Topic 1: Aerobic Respiration & Fermentation

Question 1

RESPIRATION

• There are two types of respiration;
• Aerobic Respiration
• Fermentation reactions in anaerobic conditions

Answer 1

AEROBIC RESPIRATION

• Respiration with oxygen
• C6H12O6 + 6O2 —> 6CO2 + 6H2O
• 2 types of reactions
• Synthesis- energy is required (photosynthesis)
• Breakdown- energy is released (respiration)

Question 2

ADENOSINE TRIPHOSPHATE (ATP)
- ATP is not energy, it carries energy
Transports chemical energy within cells.
- Required for movement, making biological molecules and cell division.
- Synthesis of ATP requires energy whereas the breakdown of ATP tp ADP releases energy.

Answer 2

DRAW DIAGRAMS

Question 3

STAGE 1- GLYCOLYSIS

• Occurs in the cytoplasm.
• A glucose molecule is broken down into pyruvic acid through a series of enzyme controlled reactions, releasing enough energy to synthesise 2 ATP
• Glycolysis doe not require oxygen

Answer 3

STAGE 2- KREBS CYCLE

• Occurs in the mitochondria.
• The pyruvic Acid still contains a lot of energy.
• It can only be broken down to release the rest of the energy in the presence of oxygen.
• Pyruvic Acid is broken down into carbon dioxide and water through a series of controlled enzyme reactions, producing enough energy to synthesise 36 ATP molecules.
• Stage 1 & 2 combined release 38 ATP molecules.

Question 4

FERMENTATION

• Anaerobic reactions which release a small amount of energy.
• Anaerobic = absence of oxygen.

Answer 4

FERMENTATION IN ANIMAL CELLS

• In low oxygen conditions or during heavy exercise when not enough oxygen can be supplied, muscles swap to Fermentation in anaerobic conditions.
• Glycolysis occurs and then the pyruvic acid is converted into lactic acid due to the absence of oxygen.
• Fermentation is reversible in animals. It converts lactic acid back The pyruvic acid with oxygen.