Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem > Lecture 13 Information > Flashcards

Lecture 13 Information Flashcards

1
Q

Glycolysis overall reaction

A

Glucose + 2ATP + 2 NAD+ => 2 Pyruvic acid + 2 NADH + 2ATP + 2H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How many phases and steps are in glycolysis?

A

2 phases and 10 total steps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where does glycolysis take place?

A

in the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Step 1 of glycolysis

A

convert glucose to glucose 6-phosphate

hexokinase accomplishes this

requires ATP

highly irrevisible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Step 2 of glycolysis

A

isomerize glucose 6-phosphate to fructose 6-phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Step 3 of glycolysis

A

convert fructose-6 phosphate to fructose 1,6 bisphosphate

phosphofructokinase-1 accomplishes this

requires ATP

highly irreversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which step guarentees that glucose will go through glycolysis?

A

step 3

can no longer use fructose-6 phosphate / glucose for anything else

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Step 4 and 5 of glycolysis

A

produce glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (3 carbons with phosphate)

triosephosphate isomerase converts dihydroxyacetone phosphate to glyceraldehyde 3-phosphate

happens very fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Step 6 of glycolysis

A

glyceraldehyde 3-phosphate gets 2 phosphates added (oxidized) to convert to 1,3-bisphosphate

in this step, NAD+ is reduced to NADH

glyceradehyde 3-phosphate dehydrogenase accomplishes this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Step 7 glycolysis

A

remove a phosphate from 1,3-bisphosphate to make 3-phosphoglycerate

2 ADP is converted to 2 ATP

phosphoglycerate kinase accomplishes this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Step 10 of glycolysis

A

phosphoenolpyruvate (PEP) is converted to pyrvuate

converts 2 ADP to 2 ATP

pyruvate kinase accomplishes this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens to pyruvate?

A

has energy contained in 3 carbons that can still be used for energy

pryuvate moves to the Krebs/Citric Acid Cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which steps drive glycolysis forward?

A

Steps 1, 3, and 10

all steps have large negative ∆Gs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do more unfavorable steps of glycolysis take place?

A

Change the concentrations of intermediates and substrates to make ∆G favorable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hypoxic

A

low oxygen in cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does hypoxia trigger?

A

an increase in glycolytic enzymes which increases the rate of glycolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Warburg effect

A

even after cancer cells develop blood flow and have O2 they still use just glycolysis as an energy source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why would cancer cells want to keep running glycolysis?

A

glycolysis releases hexokinase which moves to the mitochondria to stop apoptosis inducing factors from being released

factors such as cytochrome c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What molecule might be helpful in treating cancer cells?

A

DCA

DCA makes it more likely that a cell will run glycolysis and then run the Krebs Cycle/ETC

activates pyruvate dehydrogenase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Type I diabetes

A

inability of pancreas to produce enough insulin to trigger the decrease of blood-glucose concentration levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Type II diabetes

A

inability of target cells to pick up insulin signals

receptors are not as sensitive to insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does insulin trigger?

A

a pathway to place more GLU4 receptors on the cell surface

GLU4 receptors can take glucose out of the blood and into the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do high blood glucose levels do?

A

increase blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do low blood glucose levels do?

A

cause hypoglycemia and passing out since brain is not getting glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is glucose metabolism limited by?
how much glucose we can take into our cells
26
What happens when the cell does not have enough glucose?
cell relies on other sources of energy like lipids/fatty acids through beta-oxidation
27
What is a negative side effect of using lipids/fatty acids instead of glucose as energy source?
Beta-oxidation produces ketone-bodies as a result too many ketone-bodies in the blood can lower the pH of blood and trigger keto-acidosis
28
Where does glucose come from?
break off monomers from starch / glycogen chains break down sucrose into fructose/glucose gluconeogenesis
29
How can fructose be used in glycolysis?
hexokinase can convert it to fructose 6-phosphate to be used
30
What happens to carbons from glucose?
they are greatly oxidized to CO2 the energy from this oxidation goes to the ETC
31
What is a problem of too much glycolysis in anaerobic conditions?
produce a lot of NADH and deplete our NAD+ reservoirs
32
How do we replace our NAD+ reservoirs?
through fermentation
33
Different types of fermentation
lactic acid and yeast (ethanol)
34
Lactic acid fermentation
pyruvate is reduced to lactate NADH is oxidized to NAD+ lactose dehydrogenase accomplishes this (substrates are NADH and pyruvate)
35
Difference between lactic acid and Alcoholic fermentation?
lactic acid is one step and Alcoholic is 2 steps
36
Alcoholic fermentation
first, pyruvate is converted to acetaldehyde by pryuvate decarboxylase second, acetaldehyde is reduced to ethanol through alcohol dehydrogenase in second step, NADH is oxidized to NAD+
37
What happens when glucose levels are low?
have to produce glucose through gluconeogenesis
38
Where does gluconeogenesis take place?
the liver
39
Types of substrates for gluconeogenesis?
lactate, triacylglycerol and CO2
40
Gluconeogenesis step 1
use bisphosphate and pyruvate to produce oxaloacetate
41
First chokepoint of gluconeogenesis
convert oxaloacetate to PEP by using GTP PEP carboxykinase and pyruvate caroxylase accomplish this weird trip through the cytosol to mitochondria back to the cytosol
42
Second chokepoint of gluconeogenesis
convert fructose 1,6 bisphophate to fructose 6-phosphate use fructose 1,6-bisphosphatase this is reversing the highly irreversible step 2 in glycolysis
43
Third chokepoint of gluconeogenesis
convert glucose 6-phosphate to glucose glucose 6-phosphatase does the opposite of hexokinase we do not use or produce ATP here, just remove the phosphate
44
Cori Cycle
fermentation meets gluconeogenesis lactic acid from fermentation can be moved from the muscle into the liver cells in the liver, the lactate can be converted into pyruvate and go through the process of gluconeogenesis
45
The Pentose Phosphate Pathway (PPP) overview
creating pentose sugars from glucose to be used in DNA and RNA takes place in the cytosol
46
Steps of PPP
start with glucose 6-phosphate and use 2 NADP+ to oxidize twice to produce ribose 5-phosphate NADP+ is reduced to NADPH
47
NADPH
produced in the PPP can reduce the reactivity of free radicals and oxygen species
48
Ribose 5-phosphate
produced by PPP plant cells use it in chloroplasts other cells use it as an intermediate to produce nucleotides, coenzymes, DNA and RNA (expect to find in cells that are rapidly dividing)
49
Favism
people with glucose 6-phosphate dehydrogenase deficiencies can get very sick when they eat fava beans since they do not produce enough NADPH
50
Fava beans
contain an oxidizing molecule that NADPH normally reduces
51
Why does favism prevail?
individuals with this disease are protected from malaria paraise does not grow well in glucose 6-phosphate dehydrogenase deficient cells
52
What are 3 levels of control to regulate glucose and gluconeogenesis?
enzyme control, hormones, and transcription
53
What are the types of hormone control to regulate glucose / gluconeogenesis?
hexokinase bypass, PFK1 bypass, pyruvate kinase bypass
54
Hexokinases in muscle cells versus liver cells
in muscle cells, hexokinase 4 has a LOW Km so glucose will be used even without large concentrations in liver cells, hexokinase 1 has a HIGH Km so glucose will only be used at high concentrations additionally, muscle cells hexokinases are inhibited by the product G6P and liver cells are not so they can work longer
55
How is glucokinase regulated in the liver?
regulated through glucose concentrations with high concentrations, will go through glycolysis might not go through glycolysis with low concentrations
56
GKRP
"bear hug" protein takes glucokinase out of commission and places glucokinase in the nucleus stimulated by the intermediate fructose 6-phosphate signals that we have low glucose levels and don't want to go through glycolysis
57
Phosphofructokinase 1 (PFK1) regulation
allosterically inhibited by ATP and citrate ATP is both a substrate and an end product citrate is a component of the Krebs Cycle and signals that you do not need to keep going through glycolysis
58
Gluconeogenesis enzyme FBPase-1
inhibited by AMP which signals that there is not much energy in the cell (AMP > ATP) prevents gluconeogenesis from taking place need to use glucose to make fuel
59
Insulin
inactivates FBPase-2 and activates PFK-2 stimulates glycolysis and inhibits gluconeogenesis take sugar to use for ATP
60
Glucagon
activates FBPas-2 and inactivates PFK-2 inhibits glycolysis and stimulates gluconeogenesis
61
FBPase-2
when activated, stimulates gluconeogenesis
62
PFK-2
when activated, stimulates glycolysis
63
What type of receptors does insulin bind to?
tyrosine kinase receptors
64
For every one glucose molecule how many pyruvate molecules do we have?
2 pyruvate for every 1 glucose
65
What happens to glucose's carbons at the end of glycolysis?
they are oxidized to Co2 The extra energy goes into the ETC by placing placing electrons on NADH
66
2 examples of ketoacids
acetoacetate and B-hydroxybutyrate
67
How are ketone bodies used at low concentrations?
low concentrations can be used by the brain when concentrations are too high like in diabetes, trigger ketoacidosis and can have trouble transporting on hemoglobin
68
Active site versus allosteric site in PFK-1
Active site has a high affinity for ATP in order to run glycolysis Allosteric site has a low affinity for ATP because only in high concentrations of ATP do we want to inhibit PFK-1
69
What turns on PFK-1?
ADP and AMP since they indicate that there is not a lot of ATP in the cell
70
Fructose 2,6-bisphosphate
Activates PFK-1 but inactivates FBPase-1 (which is used in gluconeogensis) Turns on glycolysis and turns off gluconeogensis
71
What produces fructose 2,6-bisphosphate?
PFK-2
72
Insulin and regulating glycolysis
Insulin activates PFK-2 which produces fructose 2,6 bisphosphate which will turn on glycolysis through activating PFK-1
73
Glucagon and regulating glycolysis
Glucagon inactivates PFK-2 so fructose 2,6 bisphosphate will not be produced and gluconeogenesis can take place
74
Transcription factors
regulate the amount of enzymes we produce and therefore can regulate the amount of glycolysis that can take place

Biochem (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions