Biochemistry 1 Flashcards
1
Q
catalysts
A
- increase the rate of the reaction by
- stabilizing the TS
- reduce Ea
- does not change ΔG. cannot make a nonspontaneous reaction spontaneous.
- kinetic not thermodynamic role.
- take an already spontaneous reaction and make it go faster.
2
Q
3 defining characteristics of enzymes/catalysts
A
- must increase reaction rate
- must not be used up in the reaction - regenerated
- specific for a particular reaction
3
Q
lock and key model
A
- substrate and active site are perfectly complementary
4
Q
induced fit model
A
- binding of substrate causes conformational change in enzyme.
5
Q
active site of an enzyme stereospecificity
A
- L amino acids (LA)
- D sugars/carbs (DC)
6
Q
Vmax depends on
A
- enzyme concentration
- type of enzyme you have
7
Q
Km
A
- the concentration of substrate required to reach 1/2 Vmax
- higher affinity has smaller Km
8
Q
competitive inhibition
A
- binds reversibly at active site
- no change on Vmax
- increases Km
- overcome by adding more substrate
9
Q
non-competitive inhibition
A
- binds at allosteric site
- reduces Vmax
- no change on Km
- adding more substrate does not help.
10
Q
uncompetitive inhibition
A
- binds at allosteric site of ES complex
- reduces Vmax
- reduces Km
- limits amount of ES to be converted to product
11
Q
mixed inhibition
A
- binds at allosteric site of E alone or ES complex
- reduces Vmax
- Km varies
12
Q
if inhibitor has affinity for ES complex
A
- looks more like uncompetitive
13
Q
if inhibitor has affinity for enzyme
A
- looks like competitive
14
Q
if inhibitor has equal affinity for enzyme and ES complex
A
- looks like non competitive.
15
Q
4 biologically relevant macromolecules
A
- proteins
- carbohydrates
- lipids
- nucleic acids
- all polymers
- enzymes that make them are called polymerases
- run in polymerization reactions or dehydration synthesis
16
Q
pH < pka
A
will be positively charged
17
Q
ph > pka
A
will be negatively charged
18
Q
ph = pka
A
will be neutral (zwitterion)
19
Q
acidic amino acid has
A
(-) charge at physiological pH
20
Q
basic amino acid has
A
(+) charge at physiological pH
21
Q
2 covalent bonds in proteins
A
- peptide bond
- disulfide bridge between cysteines.
22
Q
primary structure of protein
A
- amino acid sequence
- determined by peptide bond
23
Q
secondary structure of protein
A
- hydrogen bonding interactions between backbone atoms
- alpha helix
- beta pleated sheet
24
Q
why is proline not found in the alpha helix
A
- will cause kink
25
same direction beta sheet
- parallel
26
opposite direction beta sheet
- antiparallel
27
denatured protein
- improperly folded
28
denaturation
- disruption of protein structure without breaking peptide bonds
- urea
- extreme pH and temp
- change in salt concentration (tonicity)
29
tertiary structure
- due to side chain interactions within a peptide
| - noncovalent and covalent
30
noncovalent interactions in tertiary structure
- polar/polar
- nonpolar/nonpolar
- acidic/basic
- electrostatic
31
covalent interactions in tertiary structure
- disulfide bridge
- found in extracellular protein
- stabilizes tertiary protein structure.
32
quaternary structure
- structure due to side chain interactions between different polypeptide subunits
- no peptide bonds found
33
monomer of carbs
- monosaccharide
| - CnH2nOn
34
3 common sugars
- glucose - 6 membered
- fructose - 5 membered
- galactose
C6H12O6
35
3 common disaccharides
- maltose (glucose + glucose) alpha 1-4
- sucrose (glucose + fructose) alpha 1-2
- lactose (glucose + galactose) beta 1-4
36
formula for disaccharides
C12H22O11
C12H24O12 - H2O
37
multiple monosaccharides
- polysaccharides
38
3 common polysaccharides
- glycogen - animal storage (alpha 1-4 for residues, 1-6 for linking)
- starch - plant storage (alpha)
- cellulose - plant structure (beta 1-4, 1-6)
39
functions of polysaccharides
- energy
- cell surface markers
- cell adhesion
40
hydrocarbon
- monomer of lipid
- long unsubstituted alkane that ends in a carboxylic acid
- synthesized 2 carbons at a time
41
saturated fatty acid
- covalently bound to maximum number of hydrogen
- solid at room temperature (worse for body)
- no double bonds
- more rigid less fluid
42
unsaturated fatty acid
- one or more double bonds
- Z or cis
- liquid at room temperature (better for body)
- disrupts packing
43
amphoteric
- acts as acid or base
44
amphiphilic
- both polar and nonpolar
45
triglyceride
- stored energy
- glycerol
- 3 fatty acids
46
why are fats more more efficient for energy storage than carbs
- packing - hydrophobicity allows great, close packing
| - energy content - more energy carbon for carbon. more reduced so when they are oxidized produce more energy.
47
phospholipids
- barrier between intracellular and extracellular environments
- form lipid bilayer
- driven by hydrophobic interactions. stabilized by van der waals forces between tails
48
what determines fluidity
- saturation
- tail length
- amount of cholesterol
49
how many isoprenes to make a terpene?
- 3
| - must have 2 isoprenes minimal to make a terpene
50
function of terpenes
- precursor to cholesterol, ear wax
| - vitamin A terpenoid
51
cholesterol
- 666 + 5
- obtained from diet
- synthesized in liver
- carried in blood w/ fats and proteins (lipoproteins)
52
functions of cholesterol
- cell membranes
- precursors to steroids
- bile
53
cholesterol at low temps
cholesterol at high temps
- increases fluidity
- decreases fluidity
- paradox
54
solving for enthalpy
ΔH = E + PΔV
55
reduced form of the disulfide bond
- broken
| - cysteine's acquiring H's
56
exergonic
- (-)ΔG
| - products lower in energy than reactants
57
endergonic
- (+)ΔG
| - reactants lower in energy than products
58
squalene is how many isoprenes
- 6
| - 3 terpenes
59
ATP hydrolysis
- 30.5 kJ
| - 12 kcal/mol
60
how fast something will happen?
- kinetics
61
cofactor
- metal ions or small molecules
62
coenzyme
- cofactor that is an organic molecule
63
to switch an enzyme to on/off
- phosphorylation
| - allosteric regulation
64
allosteric regulation
- bind somewhere other than active site (allosteric site) to modify enzyme function.
65
positive feedback regulator
- must have external regulator.
66
y intercept in LB
1/vmax
67
x intercept in LB
-1/Km
