Cellular Respiration

Question 1

Aim of cellular respiration

Answer 1

Refers to the biochemical pathways that release energy from glucose

Question 2

Energy from glucose

Answer 2

Energy released from glucose through cellular respiration is used to generate the coenzyme ATP

Question 3

What happens when a cell needs energy?

Answer 3

High Energy bond in ATP is broken and the phosphate is removed, releasing the energy stored in the bond

Question 4

Catabolic

Answer 4

Larger/complex compounds are broken down into simpler ones. Energy is also released

Question 5

Exergonic

Answer 5

When energy is released

Question 6

ADP to ATP

Answer 6

Cells can store excess energy by adding an Pi to the ADP, storing the energy in the bond, forming ATP once again

Question 7

Anabolic

Answer 7

Smaller compounds make larger compounds. Energy is needed

Question 8

Endergonic

Answer 8

When energy is required or is stored in a bond

Question 9

NAD+

Answer 9

-> A coenzyme
-> Is a energy carrier
-> In ETC, NADH –> NAD+ and the energy released are used in the formation of ATP

Question 10

FAD/FADH2

Answer 10

-> A coenzyme
-> Energy carrier
-> In Krebs: FAD ->FADH2
-> In ETC: FADH2 –> FAD and the released energy is used to make ATP

Question 11

2 types of Cellular respiration

Answer 11

• Anaerobic (oxygen absent )
• Aerobic (oxygen present)

Question 12

Aerobic Respiration

Answer 12

• Glucose is broken down in the presence of oxygen and is produces CO2 and H2O
• Includes Krebs and ETC ( both occur in mitochondria )

Question 13

Anaerobic Respiration

Answer 13

• Products formed depend on the type of organism this process occurs within.
• Plants and yeast carry out Alcohol fermentation:
  glucose –> ethanol + CO2 + 2 ATP
• Animal carry out lactic acid fermentation
  glucose –> lactic acid + 2 ATP

Question 14

Glycolysis- Anaerobic

Answer 14

• Location: Cytosol of the cell
  -Break down the large glucose molecules into 2 smaller molecules (Pyruvate)
  Inputs: Glucose, 2 NAD+, 2 ADP + Pi
  Outputs: 2 Pyruvate, 2 NADH, Net of 2 ATP

Question 15

Pyruvate Oxidation

Answer 15

• Pyruvate are transported by Active Transport to the fluid matrix of the mitochondria
• Pyruvate –> 2 Acetyl CoA
• 2 NADH are produced and CO2 (Waste)

Question 16

Krebs Cycle- Aerobic

Answer 16

• Location: Fluid matrix of the mitochondrion
• Is a series of biochemical reactions, each catalysed by a different enzyme

Inputs: 2 Acetyl-CoA, 2ADP+Pi, 2 NAD+, 2FAD+
Outputs: 2 ATP, 2NADH, 2FADH, 4CO2

• Contains many ribosomes due to the large number of enzymes required for the Krebs cycle

Question 17

Electron Transport Chain

Answer 17

• Location: Inner membrane of the mitochondria, the (cristae)
• Overall purpose is to transport protons ( H+ ions) and electrons across a membrane (cristae) as a system for generating ATP
  Inputs: NADH, FADH2, ADP + Pi, O2
  Outputs: NAD+, FAD+, 26 OR 28 ATP, H2O
• The more cristae there are, the more surface area there s available for carrying out the reactions of the electrons transport chain

Question 18

Aerobic Respiration Equation

Answer 18

C6H12O6 +6O2 –> 6CO2 +6H2O + 30 OR 32 ATP

Question 19

What makes up the ETC

Answer 19

In the inner membrane of mitochondria, there are protein complexes including enzymes and cytochromes which are embedded. They form an interconnected series.

Question 20

Number of ATP produced for each stage

Answer 20

Glycolysis: 2 ATP
Krebs: 2 ATP
ETC: 26 or 28 ATP
Total Aerobic Yield: 30 or 32 ATP

Question 21

Anaerobic Respiration

Answer 21

• Is far less efficient than aerobic cellular respiration
• Begins with the breakdown of glucose into pyruvate forming 2 ATP

Question 22

Lactic Acid Fermentation

Answer 22

Location: Cytoplasm
- Through glycolysis, glucose is broken down into 2 pyruvate further broken down into lactic acid
Inputs: ADP + Pi, Glucose, NAD+
Outputs : 2 ATP, NAD+ , Lactic Acid

Question 23

Ethanol Fermentation

Answer 23

Location: Cytosol
- Through glycolysis, glucose is broken down into 2 pyruvate further broken down into ethanol and CO2
Inputs: ADP + Pi, Glucose, NAD+
Outputs: 2 ATP, NAD+, Ethanol, CO2

Question 24

Temperature affecting cellular respiration

Answer 24

1. Temperature: When temp is below opt there is low kinetic energy= low cellular respiration = enzymes become inactivated due to lose of flexibility in the bonds at the active site making it unable to bind to substrates
   –> Optimal temp is when max rate of cellular respiration

Question 25

Glucose availability affecting cellular respiration

Answer 25

--> All chemical reactions are limited by the concentration of reactants --> Glucose is the substrate for glycolysis, therefore the availability of glucose will affect the rate at which this first occurs. Increased glucose availability = increased rate of cellular respiration

Question 26

Oxygen Concentration affecting cellular respiration

Answer 26

-> If oxygen availability is low = rate will decrease --> When oxygen concentration is low, cells stop aerobic and begin anaerobic cellular respiration --> HIgh oxygen concentrations will increase the rate of aerobic respiration and decrease the rate of anaerobic respiration