Exam 3: Glycolysis

Question 1

What is a catabolic reaction

Answer 1

break down large molecules to smaller

extracts energy

Question 2

anabolic reaction

Answer 2

small molecules into larger molecules, require energy input

Question 3

Is glycolysis anaerobic or aerobic

Answer 3

anaerobic

Question 4

What are the 2 stages of glycolysis

Answer 4

stage 1 energy input (2ATP used)

stage 2 energy output (use 2 ATP, produces 4ATP)

Question 5

What kind of reaction is reaction 2 in glycolysis

glucose-6-phosphate –>

Answer 5

isomerization reaction

Question 6

What is the first energy OUTPUT reaction in glycolysis (use diagram)

Answer 6

reaction 7:

glycerate 1,3 bisphosphate –>

Question 7

What kind of reaction is ADP–>ATP

Answer 7

substrate level phosphorylation, a phosphate is taken from a substrate and transferred to ADP to produce ATP

Question 8

What are the anaerobic and aerobic fates of pyruvate

Answer 8

anaerobic: fermentation
aerobic: CAC–>ETC

Question 9

What is a better way to get energy from pyruvate? Fermentation or anaerobic glycolysis

Answer 9

anaerobic glycolysis

Question 10

What is homolactic fermentation and when does it happen

Answer 10

pyruvate is transformed into lactate. Can be done during intense exercise

Question 11

What is the purpose of fermentation

Answer 11

to regenerate NAD from NADH without using O2 allowing glycolysis to continue

Question 12

Why does intense exercise cause muscle cramping?

Answer 12

because you build up lactate during homolactic fermentation making the pH levels go down and causing proteins to denature in muscles

Question 13

What enzyme catalyzes homolactic fermentation

Answer 13

LDH lactate dehydrogenase

Question 14

When does alcohol fermentation happen?

Answer 14

in bacteria, yeast.

Question 15

What enzyme catalyzes alcohol fermentation

Answer 15

PDC pyruvate decarboxylase

Question 16

Why can’t humans ferment alcohol?

Answer 16

We dont have the PDC enzyme encoded in our DNA.

Question 17

What enzyme do humans have to break down alcohol when drinking, where is it what does it do

Answer 17

ADH1 alcohol dehydrogenase 1, in our gut, converts ethanol into acetyl aldehyde and regenerates NAD+ from it, NADH–> NAD+

Question 18

what are the 3 places energy is -delta G in glycolysis in RBCs

Answer 18

hexokinase, PFK-1, pyruvate kinase.

Question 19

Where are hexokinases 1-3 located

Answer 19

in the mitochondrial membrane

Question 20

Talk about the affinity and inhibitors of hexokinase 1-3

Answer 20

small km, higher affinity for glucose

all inhibited by G-6-p

Question 21

Where is hexokinase 4 located

Answer 21

liver, pancreas, intestine, brain

Question 22

Talk about the affinity and inhibitors of hexokinase 4

Answer 22

larger km, less affinity for glucose, no inhibited by G-6-p, needs higher glucose concentration to be activated

Question 23

what happens to glucose in pancreas and liver

Answer 23

liver: stores excess glucose
pancreas: acts as glucose monitor to signal insulin secretion

Question 24

What does glucokinase or GK do

Answer 24

initiated by higher levels of glucose, binds to glucokinase regulatory protein GKRP, complex goes into nucleus and dissociated or separates, signals insulin secretion.

Question 25

When and why is glucagon secreted

Answer 25

produced by alpha cells in pancreas, secreted when glucose levels are low

Question 26

How does glucagon affect glycolysis and gluconeogenesis

Answer 26

causes glycolysis to slow down and gluconeogenesis to speed up. binds to receptor causing adenylate cyclase in membrane to activate it, catalyzes ATP--> CAMP. CAMP binds to PKA and activates it

Question 27

When and why is insulin secreted

Answer 27

secreted by pancreatic beta cells when glucose levels are high

Question 28

How does insulin affect glycolysis and gluconeogensis

Answer 28

binds to a receptor, activates ppp, increases glycolysis and decreases gluconeogenesis

Question 29

Where does gluconeogenesis occur in the body

Answer 29

only in the liver

Question 30

Where in the cell does gluconeogenesis occur

Answer 30

1st step in mitochondrial matrix, the rest in cytosol

Question 31

What are the non carbohydrate progenitors of gluconeogenesis

Answer 31

pyruvate, lactate, glycerol and some AAs

Question 32

What are the 3 places gluconeogenesis is different from glycolysis

Answer 32

hexokinase, PFK-1, pyruvate kinase

Question 33

Explain the OAA oxaloacetate/ malate shuttle

Answer 33

a transport system to move OAA in the mitochondria to the cytosol to be converted into PEP, malate is a protein transporter that carries it across. NAD+--> NADH to bind in mitochondria. Vice versa to separate once crossed to cytosol.

Question 34

What does the Cori cycle do

Answer 34

transports lactate from muscle to liver to go through gluconeogenesis

Question 35

What is cortisol, when is it released, what does it do

Answer 35

steroid hormone that is released in response to stress, causes increase in gluconeogenesis enzyme. a type of longer term control

Question 36

What are the 2 enzymes used in glycogen synthesis

Answer 36

phosphoglucomutase and glycogen synthase

Question 37

Is glycogen synthesis creating any energy? Why?

Answer 37

no, a delta G=0 reaction because ultimately UDP is given back,

Question 38

What enzyme is needed for glycogen degradation

Answer 38

glycogen phosphorylase

Question 39

Describe glycogen degradation

Answer 39

glucose is taken off of non reducing end of glycogen chain by glycogen phosphorylase, bond is replaced by phosphate (not from ATP), glycogen is converted into G-1-P

Question 40

How are glucagon and glycogen degradation/synthesis related

Answer 40

glucagon is released when blood glucose levels are low, causes more glycogen breakdown, producing more glucose

Question 41

How are Insulin and glycogen degradation/synthesis related

Answer 41

insulin is released at high glucose levels, causes less glycogen breakdown and more glycogen synthesis

Question 42

Who does epinephrine act like and what does it do to the glycogen synthesis/degradation process

Answer 42

acts like glucagon, activates adenyl cyclase and increases glycogen breakdown, decreases glycogen synthesis

Question 43

In glycolysis __ moles of ATP are produced per mole of glucose

Answer 43

2 ATP

Question 44

In anaerobic organisms pyruvate is used to regenerate cellular

Answer 44

NAD+

Question 45

In animals excess glucose is stored as

Answer 45

glycogen