Chapter 7: Cellular Respiration

Question 1

definition of cellular respiration

Answer 1

oxidation process of organic compound through several stages to release energy

Question 2

process of aerobic respiration

Answer 2

glucose –> pyruvate –> CO2 + H2O + energy (2898kJ // 38ATP)

Glycolysis ( in cytoplasm)
- break down 1 glucose into 2 pyruvate

Oxidation of pyruvate (in mitochondria)

• oxidised pyruvate into carbon dioxide, water and energy
• energy is used to produce adenosine triphosphate (ATP)

ATP

• a non-organic phosphate group is added to adenosine diphosphate (ADP), to produce ATP
• ATP have weak phosphate links
• when the link is broken, the energy released is supply to cells to carry out daily activities

Question 3

definition of fermentation

Answer 3

• incomplete break down of glucose in condition of limited oxygen or without oxygen

Question 4

alcohol fermentation

Answer 4

glucose –> pyruvate –> ethanol + CO2 + energy (210kJ)

Question 5

cellular respiration of paddy plants

Answer 5

Alcohol fermentation

• grow in water logged area with less oxygen
• paddy has higher tolerance to alcohol
• ethanol produced in tissue is toxic
• alcohol dehydrogenase enzyme is produced to break down alcohol into non-toxic carbon dioxide

Question 6

lactic acid fermentation

Answer 6

glucose –> pyruvate –> lactic acid + energy (150kJ // 2ATP)

Question 7

how does yogurt produced

Answer 7

• lactobacillus bacteria carry out milk fermentation
• act on lactose to produce lactic acid
• lactic acid coagulate casein to produce yogurt
• lactic acid is the sour taste source of yogurt

Question 8

lactic acid fermentation in human muscle cells

Answer 8

• during vigorous activities, rate of oxygen used is more than rate of oxygen supply by blood circulatory system
• muscle cell is in oxygen-deficiency state (oxygen debt)
• glucose cannot break down completely
• lactic acid fermentation is carry out by muscle cells
  lactic acid will accumulate until it reach concentration level, that can cause fatigue and muscle cramp
• once the activities stop, intake of excess oxygen will oxidise the lactic acid into CO2,water and energy
• when all the lactic acid are expelled, the oxygen debt is repaid