TJ guide Flashcards
What is positive feedback?
a system that enhances the disturbance, must be self limited
What is considered low gain?
gain less than 10
What is true about input and output in a steady state situation?
input=output
What is true about high gain regulation?
it tightly regulates a system
What will happen to vasopressin concentration if the ECF volume is low?
Body releases vasopressin to retain water and decrease urine output
What will happen to vasopressin concentration if you infuse a person with saline?
It will decrease to increase urine output
Which amino acids are prominent in the body?
L-amino acids
Which conformation is most favorable in amino acids?
trans
What’s the average weight of an amino acid?
110 g/mol
What three groups does phosphorylation typically occu on?
Ser, Thr, Trp
What are three important functions of hydrogen bonds within the cell?
DNA, secondary structure in proteins, enzyme binding sites
What do micelles aid with?
Moving and digesting fats
What is the molarity of water?
55.5 M
How do you increase buffer capacity?
Increase the amount of acid and conjugate base in the solution.
What is the H-H equation for the bicarbonate buffer system?
pH = 6.1 + log [HCO3-]/[0.03PaCO2]
Describe hydrogen bonding in an alpha helix
carbonyl of group at n, H bonds with the residue n+4 ahead in the primary sequence
How many amino acids are typical in a beta turn?
4, held together by H bonding C=O to the N-H at N+3,
What is the advantage of a protein that has no set tertiary structure?
It can bind more ligand and adjust itself to each ligand
What types of amino acids most likely form salt bridges?
Glu and Asp
T or F: protein folding is not mediated by other proteins
F
What is a protein disulfide isomerase?
Breaks and reforms cysteins until lowest energy state is achieved
What are Peptidyl propyl isomerases?
changes structure from cis to trans at prolines
What do molecular chaperones and chaperonins do?
- Bind to unfolded regions and prevent hydrophobic regions from clumping
- create bowl for hydrophobic portions to aggregate in safe conformation unitl lowest energy state is achieved
Name 3 diseases that are caused by issues in protein folding.
Cystic fibrosis, Sickle Cell, Huntington’s
Describe the mechanism of Cystic fibrosis
causes a mutation where proteins fold too slowly and are degraded. Sweat, mucus, and digestive fluid proteins never reach the membrane
Describe the mechanism of Sickle Cell Anemia
a Glu –> Val change at position 6 causes Val to bind in the hydrophobic pocket in deoxyHb forming polymers
Describe the mechanism of Huntington’s
excess glutamine reactions in protein that lead to a mutated protein that increases neuron decay rate
What is the equation for Kd?
Kd = [Prot.][ligand]/[Prot.]
What does a small Kd imply about affinity?
high affinity
What does the Langmuir Isotherm indicate?
How much protein is bound at a given ligand concentration
What is the Langmuir Isotherm equation?
r = [A]/ (kd + [A])
What is r in the Langmuir Isotherm?
r = average number of ligand molecules bound per protein molecule
What are the axis in a Langmuir Isotherm?
[A] - ligand concentration = x-axis
r - average number of ligand molecules bound per protein molecule on the x
What equation allows for a straight line to be obtained by the Langmuir Isotherm?
The Scatchard equation
What is the Scatchard equation?
r/[A] = n/kd - r/kd
What are the x, y axis, slope, and intercept of a scatchard plot?
x axis = r (amount of prot. bound to ligand)
y- axis = r/[A] (bound over free)
Slope = -1/kd
x-int = number of ligand
T or F: Hemoglobin binds oxygen most efficiently at high partial pressures?
False, Hb releases O2 at low partial pressure and binds O2 at high partial pressures. This allows for O2 to go into tissues
Oxidoreductase
Add or remove hyrdogen
Transferases
transfer a functional group from one molecule to another
Hydrolases
Add water across a bond hydrolyzing it
Lyases
add water, ammonia or CO2 to double bonds or remove these elements to make double bonds
Isomerases
Catalyze the conversion of a substrate to an isomer, epimer etc.
Ligases
Catalyze reactions where a bond is formed using energy from ATP
What is a small non-protein molecule that a protein depends on for catalytic activity?
cofactor
What is the difference between a cofactor and a coenzyme?
A coenzyme is an organic molecule where a coefactor can be a metal ion
What affect would adding more enzyme to a reaction have on velocity/rate?
Rate will increase in proportion to the amount of enzyme added
Will adding more substrate always cause the enzyme to have increased activity?
It will until the binding sites become saturated
What is an enzyme assay?
a way to determine the activity of an enzyme