Question 1

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.

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Question 2

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.).

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Question 3

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?

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Question 4

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?

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Question 5

Using the following data, arrange the proteins in order from the one having the lowest affinity for the ligand to the highest.

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Question 6

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.

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Question 7

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?

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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.

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Question 9

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.

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Question 10

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

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Question 11

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.

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Question 12

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?

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Question 13

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.

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Question 14

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

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Question 15

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

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Question 16

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

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Question 17

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.

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Question 18

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.

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Question 19

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

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Question 20

There are two main structural differences between a typical $\alpha$-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.

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Quiz 6: Protein Function

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.

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.).

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?

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?

Using the following data, arrange the proteins in order from the one having the lowest affinity for the ligand to the highest.

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.

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?

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.

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

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?

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

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

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

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.

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

There are two main structural differences between a typical $\alpha$ -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.

Quiz 6: Protein Function

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.

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.).

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?

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?

Using the following data, arrange the proteins in order from the one having the lowest affinity for the ligand to the highest.

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.

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?

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.

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

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?

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

What role do β\betaβ S-Phe85 and β\betaβ S-Leu88 play in sickle cell anemia?

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

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.

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

There are two main structural differences between a typical α\alphaα -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.

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

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

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

There are two main structural differences between a typical $\alpha$ -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.