Biology Study Sheet for Ib Students

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Study Guide for Human Reproduction – IB Biology
Draw a labelled diagram of the reproductive system of a human female. (6 Marks) Must include ovaries, Oviduct, Uterus, cervix, endometrium as shown on frontal view page 970

Draw a labelled diagram of an adult male reproductive system. (Total 6 marks)
Must include epididymis, seminal vesicle, vas deferens, testis, prostate gland, urethra, and bladder as shown on frontal view page 971

List 3 roles of testosterone males
·Development of external reproductive structures
·Sperm production
·Development of secondary sex characteristics like deepening of voice, pubic hair and muscle growth Explain how hormones control the menstrual cycle in human females (Total 8 marks)
·FSH stimulates the development of follicles;
·The developing follicle then secretes estrogen
·estrogen stimulates the thickening of the uterus lining
·estrogen also stimulates LH secretion;
·LH surge causes ovulation and development of the Corpus luteum; ·The Corpus luteum then secretes progesterone;
·progesterone causes further thickening of the uterus lining in preparation for fertilized egg implantation;
·progesterone / estrogen also inhibits the secretion of LH / FSH to prevent further ovulation ·falling progesterone levels at the end of the cycle allow FSH production to start next menstrual cycle8 max

Be Able to draw graphs B and D to go along with the explanation of hormonal changes

Outline the process of in vitro fertilization (IVF). (4 marks) ·The oocytes/eggs are mixed with sperm in culture dishes and incubated for several days to allow the fertilized eggs to start developing ·When they have developed into embryos of at least eight cells each, the embryos are carefully inserted into the woman uterus and allowed to implant. Discuss the ethical issues associated with IVF (3 marks)

·Can cause financial barriers
·There are often, many surplus fetuses conceived as a result of IVF. Some of these may be destroyed through this process. ·There are risks

Compare the processes of spermatogenesis and oogenesis. (7 marks) Similarities

·both involve meiosis;
·LH / FSH involved in both;
Differences
·testes versus ovaries;
·spermatogenesis until death versus oogenesis until menopause; ·spermatogenesis continuously versus oogenesis in a cycle; ·millions of sperm daily versus one egg per month;
·spermatogenesis involves equal divisions (all viable) versus oogenesis involves unequal cell / cytoplasm divisions resulting in smaller polar bodies; ·polar bodies are not viable and break down

·spermatogenesis involves Sertoli /
nurse cells versus oogenesis does not;

Outline the process of fertilization in humans. (5 marks)
·sperm enters oviduct (fallopian tube) and swims toward egg ·sperm attracted to egg
·When sperm contacts egg (usually in the oviduct) it releases enzymes which break down the jelly-like coating of the egg. ·this is called the acrosome reaction.
·membranes of egg and sperm fuse and sperm (head) penetrates egg membrane ending in fertilization;

Production of semen involves a series of processes, which in total take many weeks to carry out. Outline the processes involved in semen production from the start of sperm formation (spermatogenesis) to ejaculation. (Refer to Figure 46.11) (Total 9 marks)

·cell division of diploid cells by mitosis produces large numbers of Spermatogonia · growth of spermatogonia form larger cells called primary spermatocytes; ·These primary spermatocytes divide by meiosis I to form haploid secondary spermatocytes ·A second division (meiosis II) produces haploid spermatids · These spermatids differentiate (grow tail and other features) into sperm ·Sertoli Cells provide nutrients to the developing sperm

·sperm mature in the epididymis where they gain motility (ability to move); ·fluid added to sperm by seminal...
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