Dr Bell Flashcards
What’s a polymer and what’s a monomer ?
Polymer - a long complex chain of similar monomers
Glucose +glucose =
Glucose +fructose =?
Glucose +galactose=
Maltose
Sucrose
Lactose
How to test for a reducing sugar
Benedict’s and heat , brick red precipitate is a positive result.
What is the main storage material in plants ?
Starch
Describe starch
Plants store excess glucose as starch , contains amylose (long unbranched , coiled , compact ), amylopectin(long batches alpha glucose , side branches that can be easily broken down )
Insoluble in water sod oesnt affect water potential.
What is the main storage material in animals ? Describe it
Glycogen , polysaccharide of alpha glucose many side branches , very compact.
How is cellulose suites for its purpose ?
Long , unbranched beta glucose, straight cellulose chains held by hydrogen bonds , microfribrils that give good support for cell walls.
What’s the test for starch ?
Add iodine in dissolved potassium iodide solution. Positive result - blue black coloration
What are lipid made form ?
Proteins carbs and hydrocarbons
Describe a triglyceride
One molecule of glycerol , three fatty acids(hydrophobic tails men’s they are insoluble ) , three ester bonds
What’s the basic structure of a fatty acid ?
O—C—R
OH
What’s the difference between saturated and unsaturated ?
Unsaturated fatty acids have double bonds between each carbon and can cause the hydrocarbon chain to kink.
How are triglycerides formed ?
Condensation reaction between glycerol and. A fatty acid to form ester bonds.
Describe a phospholipid
Found in cell membranes , two fatty acids , one phosphate head , two ester bonds.
What are the properties of triglycerides and phospholipids ?
Triglyceride-energy storage molecules , long HC chains have lots of chemical energy , insoluble in water don’t affect water potential due to fatty acid tails facing inwards.
Phospholipids- make up Bauer of cell meme range , hydrophilic heads , centre is hydrophobic so water soluble substances can’t pass through.
How to test for a lipid
Emulsion test, shake substance with ethanol and pour solution into water , any lipid will= milky emulsion
What are proteins made from?
Monomers =amino acids , dipepride =two amino acids , polypeptide =several amino acids , proteins are made from one or more polypeptides.
What’s the general structure of an amino acid ?
Carboxyl group (-COOH) Amino group(-NH2) R group (always contain carbon apart from glycine which has H)
How are dipeptides and polypeptides formed ?
Condensation reactions
Describe primary structure
Sequence of amino acids in the polypeptides chain.
Describe secondary structure
Hydrogen bonds form between amino acids into alpha helix or beta pleated sheets
Describe tertiary structure
Cooked even more hydrogen bonds and ionic bonds , disulfide bridges between cysteine (sulfers )
Describe quarternary structure
Several polypeptide chains assembled together.
What’s the test for proteins ?
Add sodium hydroxide , then add copper sulfate solution . Purple =positive result
What do enzymes do ?
Catalyst metabolic reactions by lowering activation energy.
How does temperature affect enzyme activity ?
Low temp =low ROR
Optimum temp =highest ROR
high temp =enzyme denatures
How does pH affect enzyme activity ?
Optimum =best ROR
Too low/too High H+ and OH- ions disrupt the ionic bonds and hydrogen bonds that hold tertiary structure in place-denaturation
How does substrate conc affect enzyme activity ?
Higher conc=higher ROR , eventually plateus when all active sites are full
How does enzyme conc affect enzyme activity ?
More enzyme =higher ROR , but if substrate amount is limited the increase in enzymes has no affect .
Describe competitive inhibitors
Similar shape to substrate , compete for active site
Describe non competitive inhibitors
Bind away from the active site causing active site to change shape so substrates can no longer bind.
How to estimate initial rate of reaction
Draw tangent from 0, calculate gradient , work out the units
What’s the structure of a nucleotide ?
Phosphate , pentose sugar, nitrogenous base
Describe polynucleotide structure
Joined via condensation reactions ,?forming phosphodiester bonds , sugar phosphate back bone .
Describe the structure of DNA
Double helix , two strands , really long and cooled tightly.
How many hydrogen bonds between AT and GC
AT 2
GC 3
What’s different about RNA ?
Ribose sugar, uracil instead of thymine , single strand , shorter .
Describe the process of DNA replication.
DNA helicase breaks hydrogen bonds between bases on DNA strands , unwinds .
Each original strand acts as a template for new strand , complementary bad pairing means nucleotide join on to exposed bases
Condensation reactions join the nucleotides of the new strand together catalysts by DNA polymerase , forming hydrogen bonds
Each new dna has half the original strand
Messlson and stalls experiment
N15 put into N14 to make hybrids
Hybrids put into N14 to make 50% hybrids
Those hybrids put into N14 to make 25% hybrids. Semi conservative replication .
Describe the structure of ATP
Adenine , ribose , three phosphate heads (phosphate group )
How is energy released from ATP?
Hydrolase hydrolysis , from ATP to ADP +P, the in organic phosphate head and be used in phosphorylation to make compounds more reactive
Describe waters importance
Polar , metabolite , good solvent polarity of water pulls ions apart ,high latent heat of vapouutisation , can resist changes in temp ,very cohesive , high surface tension .
Describe the differences between prokaryotes and eukaryotes .
Eukaryotes are animal and plant cells -they have membrane bound organelles and nucleus , large 80S ribosomes
Prokaryotes (bacteria ) free genetic material , cell wall is made of morein, small 70S ribosome , fully developed flagella.
