Metabolism L1.2

Question 1

State the role of homeostasis

Answer 1

Counteracts imbalances to internal environment

It is a dynamic equilibrium.

Can exist al all levels
1. Cells (regulation of intracellular Ca2+ conc)
2. Tissue (balance between cell proliferation + apoptosis / cell death)
3. Organs (kidne regulates water + ion conc of blood)
4. Organism (maintenance of body temp)

Question 2

Describe body fluid homeostasis

Answer 2

Balance between fluid gain and fluid loss
(must be maintained at optimum level)

Question 3

Describe uses of blood

Answer 3

1. Transport
   -supplies oxygen
   -supplies nutrients for utilisation, storage, interconversion
   -removal of waste products, CO2, urea, lactic acid
   -sginalling (e.g. hormones)
2. Coagulation
3. Immune functions
4. Regulation of body pH
5. Regulation of core body temp
6. Hydraulic functions

Question 4

State the normal fasting plasma conc of glucose (mmol/L)

Answer 4

5

Question 5

Describe chemical bond energies in chemical reactions

Answer 5

Breaking chemical bonds = releasing energy
Making chemical bonds = uses energy

Question 6

Describe exergonic reactions

Answer 6

More energy released than used

Question 7

Describe endergonic reactions

Answer 7

More energy used than released

Question 8

Define Gibbs free energy (G)

Answer 8

Energy released in exergonic reaction, available to do work.
Exergonic reactions occur spontanously + provide energy to drive endergonic reactions

Question 9

Explain Gibbs free energy CHANGE

Answer 9

Measured in kj/mol or kcal/mol

If free energy change is -ve: net loss of energy, reaction occurs spontaneously

If free energy change is +ve: reaction needs input of free energy so must be coupled with exergonic reaction

Question 10

Homeostasis and Energy Questions

Answer 10

Question 11

Describe the role of H-carrier molecules

Answer 11

Carriers of reducing power for ATP production

Question 12

State examples of major carrier molecules

Answer 12

Flavin
Nicotinamide

Question 13

Which vitamin provides flavin?

Answer 13

B2

Question 14

Which vitamin provides nicotinamide

Answer 14

B3

Question 15

Give the oxidised and reduced form of flavin

Answer 15

Oxidised: FAD
Reduced” FADH2

Question 16

Give the oxidised and reduced form of nicotinamide

Answer 16

Oxidised: NAD+
Reduced: NADH + H+

Question 17

Why is the total concentration of “oxidised and reduced” carriers constant?

Answer 17

Reduced carriers quickly re-xodised

Question 18

Diagram showing overview of catabolism

Answer 18

Question 19

Breifly describe the four stages of catabolism

Answer 19

1. DIET MACRONUTRIENTS: macronutrients from diet converted to cellular fuel
2. Cellular fuel to metabolic intermediates (releases energy + some reducing power)
3. TCA cycle / citric acid cycle / krebs cycle (releases energy + some reducing power)
4. Oxidative phosphorylation (reducing power converted to ATP)

Question 20

Which pathways are activated by high energy signals?

Answer 20

Anabolic pathways
(high conc ATP)

Question 21

Which pathways are activated by low energy signals?

Answer 21

catabolic pathways
low conc atp

Question 22

Describe ATP synthesis under anaerobic conditions during exersice

Answer 22

During exercise,
CREATINE PHOSPHATE generates ATP for use by exercising muscle

Question 23

Describe ATP synthesis under anaerobic conditions during rest

Answer 23

ATP accumulates and is used to make creatine phosphate

Question 24

Describe ATP synthesis in aerobic conditions

Answer 24

ATP produced via oxidative phosphorylation

Question 25

Describe different energy stores

Answer 25

Muscle (creatine phosphate) - short term store (few seconds)

Carbohydrates - immediate use - short term (min/hours)

Fat stores (adipose tissue) long term (40 days)

Muscle protein (obtain energy under extreme conditions)

Question 26

Answer 26