Energy

Question 1

Turnover explained

Answer 1

• Molecules constantly used (degraded) and restored (synthesized)
• Catabolism & anabolism process eg energy turnover

Question 2

Energy currency of cells

Answer 2

ATP - adenosine triphosphate (24kj per mol atp)
GTP - guanosine triphosphate
UTP - uridine triphosphate

Question 3

ATP breakdown process

Answer 3

• Done w/ ATPases releases energy (is a hydrolysis reaction)
• energy used for cellular processes

Question 4

ATP equation

Answer 4

ATP + H20 –> (ATPase) –> ADP + P + Energy

Question 5

ATP homeostatsis

Answer 5

• Maintenance of constant intracellular ATP level
• degradation and resynthesise at equal rates
• energy from food used to reform ATP to then produce more

Question 6

3 activity levels

Answer 6

Power - 3 secs, immediate, atp, pcr anaerobic
Speed - 60 secs, rapid, msc glycogen & glucose anaerobic
Endurance - > 2min, prolonged, glycogen, glucose, lipid aerobic

Question 7

Rates of ATP use in exercise

Answer 7

Jogging (50% vo2 max) = 1 (mmol ATP/kg dm/s)
Running (100%) = 2
Sprinting (180%) = 3.6
maximal isometric contraction = 12

Question 8

ATP supply from different sources - ATP

Answer 8

Concentration (mmol/kg) - 24
Max resynthesise rate (mmol/s) - n/a
Time to depletion - 2s

Question 9

ATP supply from different sources - PCR

Answer 9

Concentration - 80
Max resynthesise rate - 9
Time to depletion - 8s

Question 10

ATP supply from different sources - Glycogen -> lactate

Answer 10

Concentration - 300
Max resynthesise rate - 4.5
Time to depletion - 6 min

Question 11

ATP supply from different sources - Glycogen -> Co2 + H20

Answer 11

Concentration - 300
Max resynthesise rate - 2
Time to depletion - 100 min

Question 12

ATP supply from different sources - Fat

Answer 12

Concentration - Large
Max resynthesise rate - 1
Time to depletion - days

Question 13

PCr reaction + explanation

Answer 13

PCr + ADP –> (Creatine kinase) –> ATP + Cr

• High energy phosphorylated compound provides reserve energy to regen ATP (PCr -> Cr + Pi + energy) then (Pi + ADP + energy = ATP)

Question 14

Myokinase reaction + explanation

Answer 14

2ADP -> ATP + AMP

• converts ADP back to ATP and makes AMP, only relevant in high intensity exercise

Question 15

ATP, ADP, AMP concentration roles

Answer 15

• ATP conc are poor signals for metabolic control AMP conc are powerful signals
• AMP presence activates ADP restoration to ATP

Question 16

Importance of graph analysis of energy systems

Answer 16

• ATP doesn’t change much

- AMP does change a lot so is a good regulator for exercise

Question 17

Energy charge equation

Answer 17

Energy charge = [ATP] + 0.5[ADP] / [ATP] + [ADP] + [AMP]

Energy charge = how much potential energy is in the cell

Question 18

Energy charge values

Answer 18

1 = maximum, meaning all adenylates are in ATP
Average is 0.90-0.95
0 = all ATP hydrolysed to AMP

Question 19

AMP deamination

Answer 19

AMP is deaminated (AMP deaminase) to IMP to prevent build up and subsequent reduction in energy charge
Overall = ^ energy charge & continued contraction

Question 20

IMP destiny

Answer 20

IMP -> inosine -> Hypoxanthine (then leaves muscle = loss of potential energy (bad))
Or turn it back into AMP using GTP which is better

Question 21

Integration of pathways theory

Answer 21

Old concept - systems used one after the other

New concept - overlap of all systems dependant on length of exercise (ATP, PCr, Anaerobic, Aerobic order)

Question 22

Power output in Wingate test

Answer 22

23-28% PCr
49-56% Glycolysis
16-18% Oxidative metabolism

Question 23

Fuel and energy source differences

Answer 23

• Fuel sources (PCr, CHO) can be depleted energy sources (ATP) cant

Question 24

Energy expenditure (3) & efficiency

Answer 24

Mechanical, Electrical, Heat

• 15-20% efficient

Question 25

Gross efficiency

Answer 25

(Work accomplished / energy expended) x 100

Question 26

Net efficiency | REE = resting energy expended

Answer 26

(Work accomplished / energy expended - REE) x100

Question 27

Work efficiency

Answer 27

(Work accomplished / energy expended - EE unloaded) x 100

Question 28

Delta efficiency

Answer 28

(change in work accomplished / change in EE) x 100

Question 29

Energy values of food

Answer 29

Lipid - 9.45 kcal per gram CHO - 4.3 Protein - 5.65 Alcohol - 7

Question 30

Energy content & % digestibility

Answer 30

Lipid - 95% = 9 kcal CHO - 97% = 4 Protein - 92% = 4 Alcohol - 100% = 7

Question 31

Energy balance (in/out)

Answer 31

In - Food (Lipid, CHO, Protein), Alcohol Out - Basal metabolism 60-75%, Thermogenesis 10%, PA, 15-30%

Question 32

Energy balance & body weight

Answer 32

Total daily energy intake (TDEI) = Total daily energy expenditure (TDEE) = stable weight TDEI > TDEE = weight gain TDEI < TDEE = weight loss

Question 33

Components of energy expenditure

Answer 33

PA (physical activity) (highly variable) BMR (basal metabolic rate) TEF (thermic effect of food)

Question 34

energy expenditure during rest

Answer 34

``` Skeletal muscle - 18% Liver - 27% Brain - 19% Heart - 7% Kidney - 10% ```

Question 35

Measuring energy expenditure - Direct calorimetry chamber

Answer 35

- small insulated chamber - change of water of temp in pipes from heat given off gives energy used - air filtered & analysed - expensive, needs specialists & boring

Question 36

Measuring energy expenditure - Respiration chamber

Answer 36

- no heat exchange, just measuring gas changes - control what goes in and out of box - expensive, needs specialists & boring

Question 37

Measuring energy expenditure - Douglas bag/ breath by breath systems

Answer 37

- measuring a gas sample, use equations to work out energy expenditure

Question 38

gas collection to energy expenditure equation

Answer 38

1L O2 = 5kcal 0.25L O2 per min x 60 (an hour) = 75 kcal burned

Question 39

Indirect calorimetry calculations (other methods)

Answer 39

- Heart rate (fitbit ect) (inaccurate) - Accelerometers ( potentially inaccurate but can be used by specialist) - Questionnaires (relying on honestly & recall)

Question 40

Doubly labelled water (has a heavy hydrogen & oxygen)

Answer 40

- allows heavy isotopes to be traced - Isotopes excreted - CO2 production = difference in H & O isotope excretion More O = ^ EE (in free living) very expensive

Question 41

Energy cost of different activities

Answer 41

``` V light activities - 3-5 (min energy cost kcal light - 5-7 moderate - 7-9 strenuous - 9-13 V strenuous - >13 ```

Question 42

Energy cost of running

Answer 42

1 kcal per kg BM per km Distance & BM determine kcal burned

Question 43

Upper limit of energy expenditure

Answer 43

9000 - 11000 kcal per day

Question 44

Low energy intake in some atheletes

Answer 44

- V low intake despite training - low EI = decrease TEF % RMR - negative energy balance = reduced RMR (food efficiency)

Question 45

Lower limits of energy intake

Answer 45

- 1000-1500 kcal a day (w/ exercise) - loss of muscle - anaemia - decrease BM - low bone mineral density - secondary amenorrhea

Question 46

Energy intake collection methods - 24h recall

Answer 46

- remember everything from last day (hard) | - trained interviewer needed

Question 47

Energy intake collection methods - food dairies

Answer 47

- 3/7 days - weighed or not - write everything - clear instructions

Question 48

Energy intake collection methods - food frequency quetionnaire

Answer 48

- not used for accurate measuring - wider population (larger data pool) - how often do you eat certain foods

Question 49

Energy intake collection methods - Diet history

Answer 49

- general | - what have you eaten in the past