q 
True or false?
The Urea (ornithine) cycle was discovered by Krebs 5 years before he discovred the CAC
A

true

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23
Q

What are the steps of the urea cycle in the mitochondria?

A

Ammonia + CO2 -> carbamoyl phosphate

carbamoyl phosphate + ornithine ->citrulline

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24
Q

What are the steps of the urea cycle in the cytoplasm?

A

citrulline + aspartate -> argininosuccinate

argininosuccinate -> arginine + fumarate

arginine -> urea + ornithine

note: fumarate can enter CAC

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25
Q

The rate of overall chemical reaction is determined by what?

A

concentration of the enzyme; concentration of substrate

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26
Q

When the substrate is high, what is the reaction rate determined by?

A

almost entirely by concentration of enzyme

ex: diabetes and glucose

27
Q

Explain how diabetes affects reaction rate

A

large quantities of glucose enter renal tubules; glucose (substrate) is in great excess in the tubules; transport enzymes become saturated; further increases in glucose levels in tubules have little effect on glucose reabsorption; glucose reabsorption rate is limited by concentration of transport enzymes

28
Q

What happens to the reaction rate when enzyme concentration is high?

A

reaction rate becomes directly proportional to concentration of substrate and enzyme

29
Q

What is an example of reaction rate when enzyme concentration is high?

A

absorption of substances from intestinal tract and renal tubules when concentrations of the substrate are low compared to transport enzymes

30
Q

Rate of the overall reaction is determined by both the concentration of the ___ and the concentration of the ___

A

enzyme; substrate

31
Q

True or false?

most chemical reaction in the body occur in series

32
Q

The overall rate of a series of chemical reactions is determine by what?

A

the rate of reaction of the slowest step in the series

33
Q

What is the slowest step in a reaction called?

A

rate-limiting step

34
Q

What is the major rate-limiting factor for almost all energy metabolism in the body?

35
Q

True or false?

cellular concentrations of ADP are high

A

false; low

36
Q

Chemical reactions that depend on ADP as one of the substrates are very slow? or very fast?

37
Q

All oxidative metabolic pathways and other pathways for the release of energy are examples of what?

A

ADP substrate dependence

38
Q

ATP is converted to ADP during cellular activity; therefore ADP concentration ___ during cellular activity

39
Q

Increased concentration of ADP ___ reaction rates

40
Q

About ___% of energy in foods becomes heat during ATP formation

41
Q

More ___ is produced in the transfer of energy from ATP to the functional systems of cells

42
Q

No more than ___% of energy from food is used by the functional systems.

A

27

note: most of this 27% is finally converted to heat

43
Q

Arousal vs sleeping; skeletal muscle; age; thyroid activity; testosterone; growth hormone; fever; sleep; malnutrition are all factors that influence what?

A

metabolic rate

44
Q

In regards to basal metabolic rate, ___% of energy expended by the body is derived from oxidative phosphorylation involving different kinds of foods

45
Q

Whole-body metabolic rate can be calculated from rate of what?

A

oxygen utilization

46
Q

In regards to basal metabolic rate, 1 liter of oxygen is metabolized with what?

A 
glucose = 5.01 cal
fat = 4.7 cal
protein = 4.6 cal
47
Q

In regards to basal metabolic rate, energy liberated per liter of oxygen with average diet averages about 4.825 cal = ?

A

energy equivalent of oxygen

48
Q

In regards basal metabolic rate, the average 70kg man lying in bed all day uses ___ cal per day.

49
Q

In regards basal metabolic rate, the average 70kg man lying in bed all day and eating a reasonable diet uses ___ cal per day.

50
Q

In regards basal metabolic rate, the average 70kg man sitting in a chair all day without exercising uses ___ cal per day.

51
Q

Walking up stairs requires __x the energy as sleeping in bed all day

52
Q

BMR normally averages __ to __ cal per hour

53
Q

How is BMR measured?

A

oxygen and CO2 is measured after individual has fasted for 12 hrs and is fully rested

54
Q

Does Thyroxine increase or decrease rate of chemical reactions and metabolic rate in cells?

55
Q

Maximal secretion of thyroxine may increase metabolic rate ___% to ___% above normal

56
Q

Loss of thyroid secretion decreases metabolic rate to ___% to ___% of normal

57
Q

What is testosterone’s affect on metabolic rate?

A

increases metabolic rate up to 10 to 15 %

58
Q

Testosterone is mainly related to ___ effect of increase in skeletal muscle mass

59
Q

How does malnutrition change metabolic rate?

A

decreases metabolic rate

60
Q 
Give the percentage of energy expenditure for each component:
purposeful physical activity
nonexercise acitivity
thermic effect on food
BMR
A

purposeful physical activity: 25%

nonexercise acitivity: 7%

thermic effect on food: 8%

BMR: 60%

61
Q

Because skeletal muscle accounts for 20 to 30 % of BMR even at rest, BMR is typically corrected for differences in what?

62
Q

Much of decline in BMR with increasing age is probably related to what?

A

loss of muscle mass and replacement with adipose tissue with a lower rate of metabolism

63
Q

What is gluconeogenesis?

A

formation of glucose from smaller molecules

64
Q

What is glyconeolysis?

A

breakdown of glycogen to form glucose

Physiology II (19 decks)

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