B9

Question 1

Identify structural feature that enables pigments to absorb light.

Answer 1

Conjugated system of alternating double and single bonds with delocalized electrons

Question 2

Explain the shape of the oxygen dissociation curve.
How does pH affect the curve?
How does CO2 affect the curve?
CO?
Fetal hemoglobin how does it differ?

Answer 2

-Affinity of hemoglobin to oxygen increases with increasing partial pressure of oxygen
-binding of one 02 molecule facilitates the binding of other 02 molecules (becasue it affects the shape of active sites on other peptide chains)
- low pH (high H+ conc.) decreases the affinity as H+ acts as a non-competitive inhibitor
-increasing CO2 decreases affinity, acts a non-competitive inhibitor
- CO acts as a competitive inhibitor, it has a higher affinity for hemoglobin as a result hemoglobin can transport less O2
- fetal hemoglobin has higher affinity for oxygen
- different aminoacid sequence
- less sensitive to inhibitors
- the fetus receives partially deoxygenated blood so it has to work on low O2 pressure

Question 3

Why blue color of a form of anthocyanin changes to red when the pH increased?

Answer 3

It gains protons
Decrease in electron density
Absorbs different wavelength of light