Inheritance,Variation and Evolution

    Cards (213)

    • DNA
      Deoxyribonucleic acid, the chemical that all of our genetic material is made of
    • DNA
      • It's a polymer made up of lots of similar units stuck together
      • It has two strands which are stuck together to form a double helix
    • If you unraveled all the DNA in a single cell, the strand would be over two meters long</b>
    • Chromosome
      A really tight coil of DNA, there are 46 chromosomes in each of our cells
    • There are only 23 different types of chromosomes, as we have two of each type, one from each parent
    • Sex chromosomes
      The 23rd pair of chromosomes, women have two X chromosomes, men have one X and one Y
    • Chromosomes only look like an X shape just before cell division, usually they look more like long strands
    • Gene
      A small section of DNA that codes for a particular type of protein
    • There are only 20 different types of amino acids, but they can be combined in many different sequences to form thousands of different proteins
    • Genome
      The entire set of genetic material in an organism
    • Scientists have now worked out the complete human genome, the entire code that our DNA holds
    • Genes can either directly cause certain diseases (inherited diseases) or just increase the risk of diseases
    • Genomes can be used to trace the migrations of our ancestors by looking at small differences between populations
    • Allele
      Different versions of the same gene
    • Homozygous
      Having two of the same alleles for a particular gene
    • Heterozygous
      Having two different alleles for a particular gene
    • Dominant allele
      The allele that gets expressed when present, regardless of the other allele
    • Recessive allele
      The allele that only gets expressed when two copies are present (homozygous recessive)
    • Genotype
      The entire collection of alleles an organism has
    • Phenotype
      The characteristics an organism displays, determined by its genotype
    • Characteristics are often determined by the interaction of multiple genes
    • Genes code for different forms of the same protein, which are called alleles
    • Inheriting two of the same alleles results in a homozygous genotype, while inheriting two different alleles results in a heterozygous genotype
    • When a dominant and recessive allele are present in a heterozygous genotype, the dominant allele is expressed and the recessive allele is not
    • The only way to have a recessive trait expressed is to have two copies of the recessive allele (homozygous recessive)
    • The genotype determines the phenotype, but organisms with different genotypes can have the same phenotype
    • DNA
      Two strands wrapped around each other in a double helix
    • Structure of DNA
      1. Nucleotides
      2. Complementary base pairing
      3. How a gene codes for a protein
    • Nucleotide
      Monomer that makes up DNA, consisting of a phosphate, sugar, and base
    • Bases in DNA
      • Adenine
      • Thymine
      • Cytosine
      • Guanine
    • DNA
      • Polymer made up of many nucleotides
      • Phosphate and sugar form a backbone
      • Bases stick out and pair up between strands
    • Complementary base pairing
      A pairs with T, C pairs with G
    • How to determine complementary DNA strand

      Look at original strand and pair bases accordingly
    • Genetic code
      Sequence of DNA bases
    • Gene
      Specific sequence of bases that codes for a protein
    • How a gene codes for a protein
      1. DNA sequence read as triplets
      2. Triplets code for specific amino acids
      3. Amino acids combine in order to form a protein
    • Proteins
      • Unique shape allows them to carry out specific functions
      • Main uses are in enzymes, hormones, and structural proteins
    • Protein synthesis
      The process of making proteins
    • Protein synthesis
      1. Transcription
      2. Translation
    • Transcription
      The process of taking a single gene of DNA and copying it into a structure called mRNA
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