Wk 12- Meiosis Fertilisation Development

Gametes = – individual chromosomes = h? Cell Fertilisation = 1 paternal gamete (– cells) + 1 maternal gamete (– cells) These form a z? = D ? Cell made of – PAIRS of chromosomes (– chromosomes)

Meiosis: Produces H? Cells Undergoes 2 rounds of cell division Meiosis 1 and meiosis 2 Meiosis 1 = 1 cell > ? genetically different cells sister chromatids/cells attached to one another Meiosis 2 = 1 cell > ? (t?) all genetically different cells

Mitosis: 1 cell > ? Identical daughter cells Meiosis = ? Genetically different cells

Fertilisation The fusion of s? and o? membrane Combination of 46 chromosomes forms a ? Sperm have 23 chromosomes only Oocytes have 23 chromosomes + ?

Zygote > m? in - days M? > b? in - days B? > imp? in ? Days B? secretes enzymes that burrow/ burn into endometrium

Embryonic development takes place in week ?-? Fetal development takes place in week ?-? birth

Early embryonic development Heart cells start beating Early gut and limb buds E? / e? Start develop T? Forms Blood and b? Vessels form

Embryonic 5-8 weeks Heart has - chambers Increase brain development Limbs more distinct D? Visible T? Disappears O? Develop

Fetal 3 months Heart beat detectable Head - whole body Brain increase size External e? Develop O? Begins G? Visible

Fetal 5 months Body size increases proportionate to h? E? Open Limbs lengthen Increase development of body s? N? Visible Red bone marrow produces increase b? Cells

Maternal nutrition Fetus receives nutrition from m? Fetal development can change to a? to available nutrients Decreased nutrition in utero = increase risk of C? Disease Hyper? O? Type 2 diabetes R? Failure Reduced life span