SPM Biology 2019

Question

7. (a) Diagram 7.1 shows two glands of human.
Rajah 7.1 menunjukkan dua kelenjar pada manusia.

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(i) Explain how the lack of nutrient M can affect the level of health.

Terangkan bagaimana kekurangan nutrien M boleh mempengaruhi tahap kesihatan. Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

(ii) Osmoregulation process involves gland K in Diagram 7.1 An experiment was carried out to study the relationship between the volume of water intake with the volume of urine produced. Diagram 7.2 shows two individuals, Y and Z, who drank different volume of water and produced different volume of urine.

Proses pengosmokawalaturan melibatjan kelenjar K dalam Rajah 7.1. Satu eksperimen telah dijlankan untuk mengkaji hubungan antara isi padu air yang diminum dengan isi padu urin yang dihasilkan. Rajah 7.2 menunjukkan dua orang individu, Y dan Z, telah meminum air yang berbeza isi padu dan menghasilkan isi padu urin yang berbeza. Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

Explain the role of gland K in Diagram 7.1 to regulate the water content of individual Y and Z.

Terangkan peranan kelenjar K dalam Rajah 7.1 untuk mengawal atur kandungan air bagi individu Y and individu Z.

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(b) A doctor injects a type of drug to a patient in order to reduce pain. Using the information in Diagram 7.3, explain how the injection of that drug could decrease the pain felt by the patient.
Doktor menyuntik sejenis dadah kepada seorang pesakit untuk mengurangkan rasa sakit. Mengguanakan maklumat dalam Rajah 7.3, terangkan bagaimana suntikan dadah itu dapat mengurangkan kesakitan yang dirasai oleh pesakit tersebut. Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

 

 

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    2020-12-18T09:43:18+08:00
    1. a) i) Nutrient M is iodine. A lack of iodine causes a reduction in the production of thyroxine hormone. This could lead to a swollen and enlarged thyroid gland. This can then develop into a goitre. 

    Furthermore, reduced production of thyroxine hormone could cause myxedema resulting in a slowing of the heart rate, lower body temperature and a tendency to gain weight. 

     

    ii) Gland K is the pituitary gland. The posterior pituitary gland secretes antidiuretic hormone (ADH) into the bloodstream. 

     

    For individual Y due to the high intake of water, blood osmotic pressure decreases, the posterior pituitary gland would be less stimulated thus releasing lesser amounts of ADH. A lower amount of ADH produced leads to a decrease in the permeability of the collecting duct and distal convoluted tubule (DCT) to water. Thus there is less reabsorption of water from filtrate into the blood. A larger volume of urine is  produced and is less concentrated.

     

    For individual X due to less consumption of water, blood osmotic pressure increases, the posterior pituitary gland is more stimulated to produced larger amounts of ADH into the blood. An increase in the level of ADH results in an increase in the permeability of DCT and the collecting duct to water, this increases the reabsorption of water from filtrate into the blood. Thus, more water is reabsorbed into the blood. A lower volume of urine is produced which is highly concentrated. 

     

    Both of these scenarios are due to the negative feedback mechanism to ensure that blood volume and blood osmotic pressure is within the homeostatic range. 

     

    b) The original mechanism would be that when the neurotransmitter binds to the receptors on the postsynaptic membrane this causes generation of nerve impulses which lead to the feeling of pain. The drug is able to prevent the fusion of the synaptic vesicle to the presynaptic terminal, this then blocks the release of the neurotransmitters from the synaptic vesicles into the synaptic cleft. Therefore a reduction in the amount of neurotransmitters released leads to less binding of neurotransmitters to the receptors and a decrease in pain felt.

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