Integration of Metabolism

Question 1

what metabolism does muscle tissue rely on?

Answer 1

Carboyhydrate + fatty acid oxidation

Question 2

which tissues cannot utilise fatty acids as a fuel?

Answer 2

brain and nervous tissue

Question 3

what does hypoglycaemia cause?

Answer 3

faintness and coma

Question 4

what does hyperglycaemia cause?

Answer 4

irreversible organ damage

Question 5

what substrate does the brain metabolise mostly even in the fasting state?

Answer 5

glucose

Question 6

In skeletal muscle, what occurs during vigorous contraction?

Answer 6

Oxygen becomes limiting factor
glycogen breakdown in muscles
lactate formation

Question 7

what is the heart designed for?

Answer 7

complete aerobic metabolism - rich in mitochondria

Question 8

what substrates does the heart use?

Answer 8

from the TCA cycle:
ketone bodies
free fatty acids

Question 9

what does loss of oxygen supply to the heart lead to?

Answer 9

cell death + myocardial infarction

Question 10

what is the normal glucose range?

Answer 10

4-5.5mM

Question 11

what is a key role of the liver?

Answer 11

glucose storage organ (glycogen)
plays a key role in lipoprotein metabolism (transport of triglycerides + cholesterol)

Question 12

during fasting, what does acetyl CoA turn into?

Answer 12

ketone bodies

Question 13

what can excess glucose-6-phosphate be used to generate?

Answer 13

glycogen in the liver and muscle

Question 14

what happens to excess acetyl CoA?

Answer 14

fatty acids, stored in the adipose tissue

Question 15

what is produced during extreme exercise?

Answer 15

lactate

Question 16

what molecules are involved in gluconeogenesis?

Answer 16

lactate - utilised to regenerate pyruvate by lactate dehydrogenase

amino acids - can be derived from the diet or breakdown of skeletal muscle

glycerol backbone - used to generate DHAP

Question 17

what happens when blood conc goes below 3mmol (hypoglycaemia)?

Answer 17

breakdown liver glycogen stores
release fatty acids from adipose tissue
convert acetyl CoA into ketone bodies via the liver

Question 18

when does gluconeogenesis tend to happen?

Answer 18

when the rate of glycolysis exceeds the rate of the TCA cycle

Question 19

what are glucogenic amino acids used to generate?

Answer 19

glucose via gluconeogenesis

Question 20

what are ketogenic amino acids used to generate?

Answer 20

fatty acids + ketone bodies

Question 21

what 2 things does contracting muscle require? (aerobic respiration)

Answer 21

more ATP
more glucose transporters on the membrane of muscle cells

Question 22

how does adrenaline help increase the rate of glycolysis in muscle? (aerobic respiration)

Answer 22

increase gluconeogenesis by the liver
increase the release of fatty acids from adipocytes

Question 23

what does lactate synthesis do during anaerobic respiration?

Answer 23

replenish NAD+ levels, enabling glycolysis to continue

lactate also used in gluconeogenesis to synthesise more glucose