2.1.3

• what is a nucleotide?


  Monomers that form nucleic acids
• Nucleotides contain


  A nitrogenous base

  A pentose sugar

  A phosphate group
• types of nitrogenous bases


  purine and pyrimidine
• purines


  a base that contains 2 carbon rings
• examples of purines


  adenine

  guanine
• pyrimidine


  a base with 1 carbon ring
• examples of pyrimidines


  cytosine

  thymine

  uracil
• what pentose sugar is in RNA


  ribose
• what pentose sugar is in DNA


  deoxyribose
• What charge does a phosphate group have


  negative
• nucleotide structure

  A) phosphate

  B) pentose

  C) nitrogenous base

  D) O

  E) H

  
• Adenine is complimentary to


  thymine in DNA

  uracil in RNA
• guanine is complimentary to


  cytosine
• purines are always complimentary to


  pyrimidines
• why do purines always join with pyrimidines and why do base pairs exist?


  it helps to maintains the order of the genetic code during DNA replication
• polynucleotides


  nucleotides join via condensation reaction forming a phosphodiester bond between the phosphate group of one and the pentose sugar of another known as a phosphate sugar backbone
• ATP stands for


  adenosine triphosphate
• ATP structure

  A) phosphate groups

  B) adenine

  C) nitrogenous base

  D) ribose

  E) pentose sugar

  F) adenosine

  G) AMP

  H) ADP

  I) ATP

  
• Use of ATP


  in cell metabolism as an immediate source of energy
• when is ATP formed


  during respiration when a condensation reaction occurs using ATP synthase
• formation of ATP equation


  ADP + P(i) -> ATP + H2O
• usage of ATP


  broken via hydrolysis reaction using ATP hydrolase
• ATP usage reaction

  ATP + H2O -> ADP + P(i)
• phosphorylation


  addition of inorganic phosphorus group to organic molecule
• what does phosphorylation do to a molecule

  make it more reactive
• DNA stands for


  deoxyribose nucleic acid
• what does DNA do


  code for a sequence of amino acids in the primary structure of a protein determining it tertiary shape and overall function
• what does DNA form

  a double helix of 2 antiparallel strands
• how are the strands in DNA joined


  hydrogen bonds between the complimentary bases on each strand
• how is DNA stable


  it has a strong sugar phosphate backbone
• how does DNA act as a template


  both strands can be split and used for replication
• how are DNA strands split


  braking of the hydrogen bonds between bases during DNA replication
• how big is DNA


  large compared to other cell organelles as it carries a lot of information
• why does DNA have to have complimentary bases


  it allows identical copies of the DNA to easily be formed
• how to precipitate DNA


  1. Crush the cells - destroys cell wall
  2. mix with detergent - destroys plasma membrane and nuclear envelope
  3. add salt - breaks hydrogen bonds between DNA and water so easier to remove
  4. add protease - destroys DNA proteins / histones
  5. add ice cold ethanol - precipitates DNA strands ( white )
• rRNA


  Ribosomal , makes up ribosomes
• mRNA


  Messenger , a copy of 1 gene created in the nucleus from DNA and leaves via nuclear pore to a ribosome

  Shorter than DNA as is only 1 gene long and short lived as it only needs to travel to the ribosome

  Single stranded containing codons
• tRNA


  Transfer , found in the cytoplasm

  A single strand folded into a clover shape held together by hydrogen bonds

  Brings amino acids to ribosome , the amino acid is determined by the anticodon complimentary to the codon on the mRNA
• how is DNA replication semi conservative


  each new DNA helix contains 1 old strand and 1 new one
• mutation

  a random spontaneous change in the DNA bas sequence