Genetics + Ecology P1.

Cards (68)

  • DNA
    Carries genetic information
  • RNA
    Transfers genetic information from DNA to ribosomes
  • Components of a DNA nucleotide
    • Deoxyribose
    • Phosphate group
    • Adenine
    • Cytosine
    • Guanine
    • Thymine
  • Components of an RNA nucleotide

    • Ribose
    • Phosphate group
    • Adenine
    • Cytosine
    • Guanine
    • Uracil
  • Purine bases
    Adenine and guanine
  • Pyrimidines
    Thymine, uracil and cytosine
  • Phosphodiester bonds

    Formed in condensation reactions to join nucleotides
  • DNA molecule
    Double helix composed of two polynucleotides joined by hydrogen bonds between complementary bases
  • RNA
    Relatively short polynucleotide chain
  • Genetic code
    Order of bases on DNA, consisting of triplets of bases coding for particular amino acids (codons)
  • Gene
    Sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain
  • Locus
    Location of a gene
  • Introns
    Non-coding sections of DNA
  • Exons
    Coding regions of DNA
  • Genetic code
    • Non-overlapping
    • Degenerate
    • Contains start and stop codons
  • Each amino acid is coded for by one or more combination of triplets, resulting in 64 possible triplets
  • Genes are separated by non-coding repeats of bases
  • A change in the base sequence of DNA alters the amino acid sequence and the protein, which can have various effects
  • Harmful mutations
    • Cystic fibrosis
    • Sickle cell anaemia
  • Eukaryotic cells
    DNA molecules are long and linear, found in the nucleus and associated with histones to form chromosomes
  • Prokaryotic cells

    DNA is short and circular, not associated with proteins
  • Homologous pairs
    Two chromosomes that carry the same genes, but can carry different alleles
  • Allele
    Alternative form of the same gene
  • Protein synthesis
    1. Transcription (in nucleus)
    2. Translation (in cytoplasm)
  • mRNA
    Long single strand created during transcription, with base sequence complementary to DNA
  • tRNA
    Small molecule made up of around 80 nucleotides, folded into a clover leaf shape with an amino acid attachment site and an anti-codon
  • Transcription
    DNA uncoils, one strand used as template to make mRNA, mRNA moves out of nucleus
  • Translation
    mRNA attaches to ribosome, tRNA collects amino acids and carries them to ribosome, amino acids join by peptide bonds to form polypeptide chain
  • Ribosomes can join up to 15 amino acids per second, and up to 50 ribosomes can move along the same mRNA strand
  • Substitution mutation
    One nucleotide in the DNA sequence is replaced by another
  • Deletion mutation

    A nucleotide in the DNA sequence is lost, leading to a frameshift
  • Polyploidy
    Changes in the whole set of chromosomes, resulting in more than two sets
  • Non-disjunction
    Chromosomes fail to separate correctly in meiosis, resulting in gametes and zygotes with one more or one less chromosome
  • Polyploidy
    • Many modern wheats
  • Non-disjunction
    • Down's syndrome
  • Meiosis
    Produces genetically different haploid gametes through independent assortment of chromosomes and crossing over of chromatids
  • Genetic diversity
    Total number of different alleles in a population
  • Niche
    Role of a species within its environment
  • Stages of Meiosis
    1. Meiosis 1: Homologous chromosomes pair up, crossing over may occur, cell divides with each daughter cell containing one chromosome from each homologous pair
    2. Meiosis 2: Chromatids of each chromosome are separated producing 4 haploid daughter cells
  • Genetic diversity
    The total number of different alleles in the population