Genes

• What are the four letters for the DNA bases?

  A C G T
• What are the full names for the bases?

  A - adenine

  C - cytosine

  G - guanine

  T - thymine
• what does ’A’ always pair with?


  T
• what does ‘C’ always pair with?


  G
• what are proteins made up of?

  long chains of amino acids
• different combinations of amino acids make different proteins
• how many bases are needed to make an amino acid?

  three
• What does DNA stand for?

  Deoxyribonucleus acid
• what is a chromosome made up of?

  tightly coiled DNA
• how many chromosomes do humans have?

  46, 23 pairs
• what happens during transcription?

  1. the double helix ‘unzips‘ as bonds between complimentary bases break and the two polynucleotide strands separate
  2. one DNA strand acts as a template. Free nucleotides pair up with this exposed side to copy the base sequence of the gene
  3. The complimentary template molecule is formed called MRNA
  4. the MRNA detaches from the original strand. The two DNA strands join back together and wind into double helix
• true or false, DNA can leave the nucleus but MRNA cant

  false, MRNA can leave the nucleus but DNA cant
• Where does transcription happen?

  In the nucleus
• where does translation happen?

  in the cytoplasm
• When converted to MRNA ‘T’hymine is converted to ‘U’ as MRNA doesn’t have ‘T’
• what happens in translation?

  1. the MRNA molecule moves out through nuclear pore into ribosome
  2. amino acids are brought to ribosome on carrier molecules. they’re called TRNA
  3. the ribosome now reads of the triplets of bases on the MRNA and uses this to join together the correct amino acids in the correct order
  4. the ‘empty’ TRNA leaves to pick up another amino acid. ribosome moves along MRNA by one base triplet
• what are peptide bonds?

  the bonds between amino acids
• What the human genome project in 2003?

  A project that sequenced the human genome
• what are the advantages of sequencing the human genome?

  .understanding which genes are linked to specific diseases

  .understanding inherited disorders and their treatment

  .understanding how human migration has occurred in the past
• what is a codon?

  three bases