12) Energy & Respiration Flashcards

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1
Q

name 2 anabolic reactions

A
  • protein synthesis
  • DNA replication
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2
Q

name 2 catabolic reactions

A
  • digestion of food
  • glycolysis
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3
Q

what are anabolic & catabolic reactions?

A

anabolic - build bigger molecules from smaller ones.

catabolic - breakdown of large organic molecules into smaller molecules.

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4
Q

what 3 structures does a nucleotide consist of?

A
  • pentose sugar
  • phosphate
  • base
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5
Q

a) How is energy released from ATP? &
b)what is produced?

A

a) removing of a phosphate

b) ADP + Pi (a phosphate)

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6
Q

how is ATP able to transfer energy in cells?

A
  • soluble molecule
  • transported easily/diffuses rapidly
  • synthesised from ADP and Pi
  • energy released (30.5kJ)
  • removal of third phosphate
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7
Q

what is the formula for respiratory quotient (RQ) ?

A

volume of carbon dioxide produced / the volume of oxygen consumed

(calculated as ratio)

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8
Q

4 reasons why ATP is ideal as an energy currency

A
  • water soluble so can move around the cell
  • high turnover
  • loss of phosphate/hydrolysis leads to energy release
  • immediate energy donor
  • small packets of energy
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9
Q

How is ATP made by substrate-linked reactions

A
  • addition of INORGANIC phosphate group to ADP
  • from a phosphorylated compound (like triose phosphate)
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10
Q

RQ value of carbohydrate

A

1.0

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11
Q

RQ value of proteins

A

0.9

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12
Q

RQ value of lipids

A

0.7

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13
Q

what are the 4 stages in aerobic respiration

A
  • glycolysis
  • link reaction
  • krebs cycle
  • oxidative phosphorylation
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14
Q

where do each of the 4 stages of aerobic respiration occur ?

A
  • glycolysis = cytoplasm
  • link reaction = mitochondrial matrix
  • krebs cycle = mitochondrial matrix
  • oxidative phosphorylation = inner membrane of mitochondria
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15
Q

what happens in oxidation

A
  • adding O
  • removing H
  • loss of electrons
  • releases energy
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16
Q

what happens in reduction

A
  • removing O
  • adding H
  • gain of electrons
  • stores energy
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17
Q

outline the stages of glyoclysis

A
  1. Glucose is phosphorylated 2x by adding phosphates from 2 ATPs.
  2. LYSIS causes hexose biphosphate to be split into two triose phosphate.
  3. Triose phosphates oxidised by donating hydrogen to NAD+.
  4. 4 ATP total produced.
    Net gain = 2 ATPs
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18
Q

what are the final products of glycolysis

A
  • 2 ATP
  • 2 NADH
  • 2 Pyruvate
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19
Q

what are the final products of Link reaction

A
  • 0 ATP
  • 2 NADH
  • 2 Acetyl CoA
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20
Q

what are the final products of Krebs cycle

A
  • 2 ATP
  • 6 NADH
  • 2 FADH
  • 4 CO2
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21
Q

Outline the stages of link reaction

A
  • pyruvate enters mitochondrial matrix
  • pyruvate is decorboxylated & dehydrogenated
  • acetyl group is formed
  • acetyl group combines with coenzyme A to from acetyl coA
  • acetyl coA enters krebs cycle
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22
Q

Outline the stages of Krebs cycle

A
  • acetyl coA combines with oxaloacetate
  • citrate is formed
  • citrate is decarboxylated & dehydrogenated
  • hydrogen atoms accepted by NAD & FAD
  • ATP is made by substrate-linked phosphorylation
  • oxaloacetate is regenerated
23
Q

outline how ATP is synthesised by oxidative phosphorylation (8)

A

-

24
Q

what are structures of the mitochondria related to their functions

A
  • external double membrane
  • matrix
  • inner membrane
  • inter-membrane space
25
Q

what is the function of external double membrane of a mitochondria

A
  • permeable to pyruvate, CO2, O2, NAD & reduced NAD
26
Q

what is the function of matrix

A

site of enzymes of link reaction & krebs cycle
- (enzymes have to bump into substrates so need fluid)

27
Q

what is the function of inner membrane

A
  • S.A increased by intucking to form cristae (since etc & atp synthase enzymes stored here, opportunities for atp synthesis enhanced)
  • impermeable to hydrogen ions(protons) : so potential difference between intermembrane space & matrix
28
Q

what is the function of inter-membrane space

A

relatively tiny space - allowing accumulation of hydrogen ions (protons) to generate high potential difference with matrix
(making phosphorylation possible)

29
Q

what is the big advantage of aerobic respiration?

A

way more ATPs produced (36 ATP)

30
Q

what is the only stage that can occur in the absence of oxygen?

A

glycolysis

31
Q

3 reasons why ATP will not be made from etc without oxygen

A
  • No O2 to mop up hydrogen ions

-No proton gradient across the inner membrane

-Protons do not pass through the channel of ATP synthase

32
Q

If oxygen is not present, why can’t NADH and FADH off load their hydrogens?

A

proton concentration is too high in the matrix because there is no oxygen to mop up the hydrogen

33
Q

In the absence of oxygen, why does the Kreb’s cycle and link reaction stop too?

A

As NAD is not formed to go back and pick up more hydrogens

34
Q

list the steps which occur during anaerobic respiration in plants and fungi

A
  • glycolysis
  • pyruvate cannot enter the mitochondrion
  • pyruvate becomes hydrogen acceptor/reduced by reduced NAD.
  • lactate is produced using the enzyme lactate dehydrogenase. - production of 4 ATP.
  • decarboxylation
  • ethanal is reduced using the enzyme ethanal dehydrogenase.
  • ethanol produced
35
Q

2 reasons why rice plants can cope with high levels of ethanol

A
  1. Their cells are ethanol tolerant (not killed by the toxicity)

2.They produce high levels of the enzyme ethanol (alcohol) hydrogenase which breaks down ethanol

36
Q

What colour is methylene blue when it is oxidised & reduced?

A

oxidised = blue
reduced = colourless

37
Q

what is the function of aerenchyma

A

oxygen supply to underwater roots for aerobic respiration

38
Q

why glucose is phosphorylated at the beginning of glycolysis

A
  • made reactive
  • energy level increased
  • becomes unstable
39
Q

use of the reduced NAD that is produced in glycolysis

A
  • hydrogen acceptor
  • used for redox reactions
  • used to reduce pyruvate
40
Q

the type of phosphorylation reaction by which ATP is made during glycolysis

A

substrate-linked phosphorylation

41
Q

main conditions that are required for pyruvate to enter the mitochondrion by
active transport

A
  • inner mitochondrial membrane impermeable to pyruvate
  • carrier protein
  • oxygen available
  • ATP
  • against concentration gradient
42
Q

how ATP is produced from ADP in the Krebs cycle

A
  • substrate-linked phosphorylation
  • transfer of phosphate group to ADP
43
Q

how do ethanol fermentation and lactate fermentation allow cells to continue to function in the absence of oxygen

A
  • produces NAD
  • glycolysis
  • ATP produced
  • substrate-linked phosphorylation
44
Q

explain how rice plants are adapted to grow in flooded fields

A
  • aerenchyma provides oxygen for aerobic respiration
  • high concentration of ethanol dehydrogenase
  • fast growth so leaves out of water
45
Q

State the precise locations of substrate-linked phosphorylation reactions in aerobic respiration

A

cytoplasm AND mitochondrial matrix

46
Q

why the link reaction only occurs when oxygen is available

A
  • pyruvate converted to acetyl group
  • NAD needed
  • NAD becomes reduced in link reaction
  • reduced NAD goes to etc
  • etc only works when oxygen present
47
Q

explain the role of the coenzymes NAD and FAD in aerobic respiration

A
  • hydrogen carriers
  • NAD reduced in glycolysis
  • so that triose phosphate becomes oxidised
  • NAD reduced in link reaction
  • so pyruvate oxidised
  • both NAD and FAD reduced in Krebs
  • to regenerate oxaloacetate
48
Q

explain why the inner membrane of a mitochondrion remains intact when
the organelle is placed in pure water

A
  • cristae let inner membrane expand
  • when water enters by osmosis down wpd
49
Q

Name three molecules, other than coenzymes, that are found in the mitochondrial matrix
and explain their role in aerobic respiration

A
  • pyruvate : for link reaction
  • citrate : to make reduced NAD
  • water : solvent
50
Q

Suggest why the inner membrane contains a very high proportion of cardiolipin

A

so H+
, cannot move through / must move through ATP synthase

51
Q

Explain how hydrogen atoms from reduced NAD and reduced FAD lead to a
membrane potential forming across the inner mitochondrial membrane during
oxidative phosphorylation

A

1 (H atoms) split into protons and electrons ;

2 electrons, flow / move, down ETC ;

3 (releases) energy used to move H+
to intermembrane space ;

4 more / build-up of, H+
/ positive charge, in intermembrane space ;

5 (causes / sets up) proton / electrochemical, gradient

52
Q

how Pi is transported across the inner membrane of the
mitochondrion into the matrix

A
  • facilitated diffusion
  • Pi and H+ move together
53
Q

Advantages of linking ATP transport to ADP transport across the inner membrane of the mitochondrion

A

1 correct supply / amount of, ADP

2 (so) ATP can continue to be made / so enough ATP can be made