Exam 3 - Review

Question 1

what is a by product of light reactions?

Answer 1

oxygen

Question 2

what are dark reactions?

Answer 2

The Calvin Cycle - Uses ATP, NADPH, and CO₂ to produce hexose carbohydrates

Question 3

what are light reactions?

Answer 3

transform light energy into: ATP and NADPH (biosynthetic reducing power)

Question 4

where does photosynthesis take place?

Answer 4

in chloroplasts

Question 5

what enzyme breaks down glycogen?

Answer 5

glycogen phosphorylase

Question 6

what induces glycogen degredation?

Answer 6

epinephrine and glucagon

Question 7

what does phosphoglucomutase do?

Answer 7

it takes glucose 1-phosphate and makes glucose 6-phosphate

Question 8

why does liver contain glucose 6 - phosphatase?

Answer 8

glucose 6-phosphatase generates free glucose from glucose 6-phosphate

absent from muscle

Question 9

How is glycogen phosphorylase regulated in the liver and muscle?

Answer 9

activated when phospharylated

primarily phosphorylated a in active R state in the liver

primarily unphosphorylated b state in the muscle

Question 10

what does glucose regulate?

Answer 10

phosphorylation state

binds and inhibits the allosteric site

Question 11

what does AMP, ATP, and glucose 6-phosphate do to the liver enzyme? the muscle enzyme?

Answer 11

AMP - low energy, activates glycogen phosphorylase

ATP - high energy, inhibits glycogen phosphorylase

glucose 6-phosphate - high energy, inhibits glycogen phosphorylase

Question 12

what type of regulators are AMP, ATP, and glucose 6 - phosphate?

Answer 12

isoforms

Question 13

what does phosphorylation do to each enzyme?

Answer 13

exists in two forms

b is less active

a is more active (has a phosphorylated serine residue)

Question 14

which phosphorylase state is more active?

Answer 14

R state

Question 15

which phosphorylase state is less active?

Answer 15

T state

Question 16

which phosphorylase state is usually found in muscle?

Answer 16

T state

Question 17

what does glucagon do during fasting?

Answer 17

signals low glucose levels in the blood to start gluconeogenesis

Question 18

what is UDP-Glucose?

Answer 18

higher level energy precursor for glucose to be synthesized

Question 19

what does phosphorylation do to glycogen synthase activity?

Answer 19

inhibits it

Question 20

what does glycogen synthase kinase (GSK) do?

Answer 20

it phosphorylates glycogen synthase

inhibiting it

Question 21

what does insulin do to GSK?

Answer 21

inhibits GSK to turn on glycogen synthase

Question 22

what effects do glucagon and epinephrine have on glycogen synthase?

Answer 22

inhibits synthesis

Question 23

what does high glucose do to insulin?

Answer 23

high glucose instigates the release of insulin from the pancreas to store FAs as TAGs

Question 24

what is the pentose phosphate pathway?

Answer 24

source of biosynthetic reducing power (electrons) and produces ribose phosphates for DNA/RNA synthesis, neurotransmitter synthesis, etc.

Question 25

In the oxidative phase of the pentose phosphate pathway, what is being oxidized?

Answer 25

glucose - 6 - phosphate

Question 26

In the oxidative phase of the pentose phosphate pathway, what is being reduced?

Answer 26

NADPH

Question 27

what is the oxidative phase of the pentose phosphate pathway?

Answer 27

Glucose - 6 - phosphate → 2 NADPH → Fatty Acid Synthesis, Cholesterol Synthesis, Nucleotide synthesis, Neurotransmitter synthesis

Question 28

what is the non-oxidative phase of the pentose phosphate pathway?

Answer 28

glucose - 6- phosphate → 2 NADPH + Ribose 5 - phosphate → Glycolytic intermediates →glucose - 6- phosphate and glucose - 6- phosphate → 2 NADPH + Ribose 5 - phosphate → DNA, RNA, ATP, NAD, FAD, CoA

Question 29

where are triacyclglycerols stored?

Answer 29

adipose tissue and muscle

Question 30

what hormones activate triacylglycerol breakdown?

Answer 30

epinephrine and glucagon

Question 31

what is the first step in the breakdown of fatty acids?

Answer 31

adding CoA to acyl group absorbed through intestines

Question 32

where does fatty acid oxidation occur and how does it get there?

Answer 32

mitochondrial matrix by carnitine shuttle

Question 33

what are the four steps in beta-oxidation?

Answer 33

- Oxidation (FAD) - Hydration (H2O) - Oxidation (NAD+) - Thiolysis (CoA)

Question 34

are there meaningful intermediates in the reactions of beta-oxidation of fatty acids?

Answer 34

yes, the reduced forms NAD and FAD

Question 35

unsaturated fatty acids with odd numbers of double bonds need what enzymes?

Answer 35

only isomerase

Question 36

unsaturated fatty acids with even numbers of double bonds need what enzymes?

Answer 36

isomerase and reductase

Question 37

beta-oxidation of fatty acids with odd numbers of carbons generate what intermediates?

Answer 37

Propynol CoA (3 carbon chain) becomes succinyl CoA

Question 38

where does the intermediate of beta - oxidation end up?

Answer 38

Succinyl CoA → TCA Cycle

Question 39

where does ketone body formation take place?

Answer 39

made from Acyl CoA related to glucose levels primarily in the liver

Question 40

what organs normally use ketone bodies?

Answer 40

kidney and heart

Question 41

what conditions generate abnormally high levels of ketone bodies?

Answer 41

diabetes → no insulin chronic alcohol use

Question 42

where does fatty acid synthesis occur in the cell?

Answer 42

cytosol

Question 43

what are the three stages of fatty acid synthesis?

Answer 43

1. Acyl CoA moves out of the mitochondria to Cytosol by citrate shuttle 2. activate CoA to malonyl CoA 3. addition of 2 carbon units to get to C₁₆

Question 44

what does the enzyme, acetyl CoA carboxylase do?

Answer 44

converts Acetyl CoA to malonyl CoA; regulatory enzyme

Question 45

what do the following do to the activity of acetyl CoA carboxylase? citrate, insulin, glucagon, epinephrine, ATP

Answer 45

**citrate** - partially activates acetyl CoA **insulin** - activates acetyl CoA carboxylase **glucagon** - inhibits acetyl CoA carboxylase **epinephrine** - inhibits acetyl CoA carboxylase **ATP** - downregulates (inhibits) acetyl CoA carboxylase

Question 46

what enzyme phosphorylates CoA carboxylase and what does phosphorylation do to this enzyme?

Answer 46

AMP activated protein kinase phosphorylation inhibits

Question 47

what is the most detrimental intermediate in excessive alcohol use?

Answer 47

high levels of reduced NAD glycolysis and FA breakdown

Question 48

what is LDL?

Answer 48

bad cholesterol distributes cholesterol throughout the body

Question 49

what is HDL?

Answer 49

good cholesterol less fatty acids and more good proteins takes cholesterol back to the liver

Question 50

The regulation of cholesterol synthesis is dependent on the activity of?

Answer 50

HMG CoA Reductase

Question 51

cholesterol is a precursor for what hormones?

Answer 51

sex hormones (proestrogen, androgen, and estrogen) glucocortisoids mineralcorticoids

Question 52

Vitamin D deficiency results in what condition?

Answer 52

rickets

Question 53

what function does the glucose - alanine cycle serve?

Answer 53

way of getting rid of amino groups from branched amino acids used in the urea cycle

Question 54

what does the urea cycle do? where does it occur?

Answer 54

Urea Cycle gets rid of ammonia from the body occurs in the liver cells (according to google)

Question 55

what are glucogenic amino acids?

Answer 55

amino acids that can enter glucose synthesis pathways to create glucose

Question 56

what are ketogenic amino acids?

Answer 56

only enter at acetyl CoA site can't make glucose Leucine and Lysine

Question 57

which amino acids are only ketogenic?`

Answer 57

leucine lysine

Question 58

how do we obtain nitrogen for the synthesis of biomolecules?

Answer 58

dietary sources → nitrogen fixing bacteria needs to be fixed to ammonia

Question 59

what is the difference between the de novo pathway of nucleotide synthesis and the salvage pathway?

Answer 59

de novo pathway - build from from scratch out of nucleotides salvage pathway - nucleotides “gathered” and reused after cell is broken down

Question 60

how are purines in the de novo pathway built?

Answer 60

purines are made on the ribose and then the ring is added

Question 61

how are pyrimidines in the de novo pathway built?

Answer 61

pyrimidines connect to the ring then the ribose

Question 62

what does the enzyme, ribonucleotide reductase do and how is it regulated?

Answer 62

takes ribose and reduces to get deoxy from reduced nucleotides

Question 63

how is TMP synthesized?

Answer 63

de novo from dUMP adds methyl group form methyl donor