Question 1

There are two main structural differences between a typical  
-helix and the helix formed by gramicidin A.Describe the two structural differences and choose which structural characteristic is more important in the function of gramicidin A.Explain your choice.

Accepted Answer

The answer of There are two main structural differences between...

Question 2

Decide if the rate of malate transport by the Omp32 protein of Delftia acidovorans will be affected if the pH of the system is changed from 6.8 to 8.2.Explain your reasoning.
The pKa of amino acids with ionizable side chains are provided in the table below.Note that malic acid contains two ionizable groups with pKa of 3.40 and 5.20.Assume in this scenario that the pH change does not alter the overall conformation of the protein.

Accepted Answer

The answer of Decide if the rate of malate transport...

Question 3

Describe the two functional units of myoglobin that are responsible for O₂ binding.Include the type of chemical bond involved for each binding interaction (i.e.,hydrogen bond,covalent bond,electrostatic bond,etc.).

Accepted Answer

The answer of Describe the two functional units of myoglobin...

Question 4

What is the clinical term for reduced O₂ transport efficiency from the lungs to the tissues,arising from altered hemoglobin function or reduced numbers of red blood cells per unit of blood? Provide an example of a specific type of anemia that is caused by a single point mutation.

Accepted Answer

The answer of What is the clinical term for reduced...

Question 5

What is required for the transport of a molecule by an active transporter that is not necessary for a molecule to be transported by a passive transporter?

Accepted Answer

The answer of What is required for the transport of...

Question 6

Consider the movement of fructose into a cell by passive transport.If the extracellular concentration of fructose is 0.35 mM and the intracellular concentration of fructose is 0.42 mM,what is the free energy of transport in kJ/mol?

Accepted Answer

The answer of Consider the movement of fructose into a...

Question 7

Consider the movement of glucose into a cell by passive transport.If the extracellular concentration of glucose is 4 mM and the intracellular concentration of glucose is 2 mM,what is the free energy of transport in kJ/mol?

Accepted Answer

The answer of Consider the movement of glucose into a...

Question 8

The figure below shows the oxygen binding curves of oxygen-transport protein from four different organisms.Decide which organism is the most efficient at oxygen transport and justify your choice.

Accepted Answer

The answer of The figure below shows the oxygen binding...

Question 9

The E.coli maltoporin protein is a homotrimeric porin complex.A related protein is found in another bacterial species that does not form trimers but rather functions as a monomer.A comparison of the amino acid composition of a maltoporin subunit and the new porin showed similar ratios of hydrophobic/hydrophilic amino acids for the two proteins.Explain how this can be the case.

Accepted Answer

The answer of The E.coli maltoporin protein is a homotrimeric...

Question 10

Look at the data in the figure below.One amino acid location is indicated by an arrow.Why is the amino acid at that location invariant among the three sequences?

Accepted Answer

The answer of Look at the data in the figure...

Question 11

A new protein has been discovered that may be allosterically regulated.The protein is purified and analyzed by SDS-PAGE followed by staining with Coomassie blue.A single band at 42 kDa is seen on the gel.Explain how these data may or may not support the belief that the protein is an allosterically regulated protein.If they do support an allosterically regulated protein,propose the most likely model of allostery followed by the protein.

Accepted Answer

The answer of A new protein has been discovered that...

Question 12

A passive transporter is discovered that can transport both galactose and glucose.The pore of the transporter can accommodate a single sugar at a time.If the extracellular concentrations of galactose and glucose are 0.2 and 3.6 mM,respectively,and the intracellular concentrations are 0.39 and 2.6 mM,respectively,which sugar is most likely to enter the cell through the transporter? Provide two reasons for your answer.

Accepted Answer

The answer of A passive transporter is discovered that can...

Question 13

An E.coli strain is discovered that has a mutation in the gene encoding RecBCD.The mutation causes RecBCD to not function as effectively as the wild-type RecBCD.Hypothesize how the growth rate of this strain would compare with that of the wild type.

Accepted Answer

The answer of An E.coli strain is discovered that has...

Question 14

Predict the effect on Na⁺ transport through gramicidin A if the helical structure took on the conformation of a true -helix.

Accepted Answer

The answer of Predict the effect on Na⁺ transport through...

Question 15

You design an experiment in which you can monitor the step-by-step movement of H⁺ and Ca²⁺ through the SERCA protein,starting with the protein in the E2-ATP state and moving through the transport cycle,ultimately returning to the E2-ATP state.Your control experiment includes everything required for the system to function normally,and you easily detect four distinct conformations of the protein.You then replace the ATP in the system with ATP S,a nonhydrolyzable form of ATP,and begin the experiment again with the protein in the E2-ATP state.Predict which conformations of SERCA you will detect.

Accepted Answer

The answer of You design an experiment in which you...

Question 16

An increase in sickle cell disease symptoms can occur when a person with the disease is at higher altitudes.Hypothesize how allosteric regulation at high altitudes may be related to sickle cell anemia.

Accepted Answer

The answer of An increase in sickle cell disease symptoms...

Question 17

Given the following concentrations,what is ? [Mb] = 0.07,[MbO₂] = 0.69,[O₂] = 3.5 kPa

Accepted Answer

The answer of Given the following concentrations,what is  
?...

Question 18

Using the data shown,list the porins from the most selective to the least selective.

Accepted Answer

The answer of Using the data shown,list the porins from...

Question 19

What role do _S-Phe85 and ^S-Leu88 play in sickle cell anemia?

Accepted Answer

The answer of What role do _S-Phe85 and ^S-Leu88 play...

Question 20

Explain how the five arginine residues found within the channel of Omp32 protein of the bacterium Delftia acidovorans increase the specificity of the channel.

Accepted Answer

The answer of Explain how the five arginine residues found...

Quiz 6: Protein Function

There are two main structural differences between a typical -helix and the helix formed by gramicidin A.Describe the two structural differences and choose which structural characteristic is more important in the function of gramicidin A.Explain your choice.

Describe the two functional units of myoglobin that are responsible for O2 binding.Include the type of chemical bond involved for each binding interaction (i.e.,hydrogen bond,covalent bond,electrostatic bond,etc.).

What is the clinical term for reduced O2 transport efficiency from the lungs to the tissues,arising from altered hemoglobin function or reduced numbers of red blood cells per unit of blood? Provide an example of a specific type of anemia that is caused by a single point mutation.