Biochem Test 2A

Front 1

Niacin is a _____ soluble vitamin that is used in the cofactors _____ and _____. What "B" vitamin is it?

Back 1

water; NAD+; NADP+. It's B3.

Front 2

The common cofactor containing pantothenic acid is ______. The associated deficiency disease is _____.

Back 2

CoASH; hypertension

Front 3

It is difficult to get biotin deficiency. This water soluble vitamin functions in _____ reactions.

Back 3

carboxylase

Front 4

Folic acid is involved in _____ synthesis.

Back 4

nucleotide

Front 5

Vitamin C is also called _____ acid. Lack of vitamin C causes _____.

Back 5

ascorbic; scurvy

Front 6

Vitamin B1 is known as _____. Vitamin B2 is known as _____.

Back 6

thiamin; riboflavin

Front 7

What B vitamin is thiamine? What kind of rxns is it involved in? What is the deficiency disease?

Back 7

It's B1. Aldehyde transfer reactions. Beri Beri.

Front 8

The cofactors of riboflavin are _____ and ____. Riboflavin is involved in ____ reactions.

Back 8

FAD; FMN; redox

Front 9

What vitamin (name and what "B") is most important for amino acid synthesis?

Back 9

pyridoxine, B6

Front 10

What are the fat soluble vitamins?

Back 10

A, E, D, and K

Front 11

Deficiency in which vitamin causes rickets?

Back 11

D

Front 12

Which organ might be described as an altruistic glucostat?

Back 12

the liver

Front 13

Which two hormones stimulate glycogen breakdown?

Back 13

epinephrine and glucagon

Front 14

What kind of receptors do epinephrine and glucagon bind to?

Back 14

G protein coupled receptors

Front 15

In relation to glycogen breakdown and synthesis inhibition, what enzyme does cAMP activate?

Back 15

protein kinase A

Front 16

How does protein kinase A affect glycogen synthase and glycogen phosphorylase?

Back 16

It phosphorylates both of them, however, by phosphorylating glycogen synthase, it changes it from the active a form to the inactive b.

By phosphoylating glycogen phosphorylase, it changes it from the inactive b to the active a.

Front 17

What does PPP stand for? What are its important products?

Back 17

The pentose phosphate pathway. Makes NADPH and ribose.

Front 18

In glycolysis, an isomerase converts glucose-6-P into _____.

Back 18

fructose-6-P

Front 19

Why is the action of PFK-2 described as forward feedback?

Back 19

It produces fructose-2,6-bisphosphate, which allosterically actives PFK-1, which leads to more glycolysis.

Front 20

PFK-1 is activated by ____ and inhibited by _____ and ____.

Back 20

AMP; ATP; citrate

Front 21

Glyceraldehyde-3-phosphate (PGAL) is ______ to 1,3-bisphosphoglycerate. The enzyme responsible is a _______.

Back 21

oxidized; dehydrogenase

Front 22

The coenzyme NAD+ is made from ______.

Back 22

the B vitamin, niacin

Front 23

What is substrate level phosphorylation?

Back 23

ATP is made directly.... need to flesh this out, or not. I know what this means...

Front 24

What does phosphoglyerate kinase do?

Back 24

It takes a phosphate off one of the substrates to make ATP. It's kind of a misnomer. Usually, a kinase adds phosphate.

Front 25

What glycolysis enzymes drive substrate level phosphorylation?

Back 25

pyruvate kinase, phosphoglycerate kinase

Front 26

Which substrate level phosphorylation is irreversible?

Back 26

PEP ---> pryuvate by pyruvate kinase

Front 27

Which substrate level phosphorylation is irreversible?

Back 27

PEP > pryuvate by pyruvate kinase

(Remember, PEP is higher energy than ATP, so once ATP is created, it cannot drive the rxn in the opposite direction.)

Front 28

Glycolysis takes place in the ____.

Back 28

cytoplasm

Front 29

Glucose can be created by breaking down stored _____.

Back 29

glycogen

Front 30

What kind of linkages does glycogen have?

Back 30

1,4 and 1,6

Front 31

What two kinds of tissue contain high levels of glycogen? Which has more?

Back 31

The liver and muscle. The muscle has more overall, but the liver has the highest concentration of glycogen.

Front 32

Glycogen levels are regulated by what two hormones?

Back 32

glucagon and insulin

Front 33

In muscle, glucose is converted to ____. In adipocytes, glucose is converted to _____.

Back 33

glycogen; stored fat

Front 34

What does glucagon do?

Back 34

It starts a cascade in the cell that inhibits glycogen synthesis when blood glucose levels are low

Front 35

Because muscle lacks _____, it cannot release glucose to the blood. Glucose can only be used to ____.

Back 35

glucose-6-phosphatase; create energy in the muscle cell

Front 36

As soon as glucose enters a cell, it is phosphorlyated by _____ to become _____.

Back 36

hexokinase; glucose-6-phophate

Front 37

What ions are required for hexokinase to function? What do they complex with?

Back 37

It needs Mg2+ (or Mn2+), which must complex with ATP.

Front 38

Brain hexokinase has a very ____ Km, while the Km of liver hexokinase is ____. This means that liver glucokinase is only active with ___ levels of blood glucose.

Back 38

low; high; high

Front 39

What does phosphoglucomutase do?

Back 39

It will change glucose-6-phosphate to glucose-1-phosphate.

Front 40

Glucose-1-phosphate + UTP = what?

Back 40

glucose-UDP and pyrophosphate

Front 41

The ____ end of the glucose in glycogen is tied up in a glycogen bond, while the ___ end is free to bond.

Back 41

reducing; nonreducing

Front 42

Glycogen synthesis is catalyzed by ______. What kind of bond is formed?

Back 42

glycogen synthase; this enzyme forms the 1,4 bond

Front 43

Which enzyme forms the 1,6 bond of glycogen?

Back 43

a branching enzyme

Front 44

If glycogen synthase can only add glucose to existing glycogen, how does the whole thing get started?

Back 44

Glycogenin creates primer 1-4 chains attached to tyrosine residues.

Front 45

Glycogenolysis is catalyzed by ____ in the presence of _____.

Back 45

glycogen phosphorylase; inorganic phosphate

This is like hydrolysis, except with phosphate. It's called phosphorolysis.

Front 46

What is the product of glycogenolysis?

Back 46

glucose-1-phosphate

Front 47

In the liver, what does glucose-6-phosphatase do? Where in the cell is this enzyme located?

Back 47

It's in the ER. This enzyme removes phosphate from glucose-6-phosphate, so the free glucose can get back into the bloodstream.

Front 48

Which two hormones set off the cAMP cascade to stimulate glycogen breakdown?

Back 48

This can be done by either glucagon OR epinephrine.

Front 49

Epinephrine and glucagon stimulate glycogen breakdown. What else do they do?

Back 49

The inhibit glycogen synthase by converting it to its inactive form.

Front 50

Epinephrine and glucagon work by activating _____ and deactivating _____ (by phosphorylating both!).

Back 50

glycogen phosphorylase; glycogen synthase

Front 51

What is a futile cycle?

Back 51

It's a process that wastes energy. For instance, if glycogen synthesis and breakdown happened equally, it would waste energy. G-1-P --> UDPG---> glycogen---> G-1-P ---> UDPG, etc.

Front 52

What are the possible fates of glucose-6-phosphate?

Back 52

1. glycolysis
2. glycogen synthesis
3. free glucose
4. PPP

Front 53

Most of the regulation of glycolysis occurs around which step?

Back 53

When PFK (phosphofructokinase) converts fructose-6-phosphate to fructose-1,6-bisphosphate.

Front 54

The conversion of F-6-P to F-2,6-BP instead of F-1,6-BP is an example of what kind of regulation?

Back 54

"Feed-forward" regulation. The 2,6 activates PFK to create more 1,6 and continue glycolysis.

Front 55

PFK is inhibited by high levels of what two things?

Back 55

ATP (too much energy already) and citrate (means TCA cycle already has enough). (ex of local regulation)

Front 56

Why on earth does insulin stimulate PFK-2 (which promotes glycolysis)?

Back 56

A product of glycolysis is acetylCoA, which is also used to build FATTY ACIDS. These fats are another way of storing glucose, and thus, the end result will be to get glucose out of the blood. (ex of systemic regulation)

Front 57

High levels of ____ indicate low energy in a cell and will stimulate glycolysis.

Back 57

AMP

Front 58

When F-1,6-BP is cleaved, what two products are possible? Which one continues in glycolysis?

Back 58

DHAP and and PGAL (aka G-3-P). PGAL goes on. DHAP can be converted to a glycerol backbone for membrane lipids.

Front 59

When an intermediate in glycolysis is _____, NAD+ can be _____.

Back 59

oxidized; reduced to NADH

Front 60

The _____ that catalyzes production of PEP (in glycolysis) is inhibited by fluoride.

Back 60

enolase

Front 61

Which intermediate of glycolysis is more high energy than ATP?

Back 61

PEP

Front 62

What are the products of glycolysis?

Back 62

2 pyruvate, 2 ATP, 2 NADH, 2 H+, 2 H2O

Front 63

What happens to NADH and pyruvate in anaerobic glycolysis?

Back 63

NADH reduces pyruvate to ethanol or lactate (important in tooth demineralization). This regenerates NAD+.

Front 64

Is fluoride an essential nutrient?

Back 64

maybe

Front 65

Vitamins:
1. vision
2. clotting

Back 65

1. A
2. K

Front 66

_____ is the base of all aldoses.

Back 66

Glyceraldehyde

Front 67

_____ is the base of all ketoses.

Back 67

Dihydroxyacetone

Front 68

Which is an alpha bond? Beta bond?

Back 68

Alpha is when the OH is down. Beta is when it's up.

Front 69

Glucose + fructose = ___. Describe the glycosidic bond. Is it a reducing sugar?

Back 69

sucrose; the bond is alpha for the glucose, beta for the fructose. It is not reducing

Front 70

Fiber can decrease absorption of dietary ______.

Back 70

cholesterol

Front 71

Which glucose polymer is indigestible? How does it differ from the other forms.

Back 71

Humans cannot digest cellulose. Cellulose, unlike starch and glycogen, is not branched.

Front 72

Storing carbs as polymers helps control ____ pressure, as each polymer is only counted as one unit.

Back 72

osmotic

Front 73

Salivary and pancreatic ____ break down glycosidic bonds.

Back 73

amylases

Front 74

Which mitochondrial membrane is more permeable?

Back 74

The outer membrane is more permeable. The inner membrane is relatively impermeable

Front 75

During TCA, are there more protons inside or outside the mitochondria?

Back 75

The protons are being pumped out of the inner membrane, so there is a gradient, with more protons outside.

Front 76

What are the four major products of TCA?

Back 76

CO2, NADH, FADH2, GTP

Front 77

Pyruvate must be _____ to become Ac-S-CoA

Back 77

decarboxylated

Front 78

What multienzyme array in the mitochondria is responsible for transforming pyruvate into Ac-S-CoA?

Back 78

pyruvate dehydrogenase

Front 79

The carboxyl group of pyruvate is released as what?

Back 79

CO2 (release of CO2 is a powerful driver of this rxn) and H+

Front 80

What might inhibit the formation of Ac-S-CoA from pyruvate? What might drive it?

Back 80

Inhibitors:
build up of Ac-S-CoA, build up of NADH, build up of GTP

Drivers:
high levels of AMP

Front 81

____ of pyruvate dehydrogenase at a specific serine residue inactivates the compound.

Back 81

Phosphorylation

Front 82

In adipose tissue, ____ increases PDH activity because Ac-S-CoA is required for fatty acid synthesis.

Back 82

insulin

Front 83

When does oxaloacetate come into the TCA cycle?

Back 83

It condenses with Ac-S-CoA to form citrate and CoASH.

Front 84

Isocitrate undergoes the first oxidation. What does it lose? What is produced?

Back 84

It loses a carboxyl group. The H adds to NAD+ to form NADH. The rest is lost as CO2.

Front 85

For oxidative phosphorylation, which two enzymes must be available and regenerated as part of the process?

Back 85

I'm sure there are many, but we focused on free CoA (CoASH) and NAD+.

Front 86

Does substrate level phosphorylation occur during TCA? When?

Back 86

Yes. As succinyl-CoA become succinate, inorganic phosphate transfers directly to GDP to form GTP.

Front 87

What happens to succinate? What coenzyme is involved?

Back 87

It is oxidized by FAD. (FAD --> FADH2)

Front 88

Through a series of rxns, succinate will eventually be transformed back into what?

Back 88

oxaloacetate

Front 89

Succinate ---> ______ -----> ______ -----> oxaloacetate

Back 89

fumarate; malate

Front 90

Are the enzymes of TCA linked?

Back 90

Maybe... probably? Maybe yes, but it's theoretical.

Front 91

Which TCA step requires FAD?

Back 91

succinate to fumarate

Front 92

What is the main reculator of oxphos (high levels will upregulate)? What element is needed in the tissues for this cycle to occur?

Back 92

ADP; oxygen

Front 93

During OxPhos, what will happen to these: NADH, ADP, and O2?

Back 93

NADH -->NAD+
ADP --> ATP
O2 -->H20

Front 94

What are cytochromes? What important group do they have?

Back 94

They're proteins with a heme group that function in OxPhos. The heme gets reversibly oxidized and reduced (Fe3+ and Fe2+).

Front 95

Which OxPhos complex brings H+ back INTO the mitochondrial matrix?

Back 95

Complex 5. This entrance drives the synthesis of ATP.

Front 96

What is coQ?

Back 96

It's an enzyme in the mitochondrial matrix that's active during oxphos. It carries redox potential by switching back and forth from quinone to semiquinone.

Front 97

What is the
"motor" enzyme that spins to make ATP?

Back 97

ATP synthase

Front 98

What substance's presence has the most control over the rate of respiration?

Back 98

ADP

Front 99

What kind of tissue is specialized for "uncoupling" in nonshivering thermogenesis?

Back 99

brown fat

Front 100

Which protein allows protons back into the matrix without producing ATP? What other protein upregulates the expression of this protein?

Back 100

UCP (uncoupling protein). Lectin upregulates UCP.

Front 101

The process by which ox phos creates destructive byproducts is called what?

Back 101

oxygen stress

Front 102

What are ROS?

Back 102

Reactive Oxygen Species (products from oxygen stress)

Front 103

How many ATP do we get for each intramitochondrial NADH? FADH2?

Back 103

NADH: 2.5
FADH2: 1.5

Front 104

What are the two shuttles used to get NADH into the mitochondria?

Back 104

malate-aspartate

glycerol-phosphate (brain, skeletal muscle)

Front 105

Which NADH shuttle results in less ATP production?

Back 105

The glycerol-phosphate shuttle converts NADH to FADH2, so instead of 2.5 ATP per, 1.5 ATP are instead produced. (NB: This occurs in the brain and skeletal muscle)

Front 106

How many TOTAL ATPs will be produced from the products of glycolysis?

Back 106

5 or 7 (depending on whether malate-aspartate or glucose-phosphate shuttle is used)

Front 107

How many ATPs produced from pyruvate dehydrogenase?

Back 107

5 (from 2 NADH)

Front 108

How many ATP from TCA?

Back 108

20
(2 FADH2, 6 NADH, 2 GTP)