Inheritance, Variation and evolution

    Cards (52)

    • Meiosis
      Cell divides twice to produce 4 gametes
    • Types of reproduction
      • Asexual
      • Sexual
    • Fusion of male and female gametes
      Occurs in animals with sperm and egg, and in flowering plants with pollen and egg
    • Asexual reproduction
      • One parent
      • No fusion of gametes
      • No mixing of genetic information
      • Produces clones
    • Sexual reproduction
      • Requires fusion of male and female gametes
      • Allows mixing of genetic information
      • Creates variation
      • Allows natural selection to increase the chances of surviving environmental changes
      • Allows selective breeding by humans to increase food production
    • Mitosis
      Cell divides by mitosis then differentiates
    • DNA Structure
      • Consists of 2 strands forming a double helix
      • Organised into chromosomes
      • Four types of repeated nucleotides A to T, G to C
      • Nucleotides made of sugar, phosphate, and base (A, T, G, or C)
      • Sequence of 3 nucleotides codes for an amino acid in a protein
      • Change in structure may lead to a change in the protein
      • Synthesised using a template on ribosomes
      • Carriers bring amino acids to the template in correct order
    • Genome
      • The entire genetic material in an organism
    • Gene
      • A section of DNA that codes for a sequence of amino acids to make a protein
    • Non-coding DNA
      • Controls expression of gene
    • Allele
      • Different form of a gene
    • Sex
      • Male (XY)
      • Female (XX)
      • Dominant
      • Recessive
      • Genotype (The alleles of an organism contribute to the phenotype)
      • Altered shape or function
    • Variation
      • Change in inherited characteristics over time
      • Due to natural selection
      • Can lead to formation of new species
    • Cloning animals
      1. Remove nucleus from unfertilised egg cell
      2. Replace with nucleus from adult body cell (e.g skin cell)
      3. Give egg cell an electric shock - stimulates cell division
      4. When embryo develops, place in womb of adult to develop
    • Cloning animals

      • Produces offspring with identical genetic information to parent
    • Other cloning methods
      1. tissue culture/cuttings (plants)
      2. embryo transplants (animals)
    • Cloning animals
      • Remove nucleus from unfertilised egg cell
      • Replace with nucleus from adult body cell (e.g skin cell)
      • Give egg cell an electric shock - stimulates cell division
      • When embryo develops, place in womb of adult to develop
    • Genetic engineering
      1. Desirable gene isolated using enzymes
      2. Gene inserted into vector (usually bacterial plasmid/virus)
      3. Gene transferred to target organism early in development
    • Genetic engineering
      • Involves modifying an organism's genome to give it desirable characteristics
      • Genes from other organisms can be added
    • Genetic engineering
      • Desirable gene isolated using enzymes
      • Gene inserted into vector (usually bacterial plasmid/virus)
      • Gene transferred to target organism early in development
    • Risks of genetic engineering
    • Benefits of genetic engineering
    • Benefits of genetic engineering
      • Improve crop yield
      • Produce materials for medicines
      • Less waste
    • Benefits of genetic engineering
      • Bacteria modified to produce insulin
    • Bacteria modified to produce insulin
    • Proves that bacteria are evolving
      • MRSA
    • Evidence for evolution
      • Theory of evolution
      • Speciation
      • Genetics
      • Fossils
      • Antibiotic resistance
    • Ways to combat antibiotic resistance
      • Only prescribe where needed/restrict agricultural use
      • Complete course of antibiotics
    • Extinction
    • Reasons for extinction
      • Due to: habitat destruction, hunting, climate change, pollution, competition
    • Compare ancient organisms to current organisms
      Proof that characteristics are passed onto offspring in genes
    • A new species is formed when
      The groups can no longer interbreed to produce fertile offspring
    • Charles Darwin: 'Proposed theory of evolution by natural selection'
    • Organisms with beneficial characteristics
      Are more likely to survive and reproduce so pass them on to their offspring
    • The theory of evolution by natural selection was not initially accepted due to religious beliefs at the time
    • The theory of evolution by natural selection is now widely accepted as true due to improvements in technology finding new evidence, as well as the science behind it being understood
    • Gregor Mendel: 'Parents pass characteristics to offspring through ‘units’. These are now known as genes'
    • Alfred Russel Wallace
      Population splits and the two groups become isolated for a long time - evolve differently, eventually form new species
    • Chromosomes were observed during cell division in the late 19th century
    • DNA structure was determined in the mid 20th century