Biochemistry Exam 2 Study Guide

Which amino acid does not have a primary a-amino acid group?

Proline

What level of protein structure is characterized by the amino acid sequence?

Primary

The predominant non-covalent interaction seen in a-helices and b-sheets is

hydrogen bonds

Which of the following interactions would be involved in quarternary structure?

All of these choices

Which of the following amino acids contains a side chain that is polar and uncharged from pH 1-13?

Phe

What is the net charge of the pen tape-tide Ala-Cys-Ser-Glu-Asn at pH 7?

None of these choices

A technique for determining protein structure where the protein is in solution is

NMR spectroscopy

A technique for determining protein structure that requires crystals of the protein is

X-ray crystallography

At physiological pH, all amino acids have at least ____ charged groups

2

Which of the following explains how cell division is blocked by drugs that prevent proper microtubule function?

chromosomes separate along a microtubule spindle

Which of the following explains the conversion of hemoglobin subunits from deoxygenated to oxy state?

All four subunits switch simultaneously

Hemoglobin S, the variant responsible for the misshapen red blood cells characteristic of the disease sickle-cell anemia, is potentially advantageous to heterozygotes because it confers some level of resistance to the disease _____.

Malaria

When oxygen is bound to the heme group of myoglobin, it is coordinated between ____ and ____.

E7 His; Fe2+ of heme

Proteins such as hemoglobin are known as _____ proteins since binding of a molecule to one site alter binding to other sites.

allosteric

During the formation of microfilaments, which of the following occurs?

ATP hydrolysis is catalyzed by F-actin

A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape; a similar plot for hemoglobin gives a _____ shape.

hyperbolic; sigmoidal

How does CO2 affect hemoglobin-oxygen binding?

CO2 is converted to bicarbonate and H+ which promotes the deoxy state

When a cell moves along a surface, actin ____ occurs at the leading edge while ____ occurs at the trailing edge

polymerization; depolymerization

Which of the following occurs in hemoglobin upon oxygen binding?

the central cavity between the four subunits is decreased in size

During the first half of the chymotrypsin mechanism where the acyl-enzyme intermediate is formed, what role does His play?

general base then general acid

The highest point in a reaction coordinate diagram represents ____

The transition state

The ability for an enzyme to pick out one particular substrates from the myarid of molecules floating around its environment is an example of ____

Specificity

The enzyme hexokinase catalyzes a reaction where its substrates ate completely sequestered from the aqueous environment allowing for interactions to occur between enzyme and substrates that would not normally occur in an aqueous environment. What term describes this type of catalysis?

Electrostatic catalysis

Which of the following is the most effective way to increase the rate of a biochemical reaction?

add a catalyst

An enzyme that forms a covalent bond with its substrate during the course of a reaction is considered to undergo ____

covalent catalysis

An organic molecule that is tightly bound to an enzyme and participates in an enzyme catalyzed reaction is specifically referred to as a ____

prosthetic group

Of the following ions, which would be most likely to participate in metal ion catalysis?

Zn2+

How does a catalyst increase the rate of a reaction?

it allows reacting molecules to more easily form the transition state

Different enzymes that catalyze the same reaction are known as _____.

isozymes