mock nucleic acids

• what are the functions of DNA

  1) stores genetic information 2) replicates itself
• what is the function of DNA

  protein synthesis from the instructions in DNA
• what is the structure of DNA

  two polypeptide strands joined by hydrogen bonding between the complementary base pairs the two antiparallel strands twist to form the DNA double-helix
• what does DNA stand for

  deoxyribonucleic acid
• what are the 4 bases of DNA

  Adenine, Thymine, Guanine, Cytosine
• what are the monomers of DNA

  nucleotides
• what are the 3 components of nucleotides

  pentose sugar, phosphate group, organic nitrogenous base
• list the elements found in a nucleotide

  oxygen, carbon, hydrogen, nitrogen, phosphorus
• describe the type of bond that joins nucleotides together

  phosphodiester bond (2 ester bonds) - strong covalent bond between the sugar and the phosphate group
• what is the benefit of the bond that holds the nucleotides together

  it gives the molecule strength and protects the genetic code
• How are two polynucleotide strands held together?

  weak hydrogen bonds between the bases
• define antiparallel

  the strands run next to each other from 3' to 5' in opposite directions
• what does the 5' end mean

  it ends with phosphate which has carbon 5 at the end
• what does the 3' end mean

  it ends with hydroxyl which has carbon 3 at the end
• what type of reaction occurs when a phosphodiester bond forms between 2 nucleotides

  condensation reaction - water is released
• what are adenine and guanine called and why

  purines because they have a double ring structure
• what are cytosine and thymine called and why

  pyrimidines because they have a single ring structure
• How many hydrogen bonds between A and T?

  2
• how many hydrogen bonds between C and G?

  3
• Why does a purine always pair with a pyrimidine?

  so the bases are consistent distances apart to give stability
• What are the 3 differences between DNA and RNA?

  1) DNA has a deoxyribose sugar, RNA has a ribose sugar

  2) DNA has a Thymine, RNA has Uracil

  3) DNA is usually double stranded, RNA is usually single stranded
• what are DNA and RNA

  nucleic acids
• How many DNA bases code for an amino acid?

  3
• what is another word for a base triplet

  codon
• what is the genetic code

  the sequence of codons in DNA or mRNA which codes for a specific sequence of amino acids
• what is a start codon

  when it comes at the beginning of a gene it signals the start of a sequence that codes for a protein
• what happens if the start codon is in the middle of the sequence

  it codes for the amino acid methionine
• what is a stop codon

  they don't code for any amino acids and signal the end of the sequence
• what is the purpose of stop and start codons

  they ensure that the genetic code is read from the first base so it is non-overlapping
• what is the function of DNA helicase

  travels along the DNA backbone, catalysing reactions that break the hydrogen bonds between the bases
• what is the function of DNA polymerase

  catalyses the formation of phosphodiester bonds between the nucleotides
• what are histones

  proteins that DNA wraps around to form chromatin
• list the steps for DNA extraction

  1) grind the sample using mortar and pestle

  2) add the fruit, salt and detergent to a beaker and stir

  3) place the beaker in a water bath of 60°C for 15mins

  4) filter the mixture then cool in an ice bath

  5) add protease enzyme and RNase enzyme

  6) add ice cold ethanol

  7) use a glass rod to remove the DNA
• why is the sample grinded

  to break down the cell walls
• why is salt added

  to cause the DNA to clump together
• why is detergent added

  to break down the cell membranes
• why is the mixture heated

  to denature the enzymes in the cell so they don't digest the DNA
• why is the mixture cooled rapidly

  so the protease enzymes don't denature
• why is the protease enzyme added

  to break down the histone proteins that DNA is wrapped around
• why is RNase added

  to break down the RNA