Cellular Respiration

Question 1

What is ATP?

Answer 1

Short term energy store of the cell, in its chemical bonds.
It is the ‘energy currency’ of the cell, as it picks up energy from food in respiration and passes (pays) it onto power cell process.

Question 2

What is the structure of ATP?

Answer 2

Adenosine:
Base
Sugar

Triphosphate

They are all joined by high energy bonds

Question 3

What is ADP?

Answer 3

Adenosine Diphosphate and with only 2 phosphate groups.

Question 4

How is ADP turned into ATP?

Answer 4

The energy to make ATP gain another phosphate group comes from catabolic reactions. Lots of energy is then stored in the bond between the 2 P and ‘lots’ P.

Question 5

How is ATP turned into ADP?

Answer 5

When the third phosphate group is removed it releases energy used for cellular process within the cell, that are endergonic reactions such as active transport.
The P is then available to be recycled and joined to another ATP again.

Question 6

What is cellular respiration?

Answer 6

A chemical process by which organic molecules, taken in as food, are broken down in the cell, to release energy.

Question 7

Where does cellular respiration occur?

Answer 7

It occurs in the energy cell of the body (mitochondria, chloroplast) to supply each cell with the energy it needs.

Question 8

What is used as as reactants for cellular respiration?

Answer 8

Biomolecules

Complex carbohydrates are broke down to glucose
Protein is broken down to amino acids
Lipids are broken down to fatty acids and glycerol

Question 9

What is the general chemical reaction formula for Cellular Respiration?

Answer 9

Glucose + Oxygen –> Carbon Dioxide + Hydrogen + 36ATP

C6H12O2 + 6O2 –> 6CO2 + 6H2O + 36ATP

Question 10

How many reactions approximately occur in cellular respiration?

Answer 10

Around 20, which occur in a series one after the other, seperate reactions to breakdown glucose to carbon dioxide and water.

Question 11

What occurs during these seperate reactions in cellular respiration?

Answer 11

At each step, an intermediate compound is formed and each is catalysed by different enzymes. Energy is released as these reactions proceed.

Question 12

What are the two different types of Cellular Respiration?

Answer 12

Aerobic and Anaerobic

Question 13

What is Aerobic Respiration?

Answer 13

Oxygen needs to present. Aerobic breakdown of one molecule of glucose to release enough energy to convert up to 38 molecules of ADP to ATP.

Question 14

What is the chemical reaction formula for Aerobic Respiration?

Answer 14

C6H12O6 + 6O2 –> 6CO2 + 6H2O + 38 ATP

Question 15

What are the 3 main steps of Aerobic Respiration?

Answer 15

1. Glycolysis
2. Kreb’s Cycle (Citric acid cycle)
3. Electron Transport chain

Question 16

What occurs in Glycolysis?

Answer 16

One glucose molecule is first broken down in a series of 10 steps, to two molecules of pyruvate (pyruvic acid) and 2 ATP

Does not require O2

Question 17

Where does Glycolysis occur?

Answer 17

Occurs in the cytoplasm (enzymes present)

Question 18

What are the reactants and products of Glycolysis?

Answer 18

Glucose –> 2 pyruvate molecules + 2ATP

Question 19

What occurs in Kreb’s cycle?

Answer 19

Complex series of reactions produces 2 ATP molecules and citric acid from the 2 pyruvate molecules.

O2 is present

Question 20

Where does the Kreb’s Cycle occur?

Answer 20

occurs in the inner membrane of the mitochondria

Question 21

What are the reactants and products of Kreb’s Cycle?

Answer 21

2 Pyruvate molecules –> Citric Acid

Question 22

What occurs in the Electron Transport Chain?

Answer 22

Complex series of reactions that produces up to 34 ATP molecules, the pyruvate molecules that turned into citric acid enter the mitochondrion, and produce H2O and CO2

O2 is present

Question 23

Where does Electron Transport chain occur?

Answer 23

Occurs in the mitochondrion

Question 24

What are reactants and products of the Electron Transport Chain?

Answer 24

Citric acid –> H2O + CO2

Question 25

How much ATP is created in Aerobic Respiration?

Answer 25

Aerobic respiration of one molecule of glucose has the potential to generate 38 molecules of ATP

2 from glycolysis
2 from Kreb’s Cycle
Up to 34 from the Electron transport system.

Actual ATP yield is often lower than the max of 38

38ADP + 38P –> 38 ATP

Question 26

What is Anaerobic Respiration?

Answer 26

Cellular Respiration without Oxygen, relatively fast reaction and produces 2 ATP, less than aerobic respiration

Question 27

What are two types of Anaerobic respiration?

Answer 27

Alcohol Fermentation

Lactic acid Fermentation

Question 28

What is Alcohol Fermentation?

Answer 28

Used by mostly bacteria and yeast, and sometimes plants (for a short amount of time).
It occurs in the cytoplasm.

Question 29

What are the reactants and products of alcohol fermentation?

Answer 29

Glucose –> ethanol + carbon dioxide + adenosine triphosphate
C6H12O6 –> 2CH3CH3OH + 2CO2 + 2ATP

Question 30

Why do plants use alcohol Fermentation for only short amounts of time?

Answer 30

As they are unable to utilise ethanol, it is toxic to their cells and so they can only respire anaerobically for short periods of time.

Question 31

What is the relationship between oxygen and ethanol concentration.

Answer 31

The less the oxygen, the more concentrated the ethanol will be.

Question 32

What is lactic acid fermentation?

Answer 32

Where animals produce lactic acid from anaerobic fermentation.

Question 33

What are reactants and products of lactic acid fermentation?

Answer 33

Glucose –> lactic acid + 2ATP

C6H12O6 –> 2CH3CH(OH)COOH + 2ATP

Question 34

When does lactic acid fermentation occur?

Answer 34

During strenuous exercise when the body requires rapid energy realise and there is not a lot of oxygen available. It is short lasting. Once strenuous exercise slows and oxygen is available, aerobic respiration begins.