Week 1 - Energy, Metabolism and Nutrients

Question 1

ATP hydrolysis equation

Answer 1

ATP + H20 –> ADP + Pi + Energy

Question 2

What are the 3 anaerobic ATP resynthesis pathways and how much ATP do they produce?

Answer 2

1) PCr pathway: PCr + ADP + H+ –> Cr + ATP

2) Anaerobic glycolysis: glucose (in blood) + 2ADP + 2Pi –> 2 lactate + 2H20+ 2ATP

3) Anaerobic glycolysis: glycogen (in muscle) + 3ATP + 3Pi –> glycogen + 2 lactate + 2 H20 + 3ATP

Question 3

What are the two aerobic ATP resynthesis pathways?

Answer 3

1) Carbohydrate oxidation: glucose produces 36ATP

2) Fat oxidation: palmitate produces 130ATP

Question 4

List the pathways in order of maximal rate of ATP generation

Answer 4

PCr
Glycolysis
CHO oxidation
Fat oxidation

Question 5

List the pathways in order of maximal available energy (capacity)

Answer 5

Fat oxidation
CHO oxidation
Glycolysis
PCr

Question 6

Why does power output decrease during a 30-second sprint?

Answer 6

higher contribution of aerobic energy pathways and a decrease in contribution of anaerobic energy pathways (PCr and glycolysis)

Question 7

Explain the process of fats, carbs and protein being converted to acetyl-coa which enters the TCA cycle.

Answer 7

Fats - triglyceride broken down into fatty acids (lipolysis) which undergoes beta oxidation and produces acetyl-coa

CHO - glucose/glycogen undergo glycolysis which produces pyruvate which is converted to acetyl-coa via PDH

Protein - protein broken down into amino acids (proteolysis) which is then broken down into keto acids which convert into acetyl-coa

Question 8

What is the typical blood glucose, liver glycogen and muscle glycogen values (grams) of a 70kg man?

Answer 8

Blood glucose: 3-5g / 4-6g
Liver glycogen: 80-100g / 80-110g
Muscle glycogen: 300-400g / 300-600g

Question 9

What is the typical adipose tissue and muscle triglyceride values for a 70kg man?

Answer 9

Adipose tissue: 3.5-14kg
Muscle triglyceride: 200-500g

Question 10

Influence of exercise intensity on energy fuels (plasma FFA, plasma glucose, muscle glycogen, other fat sources)

Answer 10

At rest, plasma FFA and plasma glucose contribute to energy expenditure.
As exercise intensity, the contribution of muscle glycogen and other fat sources increase.

Question 11

Influence of exercise duration on energy fuels (plasma FFA, blood glucose, muscle triglyceride, muscle glycogen)

Answer 11

As exercise duration increases muscle glycogen, blood glucose and muscle triglyceride contribution decreases whilst plasma FFA contribution increases.
Carbohydrate ingestion is needed to maintain blood glucose and carbohydrate oxidation.

Question 12

What are the 3 physiological and biomechanical functions of nutrients in the body?

Answer 12

1) Provision of energy
2) Regulation of metabolism
3) Promotion of growth and development

Question 13

Macronutrients

Answer 13

Carbs, fat, protein, water

Question 14

Micronutrients

Answer 14

vitamins, minerals and trace elements

Question 15

What % of energy intake is carbs?

Answer 15

60% of energy intake

Question 16

Are carbs and fats essential?

Answer 16

Carbs aren’t essential due to gluconeogenesis, whereas fats are essential as they have multiple roles other than being an energy sources such as protection of vital organs, cell membrane constituents, precursors of bile, hormones and steroids…

Question 17

3 types of carb-rich foods

Answer 17

1) Sugars: fruit juices, fruits, sports drinks, sweets, honey, sweetended cereals
2) Starches: cereal, potatoes, rice, bread
3) Fibre: whole-grain cereals and bread, oats, fruits and vegetables

Question 18

Main role of carbohydrates

Answer 18

Energy source for physical activity and the CNS

Question 19

Roles of fats

Answer 19

• Energy source
• Protection of vital organs
• Cell membrane constituents
• Precursors of bile, hormones, and steroids
• Essential fatty acids and fat-soluble vitamin intake (vitamins most abundant in fat foods such as vitamin A, D, E, K)

Question 20

What % of energy intake is fat?

Answer 20

30% - foods include cheese, butter, nuts, avocado, chocolate, fatty meats and fish

Question 21

What is the most abundant storage form of fat?

Answer 21

triglycerides

Question 22

What is the difference between saturated fatty acids and unsaturated fatty acids?

Answer 22

Saturated have no double bond whereas unsaturated have one or more double bond

Question 23

Describe the 3 chain lengths of fatty acids.

Answer 23

Short chain - C6 or less
Medium chain - C8-C10
Long chain - C12 or more

Question 24

Protein (amino acids) roles

Answer 24

• Provide structure to all cells in the human body
• Central roles in the metabolism of many organs and tissues
• Precursors for the synthesis of body proteins
• Regulators of the synthesis of neurotransmitters, hormones, DNA and RNA
• Enzymes that increase the rate of metabolic reactions

Question 25

What % of energy intake is protein?

Answer 25

10%

Question 26

What is the difference between complete proteins and incomplete proteins?

Answer 26

Complete proteins contain all 9 essential amino acids (fish, eggs, beef, dairy, tofu, pork) whereas incomplete proteins are deficient in one or more essential amino acids (nuts, seeds, legumes (beans, peas, lentils), whole grains, vegetables.

Question 27

What % of the adult body is water? Where is it stored?

Answer 27

60% water with 2/3 found in cells and 1/3 extracellular

Question 28

Functions of water

Answer 28

• Nutrient transport
• Protection
• Temperature regulation
• Biochemical reactions + medium for reactions

Question 29

Name 3 ways of assessing dietary intake and potential issues with such methods

Answer 29

• Diet record (3-7 days weighed food intake)
• 24hour recall
• Food frequency questionnaire

Issues: compliance, bias in memory or reporting, altered behaviour