Respiration

Question 1

the

Question 2

needs for cellular respiration

Answer 2

to transport substances across membranes
active transport
metabolic pathways

Question 3

structure of mitochondria

Answer 3

outer mitochondrial membrane - separates contents of mitochondria from the rest of the cell
inner mitochondrial membrane - contains electron transport chains and ATP synthase
cristae - increase sa for oxidative phosphorylation
inter membrane space - proteins pumped into this space by electron transport chain
matrix - enzymes for the Krebs cycle and link reaction

Question 4

what are the stages of aerobic respiration

Answer 4

1. glycolysis
   2/ link reaction
2. krebs cycle
3. oxidative phosphorylation

Question 5

reaction for aerobic respiration

Answer 5

glucose + oxygen —–> carbon dioxide + water

Question 6

what is the process of glycolysis

Answer 6

glucose is converted into pyruvate in the cytoplasm

Question 7

explain the process of glycolysis

Answer 7

• 2 ADP and 2 Phosphates combine and form 2 ATP and glucose which combine forming hexose bisphosphate (phosphorylation)
• Hexose bisphosphate splits into 2 triose phosphate (2 TP)
• to each TP molecule a phosephate group is added forming 2 triose bisphosphate (phosphorylation)
• 2 triose bisphosphate is oxidised which forms 2 pyruvate molecules

when the triose bisphosphate is oxidised a hydrogen ion is removed which the NAD coenzyme accepts, it becomes reduced NAD
ADP is phosphorylated into ATP

Question 8

where does the link reaction occur and what is it

Answer 8

it is when pyruvate becomes acetyl coenzyme A and occurs in the mitochondria (mitochondrial matrix)

Question 9

explain the link reaction

Answer 9

• pyruvate enters the mitochondrial matrix, oxidative decarboxylation takes place and it loses carbon dioxide and hydrogen and forms acetate
• hydrogen is accepted by NAD and it becomes reduced NAD
• 2 CARBON ACETYL groups combine with coenzyme A producing acetyl coenzyme A
• ACETYL COA delivers acetyl group to the Krebs cycle

Question 10

what is the krebs cycle and what occurs

Answer 10

mitochondrial matrix
acetyl coA into oxaloacetate

Question 11

explain the krebs cycle

Answer 11

• acetyl coA is delivered from the link reaction which delivers the acetyl group and combines with oxaloacetate forming citrate
• citrate undergoes decarboxylation and dehydrogenate producing co2 and reduced NAD
• citrate is converted into a 5 carbon molecule which undegoes further decarboxylation and dehydrogenation which regenerates oxaloacetate

Question 12

what does FAD do

Answer 12

it accepts hydrogens in the krebs cycle

Question 13

differences for nad and fad

Answer 13

NAD takes part in all stages FAD is only in krebs cycle
NAD accepts 1 hydrogen FAD accepts 2
reduced NAD is oxidised at the start of the electron transport chain which releases protons and electrons whilst reduced fad is further oxidised further along the chain
reduced NAD results in synthesis of 3 ATP but reduced fad results in 2 atp

Question 14

where are coenzyme derived from

Answer 14

vitamins

Question 15

what is oxidative phosphorylation

Answer 15

where atp is made
takes place in the cristae of the mitochondria

Question 16

process of oxidative phosphorylation

Answer 16

1. NAD and FAD are attached to cristae. These accept electrons in glycolysi, link and krebs cycle to become NADH/FADH
2. H atom from NADH/FADH splits into e- and H+. e- enters ETC, H+ stays in the matrix
3. e- pass down carriers in ETC in a series of oxidation, reduction reactions
4. As e- pass down carriers they lose energy, this is used to transport H+ ions across membranes into intermembrane space via active transport.
5. This creates a conc gradient and H+ passes through ATP synthase (protein channel) by facilitated diffusion which makes ADP+Pi > ATP
6. e- rejoins with H+ to make H atoms, H atoms combine with CO2 to make water.

O2 is therefore known as the terminal electron acceptor

Question 17

What causes a change of shape in the protein ATP synthase

Answer 17

The flow of H+ (protons] causes a change of shape in the protein ATP synthase and leads to ATP synthesis.

Question 18

what is chemiosmosis

Answer 18

it is when Hydrogen ions flow down a concentration gradient from intermembrane spaces to the matrix through atp synthase which provides energy to join ADP to Pi forming ATP

Question 19

WHAT IS SUBSTRTAE Phosphorylation

Answer 19

it is the production of ATP involving the transfer of a phosphate group from a short lived highly reactive intermediate e.g. creatine phosphate

Question 20

how much atp is produced from aerobic respiration

Answer 20

38 ATP molecules per glucose respired

Question 21

anaerobic respiration

Answer 21

occurs in the absence of oxygen

Question 22

obligate anaerobes

Answer 22

cannot survive in the presence of oxygen

Question 23

facultative anaerobes

Answer 23

synthesize atp by aerobic respiration if oxygen is present but can switch to anaerobic in the absence of oxygen

Question 24

obligate aerobes

Answer 24

can only synthesize atp in the presence of oxygen

Question 25

lactate fermentation

Answer 25

reduced NAD transfers hydrogen to pyruvate to form lactate ( pyruvate is reduced top lactate by enzyme lactate dehydrogenase) this regenerates more oxidized NAD for glycolysis

Question 26

alcoholic fermentation

Answer 26

pyruvate is converted into ethanal catalysed by pyruvate decarboxylase. ethanal accepts a hydrogen from reduced nad becoming ethanol. regenerated NAD continues to act as a coenzyme soo glycolysis can occur

Question 27

what is respiratory quotient

Answer 27

co2 produced divided by o2 consumed

Question 28

carbohydrates, proteins and lipids