Question 1

The following question is based on the 15 molecules illustrated in the figure.

Which of the following pairs of molecules could be joined together by a peptide bond in a dehydration reaction?

Accepted Answer

A)  2 and 3 
B)  7 and 8 
C)  8 and 9 
D)  12 and 13

Question 2

Use the following information to answer the question.
"The native structure of hemoglobin (Hb)comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)
Hemoglobin is ________.

Accepted Answer

A)  a tertiary protein with two polypeptides 
B)  a quaternary protein with two polypeptides 
C)  a tertiary protein with four polypeptides 
D)  a quaternary protein with four polypeptides

Question 3

People who are lactose intolerant cannot extract energy from milk because ________.

Accepted Answer

A)  they are missing an enzyme 
B)  lactose is too big to be digested by the enzymes 
C)  milk is fermented to a by-product, which cannot be digested 
D)  they are missing the bacteria that can digest lactose

Question 4

What does the term insoluble fiber refer to on food packages?

Accepted Answer

A)  cellulose 
B)  polypeptides 
C)  starch 
D)  amylopectin

Question 5

You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?

Accepted Answer

A)  primary structure 
B)  secondary structure 
C)  tertiary structure 
D)  quaternary structure

Question 6

The following question is based on the 15 molecules illustrated in the figure.

A fat (or triacylglycerol)would be formed as a result of a dehydration reaction between ________.

Accepted Answer

A)  one molecule of 9 and three molecules of 10 
B)  three molecules of 9 and one molecule of 10 
C)  one molecule of 5 and three molecules of 9 
D)  one molecule of 5 and three molecules of 10

Question 7

If one strand of a DNA molecule has the sequence of bases 5′-ATTGCA-3′, the mRNA synthesized following the template will be ________.

Accepted Answer

A)  5′-TAACGT-3′ 
B)  5′-TGCAAT-3′ 
C)  3′-UAACGU-5′ 
D)  5′-UGCAAU-3′

Question 8

Use the following figure to answer the question.

The molecule shown is ________.

Accepted Answer

A)  a hexose 
B)  a pentose 
C)  fructose 
D)  maltose

Question 9

Absorbance at Various pH Levels
\(\begin{array}{c}
\begin{array}{|l|}
\hline \text { Time (sec) } \
\hline20 \
\hline 40 \
\hline 60 \
\hline 80 \
\hline 100 \
\hline 120 \
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{4} \
\hline0.003\
\hline 0.009 \
\hline 0.012 \
\hline 0.020 \
\hline 0.023 \
\hline 0.025\
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{5} \
\hline0.025 \
\hline 0.109 \
\hline 0.195 \
\hline 0.215 \
\hline 0.333 \
\hline 0.360 \
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{6} \
\hline0.055 \
\hline 0.152 \
\hline 0.255 \
\hline 0.341 \
\hline 0.413 \
\hline 0.478 \
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{7} \
\hline0.146 \
\hline 0.300 \
\hline 0.432 \
\hline 0.552 \
\hline 0.659 \
\hline 0.755 \
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{8} \
\hline0.005 \
\hline 0.015\
\hline 0.038\
\hline 0.065\
\hline 0.081 \
\hline 0.090 \
\hline 
\end{array}
\begin{array}{l|}
\hline\mathrm{pH} \mathrm{9} \
\hline0.004 \
\hline 0.008\
\hline 0.010\
\hline 0.012\
\hline 0.013 \
\hline 0.013\
\hline 
\end{array}
\end{array}\)

The table represents the results of an experiment where the effects of pH buffers on an enzyme found in saliva (amylase)were studied. A spectrophotometer set at 500 nm was used to measure absorbance at the various pH levels every 20 seconds for 2 minutes. The higher absorbance values would indicate greater enzyme activity. All experiments were conducted at the same temperature.
Which statement correctly identifies the result that the optimum pH for amylase function is 7?

Accepted Answer

A)  The pH with the lowest absorbance values would indicate the optimum pH for amylase since this pH does not affect the structure or function of the protein. 
B)  The pH with the highest absorbance values would indicate the optimum pH for amylase since this pH does not affect the structure or function of the protein. 
C)  At pH 9, the enzyme is denatured and will lose its function, but not its structure. 
D)  At pH 4, the structure of the enzyme will be altered, and the enzyme would not be able to catalyze the reaction.

Question 10

If ¹⁴C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?

Accepted Answer

A)  DNA 
B)  RNA 
C)  both DNA and RNA 
D)  polypeptides

Exam 5: The Structure and Function of Large Biological Molecules

The following question is based on the 15 molecules illustrated in the figure. Which of the following pairs of molecules could be joined together by a peptide bond in a dehydration reaction?

People who are lactose intolerant cannot extract energy from milk because ________.

What does the term insoluble fiber refer to on food packages?

You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?

The following question is based on the 15 molecules illustrated in the figure. A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between ________.

If one strand of a DNA molecule has the sequence of bases 5′-ATTGCA-3′, the mRNA synthesized following the template will be ________.

Use the following figure to answer the question. The molecule shown is ________.

If ¹⁴C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?