Chapter 7KSSM FORM 4 BIO
Chapter 7KSSM FORM 4 BIO
Chapter 7KSSM FORM 4 BIO
Catabolism
Anabolism
Glucose
Anaerobic respiration occurs in the absence of oxygen while aerobic respiration occurs with
presence of oxygen.
Glucose is broken down incompletely with the absence of oxygen or limited oxygen.
-Cell division whereby new cells are produced for growth and development
9. Explain how human, animal and plants acquire (obtain) glucose to produce energy.
In human and animals, glucose is obtained through the breakdown of carbohydrates whereas in
plants, glucose is produced through photosynthesis.
Glycolysis process
Cytoplasm
Mitochondrion
16. What does the large amount of energy used after oxidation of pyruvate?
When a group of non-organic phosphate is added into adenosine diphosphate (ADP) molecule.
19. What happen when phosphate link of ATP molecule is broken down
Energy is released and supplied to body cells to carry out daily activities.
2898kJ
Both undergoes glycolysis. Difference: After glycolysis process, pyruvate will undergo either
lactic acid fermentation or alcohol fermentation in fermentation process.
23. What does the pyruvate produced undergo after glycolysis in fermentation process?
24. Suggest other substrate apart from glucose that can be used by cells for cellular respiration
Fructose, galactose(carbohydrates/monosaccharides)
210kJ
31. Why ethanol produced in paddy plant tissues alcohol fermentation does not affect growth
compared with other plants?
Paddy plant tissues has a higher tolerance for ethanol compared to other plants. Thus, paddy
plants can produce alcohol dehydrogenase enzyme to break down ethanol into non-toxic carbon
dioxide.
Carbon dioxide
Bacteria lactobacillus acts on the lactose (milk sugar) in milk into lactic acid.
Then, lactic acid will coagulate milk protein, casein into yogurt.
Lactic acid
Oxygen supplied from blood circulatory system excess the rate of oxygen usage.
37. Rate of oxygen used and oxygen supplied by blood circulatory system during vigorous
activities
Glucose cannot be broken down completely. Each molecule of glucose broken down only release
two molecules of ATP produced.
39. How many molecules and amount of energy is produced after broken down of glucose
during oxygen debt?
150kJ
Excess intake of oxygen will oxidise the lactic acid into carbon dioxide, water and energy.
-The process of break down of glucose and its conversion into chemical energy.
47. Explain cellular respiration and leg muscle cell activity when running
When sprint, lung and blood supply are unable to supply oxygen quickly enough to meet the
demands of the muscles to produce ATP. In this condition, muscle cells undergo fermentation,
whereby ATP is produced without oxygen. Fermentation in muscle cells produces lactic acid.
48. Why muscle undergo cellular respiration that produce lactic acid during vigorous activity
This is because glucose oxidation is incomplete and a part of the chemical energy is still tied in
the lactic acid molecule.
50. Explain why people feel tired easily compared with athlete when running
An athlete usually has more mitochondria in the muscle cells. Increased uptake of oxygen and
oxidation of lactic acid reduces muscle fatigue.
Sprinter complete the race fast by holding their breath. So that the runner uses existing oxygen
efficiently. However, lactic acid is accumulated because of insufficient of oxygen supply to
muscle. On the other hand, long-distance runner who run at slower speed are able to dispose off
lactic acid accumulated in early stages of running. Long-distance runners cannot hold their
breath because lactic acid accumulation causes rapid muscle fatigue. As so, long distance
runners need to breath throughout the race.
When a person sprints, their muscle cells undergo fermentation in the absence of oxygen to
produce ATPs. Muscle produces lactic acid that is toxic. Lactic acid causes muscle pain and
cramps.
The sugar in milk is oxidised by bacteria such as Lactobacillus and Streptococcus into lactic acid
that solidifies the milk and produces a sour taste until curd is formed. When kept in the fridge,
the low temperature controls bacterial activity from reproducing and spoiling the product. If
kept at room temperature, the curd will spoil as bacteria will continue to grow and oxidise the
milk sugar, casein.
56. How does high performance athlete overcome problem of lactic acid accumulation?
Someone who rarely exercises will experience muscle cramps when they do heavy exercises
because the number of mitochondria in their cells are very few. Therefore, during vigorous
exercise, complete cellular respiration does not take place and a lot of lactic acid will be formed.
To overcome this problem, an athlete needs to undergo consistent training to produce more
mitochondria in their cells. The high number of mitochondria can help an athlete’s cellular
respiration. Faster uptake of oxygen and oxidation of lactic acid can reduce muscle fatigue
during vigorous activities.
57. Explain why intake of sodium bicarbonate or baking soda can increase muscle efficiency
This is because baking soda has a high pH that is able to neutralise the lactic acid produced by
muscles during exercise. This increases muscle efficiency because lactic acid causes muscle
fatigue.
The dry yeast is not activated which is in a dormant state when environment is dry. Yeast needs
to add lukewarm water to be activated. The activated yeast will undergo respiration by breaking
down the carbohydrates in the flour and releasing carbon dioxide. Carbon dioxide causes the
bread to expand and rise.