respiration

Question 1

Respiration equation

Answer 1

C6H12O6 + O2 –> CO2 +H2O

Question 2

Main features of mitochondria

Answer 2

• outer membrane
• inner membrane
• intermembrane space
• crista
• matrix

Question 3

the advantages of many cristae

Answer 3

• larger surface area
• provides more ATP

Question 4

4 stages of aerobic respiration

Answer 4

• glycolysis
• link reaction
• krebs cycle
• Electron transport chain

Question 5

2 ways ATP can be generated

Answer 5

• Substrate level phosphorylation
  -oxidative phosphorylation

Question 6

substrate level phosphorylation

Answer 6

ATP generated directly through respiration
occurs in glycolysis and Krebs cycle

Question 7

oxidative phosphorylation

Answer 7

ATP generated from the chemical energy released when a reduced hydrogen carrier or coenzyme (NADH2 or FADH2) has been oxidised at the ETC.

Question 8

Glycolysis process

Answer 8

• occurs in the cytoplasm
• glucose is phosphorylated via the hydrolysis of 2 ATP into 2xADP into phosphorylated. glucose
  -Glucose phosphate is then split into 2x TP due to its instability
  -Triose phosphate is then oxidised into pyruvate via the loss of a H+ via dehydrogenase enzyme
  -this reduces NAD to NADH2
  -produces ATP directly via substrate level phosphorylation

Question 9

Link reaction process

Answer 9

• Pyruvate is actively transported into the matrix
• pyruvate to acetyl coenzyme A
• pyruvate is oxidised to acetate and the H+ ions are used to form NADH2
• a molecule of CO2 is lost via decarboxylation
• Coenzyme A fixes with acetate to form acetyl coenzyme A to transport the acetate to the Krebs cycle

Question 10

krebs cycle

Answer 10

• series of enzyme controlled REDOX reactions that take place in the matrix of the mitochondria
  -Acetyl CoA binds with 4C compound to form a 6C compound
  -6C compound loses a C via CO2 and reduction of NAD
  -5C compound is reduced to 4C compound via; the loss of CO2, synthesis of ATP, reduction of FAD, reduction of 2x NAD

Question 11

Kreb Cycle Yields

Answer 11

-2x CO2 produced
-ATP produced directly by substrate level phosphorylation
-3x NADH
-1x FAD

1 glucose produces 2 acetyl CoA so krebs cycle occurs twice

Question 12

how oxidation takes place in glycolysis and krebs cycle

Answer 12

-dehydrogenation
-by enzymes
-NADH formed
-In Krebs cycle FAD formed

Question 13

Electron transport chain

Answer 13

• known as the chemiosmotic theory of oxidative phosphorylation
  -NADH and FADH are oxidised so lose hydrogen
  -electrons pass down a series of electron carries within the mitochondrial membranes in a. series of redox reactions
  -electrons lose energy, some of it used to pump the H through the intermembrane space
  -some energy lost as heat
• H+ diffuse down a proton gradient into the matrix via ATP synthase enzymes
  -enough energy is formed to produce ATP
  -electrons and H+ recombine with oxygen gas to form water
  -oxygen is the terminal electron acceptor
  -without the removal of he H and electrons via oxygen there would be a backup of electrons along the ETC
  -cellular respiration would come to a halt

Question 14

Water is a waste product of aerobic respiration. Describe how water is formed at the end of aerobic respiration.

Answer 14

• oxygen is terminal
• combines with electrons and protons to form water

Question 15

Describe how ATP is made in mitochondria (6)

Answer 15

-substrate level phosphorylation
-krebs cycle produces NADH
-electrons released from NADH
-electrons pass along carries through a series of redox reactions
-energy released
-protons pumped into intermembrane space
ADP +Pi —>ATP via ATP synthase

Question 16

Describe the roles of co-enzyme and carrier proteins in the synthesis of ATP (6m)

Answer 16

-NADH electrons transferred from co-enzyme to co-enzyme
-energy released as electrons passed on
-energy used to synthesise ATP from ADP +Pi via ATP synthase
-H+ pumped into intermembrane space
-H+ diffuse back through ATP synthase enzyme

Question 17

describe the events of oxidative phosphorylation

Answer 17

-NADH
-ETC on cristae
-H+ ions transferred from co-enzyme to co-enzyme
-releases energy as electrons passed on
-H+ pumped into the intermembrane space
-H+ flow back through enzyme
-energy used to synthesize ATP from ADP and Pi

Question 18

Anaerobic respiration

Answer 18

-absence of oxygen
-link reaction, krebs cycle and electron transport chain stop as there is no oxygen to act as the terminal electron transporter
-glycolysis does not require oxygen and can continue in the absence of oxygen but NAD must be regenerated
-H from NADH is now accepted by pyruvate rather than passing through the ETC
-pyruvate is reduced to lactate in animals and ethanol in plants

Question 19

explain how the amount of ATP is increased by reaction occurring inside a mitochondria

Answer 19

-oxidation of pyruvate
-substrate level production of ATP in krebs cycle
-production of NADH in the matrix of mitochondria
-electrons fed into ETC via phosphorylation on cristae linked to ATP production via ATP synthase
-electrons lose energy as passed along chain
-arranged in order of decreasing energy levels

Question 20

Respirometers

Answer 20

-oxygen is used for aerobic respiration
-reduces the amount of oxygen therefore reducing the pressures
-solution of potassium hydroxide absorbs the CO2 released by the animal/plant
-ink solution moves from a high to low pressure along the graduated scale
-measure time taken

Question 21

measure the rate of respiration

Answer 21

-measure the distance the ink/bubble moved
-over a fixed time
-volume of tube