Respiration

Question 1

What does ATP stand for?

Answer 1

Adenosine Triphosphate

Question 2

What is respiration?

Answer 2

Respiration is the process by which organisms release energy from organic compounds via oxidation.

Question 3

Describe the structure of ATP

Answer 3

A adenine molecule attached to a 5 carbon sugar- ribose, then attracted to 3 phosphate groups.

Question 4

What is aerobic respiration?

Answer 4

The process by which organisms release energy from organic compounds using oxygen.

Question 5

Why is ATP a the universal energy currency- used by all living things

Answer 5

1. ATP is water soluble
2. ATP diffuses through a cell easily
3. ATP is easily hydrolyzed to release energy
4. It recycles

Question 6

What is glycolysis

Answer 6

Glycolysis involves the splitting of the glucose molecule into two 3-carbon pyruvate molecules.

Question 7

Where does glycolysis take place?

Answer 7

In the cytoplasm of the cell

Question 8

What are the 3 main steps of glycolysis

Answer 8

Glycolysis has 10 steps that may be broken down into 3 main steps- (i) Phosphorylation

(ii) Lysis (Splitting) of the sugar molecule

(iii) Oxidation Reaction by Dehydrogenation

Question 9

Why is ATP the universal energy currency?

Answer 9

All cells require energy (in all organisms) and all cells in all organisms use ATP as their energy source to do work. ATP is therefore the universal energy currency of all cells.

Question 10

What are anabolic and catabolic reactions and what are their relationships tp ATP

Answer 10

Anabolic reactions are driven by ATP. These are reactions to put together smaller molecules to make ;larger macromolecules.

Catabolic reactions create ATP. These are reactions that break down macromolecules into smaller compounds.

Question 11

How much energy is needed to produce one ATP molecule?

Answer 11

30.6KJ

Question 12

How much ATP is produced from one glucose molecule

Answer 12

38

Question 13

Explain the intermembrane space of the mitochondria

Answer 13

The space between the inner and the outer membrane is known as the intermembrane space which has a high proton concentration for the electron transport chain. It is the site of oxidative phosphorylation. The intermembrane space has the same composition of the cytoplasm of the cell but it differs in the protein content.

Question 14

What is the function of the cristae in the mitochondria?

Answer 14

Each crista has little projections called elementary/stalked particles. It is in these projections that the enzyme ATPase is found. The cristae increase the surface area for reactions. It contains complexes of the electron transport chain (ETC) and ATP synthase.

Question 15

What are functions of the inner membrane of the mitochondria? (excluding the cristae)

Answer 15

The inner membrane is permeable to oxygen, carbon dioxide and water, ATP and ADP. It contains the proteins involved in ATP synthesis. It regulates the transfer of metabolites (molecules involved in a particular reaction) in the respiratory pathway. Finally, it makes diffusion of substances from the matrix easy. It is also the site of oxidative phosphorylation.

Question 16

What is the function of the matrix within the mitochondria?

Answer 16

The matrix is the site where the Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle, takes place.

Question 17

List all the functions of the mitochondria.

Answer 17

1. It is the site of ATP synthesis via oxidative phosphorylation.
2. It maintains the concentration of calcium ions within the cell.
3. It stores calcium ions which are involved in cell differentiation, the cell cycle, cell growth
4. It is involved in building parts of the blood and hormones
5. It is where the Haem group is made
6. The mitochondria that are found inside the liver contain enzymes which detoxify ammonia.
7. It plays a role in cell death (if it becomes dysfunctional or shuts down, the cell will eventually die)
8. It is involved in heat production which is a waste product of respiration but we need it to maintain our body temperature

Question 18

What are the reactions involved in Aerobic respiration?

Answer 18

(i) OXIDATION – Oxygen being added / Hydrogen being removed/ Electron being removed

(ii) DECARBOXYLATION- Molecules of CO2 being removed

(iii) PHOSPHORYLATION – This is of two types:
a. OXIDATIVE
b. SUBSTRATE LEVEL

Question 19

What is substrate level phosphorylation?

Answer 19

Substrate Level Phosphorylation occurs when an inorganic phosphate group is added to ADP to make ATP; this phosphate group comes from a donor molecule. E.g. (Phosphoglycerate). This occurs in glycolysis and the Krebs cycle.

Question 20

What is oxidative phosphorylation

Answer 20

Oxidative Phosphorylation is how mitochondria make ATP using enzymes and energy from the oxidation of hydrogen carriers, like NADH. This process includes the electron transport chain and connects to chemiosmosis, where ADP is converted into ATP. It’s called Oxidative Phosphorylation because NADH is oxidized, losing hydrogen, creating potential energy used to bind ADP and inorganic phosphate, forming ATP.

Question 21

What are the 4 main stages of aerobic cellular respiration

Answer 21

Glycolysis
Link Reaction ((The activation of pyruvate to acetyl CoA))
The Krebs (tricarboxylic) cycle
The Oxidative phosphorylation

Question 22

What are the three main stages of Glycolysis

Answer 22

(i) Phosphorylation

(ii) Lysis (Splitting) of the sugar molecule

(iii) Oxidation Reaction by Dehydrogenation

Question 23

Describe the phosphorylation stage of glycolysis

Answer 23

The phosphate groups from TWO ATP molecules are added to one glucose molecule.
This reaction is catalyzed by the enzyme phosphofructokinase
This step is important as it activates the glucose molecule and this prevents it from being transported outside of the cell.
Once the glucose is phosphorylated, it is isomerized to fructose-1,6-bisphosphate which is a 6 carbon compound.

Question 24

Explain the second main step of glycolysis

Answer 24

The fructose-1,6-bisphosphate is split into two 3-carbon sugars or triose phosphates.
One is 3-Phosphoglyceraldehyde and the other Dihydroxyacetone Phosphate.
The ketone (Dihydroxyacetone Phosphate) has to be changed to an aldehyde because that makes it more reactive. The remaining reactions will not proceed otherwise.