Lab Test 1 Flashcards
(17 cards)
Enzyme Characterization Properties
- affinity for particular substrate
- optimal temperature
- optimal pH
- speed & efficiency
- necessary cofactors or coenzymes
Michaelis-Mentel Model
model of enzyme kynetics
maximum reaction rate occurs at saturating concentration
Michaelis constant is 1/2 of Vmax
Michaelis constant
Inversely proportional to the enzyme’s affinity for a subsrate
1/2 of Vmax
Turnover number
Subtrate converted to product per unit time per unit of enzyme
Enzyme Specific Activity
Activity per unit mass of protein at a specific substrate concentration & under specific reaction conditions (usually saturating concentration)
Way of standardizing rates relative to the amounts
Catalase
Remove hydrogen peroxide by breaking it down into water and oxygen gas
Located in peroxisomes
Oxireductase
Competitive vs Non-Competitive Inhibitor
Competitive
- reacts to active site of enzyme
- can get “saturated out” of the system
- presence will mean same Vmax, but higher Km
Non-Competitive
- reacts to non-active site of enzyme
- presence will mean lower Vmax, but same Km
Diffusion
Spontaneous process, so not requiring energy
Net movement of substance down concentration gradient
Dynamic equilibrium
No net movement
Movement still happening
Osmosis
Diffusion of solvent across semi-permeable membrane
Powered by osmotic gradient, produced by different concentrations of solutes on each side of membrane
Osmotic pressure
Measure of the ability of a solution to cause osmosis
Defined by minimum pressure needed in order to prevent passage of pure solvent into a solution
Effective osmolarity
Osmolarity of a solution with respect to a particular membrane with specific characteristics.
Considers the substance Van’t Hoff factor
Cell shapes depending on tonicity
Animal cell: Hypotonic - swollen or lysed Hypertonic - crenated or shriveled Plant Cell: Hypotonic - turgid Isotonic - flacid Hypertonic - plasmolyzed
Osmometer
measured osmosis
uses dialysis tubing and a pipette for measuring solute displacement
OGTT Purpose
Oral Glucose Tolerance Test
Indicate patient’s ability to clear glucose in the blood
Blood Glucose Homeostasis
Normal range around 3.9 & 6.1 mM
Lowest level is normal fasting level
Lower than that is hypoglycemia, after starvation or intense exercise
Re-established by breaking down glycogen or fat
Higher than that is hyperglycemia
Excess is converted to glycogen or fat
Diabetes mellitus
Type 1
Inability of beta cells to create insulin
juvenile diabetes
Type 2
Loss of sensitivity to insulin in target cells
adult-onset diabetes
