Energy, Metabolism and Nutrients

Question 1

ATP requirements during exercise

Answer 1

• success in athletic competition is dependent upon the ability to provide energy for muscle contraction
• ATP hydrolysis (ATP + H20 -> ADP +Pi + energy)

Question 2

Energy systems: ATP resynthesis

Answer 2

• ATP resynthesis (to match the rate of utilisation)
• Anaerobic (fast)
  
  • PCr +ADP + H+ -> Cr + ATP
  • Glucose +2ADP +2Pi -> 2Lactate + 2H2O +2ATP
  • Glycogenn + 3ADP + 3Pi -> glycogenn-1 + 2lactate + 2H20 + 3ATP
• aerobic (slow)
  
  • glucose + 6O2 +36ADP -> 6CO2 + 6H2O + 36ATP
  • palmitate + 23O2 + 130ADP -> 16CO2 + 16H2O + 130ATP

Question 3

Energy systems: power vs capacity

Answer 3

• since the intramuscular stores of ATP are small, ATP must be regenerated at a rate sufficient to sustain the level of contractile activity
• at exercise intensities that can be sustained for more than a few minutes, ATP requirements are met through aerobic metabolism

Question 4

carbohydrate stores

Answer 4

(for 70kg man)
- blood glucose (3-5g)
- liver glycogen (80-100g)
- muscle glycogen (300-400g)
approximately 1500-2000kcal (6000-8000kJ)
1kcal = 4.184kJ

Question 5

fat stores

Answer 5

adipose tissue (3.5 - 14kg)
muscle triglyceride (200-500g)
approximately 31,500 - 126,000 kcal for a 70kg man with body fat of 5-20%

Question 6

Carbohydrate-rich foods

Answer 6

• sugars (simple carbohydrates)
  
  • fruit juices, fruits, sweetened cereals and baked goods, jam, sweets, sports drinks, beet and cane sugar, maple syrup, honey
• starches
  
  • cereals, potatoes, pasta, rice, bread
• fibre
  
  • whole-grain cereals and bread, oats, fruits and vegetables

Question 7

types of carbohydrate

Answer 7

• glucose
• fructose
• galactose
• maltose
• sucrose
• lactose

Question 8

fats

Answer 8

• energy source
• protection of vital organs
• cell membrane constituents
• precursors of bile, hormones and steroids
• fat-soluble vitamin intake
• palatability
• (30% energy intake)

Question 9

types of fat

Answer 9

• triglycerides are most abundant dietary fat
• fatty acids vary in chain length
  
  • short chain (SCFA; C6 or less)
  • medium chain (MCFA; C8-C10)
  • long chain (LCFA; C12 or more)
• saturated fatty acid (no double bond)
• unsaturated fatty acid (one or more double bond)

Question 10

protein (amino acids)

Answer 10

• proteins (made up of amino acids) provide structure to all cells in the human body
• amino acids have central roles in the metabolism of many organs and tissues
• amino acids are precursors for the synthesis of body proteins
• amino acids are regulators of the synthesis of neurotransmitters, hormones, DNA, and RNA
• (10% energy intake)

Question 11

nonessential amino acids

Answer 11

• alanine
• arginine
• asparagine
• aspartate
• cysteine
• glutamate
• glutamine
• glycine
• proline
• serine
• tyrosine

Question 12

essential amino acids

Answer 12

• histidine
• isoleucine
• leucine
• lysine
• methionine
• phenylalanine
• threonine
• tryptophan
• valine

Question 13

protein quality

Answer 13

• complete protein (contains all 9 essential amino acids)
  
  • fish, poultry, eggs, beef, pork, dairy, whole sources of soy (tofu, edamame, miso)
• incomplete protein (deficient in one or more essential amino acids)
  
  • legumes (beans, peas, lentils), nuts, seeds, whole grains, vegetables

Question 14

water

Answer 14

• adult body = 60% water
  
  • 2/3 found in cells
  • 1/3 extracellular
• functions
  
  • nutrient transport
  • protection
  • temperature regulation
  • biochemical reactions
  • medium for reactions