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Igcse biology edexcel 3.8 3.12

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Edexcell ppt Biology 3.8 - 3.12

Used in lessons to scaffold class teaching and as a revision resource for students

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Igcse biology edexcel 3.8 3.12

  1. 1. REPRODUCTION 3.1 understand the differences between sexual and asexual reproduction There are two types of reproduction; • Sexual: reproduction in which two gametes (sex cells) fuse to create a new offspring that is genetically different to the parents. Two parents are involved. • Asexual: reproduction without fusion of gametes. It involves one parent only and produces offspring that are genetically identical to the parent (clones).
  2. 2. Fertilization 3.2 understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo Definitions • Fertilization: • Zygote: • Embryo: A male and a female gamete fuse to form a zygote a cell that is the result of fertilization. It will divide by mitosis to form an embryo An organism in its early stages of development, especially before it has reached a distinctively recognizable form.
  3. 3. Structure and Function of Reproductive systems 3.8 describe the structure and explain the function of the male and female reproductive systems
  4. 4. Structure and Function of Reproductive systems 3.8 describe the structure and explain the function of the male and female reproductive systems
  5. 5. Structure and Function of Reproductive systems 3.8 describe the structure and explain the function of the male and female reproductive systems DRAW IN YOUR OWN DIAGRAM LABLE
  6. 6. MENSTRUAL CYCLE 3.9 understand the roles of oestrogen and progesterone in the menstrual cycle The menstrual cycle in women is a recurring process, taking around 28 days. During the process, the lining of the uterus - womb - is prepared for pregnancy. If pregnancy does not happen, the lining is then shed at menstruation. Several hormones control this cycle. Oestrogen The hormone oestrogen is secreted by the ovaries. Oestrogen makes two things happen: it stops more ovum being matured it causes the thinkening of the uterus lining Progesterone Progesterone is a hormone secreted by ovaries. It maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy.
  7. 7. MENSTRUAL CYCLE 3.9 understand the roles of oestrogen and progesterone in the menstrual cycle
  8. 8. MENSTRUAL CYCLE 3.9 understand the roles of oestrogen and progesterone in the menstrual cycle
  9. 9. PLACENTA 3.10 describe the role of the placenta in the nutrition of the developing embryo (TA) Diffuse from foetus to mother: 1) CO2 2) water, 3) Urea Diffuse from mother to foetus: 1) O2 2) glucose, 3) amino acids, 4) minerals
  10. 10. PLACENTA 3.10 describe the role of the placenta in the nutrition of the developing embryo (TA) The placenta is adapted for diffusion in much the same way as other exchange organs: 1. Huge surface area (it has lots of villi-like projections) 2. Only a few cells thick 3. Blood supplies keep the concentration gradients high 4. Counter-current system
  11. 11. AMNIOTIC FLUID 3.11 understand how the developing embryo is protected by amniotic fluid (TA)
  12. 12. SECONDARY SEXUAL CHARACTERISTICS 3.12 understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.

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