Mr G bio 2 respiration

Question 1

where does respiration take place?

Answer 1

mitochondria

Question 2

what are the 4 main stages of respiration?

Answer 2

glycolysis, link reaction, Kerb’s cycle, electron transport chain

Question 3

what is the process of glycolysis?

Answer 3

1. glucose is phosphorylated using a phosphate from a molecule of ATP
   2.phosphorylated glucose is split into two triose phosphates
2. triose phosphates are oxidised to 2 molecules of pyruvate and the hydrogen ions lost reduce NAD to 2 reduced NADs
3. 4 ATP are also produced but 2 used in phosphorylation so net gain of 2

Question 4

where does glycolysis occur?

Answer 4

cytoplasm

Question 5

what are the two methods in which ATP can be generated?

Answer 5

substrate phosphorylation and oxidative phosphorylation

Question 6

what is substrate phosphorylation?

Answer 6

ATP generated directly through respiration

Question 7

what is oxidative phosphorylation?

Answer 7

ATP generated from the chemical energy released when a hydrogen carrier or coenzyme has been reduced

Question 8

what are the products if glycolysis?

Answer 8

-2 ATP
-2 reduced NAD
-2 molecules of pyruvate

Question 9

what has to happen for the link reaction to occur?

Answer 9

Pyruvate needs to enter the mitochondrial matrix. it moves across the double membrane of the mitochondria via active transport to get into the matrix. requires a transport protein and a small amount of ATP

Question 10

what 2 products (during anaerobic respiration) is pyruvate converted into and through what processes?

Answer 10

-ethanol through alcoholic fermentation in yeast and plants
-lactate through lactate fermentation in animals and some bacteria
-both use reduced NAD

Question 11

what does the production of lactate or ethanol regenerate and why?

Answer 11

regenerated NAD so glycolysis can still continue even when not much O2 available so small amount of ATP can still be produced to keep some biological processes going

Question 12

what is released during alcoholic fermentation (pyruvate-> ethanol)?

Answer 12

CO2

Question 13

where does the link reaction take place?

Answer 13

the matrix of the mitochondria

Question 14

what is the process of the link reaction?

Answer 14

1.pyruvate is decarboxylated so one carbon atom is removed from pyruvate in the form of carbon dioxide
2.at the same time pyruvate is oxidised to form acetate and NAD is reduced to reduced NAD
3.Acetate and coenzyme A combine to form acetyl coenzyme A
4. no ATP produced during this reaction

Question 15

how many times does the link reaction and krebs cycle occur per glucose molecule and why?

Answer 15

happen twice because each glucose molecule produces two pyruvate molecules

Question 16

what is the link reaction yield?

Answer 16

-the reduced NAD will be used to produce ATP by oxidative phosphorylation
-2 molecules of coA produced
-CO2 is also released

Question 17

where does the kreb’s cycle occur?

Answer 17

mitochondrial matrix

Question 18

what is the process of the Kreb’s cycle?

Answer 18

1.acetyl coA (2c) from link reaction combines with a 4c compound (oxaloacetate) to form a 6c (citrate) compound + coA back to link reaction
2.6c molecule is converted into a 5c molecule and decarboxylation occurs, where CO2 is removed and oxidation also occurs where hydrogen is removed to produce reduced NAD
3.5c molecule is converted into 4c molecule and decarboxylation and oxidation occur providing one reduced FAD, 2 reduced NAD and CO2

Question 19

what are the products of the Kerb’s cycle?

Answer 19

-CO2 produced
-some ATP produced directly (substrate phosphorylation)
-Reduced Nad and FAD produced to be used in oxidative phosphorylation

Question 20

what is the process of oxidative phosphorylation?

Answer 20

-hydrogen atoms are released from reduced NAD and FAD as they are oxidised to NAD and FAD and the hydrogen atoms split into protons and electrons
-the electrons move down the electron transport chain through a series of redox reactions, losing energy at each stage
-the energy is used by electron carriers to pump protons from the mitochondrial matrix into the intermembrane space (between inner and outer membranes)
-the conc of protons is now higher in the intermembrane space than in the matrix- electrochemical gradient formed
-H+ ions diffuse via chemiosmosis through ATP synthase driving the production of ATP from ADP and Pi
- in the matrix, at the end of the transport chain, the protons, electrons and oxygen (from the blood) combine to form water; oxygen is said to be the final electron acceptor

Question 21

what are the effects of mitochondrial diseases?

Answer 21

-decreases ATP production
-may cause rate of anaerobic respiration to increase to make up for the shortage in ATP production
-> more anaerobic respiration= lots of lactate produced causing muscle fatigue + weakness and some may diffuse into the bloodstream

Question 22

what is the equipment used to measure rate of respiration?

Answer 22

respirometers can be used to indicate the rate of aerobic respiration by measuring the volume of O2 consumed by an organism over a period of time and can be used for small animals (like woodlice) +seeds/ plants

Question 23

common markpoints for respirometer investigation? why does the coloured liquid move towards the test tube containing the respiring organism?

Answer 23

coloured liquid moves towards the test tube containing the respiring organism as O2 is taken up by the plant/ animal/ seeds and CO2 is absorbed by the solution and a decrease and pressure and increase in volume causes the coloured liquid to move towards the test

Question 24

give the similarities in the structure of a mitochondrion and a chloroplast

Answer 24

-two membranes
-smooth outer membrane
-DNA
-ribosomes
-electron carriers
-internal membranes

Question 25

Describe how ATP is produced during aerobic respiration (6 marks)

Answer 25

1 ATP produced in glycolysis;
2 Involving the oxidation of glucose/TP to pyruvate;
3 ATP production directly from Krebs cycle;
4 Glycolysis/Krebs cycle produce reduced NAD/FAD/co-enzyme (in context);
5 Reduced NAD/FAD transfer electrons/H to chain of electron carrier
molecules/electron transport chain;
6 Electrons transferred down a chain of carriers;
7 (Carriers) at decreasing energy levels;
8 Energy (lost by electrons) used to produce ATP;
9 From ADP and (inorganic) phosphate; 6 max

Question 26

there are different ways in which ATP is made in glycolysis and in the electron transport chain. Name one of these differences

Answer 26

substrate level phosphorylation in glycolysis vs oxidative phosphorylation in the ETC

Question 27

what are the products of the kreb’s cycle?

Answer 27

6 NADH
2 FADH2
4 CO2
2 ATP

Question 28

what is the process by which ATP is produced during the Krebs cycle?

Answer 28

substrate level phosphorylation

Question 29

plant produce ATP in their chloroplasts during photosynthesis. they also produce ATP during respiration. Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis

Answer 29

1. in the dark no ATP production in photos