INHERITANCE/VARIATION/EVOLUTION

    Cards (81)

    • what is asexual reproduction?
      • only one parent
      • no fusion of gametes so no mixing of genetic information
      • genetically identical oddspring
      • mitosis
    • what reproduces asexually?
      PLANTS: strawberry plants send out long shoots called runners which touch the grown and grow a new plant
      PLANTS: daffodils produce lots of smaller bulbs which can grown into new plants
      FUNGI: spores
      MALARIA PROTISTS: when they are in human hosts
    • what is sexual reproduction?
      • 2 parents
      • fusion of gametes - male and female
      • sperm and egg cells
      • pollen and egg cells in flowering plants
      • varied genetic information
      • meiosis
    • what is meiosis?
      1. cells with two pairs of chromosomes (diploid cell)
      2. each chromosomes replicates itself
      3. chromosomes part company and move to opposite poles
      4. cell divides for the first time
      5. copies now separate and the second cell division takes place
      6. 4 haploid cells each with half the number of chromosomes of the parent cell
    • what happens when a cell divides via meiosis?
      • copies of the genetic information are made
      • the cell divides twice to form 4 gametes each with a single set of chromosomes
      • all gametes are genetically different from each other
    • what is a gamete?
      a sex cell
    • why is meiosis important?
      it halves the number of chromosomes in gametes - meaning that fertilisation can restore the full number of chromosomes in a noraml adult body cell
    • what is DNA?
      the genetic material in a nucleus of a cell is made of a chemical called DNA
    • where is DNA contained?
      in structures called chromosomes
    • what is a gene?
      a small section of DNA on a chromosome
    • what does each gene code for?
      a particular sequence of amino acids to make a specific protein
    • what is a genome?
      the entire genetic material of the organism
    • what are the important uses of the whole human genome?
      • doctors can search for genes linked to different disorders
      • it can help scientists to understand the cause of inherited disorders and how to treat them
      • scientists can investigate how humans may have changed over time
    • size order?
      DNA
      GENE
      CHROMOSOME
      NUCLEUS
      CELL
    • what are some characteristics controlled by?
      a single gene
    • what is an allele?
      An allele is a variant form of a gene that determines a specific trait or characteristic.
    • where does an individual get its alleles from?
      parents - one from the father and one from the mother
    • what is a genotype?
      the combination of alleles present in a gene - represented by two letters one for each allele like BB or Bb or bb
    • what is a phenotype?
      how the alleles are expressed (what characteristics appears) like eye colour so blue/brown/green
    • what can alleles be?
      recessive or dominant
    • what is homozygous?
      if the two alleles present are the same like BB or bb
    • what is heterozygous?
      if the two alleles present are different like Bb
    • what are most characteristics controlled by?
      several genes working together
    • what is monohybrid inheritance?
      if only one gene is involved
    • what are Punnett squares used for?
      Predicting genetic outcomes
    • what can Punnett squares use?
      capital letters for dominant alleles and lower case letters for recessive alleles
    • this is an example of what?
      a punnett square
    • what is Polydactyly?
      • having extra fingers or toes
      • caused by a dominant allele
      • only one copy of the dominant allele is needed for the Polydactyly pheneotype
    • what is Cystic fibrosis?
      • a disorder of cell membranes
      • caused by a recessive allele
      • both copies of the recessive allele are needed for the cystic fibrosis phenotype
    • what are the risks of embryonic screening tests?
      it could be false positive or negative
    • what are sex chromosomes?
      Chromosomes determining biological sex.
    • what is XX?
      female
    • what is XY?
      male
    • inherited sex chromosomes?
      • one sex chromosome from the mother (always X)
      • one sex chromosome from the father (X or Y)
      1. half the sperm cells carry X chromosomes and half carry Y
      2. all egg cells carry X chromosomes
      3. if an X sperm fertilises the egg a girl is produced
      4. if an Y sperm fertilises the egg a boy is profuced
    • what is variation?
      the difference in characteristics of an individual
    • what factors may affect variation?
      • the genes that individuals have inherited (genetic)
      • the conditions in which individuals have developed (environmental)
      • a combination of genetic and environmental
    • what are mutations?
      create new alleles
    • mutations?
      • permanent changes in the DNA of a cell
      • occur continuously in organisms at a very low rate
      • often have no effect on the phenotype (the protein produced is unaffected by the mutation)
      • can more often be harmful but are occasionally useful
    • what is evolution?
      the gradual change of the characteristics of a species over a long period of time - this can lead to a formation of a new species