12) Energy & Respiration Flashcards
1
Q
name 2 anabolic reactions
A
- protein synthesis
- DNA replication
2
Q
name 2 catabolic reactions
A
- digestion of food
- glycolysis
3
Q
what are anabolic & catabolic reactions?
A
anabolic - build bigger molecules from smaller ones.
catabolic - breakdown of large organic molecules into smaller molecules.
4
Q
what 3 structures does a nucleotide consist of?
A
- pentose sugar
- phosphate
- base
5
Q
a) How is energy released from ATP? &
b)what is produced?
A
a) removing of a phosphate
b) ADP + Pi (a phosphate)
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
7
Q
what is the formula for respiratory quotient (RQ) ?
A
volume of carbon dioxide produced / the volume of oxygen consumed
(calculated as ratio)
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
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)
10
Q
RQ value of carbohydrate
A
1.0
11
Q
RQ value of proteins
A
0.9
12
Q
RQ value of lipids
A
0.7
13
Q
what are the 4 stages in aerobic respiration
A
- glycolysis
- link reaction
- krebs cycle
- oxidative phosphorylation
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
15
Q
what happens in oxidation
A
- adding O
- removing H
- loss of electrons
- releases energy
16
Q
what happens in reduction
A
- removing O
- adding H
- gain of electrons
- stores energy
17
Q
outline the stages of glyoclysis
A
- Glucose is phosphorylated 2x by adding phosphates from 2 ATPs.
- LYSIS causes hexose biphosphate to be split into two triose phosphate.
- Triose phosphates oxidised by donating hydrogen to NAD+.
- 4 ATP total produced.
Net gain = 2 ATPs
18
Q
what are the final products of glycolysis
A
- 2 ATP
- 2 NADH
- 2 Pyruvate
19
Q
what are the final products of Link reaction
A
- 0 ATP
- 2 NADH
- 2 Acetyl CoA
20
Q
what are the final products of Krebs cycle
A
- 2 ATP
- 6 NADH
- 2 FADH
- 4 CO2
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
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
what is the function of external double membrane of a mitochondria
- permeable to pyruvate, CO2, O2, NAD & reduced NAD
26
what is the function of matrix
site of enzymes of link reaction & krebs cycle
- (enzymes have to bump into substrates so need fluid)
27
what is the function of inner membrane
- 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
what is the function of inter-membrane space
relatively tiny space - allowing accumulation of hydrogen ions (protons) to generate high potential difference with matrix
(making phosphorylation possible)
29
what is the big advantage of aerobic respiration?
way more ATPs produced (36 ATP)
30
what is the only stage that can occur in the absence of oxygen?
glycolysis
31
3 reasons why ATP will not be made from etc without oxygen
- 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
If oxygen is not present, why can't NADH and FADH off load their hydrogens?
proton concentration is too high in the matrix because there is no oxygen to mop up the hydrogen
33
In the absence of oxygen, why does the Kreb's cycle and link reaction stop too?
As NAD is not formed to go back and pick up more hydrogens
34
list the steps which occur during anaerobic respiration in plants and fungi
- 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
2 reasons why rice plants can cope with high levels of ethanol
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
What colour is methylene blue when it is oxidised & reduced?
oxidised = blue
reduced = colourless
37
what is the function of aerenchyma
oxygen supply to underwater roots for aerobic respiration
38
why glucose is phosphorylated at the beginning of glycolysis
- made reactive
- energy level increased
- becomes unstable
39
use of the reduced NAD that is produced in glycolysis
- hydrogen acceptor
- used for redox reactions
- used to reduce pyruvate
40
the type of phosphorylation reaction by which ATP is made during glycolysis
substrate-linked phosphorylation
41
main conditions that are required for pyruvate to enter the mitochondrion by
active transport
- inner mitochondrial membrane impermeable to pyruvate
- carrier protein
- oxygen available
- ATP
- against concentration gradient
42
how ATP is produced from ADP in the Krebs cycle
- substrate-linked phosphorylation
- transfer of phosphate group to ADP
43
how do ethanol fermentation and lactate fermentation allow cells to continue to function in the absence of oxygen
- produces NAD
- glycolysis
- ATP produced
- substrate-linked phosphorylation
44
explain how rice plants are adapted to grow in flooded fields
- aerenchyma provides oxygen for aerobic respiration
- high concentration of ethanol dehydrogenase
- fast growth so leaves out of water
45
State the precise locations of substrate-linked phosphorylation reactions in aerobic respiration
cytoplasm AND mitochondrial matrix
46
why the link reaction only occurs when oxygen is available
- 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
explain the role of the coenzymes NAD and FAD in aerobic respiration
- 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
explain why the inner membrane of a mitochondrion remains intact when
the organelle is placed in pure water
- cristae let inner membrane expand
- when water enters by osmosis down wpd
49
Name three molecules, other than coenzymes, that are found in the mitochondrial matrix
and explain their role in aerobic respiration
- pyruvate : for link reaction
- citrate : to make reduced NAD
- water : solvent
50
Suggest why the inner membrane contains a very high proportion of cardiolipin
so H+
, cannot move through / must move through ATP synthase
51
Explain how hydrogen atoms from reduced NAD and reduced FAD lead to a
membrane potential forming across the inner mitochondrial membrane during
oxidative phosphorylation
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
how Pi is transported across the inner membrane of the mitochondrion into the matrix
- facilitated diffusion
- Pi and H+ move together
53
Advantages of linking ATP transport to ADP transport across the inner membrane of the mitochondrion
1 correct supply / amount of, ADP
2 (so) ATP can continue to be made / so enough ATP can be made
