Lecture 27: Power Sources and Metabolism

Question 1

What is glycogen used for?

Answer 1

Short term energy store

Question 2

What happens to our glycogen overnight?

Answer 2

Our glycogen stores decrease, as they are used to generate glucose for the needs of the body

Question 3

What is beta-oxidation?

Answer 3

Cyclic process, taking off two carbons each cycle

Question 4

What does one cycle of beta -oxidation release?

Answer 4

One molecule of acetyl-CoA

Question 5

What happens in the liver after a few days without food?

Answer 5

The liver starts to produce ketone bodies

Question 6

Why do these ketone bodies form?

Answer 6

The TCA cycle is unable to further oxidize all the acetyl-CoA produced from fatty acids

Question 7

What do ketone bodies supply?

Answer 7

A water soluble transportable form of energy as they are much more soluble than free fatty acids

Question 8

What is ketoacidosis?

Answer 8

When large amounts of the ketone bodies acetotate and beta hydroxybutyrate are released from liver, the blood pH drops because they are acids

Question 9

How is blood glucose levels maintained?

Answer 9

Through gluconoeogenesis but this requires pyruvate which cannot be produced from fatty acids

Question 10

What do hormones do metabolically?

Answer 10

Integrate metabolism

Question 11

What four major organisms are important to fuel metabolism?

Answer 11

Liver
Adipose tissue
Muscle
Brain

Question 12

What is insulin?

Answer 12

An anabolic hormone of the well fed state

Question 13

What does insulin do ?

Answer 13

Stimulates glycolysis
Stimulates lipogenesis by activating acetyl-CoA carboxylase
Insulin shuts down glucose- generating pathways and inhibits hormone-sensitive lipase in adipose tissue
Reduces blood glucose levels

Question 14

How does insulin reduce blood glucose levels?

Answer 14

Glycogen synthesis
Lipogenesis
Glycolysis are all increased

Gluconeogensis
Glycogenolysis
Ketogenesis are all decresaed

Question 15

What does glucagon do to blood levels?

Answer 15

Elevates blood levels- opposite effect of insulin

Question 16

When and where is glucagon released?

Answer 16

When blood glucose levels drop and glucagon is released from the alpha- cell of the pancreas

Question 17

What does glucagon do?

Answer 17

Acts only on the liver to stimulate glucogenesis, glycogenolysis , and shut down glycogen and lipid synthesis

Question 18

When is adrenaline released?

Answer 18

During stress

Question 19

Where is adrenaline released from?

Answer 19

The adrenal meduula

Question 20

What does adrenaline produce?

Answer 20

a fight or flight response

Question 21

What does adrenaline do?

Answer 21

Inhibits insulin secretion

Question 22

What is cortisol?

Answer 22

A steroid hormone with longer catabolic effects

Question 23

What produces cortisol?

Answer 23

Adrenal cortex

Question 24

What are the effects of insulin after a meal?

Answer 24

Inhibits HSL- triglycerides not broken down to fatty acids

Insulin activates the glucose transporter- glucose is taken up by cells

Insulin activates acetyl-CoA - fatty acid synthesis increases

Question 25

What is diabetes?

Answer 25

A disorder of reduced insulin production or reduced response to insulin

Question 26

What is Type 1 diabetes?

Answer 26

Usually starts in childhood: caused by autoimmune destruction of beta-cells in the pancreas, so no insulin is produced

Question 27

What is type 2 diabetes?

Answer 27

The most common, and occurs later in life.Insulin may be produced, but response to insulin is impaired-i.e insulin resistance