Biology

• Follicle stimulating hormone (FSH)


  Secreted by pituitary gland, causes egg to mature and stimulates ovaries to release estrogen
• Where and by what Is oestrogen Produced

  Oestrogen is produced in the ovary by the Graafian follicle
• what are sex hormones

  Hormones involved in sexual development and reproduction
• Oestrogen


  Hormone produced in the ovaries by the Graafian follicle
• Progesterone


  Hormone produced in the ovaries by the corpus luteum
• Oestrogen and Progesterone during pregnancy


  Produced by the placenta
• Role of hormones in controlling the menstrual cycle and pregnancy

  1. Oestrogen repairs and thickens the uterus lining

  2. Oestrogen stimulates the pituitary gland to produce LH

  3. Progesterone maintains the lining and prevents it from breaking down

  4. Progesterone thickens the uterus lining even more

  5. Progesterone inhibits the production of FSH by the pituitary gland

  6. A fall in progesterone leads to menstruation
• 6 causes of infertility

  • Gonorrhoea which leads to blockage of oviducts or sperm duct
  • Irregular menstrual cycle- decreases chances of fertilisation
  • Non production of ova-no ovum is present in the duct
  • Embryo not implanting
  • Chemical contraceptive causing infertility
  • Low sperm count in males
• where is the graafian follicle contained

  Contained in the ovaries
• what is contracept

  Any artificial method that people use to prevent pregnancy
• How pregnancy starts


  1. FSH stimulates an egg in one of the ovaries to develop

  2. LH triggers the release of the egg (ovulation)

  3. Egg passes along the fallopian tube

  4. Egg could combine with a sperm cell to form a fertilized egg

  5. Fertilized egg continues along the fallopian tube to the uterus and implants into the wall
• Cervix

  The entrance to the uterus
• Copper IUD


  Doesn't involve hormones, prevents sperm from surviving in the uterus
• Name the four types of birth control

  1. Natural method
  2. surgical
  3. barrier/mechanical
  4. surgical
• progesterone in contraceptive pill

  The hormone progesterone is contained in the contraception pill to prevent ovulation. It also thickens the cervical mucus to prevent sperm cells from entering
• What does the IUD stand for and what does it prevent

  it’s stands for intrauterine device and it prevents fertilization and implantation
• Explain the contraception method of the implant

  • it is a small rod that is about the size of a matchstick and it’s filled with progestero.
  • it is placed under the skin of the upper arm and releases hormones to prevent ovulation
  • it also thickens the cervical mucus to prevent the Sperm to travel to the egg
• What is a diaphragm


  it is a device that is placed into the vagina and covers the cervix to prevent sperm from reaching the eggs
• What is tubal ligation

  This is a surgical procedure which involves the blocking or sealing of the fallopian tubes which link the ovaries to the uterus. The eggs wont reach the sperm cells and therefore won’t be fertilized
• Will eggs still be released from the ovaries after a woman has been Sterilised

  Yes the egg will still be released but will be absorbed into the womAns bo naturally
• Most genes have more than one form what are these different forms of genes called

  Alleles
• What is inheritance 


  The transmission of genetic information from generation to generation
• Chromosome


  A thread-like structure of DNA, carrying genetic information
• Inheritance


  The transmission of genetic information from generation to generation
• Haploid nucleus


  A nucleus containing a single set of unpaired chromosomes (e.g. in gametes)
• Diploid nucleus


  A nucleus containing two sets of chromosomes (e.g. in body cells)
• Gene


  A length of DNA coding for a specific protein
• Alleles


  Alternative forms of the same gene that code for different versions of the same characteristics
• Genetic code


  The sequence of bases in a gene to form an order for a specific protein
• DNA controls cell function


  By controlling the production of proteins, antibodies and receptors for neurotransmitters
• Genotype


  The genetic make-up of an organism in terms of the alleles present
• Phenotype


  The observable features of an organism
• Homozygous


  Having two identical alleles of a particular gene
• Heterozygous


  Having two different alleles of a particular gene
• Dominant allele


  An allele that is expressed if it is present
• Recessive allele


  An allele that is only expressed when there is no dominant allele of the gene present
• What are chromosomes made up of 


  They are made up of deoxyribonucleic acid and protein
• Genotype


  The genetic make-up of an organism in terms of the alleles present
• Phenotype


  The observable features of an organism
• Homozygous


  Having two identical alleles of a particular gene