UNIT 2: Respiration

Question 1

internal respiration

Answer 1

the enzyme-controlled release of energy from food

Question 2

external respiration

Answer 2

the exchange of gases with environment

Question 3

aerobic respiration

Answer 3

the enzyme-controlled release of energy from food using oxygen.
occurs in the mitochondrion

Question 4

anaerobic respiration

Answer 4

the enzyme-controlled release of energy from food without the use of oxygen.
occurs when no oxygen or limited oxygen is present:
1. glycolysis
2. lactic acid fermentation / alcohol fermentation

Question 5

stage 1 of aerobic respiration: glycolysis

Answer 5

• oxygen independent (can occur in presence/absence of oxygen)
• occurs in cytosol.
• glucose (a 6-carbon molecule) is changed into 2 3-carbon molecules (pyruvate).
• this breaking down of glucose releases high energy electrons and protons - they are captured by NAD+ to become NADH.
• glycolysis also produces 2 molecules of ATP directly

Question 6

stage 2 of aerobic respiration: Krebs cycle & electron transport chain

Answer 6

• oxygen dependent (can only occur in the presence of oxygen)
• occurs in the lumen of the mitochondrion (matrix)
• pyruvate enters the mitochondrion and is converted to a 2-carbon molecule (acetyl-coA) with release of NADH and carbon dioxide.
• the acetyl-coA then joins with 4-carbon molecule from the previous krebs cycle to form 6-carbon molecule.
• the 6-carbon molecule is then broken down into 5-carbon molecule with release of carbon dioxide and NADH.
• the 5-carbon molecule is the broken down into a 4-carbon molecule with release of ATP, carbon dioxide and 2NADH.
• the 4-carbon molecule goes into the next krebs cycle.
• the ATP goes to power metabolism.
• the NADH is an energy carrier that goes to the electron transport chain where its energy is used to power the production of 3 ATP molecules.
• the electron transport chain is located in the inner membranes of the mitochondrion (cristae).

Question 7

Fermentation

Answer 7

Another form of anaerobic respiration

Question 8

Biotechnology

Answer 8

The use of living things or their components to manufacture useful products to carry out useful reactions