Reproduction

    Cards (45)

    • Mitosis involves only one parent. the offspring have identical genes to the parent - so there’s no variation between parent and offspring
    • what can mitosis be used for?

      Cell growth, repair, cloning and asexual reproduction.
    • Mitosis is when a cell reproduces itself by splitting to form two cells with identical sets of chromosomes
    • Mitosis:
      A diploid cell duplicates, the chromosomes line up, the spindle pulls the identical strands apart, the cytoplasm splits
    • Meiosis:
      A diploid cells chromosomes are copied, chromosomes with the same genes and similar sequences pair up and swap some DNA, the pairs divide creating 4 unique haploid cells
    • 1= bladder
      2= glands
      3= penis
      4=urethra
      5= sperm duct
      6= testes
      7= scrotum
    • 1= fallopian tube/oviduct
      2= ovary
      3= cervix
      4= uterus
      5= vagina
    • In meiosis the daughter cells are unique and have 23 chromosomes each. It is used to make sex cells (gametes)
    • (male) Urethra - contains urine or semen
    • Glands - produce fluid which combines with sperm to make semen
    • The penis ejaculates sperm into the vagina during sexual intercourse
    • Foreskin - protects the tip of the penis
    • Sperm duct - (aka vas deferens) connects testes with the urethra
    • Testis - make and store sperm
    • Scrotum - bag of skin allowing the testes to hang outside the body, keeping the sperm cells cool
    • Oviduct/ fallopian tube - where fertilisation occurs, ciliates cells help push the egg along, caries the ovum from ovary to uterus
    • Uterus - where the embryo implants and develops
    • Cervix - ring of muscle
    • Bladder - stores urine
    • (female) Urethra - urine leaves through
    • Vagina - where penis is placed during sexual intercourse
    • Ovary - contains sex hormones and egg cells that can mature each month
    • erectile tissue - swells when filled with blood to make the penis errect
    • endometrium - lining of uterus, has a good blood supply for implantation of an embryo
    • hormones:
      female = oetrogen
      male = testosterone
      these trigger secondary sexual characteristics
    • ova - female gametes
      sperm - male gametes
    • the menstrual cycle lasts for 28 days:
      • day 1-4 = menstruation starts, uterus lining breaks down
      • day 4-14 = uterus lining builds up into a thick, spongy layer full of blood vessels, ready to receive a fertilised egg
      • day 14 = ovulation, an egg develops and is released from the ovary
      • day 14-28 = the wall is maintained, waiting for a fertilised egg, then starts to brak down again
    • FSH - follicle stimulating hormone
      • produced in the pituitary gland
      • causes an egg to mature in one of the ovaries
      • stimulates ovaries to produce oestrogen
      • oestrogen the prevents the release of FSH
    • oestrogen:
      • produced in ovaries
      • stimulates the release of LH
    • LH - luteinising hormone:
      • produced by pituitary gland
      • stimulates release of an egg on day 14
    • progesterone:
      • produced in the ovaries after ovulation
      • maintains the lining of the uterus during second half of the cycle. when progesterone levels fall, the lining breaks down
      • prevents release of FSH and LH
    • Placenta - lets the blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste (urea and carbon dioxide) by diffusion
    • amniotic sac - surrounds the embryo and is full of amniotic fluid, protecting the embryo against bumps
    • During the first week of development, the zygote moves through the Fallopian tube towards the uterus where it implants itself into the endometrium (lining).
    • if pregnancy occurs progesterone continues to be produced from the follicle
    • at week 12 of pregnancy an embryo becomes a foetus
    • During the first week of development, the zygote moves through the Fallopian tube towards the uterus where it implants itself into the endometrium (lining).
    • stamen contains:
      • anther - contains pollen (male gametes)
      • filament - stalk that supports the anther
    • carpel contains:
      • stigma - pollen grains stick to
      • style - supports the stigma
      • ovary - contains ovules (female gametes)
    • pollination - the transfer of pollen from an anther to a stigma so the male gamete can fertilize the female gamete in sexual reproduction
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