Unit 1

Cards (62)

  • what is a monomer
    small units that join together to form larger molecules
  • what is a polymer
    large molecules made from many monomers joined together
  • what is the name of this molecule?
    alpha glucose
  • what is the name of this molecule?

    beta glucose
  • what is the name of the bond between monosaccharides
    glycosidic
  • what monomers join to make sucrose
    glucose and fructose
  • what monomers join to make maltose
    two alpha glucose
  • what monomers join to form lactose
    glucose and galactose
  • describe the properties of starch
    large to cannot leave the cell
    helical so compact
    insoluble so doesn't affect water potential
  • describe the structure of amylose
    polymer of alpha glucose
    has 1-4 glycosidic bonds
    has helical shape
  • describe the structure of amylopectin
    polymer of alpha glucose
    has 1-4 and 1-6 glycosidic bonds
    branched
  • what is the advantage of amylopectin being branched
    provides a larger surface area for enzymes to attach
    so starch can be readily hydrolysed into glucose
  • describe the structure of proteins
    primary - amino acids joined together by peptide bonds via condensation
    secondary - the polypeptide chain folds into alpha helixes and beta pleated sheets they have hydrogen bonding
    tertiary - 3d shape with hydrogen and ionic bonding and disulphide bridges
    quaternary - two or more polypeptide chains
  • state how ATP is a good source of energy
    releases energy instantaneously
    releases energy in small amounts
    phosphorylates other molecules to make them more reactive
    can be resynthesised rapidly
    does not leave cells
  • explain the importance of water
    a metabolite in condensation , hydrolysis and respiration
    a solvent so allows transport of substances
    large latent heat of vaporisation - provides a cooling effect
    high specific heat capacity - buffers temperature changes
    cohesion - produces surface tension so small animals can walk on water
    cohesion so supports columns of water in plants
  • label the groups in the amino acid
    .
    A) carboxyl group
    B) amine group
  • define the term isomers
    molecules with the same molecular formula but different structure
  • relate the structure and function of triglycerides
    insoluble hydrocarbon chain - has no affect on water potential of cells
    large molecules - large chemical energy store
    high ratio of carbon to hydrogen bonds in fatty acid tails - lots of energy released when respired + water released when respired ( useful for desert animals )
    low mass to energy ratio - low density so lots of energy stored with low mass + useful as a buoyancy aid as lower density than water
  • relate the structure of DNA to its function
    sugar phosphate backbone and many hydrogen bonds provide stability
    long polynucleotide chain stores lots of genetic information
    weak hydrogen bonds break so strands separate for replication
    many hydrogen bonds stabilise the helix
    double stranded for semi conversative replication
    antiparallel strands for complementary base pairing
  • describe semi conservative replication of DNA
    double helix unwinds
    DNA helicase breaks hydrogen bonds between base pairs in the polynucleotide strands
    each strand acts as a template
    free nucleotides form complementary base pairs with the single stranded template strand
    DNA polymerase joins adjacent nucleotides causing the formation of phosphodiester bonds
    hydrogen bonds reform
    semi conservative as each replicated DNA double helix contains one old strand and one new strand
  • why is ATP useful
    releases energy in small amounts so energy isnt wasted
    quickly broken down so energy is released quickly
    ATP cannot pass out of the cell so cells have an immediate supply of energy
    phosphorylates other compounds to make them more reactive by lowering the activation energy
  • Describe the biochemical tests you would use to confirm the presence of lipid
    add / dissolve in ethanol
    add water and mix
    positive result : white emulsion
  • Describe the biochemical tests you would use to confirm the presence of non-reducing sugar
    add benedicts reagent
    solution remains blue
    boil with acid then neutralise with alkali
    heat with benedicts reagent
    positive result : brick red precipitate
  • Describe the biochemical tests you would use to confirm the presence of protein in a sample
    add biurets reagent
    positive result : lilac
  • Describe two differences between the structure of a tRNA molecule and the structure of an mRNA molecule.
    tRNA is clover shaped but mRNA is linear
    tRNA has an amino acid binding site but mRNA doesnt
    tRNA has anticodons mRNA has codons
    tRNA has hydrogen bonding mRNA doesnt
  • why are lipids not polymers
    they are not made from repeating monomers
  • why is the function of starch
    energy store in plants
  • what is the function of glycogen
    energy store in animal cells
  • describe the structure of glycogen
    polysaccharide of alpha glucose
    1-4 and 1-6 glycosidic bonds
    highly branched
  • relate the structure and function of glycogen
    branched - more ends for enzymes to attach for faster hydrolysis so glucose can be released for respiration to make ATP
    large - cannot leave the cell
    insoluble - water potential of the cell is not affect
  • what is the function of cellulose
    strength and structural support to plant and algal cell walls
  • name a non reducing sugar
    sucrose
  • suggest a method to measure the quantity of sugar in a solution
    carry out benedicts test
    filter then dry the precipitate
    measure mass using a balance
  • suggest another method to measure the quantity of sugar in a solution
    make a series dilution of different sugar concentrations
    heat each dilution with the same volume of benedicts reagent
    ensure the volume of each dilution is the same
    use a colorimeter to measure absorbance of each known concentration
    plot calibration curve - concentration on x axis and absorbance of y axis
    repeat the benedicts test with an sample of unknown concentration and measure absorbance
    read off the calibration curve to find the concentration of the unknown sample
  • describe the biochemical test for starch
    add iodine dissolved in potassium iodide
    shake
    positive result : brown to blue-black
  • unsaturated hydrocarbons have...
    one or more carbon to carbon double bonds
  • how do enzymes act as biological catalysts
    lowers activation energy of a reaction
    speeds up the rate of reaction
  • describe the induced fit model
    active site is not completely complementary to substrate
    substrate binds to active site
    active site moulds around the substrate
    enzyme-substrate complex forms
    puts strain on bonds in substrate
  • Describe and explain the effect of enzyme concentration on the rate of enzyme-controlled reactions
    as enzyme conc increases rate of reaction increases
    enzyme concentration is a limiting factor as there may be excess substrate
    more enzymes so more available active sites
    more enzyme-substrate complexes form
    as a certain point the rate of reaction plateaus as substrate concentration in a limiting factor - all substrates are in use
  • Describe and explain the effect of substrate concentration on the rate of enzyme-controlled reactions
    ● As substrate conc. increases, rate of reaction increases
    ○ Substrate conc. = limiting factor (too few enzyme
    molecules to occupy all active sites)
    ○ More Enzyme-substrate complexes form
    ● At a certain point, rate of reaction stops increasing / levels off
    ○ Enzyme conc. = limiting factor
    ○ As all active sites saturated / occupied (at a given time)