Respiration

Question 1

what are the two forms of energy released in respiration

Answer 1

Chemical energy in the form of ATP and heat energy

Question 2

the four steps involved in aerobic respiration

Answer 2

glycolysis, link reaction, Krebs cycle, Electron transport chain and chemiosmosis

Question 3

the two steps involved in anaerobic respiration

Answer 3

glycolysis
fermentation

Question 4

products of glycolysis per glucose

Answer 4

2 reduced NAD molecules (NADH)
net gains of 2 ATP molecules
2 pyruvate molecules

Question 5

in which type of respiration does glycolysis occur

Answer 5

it is the first stage of both aerobic and anaerobic respiration

Question 6

where does glycolysis occur in the cell

Answer 6

the cytoplasm

Question 7

the enzymes involved in respiration are found where

Answer 7

in the cytoplasm

Question 8

outline the processes involved in glycolysis

Answer 8

glucose is phosphorylated to glucose 1,6-bisphosphate (GP)

the GP is split into 2 triose phosphate molecules (TP)

2 phosphate ions from the cytoplasm are added onto the 2 TP to form 2 triose bisphosphate molecules (TP)

the resulting molecules are then oxidized into 2 pyruvate molecules by the removal of hydrogen ions by the coenzyme NAD.

the formation of pyruvate is also aided by the removal of two phosphate molecules from each TP, to synthesize 4 ATP molecules

Question 9

why is glucose phosphorylated during the first stage of glycolysis

Answer 9

to make the glucose (a hexose sugar) more reactive, so less activation energy will be required for the enzyme-controlled reactions.

and to prevent the glucose molecule from diffusing out of the cell, as the phosphorylated glucose is polar, thereby making it more difficult to diffuse out of the cell

Question 10

name the co-enzyme involved in glycolysis and it’s functions

Answer 10

NAD
to take 2 hydrogen ions from each TP molecule to form reduced NAD (NADH), thereby oxidizing the TP

Question 11

2 paths that pyruvate takes after glycolysis

Answer 11

the aerobic respiration path
the anaerobic respiration path

Question 12

Function of the inter membrane space in respiration

Answer 12

Protons are pumped are pumped into the inter membrane space using the energy released by electron transport

Question 13

Function of the Matrix in respiration

Answer 13

Contains enzymes of the link reaction and krebs cycle

Question 14

Cristae function in respiration

Answer 14

Folding of the cristae provides a large internal surface area
Membrane of the crustose contains the electron transport chain and ATP synthase

Question 15

How many types of functions does the proteins in the inner membrane have, and state these functions

Answer 15

3 types of functions

Proteins that carry out the oxidation reactions of the respiratory chain (electron carriers)

ATP synthase , which uses the H+ to make ATP

Specific transport proteins that regulate the passage of metabolites into and out of the matrix

Question 16

Is the inner membrane of permeable ? Give a reason for your response

Answer 16

No it is highly impermeable , because it does not contain porins

Question 17

Location for the link reaction

Answer 17

Mitochondrial matrix

Question 18

State the processes involved in the link reaction

Answer 18

1. Dehydrogenation of pyruvate by a dehydrogenase enzyme
2. Released hydrogen accepted by NAD to form NADH
3. Decarboxylation of pyruvate by decarboxylase enzyme
4. Formation of acetate (a 2-carbon molecule )
5. Coenzyme A reacting with Acetate to form Acetyl Coenzyme A (Acetyl Coa)

Question 19

Why does Coa combine with acetate in the link reaction

Answer 19

To temporarily stabilise the acetate (acetic acid )

Question 20

Products Of the link reaction using one glucose molecule

Answer 20

2 reduced NAD
2 Acetyl Coa
2 CO2 produced

Question 21

Location of the Krebs cycle

Answer 21

Mitochondrial matrix

Question 22

Processes of the Krebs cycle

Answer 22

Offloading of acetate from Acetyl Coa

Combination of acetate with the oxaloacetate( 4- carbon molecule) , to form citrate (6- carbon molecule)

Oxidation of citrate by NAD to form reduced NAD

Decarboxylation of citrate to form 5-carbon compound

Oxidation and Decarboxylation of the 5- carbon compound to form a 4- carbon compound and reduced NAD

The 4-carbon compound is changed into another 4-carbon compound. During this reaction, enough energy is released to phosphorylate ADP to ATP(substrate level phosphorylation)

The 4-carbon molecule is change into another 4C molecule, Oxidation of this molecule is carried out by FAD to form FADH

further oxidation ation of the third 4C molecule regenerates oxaloacetate. NADH is formed through the reduction of NAD

Question 23

are the proteins embedded in the inner membrane or not it?

Answer 23

embedded in it

Question 24

is the outer membrane of the mitochondria permeable? Give a reason for your answer

Answer 24

yes
because it has porins which make it permeable

Question 25

products of the krebs cycle per glucose molecule

Answer 25

6 NADH
2 ATP
2 reduced FAD
4 carbon dioxide molecules

Question 26

how many turns of the krebs cycle are there per glucose molecule

Answer 26

there are 2 turns of the cycle per glucose molecule

Question 27

locations of oxidative phosphorylation

Answer 27

mitochondrial matrix, intermembrane space and inner mitochondrial membrane

Question 28

final stage of aerobic respiration

Answer 28

oxidative phosphorylation and chemiosmosis

Question 29

what happens in oxidative phosphorylation

Answer 29

Reduced NAD and FAD are re-oxidized when they donate hydrogen atoms, which are split into hydrogen ions (protons) and electrons

the electrons are passed along a chain of electron carriers( in the electron transport chain) and then donated to molecular oxygen (the final acceptor)

H+ stays in the mitochondrial matrix

when the electrons are transferred to O2, H+ is removed from the mitochondrial solution to reduce it to water

Question 30

the process of chemiosmosis in oxidative phosphorylation

Answer 30

As electrons move through the electron transport chain, energy is released which is used to pump H+(protons) through proton pumps to the intermembrane space

the builds up an electrochemical gradient

the protons then flow back into the matrix through ATP synthase, down their concentration gradient

ATP is formed as a result

Question 31

where does ATP synthase get the energy to synthesize ATP

Answer 31

from the potential energy generated by the electrochemical gradient

Question 32

the three electron carriers involved in oxidative phosphorylation

Answer 32

NADH reductase( 1st)
Cytochrome reductase(2nd)
Cytochrome oxidase (3rd)

Question 33

Substrate level phosphorylation

Answer 33

ATP production without the use of electron transport chain and ATP synthase. Here , ADP is phosphorylated by an unstable intermediate to form ATP

Question 34

Where does the pyruvate formed in glycolysis go in aerobic respiration

Answer 34

The link and Krebs cycle

Question 35

How many ATP molecules can each NAD molecule form

Answer 35

3

Question 36

Fermentation

Answer 36

Breaking down of large complex molecules into simpler molecules without the use of the ETC or oxygen

Question 37

In which organisms do Lactate acid fermentation normally happen

Answer 37

In animals

Question 38

Where does lactate acid fermentation happen

Answer 38

Cytoplasm

Question 39

suggest three reasons why aerobic respiration is not very efficient in ATP production

Answer 39

some protons leak across the mitochondrial membrane during oxidative phosphorylation

due to ATP being used to actively transport NADH and pyruvate into the mitochondrial matrix

some energy is lost as heat

Question 40

between the link reaction and the krebs cycle, how many ATP molecules are being produced per glucose molecule

Answer 40

1