REVISING REPRODUCTION (LIVE) 29 JUNE 2015 Exam Questions

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1 REVISING REPRODUCTION (LIVE) 29 JUNE 2015 Exam Questions Question 1 (Adapted from DBE November 2014, Question 2) Study the diagrams below showing the male and female reproductive systems. 1.1 Identify parts A, B and F respectively. (3) 1.2 State ONE function of each of the following a.) The fluid produced by part C b.) Part E (2) 1.3 Give the LETTER ONLY of the organ where meiosis takes place in the : a.) Male reproductive system b.) Female reproductive system (2) 1.4 Name the type of gametogenesis that a.) Male reproductive system b.) Female reproductive system. (2) 1.5 State TWO functions of part H. (2) 1.6 Explain why it is necessary for part D to be 'outside' the body in males. (2) Page1

2 (Taken from Learner Workbook, Mindset Learn, Chapter 1, Question 2, Pg 7) The diagram below shows some of the changes that take place during the menstrual cycle. 1.7 The menstrual cycle is controlled by hormones. Name ONE hormone which will increase in level between day 2 and day 10. (1) 1.8 Give ONE observable reason for your answer to QUESTION 1.7. (2) 1.9 Explain evidence from the diagram which indicates that fertilisation took place. (3) 1.10 Describe the developmental changes in the fertilised ovum until implantation occurs in the uterus. (5) 1.11 Some females use an ovulation monitor so that they can be aware of the days when they are fertile. These monitors measure the level of hormones in the blood. Question 2 a.) Why would females want to know when they are fertile? (1) b.) Explain which hormone is likely to be monitored by the ovulation monitor. (3) (Adapted from DBE November 2014, Question 2) The unicellular zygote undergoes many developmental changes until it becomes a multicellular foetus, nourished and protected by the mother. Describe the changes that allow the zygote to eventually develop into a foetus and how this foetus is nourished and protected during the period of pregnancy. Content (17) Synthesis (3) Page2

3 Question 3 (Adapted from DBE Feb/March 2015, Question 2) Study the diagram below. 3.1 Give labels for each of the following: a.) b.) A B c.) C (3) 3.2 State ONE function of part A. (1) 3.3 Explain the consequences for reproduction if part C is surgically cut. (3) 3.4 Explain why it would still be possible for an HIV positive man to infect another person during sexual intercourse after part C is surgically cut. (2) Read the passage below and answer the questions that follow. About 400 million sperm cells are produced daily in the body of a healthy male. Studies have shown that the sperm count drops as a result of heated car seats, anti-sperm antibodies and the abuse of substances like marijuana and alcohol. 3.5 List TWO causes of male infertility mentioned in the passage above. (2) 3.6 Describe briefly how sperm cells are produced. (3) 3.7 Name the structure in the sperm cells that contains the enzymes that aid fertilisation. Where does fertilisation occur in the female reproductive system? (1) 3.8 Describe the role of hormones in preparing the female body for the process mentioned in QUESTION 3.7. (4) Page3

4 Question 4 (Adapted from DBE Sept Prelim 2015, Question 3) The diagram below shows the structure of a developing human foetus in the uterus. Study the diagram and answer the questions that follow. 4.1 Identify the LETTER that represents the following: a.) Foetus b.) Umbilical cord (2) 4.2 Give ONE function of amniotic fluid. (1) 4.3 Region D serves as a barrier between the growing foetus and the mother. Provide TWO reasons why this barrier is necessary. (2) 4.4 Tabulate TWO differences between the blood that moves from the mother to region D and the blood that goes from region D to the mother. (5) Question 5 (Adapted from IEE Nov 2013, Question 1) An incomplete graph illustrating changing human hormones, the ovarian cycle and endometrium thickness has been drawn below. Complete the graph by adding the following information in the spaces provided on the graph. 5.1 Give the function of hormones A and B. (2) 5.2 Label the hormones C and D. (2) 5.3 Draw a diagram of a Graafian follicle; a ruptured Graafian follicle; and a corpus luteum at a correct position on the day line of the ovarian cycle. Name each diagram. (6) 5.4 Draw in the thickness of the endometrium to show the menstrual cycle. (2) Page4

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6 Question 6 The figure below shows the oestrus (menstrual) cycle for a cow. Study the figure and answer the questions which follow. 6.1 Name the two hormones shown at i) 5; and ii) 6 respectively. (2) 6.2 Name the structure numbered a.) i 1; and b.) The hormone indicated as number 7 that it secretes. (2) 6.3 Identify structure 3 and state a function of the hormone numbered 8 that it secretes (2) 6.4 Explain the significance of structure 9 becoming thicker during the cycle. (1) 6.5 Many dairy cows are fertilised by artificial insemination. It is important for the dairy farmer to know whether a cow has been fertilised. One test for pregnancy depends on determining the progesterone level in the milk. Explain why the farmer checks the milk progesterone after day 21. (2) 6.6 Using your knowledge of the human menstrual cycle state two differences between the oestrous cycle of a cow and the menstrual cycle of a human. (2) Page6

7 Solutions to Exam Questions Question 1 (Adapted from DBE November 2014, Question 2) 1.1. A - Urethra B - Vas deferens/sperm duct F - Fallopian tube /oviduct (3) 1.2. (a) - Protects the sperm cell against the acidic environment of the vagina - Increases the motility of the sperm - Provides nutrients (Mark first ONE only) (b) - Place for foetus to develop - Maintain pregnancy - Assist in childbirth - Implantation of blastula - Protects the foetus /prevents infections (mucus plug forms by cervix) - Passage for sperm cell s between vagina and fallopian tubes (Mark first ONE only) 1.3. (a) D (b) G 1.4. (a) Spermatogenesis (b) Oogenesis 1.5. Serves as a birth canal Allows for passage of blood/ endometrial lining/amniotic fluid/placenta Facilitates sexual intercourse /receives semen Secretes acid which prevents infections (Mark first TWO only) 1.6. To keep the testes at a temperature that is lower than body temperature /optimum temperature for sperm production which is necessary for the production of healthy sperm /so that healthy sperms can survive 1.7. FSH OR Oestrogen (Mark first ONE only) 1.8. The follicle develops during this period stimulated by increased levels of FSH -The lining of the endometrium thickens during this period stimulated by increased levels of oestrogen (Mark first ONE only) Any(1 x 2) 1.9. Corpus luteum has not disintegrated it continues to secrete progesterone so the endometrial lining remains thickened The zygote - undergoes mitosis - until a ball of cells is formed called a morula The morula continues to divide and forms a mass of cells with a hollow cavity called a blastocyst the outer membrane of the blastocyst forms chorionic villi / attachment villi which attaches it to the endometrium (Any 3) (a) For family planning / to know when they can get pregnant (b) LH /FSH/oestrogen There is a rise in levels of LH/FSH/oestrogen around the time of ovulation (3) Question 2 The zygote divides by mitosis - to form a ball of cells - called the morula - More mitotic divisions of the morula occurs to form a hollow ball of cells - called a blastocyst - The blastocyst attaches to the endometrial lining - The outer wall of the blastocyst, called the chorion, - develops projections called villi which - embeds/implants into the uterine wall - The cells of the embryo continues to divide - and differentiate - to form the different organs and limbs - and is now called a foetus - The foetus is enclosed in a sac called the amnion - filled with amniotic fluid - which protects the foetus against temperature fluctuations - protects the foetus against dehydration - and protects the foetus against mechanical injury /acts as a shock absorber - The chorionic villi and the endometrium form the placenta - where the blood of both the foetus and the mother - run close to each other - allowing for nutrients to diffuse into the blood of the foetus - The umbilical vein - carries the absorbed nutrients from the mother to the foetus Page7

8 Question Epididymis (b) Testis (c) Vas deferens /sperm duct 3.2 Stores sperm cells (Mark first ONE only) 3.3 Sperm cells will not pass to urethra to fertilise the egg and hence he will not be able to have children (3) 3.4 The HI virus may still be passed on during sexual intercourse through the secretions of the accessory glands (3) 3.5 Heated car seats/ Substance abuse/ Anti-sperm antibodies/mark FIRST TWO only (2 x 1) 3.6 Diploid /germinal epithelial cells/ in the seminiferous tubules of the testes undergo meiosis to form haploid sperm cells Any three (3) 3.7 Acrosome /Fallopian Tube (2) 3.8 FSH is secreted by the pituitary gland to stimulate follicle development LH is secreted by the pituitary gland to stimulate ovulation (4) Question a. B (b) A (2) 4.2. It allows free movement of the foetus / Maintains a constant temperature/ Acts as a shock absorber/ Prevents desiccation/drying out of the foetus Mark FIRST ONE only (1) 4.3. Helps to prevent infections from passing from mother to foetus Helps to prevent blood from mixing (2) 4.4. Mark FIRST TWO only+1(table) (5) Page8

9 Question 5 Question i. 5 FSH; ii. 6 LH (2) 6.2. i. 1 Graafian follicle; ii. 7 - oestrogen. (2) Corpus luteum progesterone maintenance of endometrium (2) 6.4. So attachment of the blastocyst can occur (1) 6.5. End of cycle, so menstruation should occur (progesterone and oestrogen should fall), unless pregnant (2) 6.6. Shorter in cow, less time for ovulation to occur. (2) Page9

10 Multiple Choice Questions Question 1 The type of reproduction in which young develop from the eggs that are kept in the mother's body but do not receive nutrition from the mother: A. Vivipary B. Ovipary C. Ovovivipary D. Altricial Question 2 Which ONE of the following hormones is responsible for the development of secondary male characteristics? A. FSH B. Testosterone C. Oestrogen D. Progesterone Question 3 The number of chromosomes found in a human sperm cell is A. 23. B. 22. C. 46. D. 47. Question 4 Spermatozoa (sperm cells), from the time of their development until the time of ejaculation, are transported through the male reproductive passageways. A number of structures of the reproductive system are listed below: 1. seminal vesicles 2. vas deferens 3. seminiferous tubules 4. urethra 5. epididymis Which sequence of numbers best describes the route taken by the sperm cells from where they are produced until they leave the male s body? A. 1, 2, 5, 4 B. 3, 1, 5, 4 C. 3, 5, 2, 4 D. 5, 3, 2, 4 Question 5 During the development of the embryo, the function of the amnion is to A. give rise to the placenta B. protect the embryo against harmful chemical substances C. enclose the fluid which protects the embryo against injury D. prevent the developing embryo from moving about Question 6 The following is NOT a function of the placenta of mammals: A. transports nutrients to the embryo B. removes waste products from the embryo C. protects the embryo against mechanical injury D. protects the embryo against harmful chemical substances Page10

11 Question 7 The fusion of an egg cell and a sperm cell is known as A. fertilization B. cleavage C. copulation D. ovulation Question 8 The human embryo obtains: A. nutrients and oxygen from the mother s blood B. nutrients and CO 2 by diffusion across the placenta C. yolk and albumen from the allantois D. nutrients and oxygen by diffusion across the placenta Question 9 Which of the following pairs indicates a reproductive structure and its function accurately? A. Fallopian tube production of sperm B. Vagina fertilisation C. Uterus development of the embryo D. Testes production of the ovum Question 10 The following are various forms of contraception: (i) (ii) (iii) (iv) (v) condoms the pill IUD abstinence vasectomy Which of the following contraception methods will reduce the risk of transferring STDs? A. (i), (ii) and (iii) B. (i) and (v) C. (i) and (iv) D. (i), (iii) and (iv) Solutions to Multiple Choice Questions 1. C 2. B 3. A 4. C 5. C 6. C 7. A 8. D 9. C 10. C Page11