Week 1

Question 1

How does the structure of ATP allow us to perform work

Answer 1

Energy stored in the chemical bonds between phosphate groups
A P-P bond is broken to liberate energy to allow us to perform work - forms ADP.

Question 2

How is ATP resynthesized and why is it important?

Answer 2

Condensation of ADP and Pi through enzyme ATP synthase

Important as we only have a small amount of ATP that needs to be maintained to a narrow range. We cant let [atp] drop too much.

Question 3

When is ATP turnover highest?

Answer 3

During max intensity ex e.g. sprinting

Question 4

Since the _____________ are small, ATP must be regenerated at a rate sufficient to sustain ______________

Answer 4

Since the intramuscular stores of ATP are small, ATP must be regenerated at a rate sufficient to sustain the level of contractile activity

Question 5

How is the maximal rate of atp generation (turnover rate) measured

Answer 5

mmol ATP/kg dm/ sec

Question 6

How is the maximal energy available measured

Answer 6

mol ATP

Question 7

How are ATP resynthesis and utilisation related?

Answer 7

ATP resynthesis must match rate of utilisation. Harder work means more ATP resynthesis

Question 8

The anaerobic ways of ATP resynthesis

Answer 8

PCr conversion into Cr and ATP BUT only produces 1 ATP
Anerobic glycolysis of glycogen and glucose
Glucose substrate produces 2 ATP and glycogen 3 ATP.

Question 9

The aerobic ways of ATP resynthesis

Answer 9

Reaction of glucose, oxygen and ADP produces 36 ATP - able to feed biproducts of glycolysis into mitochondria to liberate more ATP
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP (release of energy during cellular respiration)

Palmitate (fat metabolism) - 130 ATP
Palmitate is a fatty acid containing 16 carbons

However, occurs more slowly so exercise has to be low so oxygen is readily available

Question 10

What happens if athletes run out of CHO stores?

And what should they do to avoid this?

Answer 10

Athletes should fuel themselves with enough carbohydrates (before and during race) to keep higher rates of energy production. Run out of cho stores – forced to rely on fat stores – rate of ATP production of fat is approx half of cho stores – have to therefore slow down.

Question 11

As exercise intensity increases, what happens to:
-[ATP]
-PCr stores
-Lactate

Answer 11

[ATP] stays constant – rate of ATP resynthesis is matching rate of ATP breakdown

PCr stores are declining (even at 30% vo2 max)

Accumulation of lactate –shows increase in contribution of anaerobic glycolysis

Question 12

What is the reason for a decline in ATP utilisation during a max 30s sprint
What can be done to not make this decline as bad?

Answer 12

Decline in ATP utilisation mainly due to decline in PCr as its stores run out.
Supplementation of creatine to raise PCr stores would aid sprint performance.

Question 13

During a max 30s sprint, mean power output dosent decline as steeply as the fall in anaerobic metabolism suggests. Why?

Answer 13

Mean power output doesn’t decline as steeply as the fall in anaerobic metabolism would suggest – due to increasing concentration of aerobic metabolism to safeguard us slightly.

Question 14

What are the 2 sources of triglyceridess?

Answer 14

Intramuscular TG and adipose tissue

Question 15

How are triglyerides broken down and shuttled into the mitocondria?

Answer 15

They are broken down by lipolysis into FFAs, which enter mitocondria. They undergo beta oxidation (when they are shortened to acetyl coA)

Question 16

What is the same about triglyceride, glycogen/glucose and protein metabolism?

Answer 16

When they enter the mitocondriathey all follow the same path, entering the TCA cycle, then the ETC, forming ATP via ATP synthase.

Question 17

As ex intensity increases, how does the proportion of CHO and fats change?

Answer 17

CHO sources - plasma glucose and muscle glycogen
Fat stores - plasma FFA, other fat sources (IM fat)

At 40% Wmax, approx 50/50 split
Increasing to 55%, still 50/50 split, but there is a greater EE

At 75% Wmax, fat ox declines (20-30%), rest is CHO, mostly coming from muscle glycogen

Question 18

Influence of exercise duration on muscle glycogen, blood glucose, muscle triglycerides and plasma FFA

Answer 18

Muslce glycogen decreases as exercise duration goes on. Other substrates therefore have to contribute. Blood glucose contributes towards this, but only for so often as you deplete your liver glycogen stores (after 2hr ex, cho ingestion is needed to maintain blood glucose and cho ox)
Muscle triglyceride cont falls and plasma FFA increases (will never run out of this).

Question 19

Give approximate amounts for the amounts of blood glucose, liver glycogen and muscle glycogen (carbohydrate stores) for a 70kg man

Can these values be changed?

Answer 19

Blood glucose 3-5g
Liver glycogen 80-100g
Muscle glycogen 300-400g

Blood glucose and liver glycogen stores are maintained in a narrow range

Muscle glycogen stores have the capability to be changed through endurance training and high carb diet.

Question 20

Food provides nutrients that provide 3 key physiological and biochemical functions in the body

Answer 20

1. Provision of energy (mainly from carbs and fat, only about 5% from proteins)
2. Promotion of growth and development – maintenance of tissue (calcium, phosphorous)
3. Regulation of metabolism (micronutrients, protein)

Question 21

Key info about carbs
Role
examples
types

Answer 21

Provides energy to perform physical activity and for CNS (to maintain signalling activities of CNS cells)
Most carbs are broken down into sugar molecules called glucose.
Fibre is a type of carbohydrate that the body cant digest.
Carb would be 60% of energy intake
Carbohydrate rich foods – sugars (simple carbs e.g. fruit juices, sports drinks, honey), starches (cereal, potatoes, pasta, rice, bread), fibre (whole grain bread, oats, fruit and veg)
Types of carbs
Monosaccharides – glucose, fructose, galactose
Disaccharides – maltose, sucrose, lactose (2 sugar molecules together)
Strings of carbs: Maltodextrin – polymer of glucose and starches such as amylose starch and amylopectin starch.

Question 22

Key info about fats

Answer 22

Essential energy source
Protection of vital organs, make up cell membrane, precursors of bile, hormones and steroids
Foods high in fat= fatty meats and fish, cheese, chocolate, avocado, nuts and seeds
30% of energy intake
Types of fat
Triglycerides are the most abundant dietary fat – glycerol+ 3FAs. FAs vary in chain length. No. of Cs affects classification. Short chain (C6 or less), Long chain (12+), medium chain (8-10 Cs)
Saturated fatty acids (no double bond), unsaturated fatty acids have a double bond.
Dietary advice – take less saturated fats, although this is a topic for debate – do saturated fatty acids contribute to cardiovascular disease?

Question 23

Key info about proteins

Answer 23

Proteins provide structure to all cells in body
AAs have central roles in metabolism of many organs and tissues
AAs are precursors for the synthesis of body proteins
Only 10% of energy intake
Endurance and resiatance athletes consume more proteins than sedentary individuals.
AAs are nonessential (don’t have to consume in diet as can synthesise them ourselves) or essential (cant produce them meaning they have to come from diet)

Question 24

Protein quality
Complete/incomplete proteins
Protein score - + limitations?

Answer 24

Complete protein – contains all 9 essential AAs (fish, poultey,eggs, pork, diary, tofu, edamame). Mostly animal protein sources but a couple of plant protein sources
Incomplete protein – deficient in one or more essential AAs (legumes, nuts, seeds, veg) – all plant protein sources
Just because its incomplete does not mean it’s a bad protein

High PDCAAS protein score (1.0) indicates that the protein will provide 100% of all the amino acids required in the diet
Scoring tools may have limitations – if you are deficient in one protein (say chickpeas), on the same plate you will have another food source contributing to that deficiency, so once you take a whole meal approach, its not quite as simple as the scoring chart suggests.

Question 25

Key info about water

Answer 25

Adult body = 60% water
2/3 extracelluar, 1/3 intracellular
Functions= nutrient transport, protection, temp regulation, biochemical reactions

Question 26

General dietary guidelines (not athletes) - based on 2000kcal
Total fat
Saturated fat
Total carbs
Dietary fibre
Protein

Answer 26

Total fat = less than 65g (30% of energy intake)
S Fat = less than 20g (10% energy intake)
Total cho = 300g (60% energy intake)
Dietary fibre - 25g
Protein = 50g (10% energy intake)

Question 27

Different measures as assessing dietary intake and possible limitations?

Answer 27

Diet record (3-7 days weighed food intake) – if 3 days, would usually be 2 weekdays and 1 weekend day to reflect how eating habits change
24h recall – problems with forgetting or measurement issues (how much is one cup?)
Food frequency questionnaire
Common issue – compliance/bias in memory or reporting/altered behaviour (if you usually cook with lots of ingredients, you may not be bothered to weigh them all out so change eating habits), underestimating intake (reduced intake as they are being observed, or sloppiness of measurement or inaccuracy of tools).