Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FLS > Glycolysis > Flashcards

Glycolysis Flashcards

1
Q

Why do we eat?

A

To maintain cell integrity.
e.g. replace cells that are dying from apoptosis.

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

What are the main phases of cellular respiration?

A

Glycolysis
TCA cycle
Electron Transport Chain

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

What are fats broken down into?

A

Fatty acids and glycerols
In adipose tissue
Lipolysis breaks down fatty acid into pyruvate and acetyl-CoA.

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

What are carbohydrates broken down into?

A

Monosaccharides
In the liver and muscle
Liver stores glycogen and makes pyruvate and acetyl CoA.

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

What are proteins broken down into?

A

Amino acids
In the muscle
Produces pyruvate and into the citric acid cycle.

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

What are complex polymers broken down into?

A

Polymers or oligomers
Monomers

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

What happens to lipids in the 4 hours after eating?

A

Lipids are absorbed into the gut.
Lipids pass into the liver, which packages the triglycerides into Low Density lipoproteins and stores them in the adipose tissue, until needed, or delivered to the muscle.

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

What happens to glucose in the 4 hours after eating?

A

Glucose is absorbed into the gut then distributed everywhere - liver, muscles, adipose - primarily the brain as glucose is the main source of energy.

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

What happens to amino acids 4 hours after eating?

A

Absorbed into the gut, then delivered to the muscles and used as a fuel source.

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

What is the structure of glycogen?

A

Highly branched glucose polymer with a-1,4 and a-1,6 linkages.
Stored as granules in the cytosol of cells.

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

Where is glycogen found?

A

High concentration in the liver so it is releasable into the circulation.
N-glycogen is found in muscles for local use during exercise or fasting, as there is no enzyme in muscle to allow glucose to go back into circulation.

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

How is glycogen regulated?

A

Synthesis and breakdown are highly regulated by glucagon and insulin through protein phosphorylation cascades which control when glycogen is utilised or stored.

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

What happens in the fasted state?

A

4-12hrs after eating:
Adipose tissue releases free fatty acids into circulation to use as fuel.
Brain continues using glucose, taken from glycogen and broken down by liver, then metabolised by the brain.

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

What is the starved state?

A

12-20 hours after eating

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

What do fats do in the starved state?

A

Accelerated release of free fatty acid from the adipose tissue into the liver to be converted into energy.

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

What does glucose do in the starved state?

A

More glucose is released from gluconeogenesis and delivered to the brain.
Ketones can also be used as an energy source.

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

What do amino acids do in the starved state?

A

The muscle generates lactate by anaerobic metabolism, and uses amino acids as an energy source.
Transamination of the muscle and liver to detoxify as a result of urea.

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

What is glucose?

A

The main energy source.
Generates 28-32 ATP molecules per glucose.

19
Q

What are the two major elements of glycolysis?

A

The investment phase - adds 2 ATP to glucose so it can split into 2 molecules.
The Generation/ Pay-off phase - converts 3 C sugars into pyruvate, generates 4 ATP.
Net 2 ATP.

20
Q

What are the 3 key aspects of the process of glycolysis?

A

The trap - adding a phosphate
The split - 6 C glucose becomes 2 3C carbon molecules
The pyruvate maker.

21
Q

What is transamination?

A

If there is not enough amino acid alanine for gluconeogenesis, pyruvate can be converted by adding NH3, but this forgoes creating energy.

22
Q

What is anaerobic respiration?

A

If there is little oxygen available - lactate produced.
Yeast can produce ethanol from it.

23
Q

What is glucose uptake?

A

Cells can only take up glucose by facilitated diffusion through hexose transporters.
In many tissues - muscle - major transporter is GLUT4, and made available in plasma membrane through insulin.

24
Q

What are the steps in the investment phase?

A

Glucose uses ATP to be converted by hexokinase into glucose-6-phosphate.
Converted to fructose-6-phosphate
Phosphofructokinase uses ATP to convert into fructose 1,6-bisphosphate.

25
Q

What is the glycolysis pathway diagram?

A
26
Q

What are the steps in the payout phase?

A

Fructose-1,6-bisphosphate converted to x2 glyceraldehyde-3-phosphate.
Regenerates 2 NADH to form 1,3-bisphosphoglycerate.
Generates 2 ATP to form 3-phosphoglycerate, then to 2-phosphoglycerate, then phosphoenolpyruvate.
Then 2 ATP are generated and pyruvate is formed.

27
Q

What is important to remember about the payout phase?

A

4 ATP are generated per glucose molecule, and 2 ATP are used in investment phase so net 2 ATP generated.
2 NADH are generated.
Fructose-1,6-bisphosphate is split into 2 molecules.

28
Q

What can enzyme deficiency do during glycolysis?

A

If an enzyme for an irreversible step stops working, there is a build up of metabolite because the molecules can’t be converted back.

29
Q

What are the irreversible steps of glycolysis?

A

Glucose to glucose-6-phosphate by hexokinase.
Fructose-6-phosphate to fructose-1,6-bisphosphate by PFK.
Phosphoenolpyruvate to pyruvate by pyruvate kinase.

30
Q

Why does glucose need generating?

A

The body store of carbohydrate is 180g, but the brain requires 130g glucose per day.
So glucose needs generating from other sources - pyruvate or fatty acids.
So gluconeogenesis must occur.

31
Q

What is gluconeogenesis?

A

Glycolysis reactions can be replaced by a bypass to circumvent the irreversible pathway.
It uses different enzymes, so that glucose can be generated, and also uses different values of ATP.

32
Q

What is the bypass reaction for pyruvate and phosphoenolpyruvate?

A

Pyruvate uses 1 ATP by pyruvate carboxylase to create oxaloacetate.
Phosphoenolpyruvate carboxykinase then converts it to phosphoenolpyruvate, which uses 1 GDP.

33
Q

What is the bypass for the reaction of fructose-6-phosphate and bisphosphate?

A

Fructose 1,6-bisphosphate is converted to fructose-6-phosphate by fructose 1,6-bisphosphatase.

34
Q

What is the bypass for the reaction of glucose?

A

Glucose 6 phosphate is converted to glucose by glucose-6-phosphatase.

35
Q

What is the energy cost for the bypass reactions?

A

Costs 4 ATP, 2 GTP, 2 NADH.
2 pyruvate is needed for each glucose.

36
Q

How is glycogen converted into glucose?

A

Glycogen acted on by phosphorylase to create glucose-1-phosphate, which is acted on by phosphoglucomutase to create glucose-6-phosphate.

37
Q

How does fructose enter the glycolysis pathway?

A

Acted on by hexokinase to form fructose-6-phosphate.
Fructose can enter cells without insulin sensitivity so is hard to regulate.

38
Q

How can NAD+ be regenerated?

A

During anaerobic respiration, pyruvate is acted on by lactate dehydrogenase to form lactate, which then goes to the Cori cycle.
In this, NADH is converted to NAD+ and so is very important for there being enough NAD+ in glycolysis.

39
Q

What is lactate acidosis?

A

When lactate levels go above 5mM.

40
Q

What happens in the Cori cycle?

A

Lactate transported to liver and converted into pyruvate then glucose.
During anaerobic respiration there is short term energy gain, but for cori cycle 6 ATP is needed, so 4 ATP are lost.
But it is more important to detoxify than to conserve ATP - there is a big store in the liver.

41
Q

What happens to pyruvate under aerobic conditions?

A

Pyruvate converted to Acetyl CoA by Phosphate dehydrogenase and bringing in CoA.
Also generates NADH which is important for ETC.

42
Q

Why is acetyl-CoA important?

A

It is a carrier protein which allows many reactions in the body to take place because it has a high energy bond.

43
Q

What is the breakdown of energy expenditure of gluconeogenesis?

A

2x ATP used by pyruvate carboxylase.
2x GTP used by phosphoenolpyruvate carboxykinase.
2x ATP used by phosphoglycerate kinase.
2x NADH used by glyceraldehyde 3-phosphate dehydrogenase.
4 ATP, 2NADH, 2GTP

FLS (14 decks)

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