Question

1. A researcher suspects that consumption of some fruit berries found in the amazon basin may have positive or negative effects on hemoglobin function. Can you predict what the effect of eating a significant amount of the berries would be on adult hemoglobin binding and distribution of oxygen if one of the phytochemicals in the berries has been found to be a competitive inhibitor of 2,3-Bisphosphoglycerate (2,3 BPG) (3 points). What do you think would be the effect of the same phytochemical on fetal hemoglobin? (2points, Justify your response ]

2. "Structure determines function" Based on your knowledge of hemoglobin structure, identify at least three structural features of hemoglobin that makes it suitable for transportation and delivery of oxygen to tissues.

3. Giving relevant examples, explain why despite being such weak interacting forces, hydrogen-bonds are so important in biological systems?

4.  Your local senator is calling for an immediate ban on all animal studies proposing that all experiments should be done using cell cultures. Explain to the senator why cell culture may not be adequate on their own and why it may be necessary for researchers to continue using experimental models like small rodents and fruit flies (Drosophila melanogaster) to fully understand human biochemical processes and diseases?

8. Giving appropriate examples describe how a point mutation that result in one amino acid being replaced with a different amino acid in a protein can affect the tertiary structure of that protein. Identify at least three possibilities. [5]

9. After discovering a compound that has been confirmed to have inhibitory effects on enzyme X that catalyzes conversion of substrate Y to a colored product Z, Describe in specific detail how one can design and execute an experiment to determine whether the newly discovered compound  is acting as a competitive or non-competitive inhibitor to enzyme X? [5]

10. Giving examples, explain why changing the pH to extreme values can have significant effects on catalytic function of enzymes  [4 points]. What can you use to minimize effects of changing pH on enzymatic reactions? [ 1 point]

11. Providing at least three appropriate examples, describe mechanisms that biological systems use to avoid futile cycles (opposing reactions occurring at the same time) [5]

12.Describe the reciprocal regulation of glycogenolysis and glycogenesis, highlighting the major hormonal differences. [5]

Just need a short 2-3 sentence answer thanks!

Answer 1

1) 2, 3 BPG is a byproduct of glycolysis pathway. 2,3 BPG binds with de oxy Hb ( Ntermial or beta chain) and stabilize it , thus causing more release of oxygen from Hb and cause shift of oxygen- Hb dissociation curve to right.

But if berries contains inhibitor which act as a competitive inhibitor for 2,3 BPG than they will compete with 2,3 BPG to bind with Hb. So in presence of additive inhibitor, less 2,3 BPG will bind to Hb. So now Hb will release less oxygen at tissue level compared to the Hb in absence of additive inhibitor. Here there additive is acting as a negative regulator.  

In case of fetal Hb . , there will be no effect in presence of additive. Fetal Hb is made up of 2 subunits ( 2 alpha and 2 gamma). As 2, 3 BPG binds to beta subunit only , but here in place of beta subunit gamma is present. So no binding site for 2,3 BPG and no competition between 2, 3 BPG and additive.

2) structural features of Hb which facilitate in transport of oxygen are-

a) Hb is tetramer protein , made up of 4 subunits ( 2 alpha and 2 beta). Each subunit contains one haem group and can carry one oxygen . Thus 1 Hb molecule transfer 4 molecules at a time due to presence of Fe in haem group.

b) Ha has capacity that it can bind as well as release oxygen, so it can take oxygen at lung ( in presence of high pO2 in lungs ) and release oxygen ( at tissue level ).

c) it is an allosteric protein ( protein which has addition sites than active site) , so various modulators can bind to Hb and regulate its activity according to the environment conditions. Like low pH, increase Co2 favored more release of oxygen from oxy Hb.

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