Chapter 12.6

Question 1

What are the major sites of metabolic activity in the body

Answer 1

• the major sites are the liver, skeletal muscles, cardiac muscles, brain and adipocytes
• > connective tissues and epithelial cells do not make major contributions to the consumption of energy

Question 2

What happens to fatty acids converted to triacylglycerols in th eliver

Answer 2

-these triacylglycerols are released into the blood as very-low-density lipoproteins(VLDL)

Question 3

Describe where the liver gets most of its energy from in the well fed state

Answer 3

-it gets its energy from oxidation of excess amino acids

Question 4

What is lipoprotein lipase? When is it activated

Answer 4

• it is an enzyme found in the capillary bed of adipose tissue
• > it is induced by insulin
• > fatty acids that are released by lipoproteins are taken up by adipose tissue and made into triacylglycerol for storage

-it is activated during the fasting state

Question 5

Where does the glycerol phosphate that is required for triacylglycerol synthesis come from

Answer 5

• it comes from glucose that is synthesized in adipocytes

- >as an alternative product of glycolysis

Question 6

What happens to adipose tissue during the fasting state

Answer 6

• there are decreased levels of insulin and increased levels of epinepherine
• > so hormone sensitive lipase is activated in adipose tissue
• > allowing fatty acids to be released into the circulation

Question 7

What is the major fuel source for skeletal muscle during the well fed state and the fasting phase?

Answer 7

Well fed
->it is glucose

Fasting

• > it is fatty acids in the blood
• > may also use ketone bodies

Question 8

Is creatine phosphate a long lived source of energy

Answer 8

• no it is short

- >it transfers a phosphate group to ADP to form ATP

Question 9

What do skeletal muscles use during short amount of exercise for fuel and what do they use during long amounts of exercise for fuel

Answer 9

For short amounts of exercise
->use glucose and stored glycogen

For long amounts of exercise

• > start using fatty acids
• > so oxidation of fatty acids

Question 10

What energy source do cardiac muscles use in well fed state and fasting state

Answer 10

• for both states
• > they use fatty acids
• they can also use ketones during prolonged fasting
• > therefore, cardiac muscles mimic skeletal muscles during prolonged periods of fasting