25-30

Question 1

What is food intake equal to?

Answer 1

energy used + weight gain

heat production + weight gain

Question 2

Calorie to joules

Answer 2

1kCal

4.19kJ

Question 3

What process devour food energy

Answer 3

1. 1500kcal = energy to maintain basics of life - maintenance of cellular homeostasis, cardiovascular, respiratory, renal and brain functions.
   = BMR - basal metabolic rate
2. 200+ = energy to eat and digest food - enzymatic processes (mainly liver) that convert absorbed nutrients into useful and storable molecule
3. roughly 200 = energy for the muscle tone needed to maintain a sitting position
4. 200 = energy to maintain body temp in a non-neutral environment
5. 200-5000 = walking, working out or exercising

Question 4

30%-40% of BMR used by what?

Answer 4

450-600kcal per day used by the CNS

• 40-60% may be used to pump ions across cell membranes - CNS does this a lot

Question 5

What is the kcal of 1g of carbs, fat and protein

Answer 5

Carb = 4.2 (dry)
fat = 9.4
protein = 4.3

Question 6

Where are the sugars and starches from?

Answer 6

milk, fruit, seeds and plant storage organs
- true carnivores eat none so make glucose from amino acids

200-400g per day

Question 7

Where get fats from?

Answer 7

cell membranes, adipose tissue, milk fats and some seeds and fruit - 30-70g needed per day

Question 8

Protein - where from

Answer 8

from seeds, milk, eggs and meat

- 30-70g amino acids per day

Question 9

Protein turnover

Answer 9

during a typical day some 300g of protein may be broken down and replaced

• 40% is enzymes, mucin and epithelial cells released in digestive tract

Question 10

What is the purpose of insulin?

Answer 10

secreted by the β-cells of pancreas

- response to elevated blood glucose levels, promotes storage of the products of digestion

Question 11

Purpose of glucagon

Answer 11

released when glucose is ‘gone’ (low)

• from α-cells of pancreas
• maintain at 5mmol/litre
• glycogen breakdown

Question 12

How much water associated with 1g of glycogen

Answer 12

3g

• 1g of fat needs no water

Question 13

Where is glucose stored?

Answer 13

Glucose in solution in extracellular fluid = 30g
Glycogen in liver = 100g
Glycogen in muscles = 400g

Fat = 10,000g
Protein = 5500g

Question 14

Point of white fat

Answer 14

1. efficient energy reserve
2. insulation
3. mechanical padding
4. crucial to sex phenotype
5. endocrine gland (it releases hormone)
6. source of water for sea mammals

Question 15

Which tissues can only use carbohydrates as fuel?

Answer 15

brain and spinal cord

• brain needs glucose
• must come from liver as cannot from muscle glycogen
• as muscle lacks enzyme glucose-6-phosphatase
• so cant get glucose from glycogen and cant export glucose-6-phosphate
• glycerol from fat not enough overnight for the brain

Question 16

Plant storage of carbohydrate

Answer 16

amylopectin

• so starch found in special plastids called amyloplasts
• abundant in tissues used in storage = shoot and root and seeds

Question 17

Fats in plants

Answer 17

mainly as a store of reduced carbon for biosynthetic processes - building complex molecules

• fats and oils stores of carbon in many agriculturally important plants
• cotton, sunflower, soybean

Question 18

Waxes in plants

Answer 18

cuticle that prevents water loss

• also sterols form components of cell membranes and carotenoids are involved in photosynthesis

THESE ARENT TRIGLYCERIDES

Question 19

Triglycerides in plants

Answer 19

in organelles called oleosomes

• but in germinating seeds must be converted to sucrose
• fats cannot be transported

Question 20

The endosperm of plants

Answer 20

highly specialised fuel store formed in angiosperms
- developing seed

contains fuel in form of starch, sucrose, triglycerides or protein