Quick Review

Question 1

What must be recycled for glycolysis to continue?

Answer 1

NADH to NAD+

Question 2

Why is citrate used in IV lock?

Answer 2

Keep blood from clotting

It’s a chelator: contains carboxylic acids, which will bind calcium (calcium is required for coagulation)

Question 3

What are anapleurotic reactions?

Answer 3

Many of the intermediates can be synthesized by other enzymes and fed into the TCA cycle to REFILL it

Likewise, many TCA intermediates feed out to make important metabolites

Question 4

Succinyl CoA from TCA can be used to synthesize….

Answer 4

d-aminolevulinate for porphyrins

Question 5

What does arsenic target in metabolism? What is the implication?

Answer 5

Inhibition of dehydrogenases

Both aerobic and anaerobic pathways are impacted

Question 6

Which five enzymes are regulated in the TCA cycle?

Answer 6

Pyruvate dehydrogenase
Pyruvate carboxylase
Citrate synthase
Isocitrate dehydrogenase (rate-limiting)
alpha-ketoglutarate dehydrogenase

Question 7

What energy does the TCA cycle produce?

Answer 7

GTP
NADH
FADH2

Question 8

Where does the TCA Cycle occur?

Answer 8

Mitochondrial matrix
(except Succinate DH, which is in the inner mitochondrial membrane)
**THIS is complex II of the ETC; this is where they are linked

Question 9

Where does the ETC occur?

Answer 9

Inner mitochondrial membrane

Question 10

Where does OXPHOS occur?

Answer 10

Mitochondrial matrix

Question 11

How many electrons does Coenzyme Q carry?

Answer 11

2

Question 12

How are complexes III and IV connected?

Answer 12

cytochrome c (water soluble protein)

Question 13

Complex I

Answer 13

Oxidizes NADH

Reduces Coenzyme Q

Question 14

Complex II

Answer 14

Oxidizes succinate

Reduces Coenzyme Q

Question 15

Complex IV

Answer 15

Cytochrome oxidase

Transfers four electrons from cytochrome c to O2, making H2O

Question 16

What is the driving force of OXPHOS?

Answer 16

Delivering electrons to O2

Question 17

How many electrons can cytochrome c carry?

Answer 17

1

Question 18

How do cyanide, azide, and CO affect ETC?

Answer 18

Inhibit Complex IV

Question 19

What is the uncoupler protein?

Answer 19

Thermogenin

Question 20

Net yield of ATP from OXPHOS

Answer 20

30 ATP per glucose (G-3-P shuttle)

32 ATP per glucose (mal-asp shuttle)

Question 21

What is a reperfusion injury?

Answer 21

Occurs after ischemia. When O2 finally returns, causes burst of ROS due to O2 reacting with many reduced CoQ, cytochromes, flavins, etc

Question 22

What is the rate-limiting step of fatty acid synthesis?

Answer 22

Carboxylation of Acetyl CoA by ACC to make Malonyl CoA

Question 23

carbons in citrate

Answer 23

6

Question 24

carbons in Acetyl CoA

Answer 24

2

Question 25

carbons in malate

Answer 25

4

Question 26

carbons in pyruvate

Answer 26

3

Question 27

What cofactor does ACC require? What does it do?

Answer 27

Biotin. Acts as CO2 carrier/activator-bound to NH3 of lysines

Question 28

What is more specific: malonyl transferase or acetyl transferase?

Answer 28

Malonyl

Question 29

Starting molecule for building odd chain FAs

Answer 29

Proprionyl group (C3) instead of acetate (C2)

Question 30

What is the reducing agent in fatty acid synthesis?

Answer 30

NADPH

Question 31

When does FA synthesis stop?

Answer 31

When C16 palmitoyl group is formed

Question 32

What type of enzyme hydrolyzes palmitoyl-ACP?

Answer 32

Thioesterase

Question 33

Four levels of ACC regulation

Answer 33

1. Transcriptional 2. Polymerization 3. Phosphorylation 4. Hormones

Question 34

What is polymerization of ACC?

Answer 34

Allosteric control by palmitoyl CoA and citrate

Question 35

What does 16:1, delta 9 mean?

Answer 35

16 carbon molecule with one double bond between carbons 9 and 10

Question 36

FAS overexpression is associated with...

Answer 36

Tumors | FAS is proposed to act as an oncogene

Question 37

What must happen to TGs before they can undergo oxidation?

Answer 37

Must chop off FAs using triacylglycerol lipases. Free FAs then enter mitochondrial matrix

Question 38

What are free fatty acids typically bound to in cytoplasm?

Answer 38

Glycerol CoenzymeA Carnitine

Question 39

What are free fatty acids typically bound to in blood?

Answer 39

Typically found in lipoproteins | Also circulate found to serum albumin

Question 40

What drives fatty acid oxidation strongly forward?

Answer 40

Hydrolysis of PPi (effectively breaking 2 ATP)

Question 41

Four key repeated actions of fatty acid oxidation

Answer 41

Oxidation Hydration Oxidation Thiolysis

Question 42

What is the point of fatty acid oxidation?

Answer 42

Create ATP and NADPH (reducing power)

Question 43

Two sites of FA oxidation

Answer 43

Peroxisomes | Mitochondrial matrix

Question 44

Where are FAs elongated?

Answer 44

ER

Question 45

What part of FA can be used to make glucose?

Answer 45

Odd chain omega end

Question 46

What are main ketone bodies?

Answer 46

Acetone Acetoacetate B-hydroxybutyrate

Question 47

How are ketones transported in blood?

Answer 47

Easily. Do not require albumin or other binding proteins

Question 48

Glucose lower than _____ results in coma, death

Answer 48

2.2 mM / 40 mg

Question 49

Normal blood glucose range

Answer 49

60-90 mg/mL | 3.3-5 mM/mL

Question 50

What is a sterol?

Answer 50

Contains hydroxyl group at C3

Question 51

Cholesterol is converted to ______ for cell _____ or _____ in blood

Answer 51

Cholesteryl esters Storage Transport

Question 52

Three levels of HMG-CoA regulation

Answer 52

1. SREBPs 2. SRE (Sterol-Regulatory Elements) 3. SCAP (SREBP-Cleavage Activating Protein)

Question 53

Which cholesterol intermediate is used as a precursor for many molecules?

Answer 53

5-carbon isoprene

Question 54

Cholesterol is the precursor of _____ hormones

Answer 54

Steroid

Question 55

atherosclerosis

Answer 55

Macrophages are recruited into the arterial intima by upregulated adhesion molecules, where they relentlessly ingest oxidized LDL or cholesterol-rich lipoprotein remnants, becoming 'foam cells.' These cells are the beginning of arterial plaques.

Question 56

Cholestyramine mechanism

Answer 56

Inhibits enterohepatic circulation of bile acids