• What bonds do DNA/RNA polymerase catalyse?

  Phosphodiester bonds
• Name the monomer of a nucleic acid.

  Nucleotide
• State the five possible bases of a nucleotide.

  Adenine, guanine, thymine, cytosine, uracil
• State the three components to a DNA nucleotide.

  Deoxyribose + Nitrogenous base + Phosphate group
• The two strands of the double helix are ............. to each other.

  antiparallel
• Thymine, cytosine and uracil belong to a group of bases. Name the group.

  Pyrimidines
• Adenine and guanine belong to a group of bases. Name the group.

  Purines
• State the complementary base pairings.

  A-T/U, C-G
• State the number of hydrogen bonds formed between adenine and thymine/uracil.

  2
• State the number of hydrogen bonds formed between cytosine and guanine.

  3
• Why is DNA replication described as semi-conservative?

  Each new DNA molecule is made up of one new and one old/template strand
• State the enzymes involved in DNA replication.

  DNA helicase + DNA polymerase
• State the function of DNA polymerase.

  Catalyses formation of phosphodiester bonds between DNA nucleotides
• State the function of DNA helicase.

  Unzips DNA double helix, breaking hydrogen bonds
• The free nucleotides pair up with the exposed bases on the DNA strands based on ...... (which principle?)


  Complementary base pairing
• DNA polymerase can only build phosphodiester bonds on the daughter strand in a particular direction. What is this direction?

  5' to 3
• In which direction of the template strand does the DNA polymerase move in?

  3' to 5
• Define 'genetic code'.


  The sequence of bases in DNA that codes for the sequence of amino acids in protein production
• The genetic code is described as 'degenerate'. What does that mean?

  Many different triplet codes/codons can code for the same amino acid
• Define 'gene'.


  A section of DNA containing the base sequence that codes for a protein
• What is a codon?


  Triplet bases on RNA that codes for an amino acid
• What are the two differences between DNA and RNA?

  - DNA has deoxyribose and RNA has ribose

  - DNA has thymine and RNA has uracil
• Name the enzymes involved in transcription.

  DNA helicase + RNA polymerase
• Why is the antisense strand needed even though it does not code for proteins?

  - it acts as the template strand

  - to form the complementary mRNA with the same base sequence as the sense strand
• What type of bond does mRNA have?

  phosphodiester bonds
• Even though DNA codes for proteins directly, why is mRNA needed to be made for making proteins?

  DNA is too large to leave the nucleus through the nuclear pores
• How is rRNA involved in catalysing translation?


  - peptidyl transferase is an rRNA component

  - it transfers one amino acid to another
• Which part of tRNA binds to the mRNA?

  anticodon loop
• Name the amino acid that is always at the start of a protein.

  Methionine
• Describe what happens to the amino acid chain to make it a fully functional protein.


  - The amino acid chain folds into secondary and tertiary structures

  - May undergo further modifications at Golgi
• State the two stages of protein synthesis.

  Transcription + Translation
• Name the product of transcription.

  mRNA
• Name the product of translation.

  Polypeptide (then becomes functional protein after modification in Golgi)
• State the location where translation occurs.

  Ribosomes
• What are the three main types of activities in cells that require energy?

  Synthesis, transport, movement
• What does 'ATP' stand for and what is it?

  Adenosine triphosphate, energy currency
• Draw the structure of ATP.

  Ribose sugar (pentose with O on top) + adenine on C1 + 3 phosphate groups on C5 (must show C5 as an angle off the pentose sugar)
• How does ATP release energy?

  ATP is hydrolysed into ADP + Pi, releasing energy
• State 3 properties of ATP.

  - Small - easy to move into and out of cells - Water-soluble

  - Releases energy in small quantities - so no heat loss

  - Easily regenerated by phosphorylation of ADP
• Describe DNA in eukaryotes

  - in the nucleus, wound around histone proteins into chromosomes

  - in a loop without histone proteins in mitochondria and chloroplasts