Lec 13 and 14: Cellular Respiration I and II Flashcards

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1
Q

explain the diffference between metabolism, catabolism and anabolism

A

metabolism: all the chemical reactions in the body
catabolism: beaking down complex molecules

Anabolism: (endergonic) building of complex molecules

metabolism is the balance between the energy inputs and outputs of anabolism and catabolism

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2
Q

in what type of reactions is ATP used and made?

A

ATP is used in anabolic reactions

can be made in catabolic reactions

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3
Q

how is catabolism and anabolism coupled by ATP?

A
  • catabolic reactions transfer energy from moleciles to ATP (releasing heat)
  • these are simple molecules such as glucose, amino acids, glycerol and fatty acids.
  • anabolic reactions transfer energy from ATP to complex molecules (releasing heat)
  • these are molecules such as starch, proteins and lipids

cycle starts again

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4
Q

In starvation catabolism drops, explain what happens to the rate of anabolic processes

A

drop in catabolism means a drop in the break down of complex molecules

that provide energy for the production of ATP

therefore resulting in less amount of energy from ATP being provided

for the building of complex molecules (anabolic reactions)

rate of anabolic processes lowers

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5
Q

In liver cells (metabolises poisons) does anabolism or catabolism predominate?

A

catabolism

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6
Q

In a pancreatic cell producing digestive enzymes does anabolism or catabolism predominate

A

anabolism

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7
Q

What are the bodies main ways of storing energy

A

stores energy in nutrients

molecules such as glycogen (in liver) and triglycerides (in adipose tissue) store energy

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8
Q

why is ATP a good energy source for cells?

A
  • contains high energy phospahte bond
  • which can be released easily and quickly
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9
Q

what is oxidation

A

removal of electrons or hydrogen

/

addition of oxygen

decreasing potential energy

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10
Q

does oxidation or reduction take place in dehydrogenation reactions?

A

oxidation

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11
Q

what is NAD?

give the eqaution for the reduction of NAD

A

nicotinamide adenine dinucleotide

a derivative of the B vitamin niacin

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12
Q

what is FAD?

give the eqaution for the reduction of FAD

A

flavin adenine dinucleotide

derivative of the B vitamin riboflavin

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13
Q

how does phosphorylation (addition of P group) affect potential energy?

A

increases a molecules potential energy

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14
Q

what is subtrate level phosphorylation?

where does it occur

A

Transferring high-energy phosphate group from an intermediate directly to ADP

(occurs in the cytosol)

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15
Q

what is oxidative phosphorlyation?

where does it occur?

A

Remove electrons and pass them through electron transport chain to oxygen

occurs in the inner mitochondrial membrane

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16
Q

where is the only place Photophosphorylation takes place?

A

Only in chlorophyll-containing plant cells

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17
Q

what type of cell converts fructose to glucose

A

intestinal epithelial cells

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18
Q

what type of cells convert fructose and galactose to glucose?

A

hepatocytes

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19
Q

how does glucose move into the cells of the Gi tract?

A

by co transport

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20
Q

what is insulin and what is its function?

A

Insulin is a hormone

made by the pancreas

that allows your body to use glucose from carbohydrates in the food

for energy or to store glucose for future use.

Insulin helps keeps your blood sugar level from getting too high (hyperglycemia) or too low (hypoglycemia).

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21
Q

what happens in glycolysis?

steps 1-5

A
  • Splits 6-carbon glucose into two 3-carbon molecules of pyruvic acid
  • Consumes 2 ATP but generates 4
  1. Glucose –> Glucose 6-phosphate

(hexokinase, uses ATP and produces ADP + H+)

  1. Gluocse 6-phosphate –> Fructose 6-phosphate

(isomerase)

  1. Fructose 6-phosphate –> Fructose 1,6-biphosphate

(phosphofructase, uses ATP ad produces ADP + H+)

4a. Fructose 1,6-biphosphate –> Glyceraldehyde 3-phosphate

(aldolase)

4b. Fructose 1,6-biphosphate –> dihydroxyacetone phosphate

(aldolase)

  1. Glyceraldehyde 3-phosphate –> dihydroxy acetone phosphate

(triosephosphate isomerase)

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22
Q

what is the key regulator of glycolysis?

A

Phosphofructokinase

PFK

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23
Q

when are phosofructokinase levels high?

A

when ADP levels are high

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24
Q

how do ADP levels affect glycolysis

A

high ADP levels

indicate high phoshofructokinase acitivity

so high rate of glycolysis

/

low ADP levels

glucose is shunted away from glycolysis

to the glycogen storage pathway

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25
Q

what is Tarui disease?

A

where there is a lack of PFK

results in exercise intolerance, with pain, cramps and, occasionally, myoglobinuria (acute muscle breakdown leading to rust-colored urine).

A partial deficiency of phosphofructokinase in the red blood cells results in the breakdown of those cells and an increase in blood levels of bilirubin (a chemical found in red blood cells)

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26
Q

what happens in glycolysis?

steps 6-10

A
  1. Glyceraldehyde 3-phosphate –> 1,3-biophosphoglycerate

(glyceraldehyde phosphate dehydrogenase uses NAD and HPO42- to make NADH + H+)

  1. 1,3-biphoshpoglycerate –> 3-phosphoglycerate

(phosphoglycerate kinase, uses ADP to make ATP)

  1. 3-phosphoglycerate –> 2-phosphoglycerate

(phosphoglycerate muatase)

  1. 2-phosphoglycerate –> phosphoenolpyruvate

(enolase)

  1. phosphoenlpyruvate –> pyruvate

(pyruvate kinase, uses ADP + H+ to make ATP)

27
Q

In glycolysis;

how many NADH + H+ molecules are made

how many ATP molecules are used and generated

A

6 NADH + H+ molecules

use 2 ATP molecules and generate 4

28
Q

what are the NADH + H+ molecules used to make? and in which cells?

A
  • Most cells use these to generate 4 ATPs in the electron transport chain
  • Hepatocytes and cardiac muscle fibres generate 6 ATPs from them
29
Q

where is the location of glycolysis?

A

cystosol

30
Q

what is the fate of pyruvic acid depending on whether anaerobic or aerobic respiration takes place?

A

anaerobic: reduced to 2 lactic acid molecules

2 molecules are reduced by 2 H atoms from NADH

lactic acid enters the blood and is converted back to pyruvate by hepatocytes

aerobic: converted to acetylcoenzyme A

31
Q

why is the reduction of pyruvate in anaerobic respiration important to glycolysis?

A

when 2 pyruvates are reduced by 2 NADH

it regenerates 2NAD+

which are required in step 6:

  1. Glyceraldehyde 3-phosphate –> 1,3-biophosphoglycerate

(glyceraldehyde phosphate dehydrogenase uses NAD and HPO42- to make NADH + H+

without the NAD glycolysis can not continue

32
Q

what is the importance of converting pyruvate to acetyl coenzyme A in aeoribic respiration

A
  • molecule links glycolysis (cytoplasm) to Krebs (matrix of mitochondria)
  • RBC’s lack mitochondria so can only perform glycolysis
33
Q

what enzyme converts pyruvate to acetyl coenzyme A?

A

pyruvate dehydrogenase

34
Q

what is the net gain of ATP, NADH and Acetyl coenzyme A molecules in glycolysis and krebs cycle?

A

Net gain from glycolysis and link reaction

  • 2 ATP molecules
  • 4 NADH molecules
  • 2 Acetyl coenzyme A molecules
35
Q

what is Pyruvate dehydrogenase deficiency?

A

a sex linked disease

Pyruvate dehydrogenase deficiency

36
Q

where does the krebs reaction take place?

A

in the matrix of the mitochondria

37
Q

*NOTE* Krebs cycle overview

A

start of with:

3 NADH

1 FADH2

Contain the energy originally stored in glucose

Later each NADH makes 3 ATP molecules

FADH2 makes 2 ATP molecules

1 ATP made by substrate level phosphorylation

38
Q

how many ATP molecules are made in total in the krebs cycle?

A

12 ATP (24 per glucose molecule)

39
Q

what are the steps in the krebs cycle?

A
  1. Entry of acetly group to create citrate & regeneration of CoA
  2. Isomerisation to isocitric acid
  3. Oxidative decarboxylation. Remove CO2 & formation of NADH & alpha ketoglutarate
  4. Oxidative decarboxylation and addition of CoA to form succinyl-CoA & NADH
  5. Substrate level phosporylation. CoA is displaced for a phosphate group, which is transferred to GDP and donated to ATP. Forms succinate
  6. Dehydration. Succiante is oxidised furmarate by FADH2 formation
  7. Hydration. Furmarate is converted to malate by addition of water
  8. Dehydrogenation to oxaloacetate & formation of NADH
40
Q

how many CO2 molecules does krebs produce from each glucose molecule?

A

4

41
Q

1Which enzyme in Krebs allows for substrate level phosphorylation?

A

succinyle co-A synthetase

42
Q

why do you breathe out more CO2 after excersise?

A

more turns of krebs

43
Q

which three enzymes in krebs reduce NAD?

A
  • isocitrate
  • ketogluterate
  • malate dehydrogenase
44
Q

what is the electron transport chain?

A

a series of electron carries in the inner mitochondrial membrane

45
Q

what is the final electron acceptor?

A

oxygen

46
Q

what happens in the electron transport chain?

A
  1. Energy from NADH + H+ passes along the electron transport chain (via REDOX) & is used to pump the proton pump
  2. A high concentration of H+ accumulates between the membranes
  3. ATP synthesis occurs as the H+ ions flow back into the matrix through the H+ channels
47
Q

how many molecules of ATP are produced in the electron transport chain?

A

32 or 34 per glucose molecule

48
Q

how many molecules of ATP are made from NADH + H+ and FADH2

A

10 molecules of NADH + H+ produce 28 or 30 mols of ATP

2 molecules of FADH2 produce 2 mols of ATP

49
Q

*NOTE* for NADH in krebs cycle

A
  • NADH made in glycolysis cannot enter the mitochondria.
  • They donate electrons to malate or glycerol phosphate shuttle
50
Q

which organs use the malate shuttle and how many ATP molecules are produced as a result?

A

•Liver, kidneys & the heart= 3ATP molecules result

51
Q

how many ATP molecules are made as a result of the glycerol phosphate shuttle?

A

2 ATPs

52
Q

how many molecules of ATP are made in substrate level phosphorlyation in glycolysis and krebs cycle?

A

substrate level phosphorylation in glycolysis = 2 ATP

substrate level phosphorylation in the Krebs cycle = 2ATP

53
Q

*NOTE* ATP yield per glucose molecule

A
54
Q

what is the role of NAD dehydrogenase in the krebs cycle?

A

reduces NAD/FAD by oxidising a substrate

55
Q

what is chemiosmosis?

A

the use of energy in a chemical gradien to generate ATP by the flow of hydrogen ions through ATP synthase

56
Q

how is a H+ gradient built up in the mitochondria? that is the purpose of this?

A

H+ ions from the matris are pumped into the intermembrane space

the inner mitcohondrial membrane is impermeable to H+ ions

so a gradient forms

H+ ions move down their concentration gradient, into the matrix using protein channels that are associated with the enzyme ATP synthase

ATP synthase phosphorylates 1 ADP for each H+ ion

therefore protons are a direct energy source for producing ATP

57
Q

why can a liver cell make more ATP per glucose molecule than a lung cell?

A

liver cells use the malate shuttle to recieve electrons from NAD

this results in the production of 3 ATP molecules

where as a lung cell would use the glycerol phosphate shuttle

resulting in the production of 2 ATP molecules

58
Q

what stimulates glycogenesis?

A

insulin in hepatocytes and muscle cells

59
Q

what is the role of phosphoglucomutase?

A

interconverts Glucose 6-phosphate to Glucose 1-phosphate

60
Q

under what metabolic conditions will glycogensis occur?

A

in high levels of ATP and glucose

61
Q

what hormone stimulates glycogenesis?

A

insulin

62
Q

how can the hormone glucagon help keep blood sugars up?

A
  • pancreas releases glucagon when blood glucose levels are too low
  • glucagon stimulates glycogenolysis

which produces glucose from glycogen with the use of phosporylation

63
Q

which two hormones activate glycogen phosphorylase?

A

glucagon and adrenaline

64
Q
A