Booklet 4 - DNA and Cell Division

Cards (16)

  • DNA
    The Blueprint of Life
  • DNA contains the instructions for making proteins within the cell
  • DNA
    DeoxyriboNucleic Acid
  • Nucleus
    • Contains chromosomes (a chromosome is one molecule of DNA tightly wound) that control the activities of the cell
    • Enclosed in a nuclear membrane
    • If the nucleus is removed or damaged the cell will die
  • Chromosomes and their genes are made of a molecule called DNA. DNA molecules carry the code that controls what cells are made of and what they do
  • DNA molecule
    Twisted ladder shape, called a DOUBLE HELIX
  • Chromosome
    • A tightly coiled strand of DNA found in the nucleus
    • In humans there are 46 chromosome strands (arranged into 23 homologous pairs)
    • Each chromosome has sections along it called genes, where the DNA code forms the instructions for making a protein in the cell
  • DNA was established by James Watson and Francis Crick, who discovered the shape of a double helix
  • DNA
    • Consists of two molecules arranged into a ladder-like structure called a Double Helix
    • Made up of millions of tiny subunits called Nucleotides
    • Each nucleotide consists of a Phosphate group, Deoxyribose sugar, and Nitrogenous base
  • Gene
    A segment of DNA that codes for proteins produced (traits)
  • Nucleotide
    Individual units of Nucleic Acids, consisting of a Phosphate, Deoxyribose (sugar), and Base (A,T,G,C)
  • DNA Bases
    • A, T, C, G
    • Base pairs hold the two strands of the DNA helix together
    • The sequence of these bases along a DNA molecule forms the genetic code
  • Base Pairing
    • A always pairs with T, C always pairs with G
    • Base pairs are held together by hydrogen bonds (2 bonds between A and T, 3 bonds between C and G)
  • DNA looks like a long ladder when uncoiled, with the side rails composed of Phosphates and Sugars, and the rungs composed of Base pairs joined by hydrogen bonds
  • DNA Backbone
    • The two side rails run in opposite directions, with one strand running from 3' to 5' and the opposite strand from 5' to 3'
    • The 3' and 5' refer to the carbon atoms in the sugar molecule that form a bond with the adjoining phosphate
  • It is estimated that every cell nucleus contains 2-3 metres of DNA, which is coiled around special proteins called histones to prevent tangling and affect gene expression