chapter 1 Flashcards
what is a monomer
a smaller unit from which larger molecules are made
compare structures of cellulose and glycogen
-cellulose is made up of B-glucose / glycogen is made up of A-glucose
-cellulose molecule has straight chains / glycogen is branched and coiled
-glycogen has 1-4 / 1-6 glyosidic bonds and cellulose has only 1-4 glyosidic bonds
how are starch molecules adapted to their function
-insoluble - don’t affect water potential
-helical - compact more in the same space
-large molecules- cannot leave the cell
how are cellulose molecules adapted for their function
-long and straight chains
-becomes linked together by many hydrogen bonds to form fibrils
-provide strength (to cell wall)
how glycogen act as a source of energy
hydrolyzed to glucose, glucose is used in respiration
features of starch that make it good storage molecule
-insoluble in water, don’t change water potential
- branched, molecule is compact
-polymer of A-glucose so provides glucose for respiration
-branched faster enzyme action
- large molecules so it can’t cross the cell membrane
test for lipids
EMULSION TEST
- add ethanol
-add distill water
-add sample
white emulsion formed
test for proteins
-add biuret reagent in the sample
- solution changes from blue to purple
polymer
made from lots of monomers bonded together
3 monomers example
-glucose
-amino acid
-nucleotide
condensation reaction
joining two molecules together by removing water
hydrolysis reaction
slitting apart molecules through addition of water
monosaccharide
monomers of carbohydrates
how are disaccharides formed
- made from 2 monosaccharides
- joined together by glyosidic bond
- formed via condensation reaction
word equation for formation of disaccharide
- glucose + glucose —-> maltose +water
- .glucose + fructose —–> sucrose + water
- glucose + galactose ——> lactose + water
test for reducing sugar
- add benedict’s reagent and heat
- solution turns from blue to orange/ brick red
test for non-reducing sugar
-following a negative benedict’s test
- add acid and boil ( acid hydrolysis - hydrolysis glyosidic bond
- cool solution then add alkali to neutralize
- add benedicts reagent and heat
- solutions turn from blue to green-red
test for starch
-add iodine
- solution turns from orange to blue/black
triglycerides
1 glycerol bonded to 3 fatty acids, they are held by an ester bond
saturated fatty acid
hydrocarbon chains has only single bonds between carbons
unsaturated fatty acid
hydrocarbon chains consists of at least one double bond between carbons
phospholipids
has 2 fatty acids chains a glycerol and a phosphate group
reaction that joins amino acids together
condensation reaction, peptide bonds form between OH of carboxyl group and a H from an amine group of another amino acid
primary structure of protein
the sequence of amino acids in a polypeptide chain
secondary structure
amino acid sequence coil into alpha helix or beta pleated sheets
tertiary structure
further folding of the secondary structure
forms a unique 3D shape
held in place by ionic hydrogen and disulfide bonds
quaternary structure
there’s more than 1 polypeptide chain in the protein
induced-fit model
the enzyme’s active site and substrate are not perfectly complementary in shape initially
the enzyme’s active site in induced or slightly changes shape, to molded around the substrate, once the substrate binds to the active site
enzymes
the active site is unique in shape due to the specific folding and bonding in the tertiary structure of the protein. Due to this specific active site, enzyme can only attach to substrate that are complementary in shape. The enzyme and substrate then form an enzyme-substrate complex
factors that effect the rate of enzyme-controlled reactions
- temperature
- pH
- substrate concentration
- Enzyme concentration
- inhibitors
how does temperature affects the rate of enzyme reactions
at lower temperatures as the temperature increases so does the rate of reaction
beyond the optimum temperature the rate of reaction rapidly decreases
affect of pH on enzyme action
low pH: there will be an excess of H+ ions, this can break the ionic and hydrogen bonds holding tertiary structure causes active site to change shape
high pH: there will be an excess of OH- ions released which can break hydrogen and ionic bonds changes shape of active site
how does enzyme concentration affects enzyme reaction
at a low concentration enzyme concentration is the limiting factor
when more enzyme is added rate increases
more available active site
more successful collisions
how substrate concentration effects enzyme reactions
at low concentration substrate is limiting factor
more substrate is added the rate increases there will be more successful collisions
competitive inhibitors
same shape as the substrate and can bind to the active site
prevents the substrate t bind
no enzyme-substrate complex formed
no reaction can happen
non-competitive inhibitor
binds to the enzyme away from the active site
in the allosteric site
causes the active site to change shape
substrate can’t bind to substrate
