SPM Biology 2013


6 . (a) Diagram 6.1 shows the respiratory structure of a grasshopper. Explain how the body cells obtain oxygen from the air.

Rajah 6.1 menunjukkan struktur respirasi seekor belalang. Terangkan bagaimana sel-sel badan memperolej oksigen daripada udara.


(b) Table 6 shows the breathing rate of a student during resting and during vigorous activity. Explain why the breathing rate of the student is different during resting and during vigorous activity.

Jadual 6 menunjukkan kadar pernafasan seorang pelajar semasa berehat dan semasa melakukan aktiviti cergas. Terangkan mengapa kadar pernafasan pelajar itu berbeza semasa berehat dan semasa aktiviti cergas.

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(c) Diagram 6.2 shows the concentration of acid lactic in the blood of an athlete. Explain the differences in the concentration of lactic acid in the blood of an athlete during and after doing vigorous activity.
Rajah 6.2 menunjukkan kepekatan asid laktik dalam darah seorang atlet. Terangkan perbezaan kepekatan asid laktik dalam darah seorang atlet semasa dan selepas melakukan aktiviti cergas.

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(d) Diagram 6.3(a) shows alveoli of a healthy individual. Diagram 6.3(b) shows alveoli of an individual with emphysema. Emphysema is a type of lung disease. Explain the effects of the disease to the health of the individual.

Rajah 6.3(a) menunjukkan alveolus individu yang sihat. Rajah 6.3(b) menunjukkan alveolus individu yang menghidap enfisema. Enfisema adalah sejenis penyakit peparu. Terangkan kesan penyakit tersebut kepada kesihatan individu itu.Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution


Answer ( 1 )


    6.a)-For grasshoppers, gaseous exchange occurs via a tracheal system.

    -Oxygen enters through spiracles found along the body of the insect then into the trachea.

    -Oxygen then travels into the tracheoles which penetrate the body cells.

    -The tips of tracheoles are fluid-filled for respiratory gases to dissolve. So oxygen can dissolve in this fluid and diffuse into the body cells.


    b)-During resting the student doesn’t require as much oxygen or energy.

    -In contrast, during vigorous activity, there is an increase in the breathing and ventilation rate. So that more oxygen gets into the body at a faster rate.

    -And more carbon dioxide is expired/ removed from the body.

    -Highly oxygenated blood can then be transported to working muscle tissue for cellular respiration.


    c)-In the beginning the muscle cells undergo aerobic respiration.

    -However as vigorous activity continues oxygen consumption by muscles becomes much greater than the oxygen supplied by blood.

    -This creates an oxygen deficit (oxygen debt). The muscle would then have to switch to anaerobic respiration to obtain energy due to the decrease in oxygen supply.

    -However, during anaerobic respiration, glucose partially breaks down to form lactic acid.

    -Thus as vigorous activity continues, lactic acid accumulates in the blood (as seen with the increase in the graph).

    -Afterwards, during the resting period, the athlete is then able to take in more oxygen which can then be used to oxidise the lactic acid into carbon dioxide and water molecules.

    -Thus lactic acid concentration will start to decrease.


    d)-Alveoli of the emphysema individual are damaged.

    -This would cause breathing difficulties. And it would be difficult for the individual expire air out from their lungs.

    -Stale air can get trapped within the lungs. Is not efficiently replaced with fresh air.

    -Gaseous exchange between the alveoli and blood capillaries will no longer be efficient.

    -Instead of having numerous small air sacs, the alveoli now has very few large air sacs.

    -This decreases the surface area for gaseous exchange. -Less oxygen diffuses into the blood.

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