Brainscape's Knowledge GenomeTM

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


See full index

Advanced molecular & cell L2 > Lecture 8 - Metabolism > Flashcards

Lecture 8 - Metabolism Flashcards

1
Q

What are the products of catabolism from Carbohydrates, fats & proteins?

A

CO2, H2O, NH3

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

What are the products of anabolism of amino acids, sugars, fatty acids and nitrogenous bases?

A

Proteins, polysaccharides, lipids and nucleic acids

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

What process breaks down simple sugars into energy?

A
  • Glycolysis
  • Krebs (TCA)
  • Oxidative phosphorylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe how many ATPs are produced in the process of breaking down simple sugars

A
  • Glycolysis does produce ATP (2x ATP)
  • BUT pyruvate to TCA (krebs) to oxidative phosphorylation gives a big payoff in terms of ATP
  • approx 30 ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is needed to metabolise molecules to get energy?

A

Energy carrier (ATP adenosine triphosphate)

ATP hydrolysis drives thermodynamically unfavourable reactions

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

How is ATP generated?

A
  • oxidation of glucose
  • oxidation of fatty acids
  • oxidation of amino acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are common intermediates in ATP generation?

A
  • Pyruvate
  • Acetyl CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are electron carriers?

A

NADH and FADH2

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

What is oxidation?

A
  • GAIN of oxygen
  • LOSS of hydrogen
  • LOSS of electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is reduction?

A
  • LOSS of oxygen
  • GAIN of hydrogen
  • GAIN of electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is glycolysis?

A

Degradation of glucose to pyruvate
- process results in formation of ATP and NADH
- 10 reactions (9 main ones + 1)

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

What are 2 phases of glycolysis?

A
  • Preparation Phase
  • Payoff Phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is preparation phase?

A
  • conversion of one 6-Carbon (glucose) molecule into two 3-Carbon molecules of glyceraldehyde 3-phosphate (G3P)
  • consume 2 molecules of ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is payoff phase?

A
  • conversion of glyceraldehyde 3-phosphate to pyruvate
  • produces 4 molecules of ATP and 2 molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the net production from glycolysis?

A

Produces 2 ATP and 2 NADH molecules

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

How is glycolysis controlled?

A

Pyruvate Kinase
- inhibited by ATP and Acetyl CoA (high energy state)
- activated by fructose 1,6 biphosphate (low energy state)

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

Describe the positive and negative feedback used in controlling glycolysis?

A

Starting reactants PROMOTE conversion to Acetyl CoA (positive feedback)
BUT products INHIBIT conversion to Acetyl CoA (negative feedback)

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

How many carbons feed into the TCA (krebs cycle)?

A

2 (and 2 are pulled off in the oxidation phase)

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

Describe the products from one cycle of the krebs cycle

A

2 - CO2
1 - GTP or ATP
1 - FADH2
3 - NADH + H+

Glucose (6C) is split into 2x 3C of glyceraldehyde 3-phosphate

Products of 2 cycles:
4 - CO2
2 - GTP or ATP
2 - FADH2
6 - NADH + H+

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

What else supplies the Krebs cycle??

A
  • proteins (amino acids)
  • polysaccharides (glucose + other sugars)
  • fats (fatty acids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is fat a combination of?

A

glycerol + fatty acid

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

Describe the breakdown of molecules

A
  • involves 4 enzymes
  • end result is the serial breakdown of the molecule in 2 carbon sections
  • the acetyl-CoA produced enters the Krebs cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can a fatty acid be turned into?

A
  • only ATP (not glucose)
  • glycerol (glucose - gluconeogenesis (6-8%)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a key point of amino acids in the krebs cycle?

A

Amino acids feeds into Krebs at different points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What occurs when when NADH+ & FADH2 are converted to NAD & FAD?

A
  • they feed into the electron transport chain
    achieved by means of 4 membrane protein complexes
  • electrons feed into complex 1 from NADH and complex 2 from FADH2
  • process also establishes a protein gradient across the inner mitochondrial membrane - drives ATP synthase to produce ATP.

Generates a proton gradient between the inner and outer membranes

26
Q

What is the purpose of oxygen in the electron transport chain?

A

Acts as the final electron acceptor - electrons convert oxygen to water

27
Q

Describe how regulation occurs across the electron transport system

A

ADP/ATP levels are an important determinate of the rate of electron transfer
- At rest, the PROTON MOTIVE FORCE (PMF) is high, but due to high ATP levels, there is minimal flow of protons through the synthase, and low transfer of electrons.

  • during exercise, ATP is consumed, ADP levels will rise, lead to proton movement through synthase, discharging the PMF.
  • results in increased electron transfer to regenerate the PMF.
28
Q

What are different functions of inhibitors?

A
  • Electron transport inhibitor
  • Uncoupling agent
  • Inhibits ATP synthase
29
Q

What type of inhibitor has the biggest effect?

A
  • disruption of complex IV has the biggest effect. Carbon monoxide has a bigger effect on haemoglobin and therefore reducing O2 carrying capacity of blood.
  • uncouplers - bodybuilders - very dangerous
  • H+ gradient dissipated - therefore for the same amount of ATP, electron transport has to work much harder.
  • generates lots of heat, it does work but can get out of control and you boil.
30
Q

What is 2-4 dinitrophenol (DNP)?

A

Proton ionophore - a molecule that facilitates the movement of protons (H⁺) across a biological membrane.

Binds protons on one side of a membrane and moves to the opposite site where it loses the protons.

Highest probability to bind a proton where the H+ concentration is highest. It will dissipate the H+ gradient.

31
Q

Is metabolism compartmentalized?

A

YES

32
Q

What parts of metabolism occurs in the cytosol?

A
  • glycolysis
  • pentose phosphate
  • fatty acid synthesis
33
Q

What parts of metabolism occurs in the mitochondrial matrix?

A
  • TCA
  • Oxidative Phosphorylation
  • B-ox of fatty acids
  • Ketone body formation
34
Q

What parts of metabolism occurs in the cytosol and the mitochondrial matrix?

A
  • gluconeogenesis
  • urea synthesis
35
Q

What is ATP?

A

universal currency of energy

36
Q

What different parts of the body is involved in metabolism?

A
  • brain
  • liver
  • adipose tissue
  • skeletal muscle
37
Q

What occurs in the brain?

A

Uses glucose

38
Q

What occurs in the liver?

A
  • processes fats
  • synthesises lipids, ketone bodies
  • glucose
39
Q

What occurs in the adipose tissue?

A
  • synthesizes + mobilizes tricly-glycerols
40
Q

What occurs in the skeletal muscle?

A

Uses ATP to do work

41
Q

What is needed to move your muscles?

A
  • your brain needs glucose
  • your muscles needs ATP
41
Q

Do all tissues use the same fuels to meet their metabolic needs?

A

Different tissues use different fuels to meet their metabolic needs

41
Q

Describe how ATP is generated in the brain

A

Glucose and ketone bodies is converted to CO2.

41
Q

What is used as a fuel for metabolism in the brain?

A

Glucose used in MOST conditions (even though ketone bodies are synthesized)
- except - ketone bodies replace glucose but only after several days.

42
Q

What are ketone bodies?

A

contain ketone groups, produced from fatty acids by the liver

42
Q

Describe metabolism in the kidney

A
  • kidney produces urine - i.e. secrete waste products
  • plasma is filtered 60x a day (water + glucose reabsorbed)
  • starvation - major site of gluconeogenesis (1/2 of blood glucose)
43
Q

Describe metabolism in muscle

A

Light activity:
- fatty acids
- ketone bodies
- blood glucose

These are converted into CO2

Heavy activity:
- muscle glycogen

This is converted to lactate

44
Q

Describe exercise is muscle

A

1-2 mins - anaerobic - uses glycogen or serum glucose. Eventually switch to aerobic - oxidative phosphorylation

45
Q

What is creatine is used as?

A

Creatine is used as a rapid energy supply to power the ATP-dependent motor that move your muscles.
- buys time for the glycogen stores to be mobilized

46
Q

How is metabolism in the muscle and liver is linked?

A

The muscle needs the glucose produced from recycling the lactate

47
Q

How does muscle get glucose?

A

Glycogen and from recycled lactate from the liver

48
Q

Describe metabolic regulation on the FED state

A

Insulin - regulates the metabolism of carbohydrates, fats and protein. It promotes the absorption from the blood into liver, fat and skeletal muscle cells

Glucagon - increase the concentration of glucose ad fatty acids in the blood. Stimulates glucose production in the liver.

49
Q

Describe the biological effects of insulin

A

Increase:
- glucose uptake
- glycogen synthesis
- protein synthesis
- fat synthesis

Decrease:
- gluconeogenesis
- glycogen mobilization
- lipid mobilization
- protein degradation

50
Q

Describe the biological effects of glucagon

A

Increase:
- gluconeogenesis
- glycogen mobilization
- ketogenesis
- protein degradation
- uptake of amino acids

Decrease:
- glycogen synthesis
- protein synthesis
- fat synthesis

51
Q

What does insulin do?

A
  • signals to Glut-4 to uptake glucose
  • GGLUT1,2,3 are insulin-independent
  • controls amino-acid uptake and hence DNA-replication and protein synthesis
  • numerous other effects on cells

Note where insulin-independent are located. All in tissues that need rapid glucose uptake (e.g. liver, erythrocytes and brain)

52
Q

Where are GLUT4 glucose transporters found?

A

Skeletal muscle and adipose

53
Q

Describe metabolic regulation in the early fasting state

A

As blood-glucose DROPS, insulin secretion DROPS and glucagon secretion rises.

In the liver, there are signals to breakdown glycogen, reduce glycolysis and increase gluconeogenesis

54
Q

What occurs in the fed state?

A

glucose can be turned into fat in the liver and adipose (fat) tissue

55
Q

What occurs in the fasted state?

A

When you fast, fats and glycerol and fatty acids are used to generate energy or glucose

  • glucose made from fats (etc.) is used for muscle contraction
  • BUT proteins can be broken into amino acids to make energy in the liver for example.
  • FATTY ACIDS –> can be used in muscle to make Acetyl-CoA for aerobic metabolism

There is a complex interaction between liver and muscle to keep things going

56
Q

Summarise metabolism

A
  • different phases of metabolism produce different amounts of energy
  • ‘starting’ reactants PROMOTE (positive feedback)
  • products ‘INHIBIT’ conversion (negative feedback)
  • metabolism is compartmentalized and different tissues metabolism interacts.
  • Fed and fasting states involve interaction between different key tissues

Advanced molecular & cell L2 (12 decks)

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