Lipid Metabolism

Question 1

Fatty acid molecules are mobilized from storage and made available to cells that need energy

Answer 1

Lipolysis

Question 2

Fatty acids are oxidized to produce energy

Answer 2

Beta oxidation > intermediates to yield energy

Question 3

Two types of lipid and cholesterol transport

Answer 3

Free fatty acids in blood: serum albumin

Triglyceride transport in lipoproteins mostly VLDL

Question 4

What is the signal for triglyceride breakdown to free fatty acid:

Answer 4

Tagging with coenzyme A for transport > convert into Acyl CoA

• this overcomes process of free FA from cytosol to mitochondria

Question 5

Short vs Long chain Acyl CoA transport into Mitc matrix

Answer 5

• short chain free diffuse into matrix

- long chain: carnations shuttle (control point)

Question 6

What is the goal of beta oxidation of even number saturated fatty acid (16 C)

Answer 6

• Goal: produce 2 carbon Acetyl-CoA

Question 7

Step 1 of Beta oxidation:

Answer 7

Oxidation: of acyl

Acyl CoA > Acyl CoA dehydrogenase (FAD to FADH2) > Trans delta 2 enoyl CoA’

Oxidation paired with reduction FAD to FADH2q

Question 8

Step 2 beta oxidation

Answer 8

Hydration: add water

• add beta OH to Carbon that was part of double bond
• get C=C to be able to add an oxygen > product is an Acyl

Question 9

Step 3 beta oxidation

Answer 9

Oxidation of alcohol: OH > carbonyl, paired with reduce NAD to NADH + H+
- rebuilding polar head

Question 10

Step 4 beta oxidation:

Answer 10

Thiolysis: cleavage

• Thiolase and addition CoA-SH
• produce Acyl and Acetylene CoA

Alpha: acetyl
Beta: acyl

Question 11

Odd numbered unsaturated fatty acid beta oxidation:

Answer 11

Broken down until double bond is at position 3

- Isomerase to flip to position 3 and produce trans delta 2 enoyl CoA and proceed with step 2

Question 12

Even numbered unsaturated fatty acid beta oxidation:

Answer 12

Proceed until double bond position 4

• goal: get to odd numbered unsaturated FA
• thus reductase to produce double bond at pos 3
• paired with oxidation of NADPH + H+ to NADP+
• then same isomerase from odd numbered > proceed with step 2

Question 13

Odd numbered saturated fatty acid beta oxidation:

Answer 13

• even numbered C4 cleaves to two acetyl CoA

- Odd numbered: C5 cleaves to acetyl CoA and Propionyl CoA

Question 14

Where is propionyl CoA derived from? And where does it enter as substrate?

Answer 14

It is derived from odd numbered saturated FA beta oxidation

• transferred to succinylcholine CoA to enter CAC

Question 15

Each round of beta oxidation produces what?

Final Round produces what?

Answer 15

Acetyl CoA + NADH + FADH2

2 Acetyl CoA OR Acetyl and Propionyl CoA

Question 16

FADH2, NADH, Acetyl CoA > ATP ratio

Answer 16

FADH2 > 1.5

NADH > 2.5

Acetyl CoA > 10

Question 17

FADH2 is related to how much ATP

Answer 17

1.5

Question 18

NADH is related to how much ATP

Answer 18

2.5

Question 19

Acetyl CoA is related to how much ATP

Answer 19

10

Question 20

How much ATP is produced per round of beta oxidation?

Answer 20

Around 14 ATP

N-carbons produces <7n ATP

Question 21

Small 3 or 4 carbon molecules soluble in the blood

Answer 21

ketone bodies

Question 22

where are ketone bodies produced?

Answer 22

Liver from acetyl CoA

Question 23

What is the role of liver during fasting state?

Answer 23

Send Acetyl CoA to brain and heart > ketogenesis

Question 24

When does ketogenesis occur?

Answer 24

• when glycogen stores have been depleted

- glucose is preferred energy source

Question 25

Types of ketone bodies liver can produce:

Answer 25

- Acetoacetate, Acetone, and D-beta-hydroxybutyrate

Question 26

What are the possible products of acetoacetate?

Answer 26

Acetoacetate is 4 carbon with two carbonyl and O- Reduction: to beta hydroxybutarate Spont non enzymatic decarboxy to acetone (removes CO2)

Question 27

What is ketoacidosis and where does it come from

Answer 27

Excess of acetoacetate and beta hydroxybutarate - Both acidic and can lower blood pH Nail polish smell from acetone exhalation

Question 28

Lipid vs carbs and protein energy:

Answer 28

Lipids: greater energy density - require more oxidation thats carbs and proteins - carbs require more water storage (1:3 with lipids) - Glucose oxidized much quicker than lipids

Question 29

What is the type of fat (color) we normally think of:

Answer 29

White fat Brown fat surrounds organs

Question 30

Where does fatty acid synthesis occur?

Answer 30

Cytosol

Question 31

Step 1 fatty acid synthesis

Answer 31

Acetyl to Malonyl CoA: via carboxylation

Question 32

Step 2 fatty acid synthesis

Answer 32

Acetyl and Malonly CoA loaded onto FA synthase (active site)

Question 33

Step 3 fatty acid synth:

Answer 33

Elongation: condense to 4 C chain and product CO2

Question 34

Reduction Hydration steps fo FA synth:

Answer 34

AFter 4C chain generated > Reduce > hydrate > reduce > produce acyl = FA head -each add 2 Carbon > until 16C FA palmitic

Question 35

When is fatty acid chain released from active site FA synthase: what is this fatty acid chain

Answer 35

16C palmitic acid (only natural FA synth)

Question 36

Where is natural cholesterol synthesized:

Answer 36

Liver

Question 37

Where does cholesterol synth take place in cell and what similarity does it have to FA synth?

Answer 37

Cytosol of liver cells and has Acetyl CoA as substrate

Question 38

Where does cholesterol synth travel to after Cytosol?

Answer 38

Continues in ER

Question 39

What is RLS of cholesterol synth:

Answer 39

Two acetyl CoA into Mevalonate | - Reduction of 2 NADPH

Question 40

What happens to mevalonate?

Answer 40

3ATP consumed into isoprene molecule

Question 41

How many isoprene molecules make up squalene?

Answer 41

6

Question 42

where are phosphoplipds generated?

Answer 42

- smooth ER of inter mitochondrial membrane

Question 43

Where does eicosanoid synthesize and from what?

Answer 43

- archidanoic (poly unsaturated) > PGs and Thromboxane

Question 44

What type of fat tissue (color) forms heat

Answer 44

Brown