Biological molecules and Enzymes Flashcards
(63 cards)
How do enzymes affect equilibrium constant and Gibb’s free energy?
How does it affect the rate of reaction?
How does it affect the intermediate state?
doesn’t change equilibrium or Gibb’s free energy
It lowers the activation energy without being used up in the reaction. Increase both the forward and reverse rate of reaction equally.
allow more molecules to overcome the energy barrier to achieve the intermediate state, making the intermediate state more stable
Effect of temperature and pH on enzymes
Optimal temperature is 37C and optimal pH is 7.4.
The rate of enzyme reaction increases linearly until 37C and drops rapidly fast after 37C reaching 0 rate of reaction at 50C.
The rate of enzyme reaction increases steadily and linearly upto pH of 7.4 and drops linearly and steadily down till reaching 0 at pH of 12 for most enzymes. For some enzymes like pepsin, optimal pH is at 2. So it really depends on the enzyme.
Does Michaelis-Menten enzyme kinetics apply to allosterically regulated enzymes? What is an allosteric regulation? Give an example.
Nope. An example of allosteric regulation is hemoglobin and oxygen which has a sigmoidal curve. Allosterically regulated enzymes have multiple binding sites where other binding sites regulate the activation or deactivation of the enzyme by changing its conformation.
If a forward rate constant is greater than the reverse rate constant at equilibrium, what does it imply about the concentration of products and reactants at equilibrium?
It implies that the concentration of products is higher than the concentration of reactants.
What is the Michaelis-Menten equation?
Take the two most important factors: Vmax and Km
Add both of them to S, and divide. Vmax on top and Km at the bottom
V = (Vmax + S) / (S + 1/2Vmax)
1/2Vmax = Km
When does Km, the substrate concentration at half the max velocity, indicate affinity of the enzyme to the substrate? When Km is indicative of the affinity, what is the equation of Km? What portion of the Michaelis-Menten graph is this instance?
When rate constant of ES dissociation is greater than the rate constant of product (E + P) formation. In this case, Km = rate constant ES dissociation/ rate constant E+P formation
This instance represents the linear portion of the Michaelis-Menten graph, the first order part of the graph.
What is the reciprocal of the Michaelis-Menten equation?
1/V = (Km/Vmax)(1/S) + (1/Vmax)
At what pH do the pancreatic enzymes work the best?
In alkaline conditions
Michaelis Constant, Km
1/2 Vmax
indicates how high substrate concentration must be to speed up the reaction. Km is inversely related to enzyme-substrate affinity.
lower the Km, better the enzyme is working when the substrate concentration is low
Lipids - Number of carbon formula
2n
what does amphiphatic mean
both polar and non-polar
how many rings does a steroid have
4
eicosanoids
how many carbons and what are their functions
20 C
usually local hormones, paracrine hormones like prostaglandins
What are lipoproteins?
What do they look like?
Composed by phospholipids and apoproteins
Hydrophobic core and hydrophilic shell
carbohydrates
formula
Cn(H2O)n
Type of linkage in glycogen
alpha glycosidic linkage
starch (amylopectin and amylose) linkage
difference between amylopectin and amylose
both have alpha linkage
amylopectin is branched but amylose can be branched or unbranched
cellulose linkage
beta
method of glucose absorption in the digestive tract and kidney cells
secondary active down the Na+ concentration gradient
glucose absorption method in most cells and how insulin increases the rate of absorption
facilitated diffusion
insulin increases the rate of facilitated diffusion by making more channels
what organs are capable of absorbing glucose without insulin?
brain and liver
List basic amino acids
HAL
histidine
arginine
lysine
List acidic amino acids
aspartate
glutamate
List non-polar amino acids
VIP AL PH MALT Glycine
valine
Isoleucine
Proline
Alanine
Methionine
Leucine
Trptophan
Phenylalanine
Glycine
