Lecture 27

Question 1

What do unicellular organisms do if they have abundant nutrients?

Answer 1

The cells will take up the fuels and metabolize the glucose via glycolysis, a rapid but inefficient process, this is known as proliferative metabolism

Question 2

What is a type of control that unicellular cells have?

Answer 2

have an innate control system that senses the available nutrient supply and initiates an appropriate metabolic response

Question 2

What do unicellular organisms do if they have scarce nutrients?

Answer 2

The cells will adapt to starvation metabolism. Biomass production stops in these cells, and the cells switch to a slower but more efficient oxidative metabolism in order to yield the largest amount of energy from the limiting nutrients

Question 2

What is growth dependent on in multicellular organisms?

Answer 2

They are dependent on growth factors like hormones to switch from quiescent to proliferative state

Question 3

What do non-dividing cells in multicellular cells use?

Answer 3

oxidative metabolism, which includes aerobic glycolysis and the Citric Acid Cycle, to metabolize glucose.Upon stimulation by growth factors (such as insulin), differentiated cells switch to the faster anaerobic glycolysis

Question 4

What happens if there is high amount of oxygen in a normal cell?

Answer 4

Pyruvate will enter the CAC in the mitochondria and continues through the process of oxidative metabolism to yield ~36 mols of ATP

Question 5

What is the Warburg Effect?

Answer 5

Where cancer cells have overcome their dependence on growth factors. Where cancer cells consume glucose and have high rate of glycolysis followed by lactic acid fermentation in the cytsol

Question 6

What happens if there is low amounts of oxygen in a normal cell?

Answer 6

pyruvate will remain in the cytoplasm and continues through the process of lactic acid fermentation to yield lactate and 2 mols of ATP

Question 7

How do cancer cells metabolize?

Answer 7

Cancer cells will metabolize glucose via aerobic glycolysis and lactic acid fermentation, which yields ~4 mols of ATP, this is known as the Warburg effect

Question 8

What are the regulators that inhibit food intake?

Answer 8

insulin and leptin

Question 9

What are the regulators that promote food intake?

Answer 9

ghrelin and adiponectin

Question 10

What activates AMPK?

Answer 10

ghrelin and adiponectin in response to low levels of glucose, AA, and FFA promoting food intake

Question 11

When is leptin released?

Answer 11

By adipocytes in response to sufficient fat stores and acts on arcuate nucleus

Question 12

What activates mTOR?

Answer 12

insulin and leptin

Question 13

How is ghrelin produced?

Answer 13

It is produced by cells lining the stomach and increases production before meals and decrease after

Question 14

How does adiponectin produced?

Answer 14

by adipocytes, present in higher concentrations than most hormones, lower in obese individuals

Question 15

What does adiponectin bind to?

Answer 15

binds to specific receptors in arcuate nucleus and stimulates food intake by activating AMPK

Question 16

What does ghrelin bind to?

Answer 16

specific receptors in the arcuate nucleus and promotes food intake by activating AMPK

Question 17

What is the response to high blood glucose in a normal feeding cycle?

Answer 17

1. blood glucose increase after carb, glucagon is secreted
2. glucose is made into glycogen and fatty acids
3. fatty acids are transported to adipose tissue in VLDL, stored as TG
4. glucose is transport to muscle and made into glycogen and muscles go through glycolysis
5. fatty acids used by heart(beta ox)
6. glucose used by the brain via glycolysis and ox phos

Question 18

What is the response to low blood glucose cycle?

Answer 18

1. insulin secre. reduced, glucagon increased
2. fatty acids broken down by beta ox and glycogen mobilized by the liver by activating glycogen phos
3. TG broken down and generates FA and glycerol
4. FA used for muscle and create ketone bodies
5. fatty acids used for heart
6. Glucose is used by brain for energy via glycolysis and oxidative phosphorylation.

Question 19

What happens during starvation?

Answer 19

The body make ketone bodies from fatty acids that are used for the heart and brain.

Question 20

What happens when beta cells are destroyed?

Answer 20

results in loss of in insulin production by the pancreas

Question 21

What happens during type 1 diabetes?

Answer 21

the body’s own immune system which normally fights harmful bacteria and viruses mistakenly destroys the insulin producing (islet) cells in the pancreas

Question 22

What happens during type 2 diabetes?

Answer 22

Insulin production is often normal, but cells don’t
respond correctly.

Question 23

What is lipid overload theory?

Answer 23

fuel intake exceeds storage capacity of adipose tissue, accumulates in other tissues and prevents insulin signaling pathway that translocates GLUT4

Question 24

What is the inflammation theory?

Answer 24

when adipose tissue increases in size, they secrete inflammatory cytokines which bind peripheral tissues and inhibit insulin signaling

Question 25

What does lack of insulin result in?

Answer 25

Failure of issues, muscle, and adipose to take up glucose from blood. Glucose accumulates in blood and tissues are starved of fuel. Liver increases gluconeogenesis (low insulin/glucagon ratio) from degradation of muscle proteins. TG reserves are mobilized in response to low insulin/glucagon ratio

Question 26

What happens to fatty acid due to abnormalities?

Answer 26

FA oxidation is increased and produces lots of acetyl-CoA