Biology 12 - Biochemistry Practice Exam KEY
Water:
1. The bond between water molecules is a(n)
a. ionic bond
b. covalent bond
c.
polar covalent bond
d. hydrogen bond
2.
The water properties: good solvent, temperature regulator and lubricant all depend on
a. ionic bond
b. covalent bonds
c. peptide bonds
d. hydrogen bonds
3.
The weakest bond below is
a. hydrogen bond
b. peptide bond
4.
c.
covalent bond
d. ionic bond
Describe 3 special properties of water.
Good temperature regulator – ex. sweat
Good lubricant - in joints of body
Good solvent - dissolves substances ex. blood
Acids, Bases and buffers:
5. Which of the following would be produced during exercise and cause the pH of the body to drop?
a. K
b. Clc. C a
d. H+
6.
A solution becomes more acidic when a chemical is added to it. The chemical added contains
a. sodium ions
b. hydrogen ions
c. hydroxide ions
d. bicarbonate ions
7.
What number below represents a strong acid on the pH scale?
a. 8
b. 10
c. 3
8.
9.
The purpose of buffers is to
a. increase pH
b. neutralize solution
d. 6
c. absorb all the OH ions d. control pH level
A slightly basic solution has a pH value of
a. 9
b. 6
c.
8
d. 3
10. High basicity depends on
a. high OH- ion conc. b. high H+ ion conc.
c. low dissociation level
d. polar bond formation
11. A slightly acid solution has a pH value of
a. 9
b. 6
c.
8
d. 3
12. High acidity depends on
a. high OH- ion conc. b.
c.
low dissociation level
d. polar bond formation
13. Buffers
a. keep pH at 4
high H+ ion conc.
b. keep pH neutral
c. keep pH at 7.4
d.
14. When hydrogen chloride, a strong acid, is added to water, the pH
a. goes up
b. stays the same
c. goes down
remove excess H+ and OH- ions
d.
15.
Acids have a pH that is less than 7, and bases have a pH that is greater than 7 .
16.
At pH = 7, [ H+ ] = [ OH- ]. Below pH 7, which of these is greater?
[ H+ ]
cannot be determined
17.
Which of the following represents the largest [ H+ ] pH = 3, pH = 4, pH = 8, pH = 10
18.
Define:
19.
What is the importance of pH to biological systems?
Extremes in pH cause proteins to denature, they lose their normal shape and may not function.
acid and base
acid - increase [ H+ ], pH less than 7
base - increase [ OH- ], pH greater than 7
Carbohydrates:
20. Maltose is an example of a
a. monosaccharide
b. disaccharide
c.
polysaccharide
d. protein
21. Starch, cellulose and glycogen are all
a. lipids
b. monosaccharides
c.
polysaccharides
d. disaccharides
22. In carbohydrates the ratio of hydrogen to oxygen is usually
a. 6 : 12
b. 2 : 1
c. 1 : 2
d. 3 : 1
23. Which of the following is not a carbohydrate?
a. fructose
b. glucose
d. starch
c.
amino acid
24. When many glucose molecules undergo dehydration synthesis, the result is
a. protein
b. phospholipid
c. polysaccharide
d. polypeptide
25. Glucose is an example of a(n)
a. monosaccharide
b. disaccharide
d. protein
c.
polysaccharide
26. Which of the following is not stored in animal tissues?
a. lipids
b. protein
c. glycogen
d. starch
27. Which of the following is not found in plant tissue?
a. lipids
b. starch
c.
glycogen
d. cellulose
28. Which pair is mismatched?
a. amino acid - protein
c. glucose - starch
fatty acid - glycogen
phosphate - nucleotide
29.
b.
d.
Monosaccharides, disaccharides and polysaccharides may be compared as to the number of monosaccharide
(or glucose) molecules they contain.
30. Which of the following represents the building blocks of carbohydrates? B
Proteins:
31. Proteins are polymers of
a. nucleotides
b.
amino acids
c.
fatty acids
32. The groups H - N - H and O = C - OH are both found in
a. lipids
b. polysaccharides
c. amino acids
d. monosaccharides
d. monosaccharides
33. A peptide bond
a. joins fatty acids
c. joins disaccharide sugars
b.
d.
joins monosaccharide sugars
joins amino acids
34. A chain of two amino acids is called a
a. dipeptide
b. diphosphate
c.
dinucleotide
d. disaccharide
35. A peptide bond joins
a. C with O
c.
C with C
d. O with H
b.
C with N
36. Different kinds of amino acids are usually distinguished by the
a. number of carbon atoms present
b. the R groups present
c. how many amino acids are missing
d. whether or not Nitrogen is present
37. The “backbone” of a polypeptide would be composed of
a. the bases
b. sugar-phosphate-sugar-phosphate
c. N - C - C - N - C - C etc.
d. the R groups
38. Which of the following contains the element Nitrogen?
a. fructose
b. glucose
c. amino acid
d. starch
39. A single helix shape of a protein would be described as a
a. primary protein
b. secondary protein c. tertiary protein
d. globular protein
40.
41.
The primary structure of a protein is a polymer of amino acids,
A secondary structures shape can described as bent, and the tertiary structures shape can be described as bent
and folded A quaternary structure contains more than 1 polypeptide.
Draw and label an amino acid: include functional group, amine group, carboxyl acid.
42.
Describe what makes each amino acid different.
R or functional group
43.
Define denaturation.
The change in shape of a protein
44.
State 3 ways that protein may be denatured.
Changes in pH
Extremes temperature – above 37 C in humans
Heavy metals like Pb and Hg
45.
Why is denaturation of protein a problem for organisms?
Proteins lose their shape and may not function
46.
Describe 4 functions of proteins.
Structural proteins – collagen, tendons, ligaments
Enzymes – catalysts, cause chemical reactions to occur in the body
Hormones – chemical messengers like insulin
Antibodies – proteins made by the immune system
Hemoglobin – carries O2, CO2 and H+ (buffers blood)
Muscle - helps body move
47. Which of the following represents the building blocks of proteins? A
Lipids:
48. Fats, phospholipids and steroids are all
a. proteins
b. carbohydrates
c.
lipids
d. steroids
49. Which of the following would be considered a polymer?
a. glucose
b. neutral fat molecule c. unsaturated fatty acid
d. saturated fatty acid
50. A neutral fat is composed of 3
a. glycogen
b. glucose
d. fatty acids
c.
phospholipids
51. Which molecule is unsaturated? B
52. Double bonds between the carbons indicates a (n)
a. saturated fatty acid
b.
c. neutral fat
d.
unsaturated fatty acid
phospholipid
53.
An unsaturated fatty acid contains less HYDROGEN than a saturated one.
54.
Describe the function of the 3 following lipids.
Neutral fat - long term energy storage, insulation, cushioning
Phospholids - form cell membranes
Steroids - hormones and cholesterol
55. Which of the following types of fatty acids might be considered ‘Brain food’?
a. trans fatty acids
b. omega 6 fatty acids
c. omega 3 fatty acids
d. cis fatty acids
56. Which of the following fatty acids is produced during food processing and can lead to such things as
cardiovascular disease and cancer?
a. trans fatty acids
b. omega 6 fatty acids
c. omega 3 fatty acids
d. cis fatty acids
Nucleic acids:
57. Why is ATP called the ‘energy currency’ of the cell?
ATP is the energy currency of the cell because it contains high energy bonds - energy is released when these
bonds are broken.
58.
Draw ATP and identify the high energy bonds?
59.
Describe what happens when a high energy bond in DNA is broken.
High energy bonds
Energy is released – energy for cellular processes
60.
Where does the energy come from in the following reaction?
ADP + P + energy → ATP
Energy comes from the breakdown of glucose and fatty acids (fats). In an emergency, energy can come
from the breakdown of amino acids (proteins)
61.
What are the differences between DNA and RNA?
Sugar
Nitrogenous bases
Shape
DNA
deoxyribose
A,T,C,G
double helix
Polymers, dehydration synthesis and hydrolysis:
62. Hydrolysis involves the
a. splitting of water
b.
c. joining by adding water
d.
RNA
ribose
A,U,C,G
single helix
splitting by water removal
splitting by adding water
63. Glucose to starch involves
a. hydrolysis
b.
dehydration synthesis
64. Starch to glucose involves
a. hydrolysis
b.
dehydration synthesis
c. oxidation
c.
oxidation
d. reduction
d. reduction
65. Polymers are broken down by
a. dehydration synthesis
b. polymerization
c.
hydrolysis
66. Which of the following can be formed by hydrolysis?
a. neutral fat
b. glycogen
c. cellulose
67. Which of the following best relates to dehydration synthesis?
a. cellulose to starch
b. glucose to glycogen
c. starch to glucose
68. Which of the following best relates to hydrolysis?
a. cellulose to starch b. glucose to glycogen c. starch to glucose
d. autolysis
d. glucose
d. glycogen to glucose
d. glycogen to amino acids
69. Which of the following is a polymer?
a. fructose
b. glucose
c.
amino acid
d. starch
70. Which of the following is not a polymer?
a. neutral fat
b. cellulose
c.
amino acid
d. starch
71.
What are the 4 classes of organic polymers?
Carbohydrates, proteins, lipids, nucleic acids
72.
Which polymers are most concerned with energy?
Carbohydrates
73.
Which polymers form enzymes?
Proteins
74.
Which polymers make up chromosomes and genes?
Nucleic acids
75.
Which 2 polymers may form hormones?
Proteins and lipids (steroids)