Observation

This question was not so popular among candidates. Some of the candidates that answered this question had a range of good scores although some marks were lost to the carelessness of some candidates especially in relating the structures of the palisade cell and sperm cell to their functions and drawing the front view of the female reproductive system.

In question 1 (b), some candidates were drawing the urinogenital system showing the kidneys instead of the front view of the reproductive system. Some candidates could not draw to the specification given; no titles; no ruled labels and using wooly lines.

Some candidates could also not differentiate between reproduction in mammals and in amphibians. Some candidates also stated that fertilization in mammals is intercellular and that of amphibians is extracellular instead of internal and external as the case may be.

Some candidates could not also state the methods of birth control in human beings, may be because they could not cover a wide range of the syllabus before sitting the exams.

            The expected answers are:
    1. (a)   Structure of cell relating to its function
(i)    Sperm cell

• Has a long/whip-like tail/flagellum; with which it swims to reach the egg/ovum of the female organism;
• Has a head with acrosome; for digesting/penetrating egg membrane;
• Has a nucleus in its head; which fuses with the nucleus of the ovum/egg cell during fertilization to form a zygote;
• Its middle piece contains mitochondria; for supply of energy/ATP.

          (ii)     Palisade cell

• Has thin wall; for easy penetration of light;
• Has numerous chloroplasts in peripheral cytoplasm; for maximum absorption of sunlight;
• Has large vacuole containing cell sap; for temporary storage of products of photosynthesis.                      

Note:         Structure must correspond to function to score;
Structure alone can score but function alone cannot score.

   (b)      Diagram of the front view of the female reproductive system of humans

Title   (TL)                                                                                    

Quality (Q)
Clarity of lines                  (CL)                                                   
Size                                   (SZ)     (8cm to 10cm)                        
Neatness of labels             (NL)                                                   
Details (D)
Funnel-shaped mouth of fallopian tube (FF)                               
Two ovaries close to the fallopian funnel (TF)                                                    

Labels (L)
Ovary, fallopian tube/oviduct, fallopian funnel/funnel of oviduct, uterus/womb, uterine lining/wall of uterus, cervix, vagina, vulva, fimbria.      

                 

(c)    Differences between reproduction in Mammals and Amphibians

(d)   Methods of birth control in humans       

• Abstinence;
• Use of contraceptive pills/injection of hormonal drugs;
• Coitus interruptus/withdrawal method;
• Safe period/rhythm method;
• Sterilization of men/vasectomy;
• Sterilization of women/tubal ligation;
• Use of condoms/female condom/male condom;
• Use of spermicide/foam;
• Use of implant/norplant;
• Use of IUD/intra-uterine devices;
• Use of diaphragm.                                                                   

Note: Spelling must be correct to score.