Glycolysis

Question 1

Catabolic pathways

Answer 1

Breakdown pathways
Free energy released during conversion of larger fuel molecules to smaller molecules that are converted to Acetyl CoA and enter Kreb’s
. ATP is ultimate product

Question 2

Anabolic pathway

Answer 2

. Free energy consumed when smaller molecules make larger molecules
. CONSUME ATP

Question 3

Where does regulation most often occur in pathways?

Answer 3

Irreversible steps

Question 4

Where does regulation by covalent modification occur?

Answer 4

. Key steps in pathway
. “committed” step
. Regulated in response to endocrine hormones

Question 5

How are pathways regulated by availability of substrate

Answer 5

. Limitations by metabolism

. Limitations by transport

Question 6

Epinephrine

Answer 6

. Released from adrenal glands
. Acts on many tissues
. Induced cAMP cascade activity PKA phosphorylating enzymes in metabolism

Question 7

Glucogon

Answer 7

. Released from alpha cells of pancreas in response to LOW blood glucose
. Binds to liver receptors mostly and some adipose
. Induces cAMP cascade

Question 8

Insulin

Answer 8

. Released from beta cells of pancreas in response to HIGH blood glucose
. Acts on all cells
. Opposes epinephrine and glucagon

Question 9

Glycolysis

Answer 9

. glucose (6C) Converts to 2 molecules of pyruvate (3C) w/ generation of ATP
. Operates aerobically or anaerobically

Question 10

Catabolic and anabolic purposes of pathway

Answer 10

C: atp production
A: provides basic building blocks for cellular biosynthesis

Question 11

Glycolysis net rxn

Answer 11

Glucose + 2Pi + 2ADP+ 2NAD -> 2 pyruvate + 2ATP + 2NADH + 2H + 2H2O

Question 12

Glycolysis w/ oxygen

Answer 12

Pyruvate converts to acetylene CoA then to Kreb’s

Question 13

Glycolysis if not enough oxygen

Answer 13

. Pyruvate converts to lactic acid via lactate dehydrogenase
. Regenerates NAD from NADH to pathway can continue

Question 14

Fate of NADH in aerobic conditions

Answer 14

. NADH converted to NAD to cross membrane into mitochondria

Question 15

NADH shuttle system

Answer 15

. Enable reducing equivalents from NADH to be transported into mitochondria to be used in ETC

Question 16

Difference btw glycerol 3 phosphate shuttle and malate aspartame shuttle

Answer 16

. Glycerol 3 phosphate uses FAD instead of NAD and yields less energy overall

Question 17

Total ATP from aerobic oxidation of 1 glucose

Answer 17

30-32 ATP

Question 18

Total ATP from anaerobic oxidation from 1 glucose molecule

Answer 18

2 ATP

Question 19

What happens to lactic acid that accumulates in muscle tissue after anaerobic metabolism?

Answer 19

. Travels to liver in blood
. Converted back to pyruvate for gluconeogenesis (making glucose from other molecules in body)
. Resulting glucose sent back to muscle to be used

Question 20

Accumulation of lactic acid can result in ____

Answer 20

Serum acidosis

Question 21

Irreversible steps in glycolysis

Answer 21

. Hexokinase/glucokinase
. Phosphofructokinase
. Pyruvate kinase

Question 22

What does adding phosphate to glucose do?

Answer 22

Traps glucose in the cell

Question 23

Hexokinase location, Vmax, and Km for glucose

Answer 23

. Whole human body cytosol, NOT induced by inc. glucose
. Vmax low
. Km: 0.1 mM

Question 24

Glucokinase location, Vmax and Km for glucose

Answer 24

. Liver, pancreas beta cell cytosol, IS INDUCED by inc. glucose
. Vmax high
. Km: 10 mM

Question 25

When is hexokinase and glucokinase used?

Answer 25

. Hexokinase full time | . Glucokinase part time after meals when glucose levels are high

Question 26

Committed step in glycolysis

Answer 26

Fructose-6P -> fructose 1,6=bispohosphate via PFK-1

Question 27

Positive and negative effectors of PFK-1

Answer 27

. Pos: AMP | . Neg: ATP, citrate, low pH

Question 28

Allosteric regulation of liver pyruvate kinase

Answer 28

. Activated by fructose 1,6-bisphosphate | . Feed forward regulation

Question 29

When F-2,6-BP is present, glycolysis is turned ____

Answer 29

On, when absent it is off

Question 30

Components of protein that emulates F-2,6-BP

Answer 30

. Phosphofructokinase-2 (PFK-2) is dephosphrylated . Fructose bisphosphatase 2 domain (FBPase-2) is phosphorylated . When one side is active the their side is degraded through phosphorylation/dephosphorylation

Question 31

What happens to glycolysis when insulin binds to receptor on liver cell?

Answer 31

. RTK results in glycolysis pathway proteins being depohsphorylated . PFK-2 turns on and F-2,6-BP is made and activated PFK-1 to turn on glycolysis . Pyruvate kinase is dephosphorylated and turned on to continue glycolytic pathway

Question 32

Anabolism is promoted by what hormone?

Answer 32

Insulin

Question 33

What happens to glycolysis when epinephrine binds to receptor to liver cell?

Answer 33

. PKA phosphorylated pyruvate kinase turning it off and phosphorylated FBP-ase-2 turning it on . F-2,6-BP is degraded and glycolysis shuts down . Pyruvate kinase also turned off

Question 34

Liver cell glycolysis is ___ by epinephrine but muscle glycolysis ____ w/ epinephrine

Answer 34

. Dec | . Inc.

Question 35

T/F Liver is NOT homogenous and some cells will be running glycolysis while other aren’t

Answer 35

T

Question 36

Periportal hepatocytes

Answer 36

. Closest to blood supply . Receive highest [O2] and other nutrients . Oxidative metabolism favored

Question 37

. Perivenous hepatocytes

Answer 37

. Cells farther away from blood supply . Receive much less O2 and other nutrients . Depend more on anaerobic glycolysis for ATP synthesis

Question 38

Liver role

Answer 38

. Primary biochemical role to supply rest of body w/ blood-born source of fuel . Releases glucose from gluconeogenesis or other molecules (fat, ketones)

Question 39

Regulation of glycolysis in liver guided by____

Answer 39

. Substrate availability | . Receptors for insulin, epinephrine, and glucogon

Question 40

Muscle role

Answer 40

. Role of muscle is to move | . Primarily consumer

Question 41

Regulation of muscle guided by ____

Answer 41

. Substrate availability . Allosteric regulation . If muscle is moving or at rest . Receptors for insulin and epinephrine (NO GLUCAGON)