Biology - Unit 4 - Respiration

Front 1

What are the 4 stages of Aerobic Respiration?

Back 1

Glycolysis

Link Reaction

The Krebs Cycle

Oxidative Phosphorylation

Front 2

In plants what does anaerobic respiration produce?

Back 2

Lactate, NAD and CO2

Front 3

In Anaerobic respiration what processes occur?

Back 3

Glycolysis

Front 4

How many ATP molecules are made during Aerobic respiration?

Back 4

38

Front 5

How many ATP molecules are made during Anaerobic respiration?

Back 5

2

Front 6

Where does glycolysis occur?

Back 6

In the cytoplasm

Front 7

(Simple) What happens during the reaction of glycolysis.

Back 7

One molecule of glucose is split into two molecules of pyruvate.

Front 8

How many carbons does glucose contain?

Back 8

6 carbons

Front 9

How many carbons does pyruvate contain?

Back 9

3

Front 10

What happens in the Glycolysis reaction? (long)

Back 10

1 - Glucose is activated by phosphorylation to make phosphorylated glucose. During this x2 ATP molecules are used and converted back into ADP and Pi.

2 - The phosphorylated glucose is then split into two molecules of triose phosphate.

3 - Triose phosphate is then oxidised into pyruvate. During this NAD is reduced into reduced NAD as two hydrogen's are released.

4 - x4 molecules of ATP are also released during this reaction.

OVERALL: this reaction produces x2 ATP molecules.

Front 11

What is glycolysis an example of?

Back 11

Substrate level phosphorylation.

Front 12

What is the net gain of ATP molecules during glycolysis?

Back 12

2 ATP molecules

Front 13

What is the second stage of respiration?

Back 13

The link reaction

Front 14

Where does the link reaction occur?

Back 14

The matrix of the mitochondria.

Front 15

What happens in the link reaction? (simple)

Back 15

Both pyruvate molecules to Acetyl coenzyme A.

Front 16

How many times does this reaction occur for one molecule of glucose?

Back 16

twice for one molecule of glucose.

Front 17

How many molecules of ATP does this reaction produce?

Back 17

0

Front 18

What happens during the Link reaction? (long)

Back 18

1 - One molecule of pyruvate is decarboxylated - on carbon molecule is removed as CO2.

2 - NAD is reduced as it collects a hydrogen from pyruvate changing it into acetate.

3 - Acetate is combined with coenzyme A to form Acetyl coenzyme A.

Front 19

In total how many NADH molecules (red NAD) are made during the link reaction?

Back 19

2 molecules of red NAD

Front 20

How many CO2 molecules are produced overall in the link reaction?

Back 20

2 CO2 molecules are expelled.

Front 21

How many carbons does acetyl coenzyme A contain?

Back 21

2 carbons

Front 22

What is the third stage to respiration?

Back 22

The Krebs Cycle

Front 23

Where does the Krebs Cycle take place?

Back 23

The matrix of the mitochondria.

Front 24

How many times does the Krebs cycle reaction occur for every pyruvate molecule?

Back 24

Once

Front 25

How many times does the Krebs cycle reaction occur for every glucose molecule?

Back 25

Twice

Front 26

How many molecules of ATP are produced during one cycle of the Krebs cycle?

Back 26

One molecule.

Front 27

What happens during the Krebs Cycle? (long)

Back 27

1 - Acetyl coenzyme A enters the Krebs cycle and combines with a 4 carbon molecule already present in the matrix. (oxaloacetic acid)

2 - This now 6 Carbon molecule travels through the cycle and CO2 is expelled NAD is oxidised into NADH.

3- One molecule of ATP is expelled. FAD is oxidised into FADH.

4 - This occurs once for every acetyl coenzyme A molecule.

Front 28

Overall in one reaction of the Krebs cycle what are the products?

Back 28

red NAD, red FAD, 2CO2, 2 ATP molecules

Front 29

What is the final stage of respiration?

Back 29

Oxidative phosphorylation

Front 30

What is oxidative phosphorylation an example of?

Back 30

Substrate level phosphorylation.

Front 31

Where does oxidative phosphorylation occur?

Back 31

Cristae

Front 32

What is oxidative phosphorylation mainly known for?

Back 32

The process which makes the most ATP.

Front 33

What happens during oxidative phosphorylation? (simple)

Back 33

Where energy carried by electrons for reduced coenzymes (FAD and NAD) is used to make ATP.

Front 34

What is the main point of the three stages which occur before oxidative phosphorylation?

Back 34

To make red FAD and red NAD for the final stage.

Front 35

What happens in Oxidative phosphorylation? (long)

Back 35

1 - Hydrogen atoms are released, as red FAD and red NAD are oxidised into FAD and NAD. The hydrogen's are split into protons and electrons. (H+ and e-).

2 - Electrons move along the electron transport chain, (x3 electron carriers), loosing energy at each carrier. Located in the inner mitochondrial membrane.

3 - The energy created by electrons, is used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space.

4 - The conc of protons is now higher in the intermembrane space than the mitochondrial matrix. This forms a proton/ electrochemical gradient.

5 - Protons move down the gradient, back into the mitochondrial matrix, via ATPase. This movement drives the synthesis of ADP and inorganic phosphate into ATP.

6 - Oxygen is said to be the final electron acceptor, at the end of the transport chain protons, electrons and O2 (from the blood) combine to form water.

Front 36

Where are the protons pumped during oxidative phosphorylation?

Back 36

Protons are pumped from the mitochondrial matrix (once separated from the electrons) into the intermembrane space making a gradient. The protons then move down the gradient back into the mitochondrial matrix via ATPase. This drives the synthesis of ATP.

Front 37

In oxidative phosphorylation where do the electrons come from?

Back 37

From red FAD and red NAD.

Front 38

What enzyme pumps the protons from the inner membrane space back into the mitochondrial matrix?

Back 38

ATPase

Front 39

Where is the electron transport chain found?

Back 39

In the mitochondrial membrane.

Front 40

What is the full respiration equation?

Back 40

C6H12O6 + 6CO2 = 6CO2 + 6H2O + 38ATP

Front 41

What is the main product of anaerobic respiration in animals?

Back 41

Lactate.

Front 42

What is the main product of anaerobic respiration in plants?

Back 42

Ethanol.

Front 43

Write out the equation to show how lactate is produced during a 100m sprint race.

Back 43

Pyruvate + red NAD = lactate + NAD

Front 44

What is the advantage of producing lactate in anaerobic respiration?

Back 44

Lactate is produced to regenerate NAD so glycolysis can continue and ATP can be produced during anaerobic conditions, to provide energy for biological processes.

Front 45

Carbon monoxide inhibits the final electron carrier in the electron transport chain. Explain how this affects the ATP production via the electron transport chain.

Back 45

The transfer of electrons down the electron transport chain stops , so no energy is released to phosphorylate ADP and Pi into ATP.

Front 46

Carbon monoxide inhibits the final electron carrier in the electron transport chain. Explain how this affects the ATP production via the Krebs cycle.

Back 46

The Krebs Cycle stops as there is no oxidised NAD/FAD coming from the electron transport chain.

Front 47

DNP inhibits respiration by preventing a proton gradient being maintained across

membranes. When DNP was added to isolated mitochondria the following changes were

observed

• less ATP was produced

• more heat was produced

• the uptake of oxygen remained constant.

Explain how DNP caused these changes.

Back 47

1. Less/no proton/H+ movement so less/no ATP produced;

2. Heat released from electron transport/redox reactions/energy not

used to produce ATP is released as heat;

3. Oxygen used as final electron acceptor/combines with

electrons (and protons);

Front 48

Human skeletal muscle can respire both aerobically and anaerobically. Describe what

happens to pyruvate in anaerobic conditions and explain why anaerobic respiration is

advantageous to human skeletal muscle.

Back 48

Forms lactate;

Use of reduced NAD / NADH;

Regenerates NAD;

Front 49

Apart from respiration, give three uses of ATP in a liver cell.

Back 49

Source of energy/of phosphate;

Active transport;

Phagocytosis / endo- /exocytosis / pinocytosis;

Bile production;

Cell division / mitosis;

Synthesis of: glycogen;

protein / enzymes;

DNA / RNA;

lipid /

Front 50

Name two substances for which there would be net movement into the mitochondrion.

Back 50

pyruvate;

ADP;

P / inorganic phosphate;

reduced NAD;

oxygen;

Front 51

The mitochondria in muscles contain many cristae. Explain the advantage of this.

Back 51

larger surface area for electron carrier system / oxidative

phosphorylation; provide ATP / energy for contraction;

Front 52

Give two ways in which anaerobic respiration of glucose in yeast is

similar to anaerobic respiration of glucose in a muscle cell;

Back 52

ATP formed/used;

pyruvate formed/reduced;

NAD/reduced NAD;

glycolysis involved/two stage process;

Front 53

Give two ways in which anaerobic respiration of glucose in yeast is

different from anaerobic respiration of glucose in a muscle cell.

Back 53

ethanol/alcohol formed by yeast, lactate (allow lactic acid)

by muscle cell; CO2 released by yeast but not by muscle cell;

Front 54

Other substances are produced in the Krebs cycle in addition to the carbon compounds

shown in the diagram. Name three of these other products.

Back 54

reduced NAD/NADH/NADH

2

reduced FAD/FADH/FADH2;

ATP;

Front 55

An investigation was carried out into the production of ATP by mitochondria. ADP,

phosphate, excess substrate and oxygen were added to a suspension of isolated

mitochondria.

(i) Suggest the substrate used for this investigation.

Back 55

pyruvate

Front 56

Describe the part played by the inner membrane of a mitochondrion in producing ATP.

Back 56

Electrons transferred down electron transport chain;

Provide energy to take protons/H+ into space between membranes;

Protons/H+ pass back, through membrane/into matrix/through

ATPase;

Energy used to combine ADP and phosphate/to produce ATP;

Front 57

Describe how NAD is regenerated in anaerobic respiration in yeast cells.

Back 57

Formed when reduced NAD used to reduce / donate H ions

to pyruvate

Front 58

In the presence of oxygen, respiration yields more ATP per molecule of glucose than

it does in the absence of oxygen. Explain why.

Back 58

Oxygen as terminal hydrogen/electron acceptor;

Operation of electron transport chain/ oxidative phosphorylation;

Fate of pyruvate;

Krebs cycle;

Significance of ATP formed in glycolysis;

Front 59

In China, the fern is cultivated and ploughed into fields to act as an organic fertiliser.

Explain how ploughing the fern plants into the soil results in an improvement in the

growth of the rice crop grown in these fields.

Back 59

Convert protein/organic nitrogen (in cells of fern) into

ammonium ions (allow ammonia);

Ammonium ions (ammonia) converted to nitrite;

Nitrite converted to nitrate;

Allow 1 mark for NH

3

/NH NO3

By nitrifying bacteria / correctly named;

Nitrate used to form protein / amino acids in rice;

Link between application of fern and protein/cells of rice;

Decomposers respire (suitable substrate) and release CO2;

Used in photosynthesis by rice;

Front 60

The biochemical pathway of aerobic respiration involves a number of different steps.

Name one step in which carbon dioxide is produced.

Back 60

Krebs cycle/link reaction/pyruvate to acetylcoenzyme A;

Front 61

In an investigation, scientists transferred slices of apple from air to anaerobic conditions in pure

nitrogen gas. They measured the rate of carbon dioxide production.

The scientists kept the temperature constant throughout the investigation. Explain how a

decrease in temperature would affect the rate of carbon dioxide production.

Back 61

Respiratory reactions controlled by) enzymes;

Rate decreases as less kinetic energy/fewer collisions (between substrate and active site) fewer E-S complexes formed;

Front 62

The carbon dioxide concentration was monitored at ground level in the centre of a small

roundabout. The measurements were made on a summer day. Describe and explain how

you would expect the concentration of carbon dioxide to fluctuate over the period of 24

hours.

Back 62

1 Higher carbon dioxide concentration at night/during darkness;

2 Photosynthesis only takes place during light;

3 Photosynthesis removes carbon dioxide and respiration adds

carbon dioxide;

4 Respiration taking place throughout 24 hours;

5 Quantitative consideration such as that in plants overall

photosynthetic rate greater than respiration rate;

6 Human effect such as additional carbon dioxide from heavy

daytime traffic/street lighting could prolong photosynthesis;

Front 63

Mitochondria in muscle cells have more cristae than mitochondria in skin cells.

Explain the advantage of mitochondria in muscle cells having more cristae.

Back 63

more cristae / larger surface area) for electron transport chain /

more enzymes for ATP production/oxidative phosphorylation;

muscle cells use more ATP

Front 64

The Krebs cycle, which takes place in the matrix, releases hydrogen ions. These hydrogen

ions provide a source of energy for the synthesis of ATP, using coenzymes and carrier

proteins in the inner membrane of the mitochondrion.

Describe the roles of the coenzymes and carrier proteins in the synthesis of ATP.

Back 64

NAD/FAD reduced / hydrogen attached to NAD/FAD;

H+ ions/electrons transferred from coenzyme to coenzyme/

carrier to carrier / series of redox reactions;

energy made available as electrons passed on;

energy used to synthesise ATP from ADP and phosphate /

using ATPase;

H+ / protons passed into intermembrane space;

H+ / protons flow back through stalked particles/enzyme;