Roesler final section

Question 1

Glucose can ultimately be converted into what three metabolic fuels?

Answer 1

glycogen
amino acids
fatty acids/ triacylglycerols

Question 2

Fatty acids can be converted into what other fuel in humans?

Answer 2

ketone bodies

Question 3

Amino acids can be converted into what 3 fuels?

Answer 3

Glucose / glycogen
fatty acids/ triacylglycerols
ketone bodies

Question 4

What is the most highly concentrated form of stored biological energy?

Answer 4

triacylglycerols

Question 5

Explain the major metabolic processes in the liver involving glucose?

Answer 5

• glucokinase in liver is not inhibited by glucose 6p
• liver has a high capacity for glucose metabolism
• glucose 6 phosphate is the main metabolism in the liver
• liver exports glucose to maintain blood sugar levels for brain

Question 6

In a fed state, what is the liver using glucose for?

Answer 6

glucose will go towards:
- ATP production (small %)
- glycogen
- fatty acids
- cholesterol
- NADPH
- nucleotides

Question 7

In a fasting state, how is the liver maintaining blood sugar levels?

Answer 7

• glycogen and gluconeogenesis are making glucose

Question 8

What 3 unique features of the liver contribute to it acting as a glucose sensor?

Answer 8

• liver has a specific glucose transporter GLUT2 which has a high KM for glucose meaning it can respond to high glucose concentrations
• liver has a specific hexokinase called glucokinase that has a high KM for glucose and is not inhibited by glucose 6p
• Liver glycogen phosphorylase A is inhibited by glucose

Question 9

In a fed state, what is the liver using amino acids for?

Answer 9

• to make proteins in the liver
• to make nucleotides
• exports excess amino acids elsewhere

Question 10

In a fasting state, what is the liver using amino acids for?

Answer 10

• making glucose
• making a small % of ATP

Question 11

In a fed state, what is the liver using fatty acids for?

Answer 11

• converting them to triacylglycerols and phospholipids

Question 12

In a fasting state what is the liver using fatty acids for?

Answer 12

• MAJOR source of ATP
• Ketone body formation when needed

Question 13

during prolonged fasting, what provides as much as 70% of the energy in the brain?

Answer 13

ketone bodies

Question 14

In a fed state, what are fat cells using glucose for?

Answer 14

• making a small % of ATP
• making acetyl COA and DHAP which eventually get converted into triacylglycerols
• making NADPH

Question 15

In a fasting state, what do fat cells do to triacylglycerols?

Answer 15

breaks them down to get energy, making fatty acids and glycerol

Question 16

What are the major metabolic processes in muscle cells?

Answer 16

• maximum activity - glucose is the main fuel
• since muscle lacks glucose 6 phosphatase, the glucose released from glycogen is metabolized through glycolysis
• rate of glycolysis exceeds that of the TCA cycle making excess lactate
• cori cycle uses lactate to make glucose in the liver
• basically every metabolic proesses in muscle makes ATP or expels waste (lactate)

Question 17

The heart obtains most of its ATP through oxidative phosphorylation using _____

Answer 17

fatty acids

Question 18

What are the three major metabolic hormones?

Answer 18

insulin, glucagon and epinephrine

Question 19

Which two metabolic hormones are synthesized in the pancreas?

Answer 19

• insulin and glucagon

Question 20

Does muscle respond to glucagon?

Answer 20

no because muscle cells do not have glucagon receptors

Question 21

the most common fuel used by most tissues isssss

Answer 21

fatty acids

Question 22

What are the two targets of glucagon?

Answer 22

liver and adipose tissue

Question 23

What gets synthesized under extreme fasting?

Answer 23

ketone bodies

Question 24

What metabolic processes increase when glucagon is released? (4)

Answer 24

• glycogenolysis
• triacylglycerol hydrolysis - lipolysis
• gluconeogenesis
• ketogenesis

Question 25

What are the three main targets of epinephrine?

Answer 25

liver, muscle, adipose

Question 26

What does epinephrine do in liver?

Answer 26

stimulates glycogen breakdown and glucose release

Question 27

What does epinephrine do in adipose tissue?

Answer 27

• stimulates TAG breakdown and fatty acid release

Question 28

What does epinephrine do in muscle?

Answer 28

stimulates glycogen breakdown and glycolysis

Question 29

What is the main difference between epinephrine and glucagon?

Answer 29

epinephrine acts on muscle whereas glucagon doesn’t because muscle has no glucagon receptors

Question 30

What is the only metabolic pathway that is inhibited by epinephrine?

Answer 30

glycogen synthesis

Question 31

insulin stimulates ___ uptake by tissues

Answer 31

glucose

Question 32

Most cases of diabetes in north America are type ___

Answer 32

II

Question 33

What is the blood glucose level in mM that may indicate diabetes?

Answer 33

7mM

Question 34

What test measures the amount of blood sugar attached to your hemoglobin proteins?

Answer 34

HbA1C

Question 35

If insulin is absent or non functioning, glucose cannot enter cells so all energy must be derived from ___, leading to the production of _____. What does this mean / lead to?

Answer 35

• derived from fats, leading to acetyl coa production
• because glucose is used to make oxaloacetate (?) there is insufficient amounts to react with acetyl coa from fatty acid oxidation
• so acetyl CoA builds up bc oxaloacetate cannot replenish the TCA cycle
• acetyl coa will be used for ketone body production
• can lead to diabetic ketoacidosis

Question 36

What two processes does insulin stimulate in the liver?

Answer 36

glycolysis and fatty acid synthesis

Question 37

What two tissues are not insulin dependent?

Answer 37

brain and liver