Samenvatting inheritance and evolution

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Samenvatting - inheritance and evolution

  • 1 Genotype and phenotype

  • What is the phenotype of an organism?
    the apearance (the observable features) of that orgaism.
  • Where does your phenotype consist of?
    thousands of different characteristics or 'traits'. Many of those tratis are inherited from your parents (such as the colour of your hair, the colour of your eyes adn the shape of your face)
  • What does the nucleus  contain?
    chromosomes
  • What are chromosomes?
    Chromosomes are fine thread-like strands inside a cell’s nucleus.
    – These threads contain DNA.
    – DNA contains information for inherited traits.
    – Every nucleus contains the complete info
  • When do chromosomes become visable under a microscope?
    When cells start to divide the chromosomes become shorter and thicker.
  • What is the genotype of an organism?
    is the information for all inherited traits of that organism.
  • How many chromosomes does a human cell contain?
    46,  23 pairs of chromosomes
  • Are there different numbers of chromosomes per different species?
    yes. Alle these chromosomes occur in pairs.
  • Where does the phenotype of an organism depend on?
    on the genotype and environmental factors
  • What are environmental factors?
    Several external factors that may chage the phenotype, without changing the genotype.
  • Explain genotype in further detail:
    – The nucleus of every body cell contains this information.
    – All the genes inside a nucleus produce the genotype.
    – The genotype of an organism is determined during fertilization.
  • 2 chromosomes and genes

  • What are genes?
    • A gene: part of a chromosome that contains information for one inherited trait.
    – A chromosome contains many genes.
    – Genes occur in pairs in body cells.  
    – Sex cells contain single genes.
    – Genes are on or off. If a gene is on, it can be slightly active or very active.
  • What is is when a gene is turned on-off?
    than it might be slightly active or very active for that cell
  • What happens with fertilization?
    the nucleus of a sperm cell and the nucleus of the egg ell join. So, the chromosomes of the chromosomes of both cells are joined inside the nucleus of the egg.  Both nucleuses contain 23 chromosomes. So the nucleus of the fertiziled egg cell contains 46  chromosomes which are again in identical paris.
  • How does the production of new cells happen?
    during cell division
  • How does cell divison work when just fertilized?
    Parent cell divides into two cells and produces two daugther cells
    ( nothing happens to information inheritied traits (genotype) )
  • When is the genotype determined?
    at the moment of fertilization
  • 3 sexual reproduction

  • Of what may the pair of genes for one inherited trait consist?
    of two identical genes or two different genes
  • What happens during formation of sex cells with genotypes?
    During formation of sex cells, each sex cell contains one member of the gene pair. – This results in many different genotypes in sex cells.
  • What is sexual reproduction?
    the formation of a new individual followig the fusion of two sex cells. 
    - which genotype the sex cells cerry depends on coincidence.
  • Why does offspring always have combinations of genes that are different of their parents?
    Because there are many options which genotype a sex cell can carry.  So, the offspring will have genotypes that are different to those of their parents.
  • How do non-identical twins or fraternal twins develop?
    - sometimes two cells are released during ovulation
    -both of these egg cells can be fertilized by a sperm cell
    - both fertilized egg cells develop into a cluster of cells that nestle  into the lining of the uterus
  • How do identical twins develop?
    - one eg is fertilized by on sperm cell
    - the fertilized egg cell can divide and separate into two, resulsting in two identical cells
    - these cells develop separately into two clusters of cells and evetually both nestle into the uterus lining
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Voorbeelden van vragen in deze samenvatting

What is the phenotype of an organism?
1
Where does your phenotype consist of?
1
What does the nucleus  contain?
1
What are chromosomes?
1
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