Bioenergetics

Question 1

Predictors of Successful Aging

Answer 1

• physical function (ADL’s)
• absence of hearing problems, arthritis, disability or other comorbidities
• not currently smoking
• global cognitive function
• normal systolic BP
• less severe or absence of depression
• personality traits of “can do” attitude

Question 2

Metabolism vs. Bioenergetics

Answer 2

metabolism = the sum of ALL chemical reactions

Bioenergetics = the transfer and utilization of energy
- i.e. formation & utilization of ATP

Question 3

1st Law of Thermodynamics

Answer 3

energy can neither be created nor destroyed - governs metabolism

Energy in (food) = Energy out (heat + work) +/- energy stored (fat)
- must burn more energy than taking in to lose weight

Question 4

2nd Law of Thermodynamics

Answer 4

aka entropy - all processes move from an ordered to a disordered state

• randomness increases but the process is inefficient
• 60-70% of energy used in the body is released as heat

aka energy consumption is INEFFICIENT

Question 5

Biological Reactions

Answer 5

most are thermodyncamically unfavorable; meaning you must INPUT energy in order to make the reaction occur

Our body uses ATP as energy source

This is the opposite of free energy (G

Question 6

Info about Carbohydrates as energy

Answer 6

• ingested as sugar, converted to glucose for energy use; stored as glycogen in liver
• glucose forms ATP
• 1g = 4kcals
• 1g glycogen storage = 2.6g H20 stored as well
• burned during mod-severe intensity activity
• theoretical time to exhaustion = 2 to 2.5 hours of moderate-severe activity

Question 7

Info about Fats as energy

Answer 7

• converted to triglycerides for energy; stored as glycerol or FFA’s w/n lipid droplets
• not easily accessible
• large fat reserves
• 1g = 9kcals
• burned during prolonged, low intensity exercise
• theoretical time to exhaustion = 3-5 days

Question 8

Info about Protein as energy

Answer 8

• amino acids must be converted to glucose (via gluconeogenesis) OR FFA’s (via lipogenesis)
• rarely used for energy source; starvation
• theoretical time to exhaustion = 2.5 days

Question 9

Does fat or carbs have a higher energy yield per liter of O2 consumed?

Answer 9

aka through oxidation…
Carbs = 5.1 kcal/L O2

Fats = 4.62 kcal/L O2

Question 10

Which energy source has greatest storage?

Answer 10

Fats > carbs

BUT carbs are more easily accessible b/c more rapid metabolic pathway

Question 11

How are carbs & fats metabolized?

Answer 11

Carbs = aerobic & anaerobically

Fats = aerobic

Question 12

ADV of Carbohydrates as energy source

Answer 12

• high energy yield/ L O2 consumed
• metabolized aerobically & anaerobically
• rapid metabolic pathway (easily accessible)
• stores can be increased greatly w/ training & diet
• sole source of energy during heavy exercise

Question 13

DISADV of Carbohydrates as energy source

Answer 13

• stored in relatively small amounts w/ large amounts of H2O
• accumulation of lactic acid
• once depleted, moderate intensity exercise cannot continue

Question 14

ADV of Fats as energy source

Answer 14

• greatest energy value of any fuel
• stored in large amounts
• stable energy source that can be mobilized for use during exercise

Question 15

DISADV of Fats as energy source

Answer 15

• not easily accessible
• total caloric value of intermuscular lipid is small compared to glycogen
• only metabolized aerobically
• majority of fat stored outside of muscle
• cannot serve as sole energy source

Question 16

At rest, what is the source of energy?

Answer 16

fats & carbs

Question 17

During mod-severe exercise, which source of energy predominates?

Answer 17

Carbs (RER .9 to 1.0)

Question 18

What is needed in order to metabolize carbs/fats for fuel?

Answer 18

catalyst

Question 19

Which system provides more energy? aerobic or anaerobic?

Answer 19

Aerobic!