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Biochemistry Unit Test
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Name:
___________________________
K
T
C
A
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PART A: MULTIPLE CHOICE (0.5 marks each)
K
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1. Water is a polar covalent molecule. This means that
a)
b)
c)
d)
e)
electrons are shared unequally.
hydrogen is charged.
oxygen is less electronegative.
electrons are shared equally.
all of the above.
2. Hydrogen bonding describes
a)
b)
c)
d)
e)
attraction between polar molecules.
shared electrons in a molecule, like water.
a strong bond within a molecule.
the formation of acids.
all of the above.
3. Proteins have many functions. Which function is NOT related to protein?
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b)
c)
d)
e)
a)
Transporting substances in the body.
Regulating cellular processes.
Insulating against heat loss.
Catalyzing chemical reactions.
Providing structural support.
4. The secondary structure of a protein describes
a)
b)
c)
d)
e)
the R groups involved.
the linear sequence of amino acids.
the polarity of amino acids.
the hydrogen bonding between amino acids.
complex folding.
5. Nucleic acids are responsible for
a)
b)
c)
d)
e)
organizing the structure of the nuclear membrane.
coding the amino acid sequence of proteins.
forming fibres that hold the cell together.
storing energy for a cell.
rapid energy release in a cell.
6. Enzymes interact with a substrate at
a)
b)
c)
d)
e)
the active site.
the allosteric site.
the target site.
a site.
the regulatory region.
7. A catalyst lowers the activation energy by
a) reducing the overall temperature.
b) destabilizing bonds in the substrate.
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c)
changing the order of amino acids.
d) adding energy to the substrate.
e) all of the above.
8. Which of these examples is not a monomer?
a)
b)
c)
d)
e)
Monosaccharide
Nucleotide
Amino acid
Triglyceride
All of these are monomers
9. Which of these factors has the lowest overall effect on the denaturing of a
biological catalyst?
a)
b)
c)
d)
e)
Extreme temperatures
High level of H+ ions
Concentration of substrate
Concentration of catalyst
Both c and d
10. A hypotonic solution outside a cell allows
a)
b)
c)
d)
e)
net water loss to the cell.
net water gain to the cell.
water to leave and enter at the same rate.
the membrane to shrink and break.
the loss of ions from the cell.
11. What factor is most important to the movement of molecules across a
particular protein channel?
a)
b)
c)
d)
Concentration
Shape and size
Hormonal signals
Electric charge
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e)
Polarity
12. Receptor mediated endocytosis requires the presence of
a) protein channels to mediate the activity of the receptors.
b) carrier proteins that move molecules across the membrane into the
cytosol.
c) primary active transport pumps.
d) concentrated ions for secondary active transport.
e) specialized proteins on the membrane surface.
13. A cell membrane with no proteins will still show which process?
a)
b)
c)
d)
e)
Diffusion
Facilitated diffusion
Osmosis
a and c
a, b and c
14. The energy found in chemical bonds is a form of
a)
b)
c)
d)
e)
gravitational energy.
elastic energy.
energy of motion.
potential energy.
kinetic energy.
15. An exergonic reaction
a)
b)
c)
d)
e)
requires more energy than it releases.
creates an explosion.
does not require energy energy to start.
releases more energy than it requires.
absorbs heat from the environment.
16. What molecule is capable of lipid diffusion?
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a)
b)
c)
d)
e)
Amino acids
Chlorine ions
Glucose
Sodium ions
Water
17. Of the following characteristics, which one is not true about enzymes?
a)
b)
c)
d)
e)
Some enzymes need activators and cofactors.
They are essential to the metabolism of cells for the conversion of energy.
They function best at a particular pH.
They function best at a specific temperature.
They undergo changes after reacting with the substrate.
18. The endomembrane system is responsible for
a)
b)
c)
d)
e)
synthesizing molecules.
transporting cell products.
secreting materials formed.
the digestion of matter.
all of the above.
19. The peroxisome
a)
b)
c)
d)
e)
is a vesicle for nutrients.
contains oxidase enzymes.
adds carbohydrate chains to proteins.
has ribosomes for making proteins.
has a pH of about 5.
20. A new material discovered is composed of bonds with electronegativity
difference values of 1.8. What type of bond is this?
a) Covalent
b) Hydrogen bond
c) Ionic
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d)
Polar covalent
e) None of the above
21. The cytoskeleton consists of many parts, but NOT
a)
b)
c)
d)
e)
intermediate filaments.
microtubules.
polysaccharides.
a network of protein fibres.
microfilaments.
22. A functional group is
a)
b)
c)
d)
e)
a charged group.
a nonpolar segment.
many monomers linked together.
a cluster of atoms that behave in a certain way.
all of the above.
23. What feature of lipids makes them good sources of energy?
a)
b)
c)
d)
e)
They do not dissolve easily in water.
They are easy to access by metabolic processes.
They are rich in C-H bonds.
They are large.
They accumulate into specialized organelles.
24. Feedback inhibition involves
a)
b)
c)
d)
e)
activators.
cofactors.
high concentration of substrate.
inhibitors.
low concentrations of enzymes.
25. Which functional group is polar and basic?
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a)
b)
c)
d)
e)
Carbonyl
Carboxyl
Ester
Ether
Hydroxyl
26. Some biochemical reactions require a coenzyme such as a
a)
b)
c)
d)
e)
vitamin derivative.
buffer.
protein.
metal ion.
carbohydrate.
27. Proteins have many functions in the cell membrane. Which function is not
related to a protein?
a)
b)
c)
d)
e)
Maintaining cell shape
Membrane fluidity
Reaction catalyst
Signal reception
Transport
28. The fatty acids of a saturated fat have
a)
b)
c)
d)
e)
many double bonds.
a lower number of hydrogen atoms.
greater flexibility or fluidity.
no double bonds.
fewer carbon atoms.
29. Net diffusion stops when
a) all of the materials enter the cell.
b) all the cell’s energy is used up.
c) the concentration gradient is largest.
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d)
there are equal amounts on both sides of the
membrane.
e) all of the above.
30. Which factor can change the shape of an enzyme’s active site?
a)
b)
c)
d)
e)
Enzyme concentration
pH
Substrate concentration
Temperature
b and d
PART B: SHORT ANSWER
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For questions with choice, circle the option you are answering and answer in
the space below the question. If you answer both questions and do NOT indicate
which you wish marked, the first question will be marked.
1. Intravenous bags are used to deliver fluids directly into a vein. Intravenous
bags are always filled with a salt solution and never pure water. Explain
why injecting distilled water instead of a salt solution into someone could
kill them. (2 marks) [T/1.5; A/0.5]
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2.
Draw and label a diagram of a phospholipid bilayer
and its components. Explain how various items can enter or exit cells. (6
marks) [K/2; T/1.5; C/1.5; A/1]
3. Using your understanding of the properties of intermolecular and
intramolecular forces, explain
a) how water rises in narrow tubes, against the force of gravity. (4 marks)
OR
b) how some insects can walk on the surface of water. (4 marks) [K/2;
T/2]
4. Complete this chart on the level of organization in proteins. (4 marks)
[K/2; T/1.5; C/0.5]
Level of
Organization
Description (1 mark each)
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Primary structure
Secondary structure
Tertiary structure
quaternary structure
5. Draw a hydrolysis reaction occurring on this compound. Label the
reactants and products and list what type of bond is being broken
(general names accepted). Finally, circle all the functional groups on the
products and name them. (5 marks) [K/1; T/1; C/1; A/2]
6. a) Explain the difference between competitive, and non-competitive
enzyme inhibition. Draw a diagram to support your response. (3 marks)
OR
b) Outline what allosteric regulation is and why it is important for
feedback loops in biological applications. (3 marks) [ T/2; C/0.5, A/0.5]
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7. Enzymes in the human body can undergo exergonic and endergonic
reactions. Draw and label a graph for each type of reaction. Include
uncatalyzed and catalyzed reactions on the same graph. Also explain what
the induced fit model is. (6 marks) [K/1; T/1; C/2; A/2]
8. Provide two similarities and two differences between
a) Competitive and non-competitive inhibition (4 marks)
OR
b) Allosteric regulation process and enzymes (4 marks) [K/0.5; T/2; C/1;
A/0.5]
9. Draw a condensation reaction occurring on this compound. Label the
reactants and products and list what type of bond is being formed
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(general names accepted). Finally, circle all the functional
groups on the product and name them. (6 marks) [K/1; T/1; C/1, A/3]
10. Explain the properties of a phospholipid that are responsible for forming
as a bilayer structure. (2 marks) [T/1.5; C/0.5]
11. a) Vesicles are important structures in both animal and plant cells. Provide
an example of a vesicle that is an organelle and explain its role in the cell.
Explain how vesicles can be used in the cell that does not function as an
organelle. (4 marks)
OR
b) What is a concentration gradient? How does a concentration gradient
affect movement across a membrane? (4 marks) [K/0.5; T/2; C/1; A/0.5]
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12. Cholesterol is a lipid that is required for life to exist. Where can we find
cholesterol in our membranes and what is its function? (3 marks) [T/2;
C/1]