Parts 7-12 on Insendi

Question 1

Why does ATP demand increase?

Answer 1

Increase in requirements of muscle actomyosin ATPase and cation balance as muscles contract

Question 2

During moderate exercise (when oxygen is not a limiting factor), how are the increased demands of skeletal muscle for ATP met? (two things)

Answer 2

Increased numbers of glucose transporters on the surface of muscle cells.
Increased rate of gluconeogensis induced by adrenalin.

Question 3

3 things adrenaline does?

Answer 3

• Increases rate of glycolysis
• Increases rate of gluconeogenesis
• Increases release of fatty acids from adipocytes

Question 4

Two things that occur in anaerobic respiration?

Answer 4

Glycogen is broken down in the muscle and liver and pyruvate is taken up by the liver and converted into lactate to replenish NAD+. Lactate is then used by the liver to generate glucose by gluconeogenesis

Question 5

Where is control of metabolic pathways typically centered?

Answer 5

At early, irreversible steps

Question 6

Two levels that metabolic control is seen at?

Answer 6

Product inhibition

Under the influence of signalling molecules such as hormones

Question 7

Two facts about Hexokinase I?

Answer 7

• Active at low concentrations of glucose so it operates at maximal velocity all the time
• Inhibited by accumulating levels of glucose-6-phosphate during anaerobic respiration

Question 8

Function of glucose-6-phosphatase?

Answer 8

To catalyse the generation of glucose from glucose-6-phosphate

Question 9

4 hormones involved in blood glucose control?

Answer 9

• Insulin
• Glucagon
• Adrenaline
• Glucocorticoids

Question 10

4 effects of insulin secretion?

Answer 10

• increased glucose uptake by liver – used for glycogen synthesis and glycolysis (acetyl-CoA produced is used for fatty acid synthesis).
• increased glucose uptake and glycogen synthesis in muscle.
• increased triglyceride synthesis in adipose tissue.
• increased usage of metabolic intermediates due to a general stimulatory effect on the body’s synthesis and growth.

Question 11

3 things that occur after a meal?

Answer 11

• Insulin release from pancreas
• Glucose uptake into liver and tissues stimulated
• Stimulation of synthetic (anabolic) pathways

Question 12

5 things that occur after prolonged fasting?

Answer 12

• glucagon/insulin ratio increases further
• adipose tissue begins to hydrolyse triglyceride to provide fatty acids for metabolism
• TCA cycle intermediates are reduced in amount to provide substrate for gluconeogenesis
• protein breakdown provides amino acid substrates for gluconeogenesis
• ketone bodies are produced from fatty acids and amino acids in liver to substitute partially the brain’s requirement for glucose

Question 13

Type 1 vs type 2 diabetes?

Answer 13

Beta cell dysfunction in islets in pancrease so not enough insulin secreted vs insulin resistance

Question 14

4 diabetic complications?

Answer 14

• hyperglycaemiawith progressive tissue damage (e.g. retina, kidney, peripheral nerves)
• increase in plasma fatty acids and lipoprotein levelswith possible cardiovascular complications
• increase in ketone bodies with the risk ofacidosis
• hypoglycaemiawith consequent coma if insulin dosage is imperfectly controlled