Metabolism - Introduction

Question 0

What energy is gained from alcohol, carbs, protein and fats?

Answer 0

Fats 37000kJ/kg
Alcohol 29000kJ/kg
Carbs 17000kJ/kg
Protein 17000kJ/kg

Question 1

What is energy used for?

Answer 1

1) . Resist entropy - breakdown of cells and tissues
2) . Maintain body temperature in mammals
3) . Support and activity of cells and tissues
- -> biosynthesis
- -> mechanical
- -> electrochemical
- -> transport

Question 2

What does BMR maintain?

Answer 2

1) . Digestion of food/other organs function
2) . Body temp
3) . Maintenance of cells (ion transport etc)

Question 3

What affects BMR?

Answer 3

Body size
Gender
Environmental temperature
Endocrine status (thyroid hormones etc)
Factors that affect body temp (fever etc)

Question 4

What stores can the body gain energy from?

Answer 4

1) . Glycogen - immediately used
2) . Triacylglycerides - long term store
3) . Proteins from muscle - during starvation

Question 5

What are the components of energy expenditure?

Answer 5

BMR
Exercise
Processing food

Question 6

What are the categories in the diet and what do they provide?

Answer 6

1) . Fats
- 2.2x more energy than from carbs
- absorb fat soluble vitamins
- some fatty acids are essential

2) . Proteins
- can be metabolised for energy
- can be broken down to provide amino acids required for N containing compounds

3) . Carbs
- metabolised for energy

4). Vitamins

5) . Fibre
- maintains healthy gut function

6) . Water
- maintains hydration

Question 7

What are the 2 protein deficiencies and their function?

Answer 7

1) . Marasmus -
- no proteins or carbs
- no oedema
- anaemic, diarrhoea, thin and dry hair
- muscle wasting
- cant make amino acids

2) . Kwashiorkor -
- carbs but no proteins
- oedema
- apathetic, lethargic, anorexia
- carbs are converted into lipids, but due to lack of protein, there is no carrier, so the lipid is stored in the liver = accumulates = damage

Question 8

What is the BMI calculation and categories?

Answer 8

Weight (kg)
BMI = —————
Height (m2)

< 18.5 = underweight
18.5 - 24.9 = average
25 - 29.9 = overweight
30 - 34.9 = obese
> 35 = severely obese

Question 9

What are the comorbidities of obesity?

Answer 9

Type II diabetes
Cancer
CV disease
Hypertension

Question 10

How does obesity occur?

Answer 10

When energy expenditure is less than energy intake?

Question 11

What is homeostasis?

Answer 11

The maintenance of the internal environment in order to sustain life.
It is a dynamic equilibrium

Question 12

What are some examples of what homeostasis controls?

Answer 12

Blood flow
Blood pH
Body temp
Supply of nutrients and O2
Removal of CO2 and waste

Question 13

How does homeostasis affect the blood?

Answer 13

The blood needs its conc of nutrients kept constant but need fluctuates = cells store and interconvert

Question 14

What are the levels of TAGS, a/a, cholesterol, fatty acids and glucose in the blood?

Answer 14

Cholesterol ~ 5mmol/L
Glucose ~ 5mmol/L 
TAGs ~ 2mmol/L
A/a ~ 2mmol/L
Fatty acids ~ 0.5mmol/L

Question 15

What is metabolism?

Answer 15

The process in which energy and raw materials are derived from food stuff, in order to support the growth, repair and activity of tissues to sustain life.

Question 16

What are the types of metabolism?

Answer 16

Anabolic

• reductive
• builds things up from metabolites
• uses ATP

Catabolic

• oxidative
• breaks down fuel molecules to gain metabolites
• generates ATP

Question 17

What is the function of metabolism?

Answer 17

Provides the energy we use for:

• support activity and growth of cells
• -> biosynthesis
• -> mechanical
• -> electrochemical
• -> transport
• resisting entropy
• manta inning body temp

Question 18

What does exergonic and endergonic mean?

Answer 18

Exergonic

• release energy = spontaneous so deltaG < 0
• energy released often drives substrate level phosphorylation

Endergonic
- takes in energy = non spontaneous so deltaG > 0

Question 19

How is the energy in bonds of fuel molecules released, and therefore, what is required?

Answer 19

Released via oxidation so carriers are needed for the electrons released
= NAD+
= FAD

Question 20

Why is NAD+ and FAD recycled?

Answer 20

Because the total concentration of NAD+/NADH and FAD/FAD2H is constant in the body = would run out

Question 21

What are the features of carriers?

Answer 21

Complex

Contain components from vitamins

Question 22

What happens when ATP levels are high/low?

Answer 22

High - energy levels are high, anabolic systems activated.

Low - energy levels are low, catabolic systems activated.

Question 23

What does adenylate kinase do?

Answer 23

Converts 2ADP —-> ATP + AMP

Question 24

How is energy released from ATP?

Answer 24

Via hydrolysis of the high energy bond between ADP and Pi.

Question 25

Why does ADP need recycling?

Answer 25

It is not a store

Concentration on body is constant

Question 26

Why is it important that ATP is a stable molecule?

Answer 26

It is vital for the flow of energy.

Question 27

What is creating phosphate and how is it created?

Answer 27

Creatine + ATP —————-> ADP + CrP
Creatine kinase

It is a reserve of high energy stores for periods of sudden metabolic activity.

Question 28

How is ATP generated through CrP?

Answer 28

If conc of ATP falls quickly, creatine kinase quickly uses CrP and ADP to formATP and creatine.

Question 29

What is the clinical importance of CrP?

Answer 29

1). Released by cardiac myocytes during a heart attack = can be measured in blood a few hours later as diagnosis.

2). Creatine and CrP both break down spontaneously at a constant rate to give creatinine.
Creatinine concentration in urine over 24hours is proportional to muscle mass, and therefore, can be a measure of dilution of urine, to estimate true urinary loss of a substance.