SPM Biology 2018

Question

8) The wife of a newly married couple is diagnosed with an inheritance disease. If this couple had children, the children might have genetic disorder. The doctor advised her to use some birth control methods.

Isteri kepada pasangan yang baru berkahwin didapati menhidapi satu penyakit keturunan. Jika pasangan ini memperolehi zuriat, dikhuatiri anak mereka akan mengalami kecacaran genetik. Doktor menasihati beliau untuk menggunakan beberapa kaedah pencegahan kehamilan.

(a) Table 8.1 shows the comparison of some birth control methods.

Jadual 8.1 menunjukkan perbandingan bagi beberapa kaedah mencegah kehamilan.

(i) Based on Table 8.1, choose the best two effective methods to prevent pregnancy.

Berdasarkan Jadual 8.1, pilih dua kaedah yang paling efektif untuk mencegah kehamilan. Terangkan alas an anda.

 

(ii) Beside the contraceptive methods in table 8.1, the consumption pills is also being practised. Discuss the advantages and disadvantages of this contraceptive method.

Selain daripada kaedah pencegahan kehamilan dalam Jadual 8.1, penggunaan pil pencegah kehamilan juga diamalkan. Bincangkan kebaikan dan keburukan mengamalkan kaedah pencegahan kehamilan ini.

Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

(b) A flower is the reproductive organ for a plant. Fertilisation process occurs in the ovule to form a fruit. The fruit is the ripened ovary of a flower. Diagram 8.2 shows the process of a flower which turn into a fruit. Based on Diagram 8.2, explain how a fruit is formed from a flower.

Bunga adalah organ pembiakan bagi tumbuhan. Buah ialah ovari yang telah masak pada bunga. Rajah 8.2 menunjukkan proses sekuntum bunga berubah menjadi buah. Berdasarkan Rajah 8.2, terangkan bagaimana buah terbentuk dari sekuntum bunga.

Cher Questions Solution Bank Rumusan Jawapan SPM & IGCSE Questions Answers Solution

 

 

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    2020-12-31T11:44:04+08:00

    8. a) i) One effective method would be to use an intrauterine device (IUD). The number of pregnancy per 100 women in 1 year is only 1. The reason why an IUD is so effective is because it irritates the uterine wall which prevents the embryo from implanting onto the endometrium.

    Next, the tubal ligation method would be most effective as it results in 0 pregnancies. With tubal ligation the Fallopian tubes are cut and tied so when the ovary releases an ovum, it will not meet with sperm present in the Fallopian tubes, preventing fertilization of the ovum. 

     

    ii) Consuming contraceptive pills prevents ovulation. The pills inhibit the secretion of follicle-stimulating hormone (FSH) and lutenising hormone (LH) which prevents the development of follicles and ovulation.

    For this kind of question you can  either write 3 advantages/disadvantages, or 2 advantages/disadvantages and 4 disadvantages/advantages. Just ensure that you have 6 points. 

    Advantages Disadvantages
    It is a less expensive method. So it is affordable for most of the population.  It disrupts the normal secretion of hormones, thus an individual may get side effects from hormonal imbalance.
    The pill can prevent periods from occurring, so it is very beneficial for women who have anaemia from too much blood loss due to periods. There is a possibility that if an individual is taking other medication, it may lessen the effectiveness of the pill (drug-drug interactions). 
    If an individual does not take the pill at the correct timing, accidentally missed a pill or experience severe diarrhoea/vomiting, they may get pregnant. 
    The pill does not protect an individual from sexually transmitted diseases (STD) 

     

    b) Double fertilisation will occur when the male gametes penetrate into the embryo sac. One of the male nuclei will fuse with the egg cell to form the diploid (2n) zygote. Whereas, a second male nuclei will fuse with the two polar nuclei found within the ovule to form the triploid (3n) nucleus.  

    After double fertilisation has occurred, the 2n zygote will undergo mitosis to form the embryo. The embryo will divide and differentiate into the cotyledon, plumules and radicle. Whereas, the triploid (3n) nucleus will divide and develop into the endosperm which supplies nutrients for the growing embryo.

    The integuments surrounding the embryo sac will develop into the seed coat (testa). This seed coat provides protection for the embryo and endosperm.

    Next, the ovule will form the seed. If there are multiple ovules, then there would be multiple seeds. Finally, the ovary will expand and develop into the fruit. The ovary is essentially the fruit flesh that we eat.

    As the fruit grows bigger, the petals, stigma, style and stamens will shrivel away.

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