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Biochem test 2
nwhsu
Question | Answer |
---|---|
A complete, catalytically active enzyme together with its bound coenzyme and/or metal ions is called ? | holoenzyme |
The protein portion of a holoenzyme is called ? | apoenzyme |
Inorganic ion attached to an enzyme | cofactor |
organic or metallorganic ion attached to an enzyme | coenzyme |
3 components of holoenzymes | apoenzyme (polypeptide) cofactor & coenzyme (non-amino acid) |
enzymes affect ______ | rate of reaction |
what happens to activation energy in presence of an enzyme | it decreases |
what type of response is observed in a Vo vs [S] chart | Hyperbolic |
what is Km | michaelis- menton constant the [S] where the rate is 1/2 vmax |
what is the michaelis menton equation | Vo = (vmax[S])/(Km+[S]) Vo= dependent variable [S]= concentration of substrate Vmax = theoretical maximum velocity Km = constante |
what is the inverted MM equation | (1/Vo)= (Km+[S])/(Vmax[s]) |
Lineweeaver burke equation | (1/Vo) = (Km/Vmax)(1/[S]) + (1/Vmax) y = m x + b(y intercept) |
what is the change in Y / change in X | M = Km/Vmax |
what is the X-intercept in a LB plot | -(1/Km) |
what are the three types of reversible inhibition | competitive uncompetitive mixed |
what happens to Vmax and Km in competitive inhibition | Vmax stays the same Km ^ same y intercept in lb plot |
what happens to Vmax and Km in uncompetitive | Vmax \/ Km \/ does not intercept in lb plot |
what happens to Vmax and Km in Mixed | Vmax \/ Km ^ intercepts in 2nd quadrant in lb plot |
what is it called when Vmax \/ and Km stays the same | Non-competitive inhibition |
what are 2 subtypes of enzyme regulation | noncovalent covalent |
what are 2 types of noncovalent (reversible) reculation | MM type inhibitors ( competitive, uncompetitive, mixed) Allosteric regulation (removed from active site, change of conformation of enzyme) |
what are 2 types of covalent regulation | reversible nonreversible |
2 examples of reversible, covalent regulation | phosphorylation/dephosphorylation methylation/demethylation |
example of nonreversible, covalent regulation | removal of c and or n terminals |
what is allosteric inhibition | when a modulator bonds to the enzyme ( not the active site ) and changes the shape of the active site |
an example of enzyme-phosphorylation | glycogen-phosphorylase |
what happens when [glucose] in blood falls below homeostatic value | the hormone glucagen stimulates phosphorylase-kinase |
what happens when [glucose] in blood is above homeostatic value | the hormone insulin stimulates phosphorylase - phosphatase |
what is proteolytic cleavage? | activity that leads to breaking of a covalent bond in a protein ( peptide bond ) |
how are inactive precursors to enzymes found? | prefix 'pro' or suffix 'gen' |
3 examples of non reversible enzyme regulation | Hormones Proteases in digestive tract Blood clotting cascade |
what are 4 functions of carbohydrates | energy ( source, storage ) structure ( dna backbone, cell walls) communication (glycocalyx) joint lubrication (glucosamine) |
4 classifications of carbohydrates (from smallest in size to largest) | monosaccharide: building block disaccharide: 2 monosaccharides oligosaccharides polysacharides: increasing number of building blocks |
a carbohydrate with a aldehyde group | aldose |
carbohydrate with a ketone group | ketose |
group names by # of carbons | 3-triose 4-tetrose 5-pentose 6-hexose 7-heptose |
what conformation is naturally occurring and is biologically active? | D-carbohydrate |
which carbon determines d or l | chiral carbon furthest away from c=o |
D and L configurations of the SAME sugar are ______. | enantiomers (mirror-images) |
know D-glyceraldehyde D-glucose D-Mannose D-galactose D-rhibose Dihydroxyacetone D-fructose | |
two sugars that differ only in the arrangement around 1 chiral center | epimers |
what makes an alpha or beta cyclic monosacharide | the OH on the C1 carbon opposite of the H2OH on the C6 makes alpha. same side is beta |
what is meant by hemiketal (hemiacetal) | the bond in a cyclic monosacharide formed by a ketone (aldehyde) |
Homopolysaccharides | only one type of building block |
heteropolysaccharides | more than one type of building block |
what shape do 1-4 alpha linked polysaccharides make | spiral |
explain the important features of cellulose | higher organisms cannot express hydrolytic enzymes(cellulase) therefore there is no breakdown of cellulose and it is used as fiber. beta 1-4 linked |
explain the important features of lactose | it has a beta 1-4 connection, majority of humans cannot express lactase and therefore are lactose intolerant |
what is the main storage polysaccharide in animal cells | glycogen |
give information on peptidoglycan | it is found in the cell wall of bacteria certain antibiotics inhibit peptidoglycan synthesis and prevent bacteria multiplication |
give 2 types of glucosaminoglycans | hyaluronate heparin |
function of hyaluronate | joint lubrication |
heparin | regulates blood clotting by binding to prothrombin to prevent clotting. |
know glucose family monosacharides | |
starch -monosaccharides -linkage -function | m:glucose l: 1-4 alpha br: 1-6 alpha f:energy storage in plants |
glycogen -monosaccharides -linkage -function | -monosaccharides : glucose -linkage: 1-4 alpha br: 1-6 alpha -function: energy storage in animals |
Describe Cellulose (fiber). (building blocks, location, function, bond type, etc.) | Homopolysaccharide of glucose. Beta-1,4 connection forming an acetal(glycosidic) bond. Linear/unbranched. Reducing end contains a hemiacetal. Extra-cellular. Indigestable by humans as we lack the enzyme to hydrolyze the B-1,4 bond. |
Describe Chitin (fiber). (building blocks, location, function, bond type, etc.) | Homopolysaccharide. Beta-1,4. Found in cell walls in fungi, exoskeletons in arthropods, and is indigestable by humans as we lack the enzyme to hydrolyze the B-1,4 bond. |
Describe Peptidoglycan. (building blocks, location, function, bond type, etc.) | Heteropolysaccharide. Repeating dimers. Beta-1,4. Found in bacterial cell walls. Antibiotics (Penicillin) inhibits cell wall synthesis and bacterial replication. |
Describe Hyaluronate. (building blocks, location, function, bond type, etc.) | Heteropolysaccharide. Glucosaminoglycan. Repeating Disaccharide. Associates with lots of water, lots of OH groups. Functions in joint lubrication, and extracellular structure of skin/CT. Beta-1,3 WITHIN disaccharide. Beta-1,4 BETWEEN disaccharides. |
Describe Heparin (building blocks, location, function, bond type, etc.) | Heteroploysaccharide. Glucosaminoglycan. Repeating Disaccharide. Found in blood. Regulates blood clotting. Binds to Prothrombin. Non-covalent,reversible. alpha-1,4 |
Describe Chondroitin. (building blocks, location, function, bond type, etc.) | Heteropolysaccharide. Glucosaminoglycan. Repeating Disaccharide. Associates with lots of water, lots of OH groups. Functions in joint lubrication, and extracellular structure of skin/CT. Beta-1,3 WITHIN disaccharide. Beta-1,4 BETWEEN disaccharides. SMALL! |
Describe Keratan Sulfate. (building blocks, location, function, bond type, etc.) | Heteropolysaccharide. Glucosaminoglycan. Repeating Disaccharide. Associates with lots of water, lots of OH groups. Functions in joint lubrication, and extracellular structure of skin/CT. Beta-1,4 WITHIN disaccharide. Beta-1,3 BETWEEN disaccharides. SMALL! |