Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Metabolism > Glycolysis > Flashcards

Glycolysis Flashcards

1
Q

Where is glucose a primary fuel?

A

brain, red blood cells and the renal medulla

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

Is glycolysis aerobic or anaerobic?

A

anaerobic

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

Glycolysis definition

A

Metabolic pathway that converts glucose into pyruvate and a hydrogen ion. Occurs in a hypoxic environment

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

Where does it take place?

A

cytoplasm

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

brief 3 stages

A

energy investment, 6C splitting and energy harvest

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

What mediates the control?

A

supply and demand, supply in terms of selecting the best fuel, demand in terms of the energy needs of the cell

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

What does glycolysis produce as a waste product?

A

lactate

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

How is glucose taken up into the cell?

A

GLUT1-4 mediated facilitated diffusion and SGLT1-2 mediated secondary active transport

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

Differences in tissue uptake + main transporter

A

Liver, endocrine pancreas, dependent on plasma glucose concentration- GLUT2- insulin independent

peripheral tissues- depends on energy needs of tissues and is regulated in tissues that can use non-carbohydrate substrates- GLUT 4- insulin dependent

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

When is uptake independent of substrate concentration?

A

Km is less than physiological

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

When is uptake highly dependent on substrate concentration?

A

Km is more than or equal to physiological

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

The three stages of glycolysis?

A

glucose priming, splitting of P’ated i/mediate, oxidoreduction phosphorylation

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

First reaction in glycolysis + enzyme

A

glucose phosphorylation

ATP–> ADP , glucose –> glucose 6-phosphate

hexokinase/glucokinase

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

Differences between hexokinase and glucokinase

A 
hexokinase
- most tissues
regulatory step
broad substrate specificity 
low kM (high affinity)
low vMax

glucokinase

  • liver, pancreatic islets
  • similar specificity
  • different regulation
  • high km
  • high vmax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

second reaction in glycolysis + enzyme

A

reversible isomerisation reaction

glucose 6-phosphate into fructose 6-phosphate

enzyme= phosphoglucose isomerase

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

Third reaction in glycolysis + enzyme

A

fructose 6-phosphate into fructose 1,6- bisphosphate

ATP—> ADP

phosphofructokinase-1

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

fourth reaction + enzyme

A

fructose-1,6-bisphosphate –> glyceraldehyde 3-phosphate + dihydroxyacetone phosphate

aldolase

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

Why does the proportion of glyceraldhyde 3-phosphate and dihydroxyacetone phosphate vary?

A

They can be changed from one form to the other using triose phosphate isomerase

at equilibrium, 96% of triose phosphate is DHAP

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

What if formed in the fifth reaction?

A

1,3-biphosphoglycerate

20
Q

How does the oxidation of glyceraldehyde-3-phosphate take place?

A

reduction of cofactor NAD+ and Pi to form NADH and an H+

same time OAA becomes malate, thanks to NADH

21
Q

Where is the original energy of glucose?

A

1,3-bisPGA used directly for the synthesis of ATP

NADH used indirectly for the synthesis of ATP

22
Q

6th step + enzyme

A

1,3- bisphosphoglycerate to 3-phosphoglycerate

ADP to ATP

phosphoglycerate kinase

23
Q

What type of reaction is the 6th step?

A

substrate level phosphorylation

24
Q

7th step + enzyme

A

3-phosphoglycerate to 2-phosphoglycerate

phosphoglycerate mutase

25
8th step + enzyme
phosphoglycerate to phosphoenolpyruvate with release of water enolase
26
9th step + enzyme
phosphoenolpyruvate to pyruvate ADP to ATP Pyruvate kinase
27
How many products for one molecule of glucose?
2x pyruvate 2 xATP 2x NADH
28
What happens to pyruvate in the aerobic pathway?
TCA cycle, oxidative phosphorylation
29
What happens to pyruvate in the anaerobic pathway?
pyruvate forms lactate, using NADH
30
Which muscle fibres require glycolysis the most?
skeletal muscle type IIb (fast twitch fibres)
31
Why is the phosphorylation of glucose in the first step so important?
Forms G6P which then maintains low glucose concentration in the cell, promoting continuous transport of glucose into the cell through plasma membrane transporters also prevents glucose from leaking out, as the cell lacks transporters for G6P hexokinase is inhibited by its product
32
Difference in Km between hexokinase and glucokinase
glucokinase has a lower affinity for glucose, with the Km in the vicinity of normal glycemia
33
Importance of second stage
GGP converted into fructose-6-phosphate allows the reaction to drive forward because of low conc of F6P, which is constantly consumed in the next stage of glycolysis isomerisation to a keto sugar is necessary for the carbanion stabilisation
34
What happens if F6P concentration is high? + why
reaction readily runs in reverse, explained by Le Chatelier's Principle
35
Importance of third step
the glycolytic process becomes irreversible, as phosphofructokinase 1 is coupled to the hydrolysis of ATP (an energetically favourable step) forms the rate limiting step second phosphorylation event allows the formation of two charged groups, ensuring the prevention of free diffusion from the cell destabilising the molecule, to allow next step to happen with ease
36
What inhibits PFK?
A high ratio of ATP to ADP H+ allosterically
37
what activates PFK?
Fructose 2,6-bisphosphate, which is also produced from fructose 6-phosphate by PFK1 more F6P leads to more F-2,6-BP, whose binding increases the affinity of PFK1 for F6P and minimises inhibitory effect of ATP
38
Pyruvate kinase function
catalyses last step in glycolysis transfer of phosphate group from phosphoenolpyruvate to ADP, to produce one pyruvate and one ATP
39
Two conformations of pyruvate kinase + what binds
R state- high substrate affinity, stabilised by PEP and fructose 1,6-bisphosphate T state- inactivated form, low substrate affinity, bound and stabilised by ATP and alanine- causing the phosphorylation of pyruvate kinase and inhibition of glycolysis
40
What is the cofactor? + experiment that confirmed this
magnesium 2+ in yeast cells, interaction of yeast pyruvate kinase with PEP and allosteric effector fructose 1,6-bisphosphate was shown to be enhanced by presence of MG2+
41
How does Fructose -1,6-bisphosphate allow a feed forward mechanism?
FBP is a glycolytic intermediate produced early on in the reaction binds to allosteric binding site at domain C of pyruvate kinase and changes the conformation of the enzyme the higher the conc of FBP, the greater the allosteric activation and the magnitude of pyruvate kinase activity
42
What process is able to utilise pyruvate to form new proteins?
Transamination
43
Explain transamination
chemical reaction that transfers an amino acid group to a ketoacid to form new amino acids. alanine transaminase catalyses the addition of a nitrogen group (from alpha amino acid) to pyruvate to form a ketoacid and then form alanine
44
Glycerol-3-phosphate shuttle definition
mechanism that regenerates NAD+ from NADH
45
Stages of using galactose as a fuel
1. galactose to galactose 1-phosphate (ATP to ADP) catalysed by galactokinase 2. galactose 1-phosphate uridyltransferase then catalyses the conversion into glucose 1-phosphate 3. glucose-1-phosphate isomerises and forms glucose-6-phosphate, which is then able to enter the glycolytic pathway
46
stages of using fructose as a fuel
1. fructose becomes fructose 6-phosphate, catalysed by hexokinase able to enter the pathway
47
galactosaemia definition
accumulation of galactose in blood, cannot be metabolised properly

Metabolism (13 decks)

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