Name:     ID: 
 
Email: 

Macromolecules and Membrane v.3

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The hydrogen atoms of a water molecule are bonded to the oxygen atom by __________ bonds, whereas neighboring water molecules are held together by __________ bonds.
a.
polar covalent . . . hydrogen
b.
hydrogen . . . ionic
c.
ionic . . . covalent
d.
hydrogen . . . polar covalent
e.
polar covalent . . . ionic
 

 2. 
As ice melts,
a.
water molecules become less tightly packed.
b.
the water becomes less dense.
c.
hydrogen bonds are broken.
d.
covalent bonds form.
e.
All of the choices are true.
 

 3. 
The temperature of evaporation is much higher for water than for alcohol. Without knowing more about the chemistry of alcohol, which of the following is the most logical chemical explanation for this phenomenon?
a.
Fewer hydrogen bonds form between alcohol molecules. As a result, less heat is needed for alcohol molecules to break away from solution and enter the air.
b.
Alcohol molecules are more cohesive than water molecules. This means that as alcohol molecules evaporate, they pull other alcohol molecules into the air along with them.
c.
Ionic bonds form between alcohol molecules. These are the weakest type of bond and are easier to break than the hydrogen bonds between water molecules.
d.
Alcohol has a higher surface tension than water. This means that alcohol molecules can easily break away from other alcohol molecules and evaporate at a lower temperature.
e.
None of the choices is a logical chemical explanation for this phenomenon.
 

 4. 
Compared to a solution of pH 3, a solution of pH 1 is
a.
neutral.
b.
10 times more basic.
c.
100 times more acidic.
d.
10 times more acidic.
e.
100 times more basic.
 

 5. 
A buffer
a.
donates mc005-1.jpg ions when conditions become too acidic and accepts mc005-2.jpg ions when conditions become too basic.
b.
is an acid that is used to offset overly basic conditions in the body.
c.
donates mc005-3.jpg ions when conditions become too basic and accepts mc005-4.jpg ions when conditions become too acidic.
d.
donates mc005-5.jpg ions when conditions become too basic and accepts mc005-6.jpg ions when conditions become too acidic.
e.
is a base that is used to offset overly acidic conditions in the body.
 

 6. 
Hydrocarbons
a.
consist of atoms linked exclusively by single bonds.
b.
are composed of carbon atoms that are attached to hydrogen skeletons.
c.
contain only carbon and hydrogen atoms.
d.
are inorganic compounds.
e.
All of the choices are correct.
 

 7. 
Which one of the following statements about the functional groups of organic compounds is false?
a.
Functional groups participate in chemical reactions.
b.
Functional groups help make organic compounds soluble in water.
c.
All functional groups include a carbon atom of the organic compound's skeleton.
d.
Many biological molecules have two or more functional groups.
e.
Functional groups help make organic compounds hydrophilic.
 

 8. 
Which one of the following statements about the monomers and polymers found in living organisms is false?
a.
Monomers are joined together by the process of hydrolysis.
b.
Monomers serve as building blocks for polymers.
c.
The monomers used to make polymers are essentially universal.
d.
Cells typically make all of their macromolecules from a set of 40-50 common monomers and a few other ingredients that are rare.
e.
DNA is built from just four kinds of monomers.
 

 9. 
The results of dehydration synthesis can be reversed by
a.
the addition of an amino group.
b.
hydrolysis.
c.
the addition of a phosphate group.
d.
polymerization.
e.
condensation.
 

 10. 
Which list below consists of only polymers?
a.
sugars, amino acids, nucleic acids, lipids
b.
proteins, lipids, nucleic acids, polysaccharides
c.
proteins, lipids, nucleic acids, amino acids
d.
polysaccharides, lipids, amino acids, nucleic acids
e.
proteins, lipids, nucleotides, sugars
 

 11. 
A molecule with the formula mc011-1.jpgmc011-2.jpgmc011-3.jpg is probably a(n)
a.
protein.
b.
oil.
c.
steroid.
d.
polysaccharide.
e.
wax.
 

 12. 
Molecules that taste sweet
a.
have a shape that binds tightly to sweet taste receptors.
b.
include at least one carbohydrate monomer.
c.
cause carbohydrates to break down into monomers that trigger the sweet taste reaction.
d.
must bind to the sweet and bitter receptors.
e.
are all carbohydrates.
 

 13. 
Cellulose differs from starch in that
a.
glycogen is formed by plants and cellulose by animals.
b.
starch is made of glucose monomers, whereas cellulose is made of fructose monomers.
c.
the monomers of cellulose are held together by covalent bonds, whereas the monomers of starch are held together by hydrogen bonds.
d.
most animals cannot break down cellulose, whereas starch is easily digested.
e.
All of the choices are correct.
 

 14. 
The storage form of carbohydrates in animals is __________ and in plants is __________.
a.
glycogen . . .  starch
b.
starch . . . glycogen
c.
sucrose . . . glycogen
d.
cellulose . . . glycogen
e.
glycogen . . . cellulose
 

 15. 
One way to convert an oil into a substance that is solid at room temperature is to
a.
put it in the refrigerator:  when unsaturated fats cool, double bonds form and the fats solidify.
b.
remove water, causing a dehydration synthesis reaction to occur.
c.
remove hydrogens, increasing the number of double bonds.
d.
add hydrogens, decreasing the number of double bonds in the molecules.
e.
add water and shake vigorously.
 

 16. 
Which one of the following statements about animal cell lipids is false?
a.
Steroids are lipids that function as signaling molecules.
b.
Many lipids function as enzymes.
c.
Fats are a form of lipid that functions as energy-containing molecules.
d.
Phospholipids are important components of cell membranes.
e.
Cholesterol is a type of lipid used in cell membranes and as a starting material for making steroid hormones.
 

 17. 
Proteins differ from one another because
a.
the peptide bonds linking amino acids differ from protein to protein.
b.
each protein contains its own unique sequence of sugar molecules.
c.
the number of nucleotides found in each protein varies from molecule to molecule.
d.
the sequence of amino acids in the polypeptide chain differs from protein to protein.
e.
the number of nitrogen atoms in each amino acid varies.
 

 18. 
Which of the following factors can result in the denaturation of a protein?
a.
heat
b.
chemicals that destroy hydrogen bonds
c.
changes in salt concentration
d.
changes in pH
e.
All of the choices can result in the denaturation of a protein.
 

 19. 
The __________ structure of a protein consists of a chain of amino acids assembled in a specific order.
a.
secondary
b.
tertiary
c.
quaternary
d.
primary
e.
None of the choices are correct.
 

 20. 
A new "wonder food" is being distributed by a rival company. The researchers in your company determine that the "wonder food" contains only carbon, oxygen, and hydrogen. At this point, your researchers can say with certainty that the food
a.
could only be made of carbohydrates.
b.
includes proteins.
c.
could only be made of triglycerides.
d.
does not include proteins or nucleic acids.
e.
includes nucleic acids.
 

 21. 

mc021-1.jpg

Questions (##-##) Refer to the diagram above.
This beta barrel, a beta pleated sheet that has been folded into a tube, is surrounded by many non polar hydrocarbon chains.  It normally carries a basic molecule inside it. 1 refers to the inside of the tube, and 2 refers to the outside of the tube.

What can you determine about these domains.
a.
2 must be polar because opposites attract.
d.
1 must be hydrophillic.
b.
1 and 2 are both hydrophillic, because all reactions in the body involve hydrophillic molecules.
e.
It is not possible for a molecule to have properties like this.
c.
1 and 2 must be hydrophobic because they are surrounded by non-polar molecules.
 

 22. 
If placed in a polar environment,  this protein will most likely. . .
a.
not function
d.
both A and B
b.
turn inside out
e.
none of the above
c.
refold so that it can function in the body.
 

 23. 
If this protein were placed in between a hydrophobic and hydrophillic layer, (like the hexane, disk and water problem) the protein will. . .
a.
lay out as a flat sheet.
d.
go through dehydration synthesis.
b.
curl so that the hydrophobic face/layer of the protein would face outside.
e.
not change shape at all.
c.
curl so that the hydrophillic face/layer would face inside.
 
 
The following four diagrams show the structures of different molecules.  Answer the following questions based on your ability to identify them.
nar001-1.jpg
 

 24. 
Which diagram represents the monomer units of proteins?
a.
1.
b.
2.
c.
3.
d.
4.
e.
Both (2) and (4)
 

 25. 
Which macromolecule is characterized as being hydrophobic?
a.
1.
b.
2.
c.
3.
d.
4.
e.
All molecules here are hydrophobic.
 

 26. 
Which diagram shows a structural isomer of cellulose?
a.
1.
b.
2.
c.
3.
d.
4.
e.
None of the above.
 

 27. 
Which macromolecule is best associated with the terms saturated and unsaturated?
a.
1.
b.
2.
c.
3.
d.
4.
e.
All molecules have saturated and unsaturated structures.
 
 
The following diagram shows a sequence of a reaction.  The numbers 1 through 4 identify different parts of the overall structure.
nar002-1.jpg
 

 28. 
This reaction is facilitated by which structure in the cell?
a.
DNA polymerase
b.
RNA polymerase
c.
Ribosome
d.
Nucleus
e.
Hydrolase
 

 29. 
Numbers 1-4 highlight different parts of the structures show in the diagram.  Which part is directly involved in the tertiary interactions (tertiary structure) that determine the three dimensional structure of this macromolecule?
a.
1.
b.
2.
c.
3.
d.
4.
e.
Both (1) and (2)
 



 
         Start Over