B13 Reproduction

View mindmap
  • B13 Reproduction
    • 13.1 Types of reproduction
      • asexual- one parent, cell division by mitosis, genetically identical, used for growth and repair
      • sexual -     2 parents, cell division by meiosis, genetic info inherited from parents, variation
    • 13.2 Cell division in sexual reproduction
      • in meiosis, cell divides to form 2 chromatids and divides to from 4 gametes with half the no. of chromoso-mes
        • when 2 gametes fuse, the zygote will have a full set of chromoso-mes
    • 13.3 Best of both worlds
      • Fungi use asexual reproduction
        • 2 hyphae (a mass of thin threads) from different fungi join and the nuclei fuse for two sets of chromosomes
          • they undergo mitosis to make haploid spores with only one set of chromosomes
        • Fungal spores made by mitosis are clones.
      • malarial parasites reproduce asexually in blood cells
        • when the mosquito bites the human, a temp drop occurs
          • triggers sexual reproduction
            • from a zygote and undergos meiosis to make new parasites
    • 13.4 DNA and the genome
      • chromosomes made up of dna strands
        • dna is a polymer with double helix structure
      • genome is an organisms enitre genetic info
      • genes are sections of dna that code for proteins
    • 13.5 DNA structure and protein synthesis
      • dna is made up of nucleotides
        • made of a phospate, sugar and base
          • bases A and T bond and C and G
            • Adenine, Thymine, Cytosine, Guanine
      • genes produce a template which binds to a ribosome
        • carrier molecules bind to amino acids and attach to the template
          • when complete the chain folds up in a unique shape
    • 13.6 Gene expression and mutation
      • gene is expressed when it codes for a protein
      • mutations are change in genetic material
        • mutation in amino acids changes protein shape
          • possibly losing its active site and unable to bind with substrate
    • 13.7 Inheritance in action
      • alleles are different versions of the same gene
        • homozygous means identical
        • heterozygous means 2 different
    • 13.8 More about genetics
      • male sex chromosomes are XY
      • female sex chromosomes are **
    • 13.9 Inherited disorders
      • polydactyly causes extra finger or toe, caused by dominant allele
        • purely cosmetic
      • cystic fibrosis prevents movement or substances
        • mucus becomes thick and clogs organs
        • caused by recessive allele
        • no cure
        • treatment with antibiotics or physiotherapy
    • 13.10 Screening for genetic disorders
      • cells from embryo must be harvested to screen
        • amniocentes-is, 15-16 weeks
          • takes amniotic fluid which has fetal cells
        • chorionic vilus, 10-12 weeks
          • takes tissue from placenta
      • ivf isolates dna from embryo and tests it
      • expensive and no cures for genetic disorders
        • screening could result in 'designer babies'
  • increase risk of miscarrige


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Variation and reproduction resources »