Final: fatty acid oxidation

Question 1

how can we fast for up to 2 weeks at a time?

Answer 1

we can store dietary fuels and break them down into ATP

Question 2

how do fatty acids generate ATP?

Answer 2

transfer of electrons in form of hydrogens to molecules can generate ATP

Question 3

where does fatty acid oxidation occur?

Answer 3

mitochondria of heart, liver, skeletal muscle cells

Question 4

where is fat stored?

Answer 4

in adipocytes as triglycerides

Question 5

triglyceride

Answer 5

3 fatty acids attached to glycerol

Question 6

what enzyme breaks down triglycerides?

Answer 6

Hormone sensitive lipase breaks triglycerides down into 3 fatty acids + glycerol

Question 7

starvation state

Answer 7

blood glucose decreases, pancreas secretes glucagon which increases activity of hormone sensitive lipase

Question 8

what hormone increases activity of hormone sensitive lipase?

Answer 8

increase in glucagon!

Question 9

once broken down by hormone sensitive lipase, what happens

Answer 9

fatty acids can leave fat cell and enter blood stream and bind to albumin

Question 10

albumin does what with fatty acids?

Answer 10

takes them to target cells, such as liver cells that can perform fatty acid oxidation
also makes them more soluble

Question 11

fatty acid oxidation getting into the cell

Answer 11

fatty acid dissociates from albumin and diffuses into cell

Question 12

carnitine shuttle purpose

Answer 12

carnitine can go back and forth through mitochondrial matrix to bring in more fatty acids

Question 13

carnitine shuttle regulation

Answer 13

malonyl-CoA (from fatty acid synthesis) can inhibit CAT1 and slow down fatty acid oxidation

Question 14

beta oxidation 1 cycle energy payoff

Answer 14

1 NADH, 1 FADH2, 1 acetyl-CoA

Question 15

where do NADH and FADH2 go?

Answer 15

ETC! bc they are electron rich
they can make ATP
1 NADH = 3 ATP
1 FADH2 = 2 ATP

Question 16

where does the 1 acetyl-CoA go?

Answer 16

citric acid cycle to yield NADH and FADH2 which then enter ETC and yield 12 ATP per acetyl-CoA

Question 17

1 palmitoyl-CoA yields

Answer 17

7 NADH
7 FADH2
8 acetyl-CoA
131 ATP - 2 ATP = 129 ATP

Question 18

what does propionyl-CoA get converted to

Answer 18

succinyl-CoA

a TCA cycle intermediate

Question 19

where does succinyl-CoA go (2 options)

Answer 19

1) enter TCA cycle and become oxaloacetate (extra oxaloacetate can be used in gluconeogenesis)
2) succinyl-CoA can be fully oxidized to CO2

Question 20

what triggers release of fatty acids from TAGs?

Answer 20

adrenaline, glucagon, and ACTH can activate lipases that release fatty acids from TAGs

Question 21

what happens to glycerol when fatty acids are broken down?

Answer 21

glycerol goes back to liver and can be converted to DHAP for gluconeogenesis

Question 22

how many ATP per NADH or FADH2

Answer 22

2. 5 ATP per NADH

1. 5 ATP per FADH2

Question 23

fatty acid oxidation: anaerobic or aerobic?

Answer 23

aerobic: requires oxygen!

Question 24

when do we use more fatty acids as fuel

Answer 24

long duration = use more fats

higher intensity = more carbs as fuel

Question 25

ketone bodies

Answer 25

alternate source of fuel
produced in liver mitochondria (ketosis or ketogenesis)
can’t be used by liver!
transported in blood for use by other tissues

Question 26

ketone bodies unique facts

Answer 26

soluble form of fats
can cross blood-brain barrier (can be used by brain when glucose is unavailable)
EX: starvation/low carbs or Diabetes Mellitus

Question 27

ketoacidosis

Answer 27

caused by very high amounts of ketone bodies in blood
acidify blood, put strain on kidney
occurs during uncontrolled diabetes mellitus (without insulin, cells can’t use glucose in body)
fatty acids broken down and acetyl-CoA used to produce ketone bodies