Lecture 15

Question 1

Triglyceride breakdown

Answer 1

• lipolysis

- breakdown/catabolism of a triglyceride to glycerol and the energy-rich FA molecules

Question 2

Triglycerides break down to glycerol and 3 fatty acids:

Answer 2

1- Fatty acids (FA) leave the adipocyte cell and enter the blood.
2- Fatty acids (FA) combine with the blood protein albumin for transport throughout the body.
3-This albumin-fatty acid combination = free fatty acid (FFA)

Question 3

Fats during moderate intensity to prolonged exercise

Answer 3

• During the first 20 mins of moderate exercise, CHO and fats supply energy ~ equally (fat – 50%)
• When exercise continues for an hour or more, lipids gradually supply a greater % of energy is no CHO feeding.
• Toward the end of prolonged exercise, when glycogen reserves become depleted, lipids supply nearly 80% of the total energy required.

Question 4

After 6 hours of exercise - fat contribution

Answer 4

• After 6 hr exercise, ~80% of total energy came from fat breakdown.
• as glycogen stores are depleted, there will be a greater dependence on fat catabolism, and will affect exercise intensity
• Exercise intensity will decrease to a level governed by the body’s ability to mobilize and oxidize fat

Question 5

Why are fats slow to oxidise

Answer 5

1- FA mobilization from adipose tissue
2- FFA transport to skeletal muscle via the circulation
3- FFA uptake by the muscle cell
4- FFA transport into the mitochondria
5- FFA oxidation within the mitochondria

Question 6

exercise training and fat use

Answer 6

Regular aerobic exercise profoundly improves the body’s ability to use lipids as a fuel during slow to moderate intensity exercise.
- body learns to be more effceient

Question 7

improved fat oxidation is due to

Answer 7

1- Increased rate of lipolysis within adipocytes
2- Increased no. capillaries in trained muscle which increases the body’s capacity to deliver lipids to working muscle
3- Improved transport of of FFAs through the muscle fibres/cells plasma membrane
4- Increased size and no. of mitochondria
5- Increased rate of enzyme activity that assists in the oxidation of lipids.

Question 8

protein contains

Answer 8

Protein contains: carbon, oxygen, hydrogen and nitrogen atoms

Question 9

structure of a protein

Answer 9

• Positively charged amine group.
  = 2 x H atoms attached to nitrogen (NH2).
• Negatively charged carboxylic acid group - COOH.
• In the middle = central carbon and H
• The remainder of the amino acid is referred to as the R group (or side chain) and this can take on a variety of forms.

Question 10

how are amino acids joined together

Answer 10

by attaching the carboxylic group of one amino acid to the amine group of another amino acid – CONDENSATION process.

Question 11

peptide bonds

Answer 11

• The binding of these two amino groups forms a peptide bond. A water molecule is liberated.
• Two joined amino acids produce a dipeptide
• The linking of three amino acids produces a tripeptide
  A long chain of amino acids =
• polypeptide

Question 12

amino acids

Answer 12

• 20 required by the bodu

- 8 cannot be produced by the body (essential amino acids)

Question 13

complete protein

Answer 13

contains all of the essential AA in the right quantity and ratio to maintain nitrogen balance and for tissue growth and repair.
eg eggs

Question 14

recommened diteray intake fo protein

Answer 14

• 10-15% of total caloric intake = protein

Question 15

excessive protein consumption leads to

Answer 15

= converted to glucose or triglycerides.
- Places a strain on liver and kidney function
= harmful!