Introductory Chemistry, 5e (Tro)
Chapter 19 Biochemistry
19.1 True/False Questions
1) The human genome project was embarked upon in the late 1970s with the goal of mapping the
entire DNA molecule.
2) Biochemistry is the study of chemical substances and processes that occur in plants, animals
and microorganisms.
3) The four main classes of biochemical compounds are carbohydrates, lipids, proteins and
nucleic acids.
4) The smallest structural unit of a living organism is the cell nucleus.
5) Carbohydrates provide short term energy storage in cells.
6) Carbohydrates have the general formula of (CH2O) n.
7) The structure of a carbohydrate shows that water molecules are connected to carbon atoms.
8) A carbohydrate that cannot be broken down into simpler carbohydrates is called a
monosaccharide.
9) A disaccharide is composed of two monosaccharides connected together by a glycosidic
linkage.
10) The only structural difference between starch and cellulose is the type of linkage between
glucose units.
11) If a polysaccharide is digested in the body , it will yield many monosaccharide units.
12) Glucose is an example of a monosaccharide.
13) Monosaccharides typically rearrange in aqueous solution to form double helix structures.
14) Fructose is an example of a hexose, a six-carbon sugar.
15) A pentose sugar contains more carbon atoms than does a hexose sugar.
16) The many OH groups present in carbohydrates such as glucose make them quite insoluble in
water and blood.
17) Humans are better able to digest cellulose rather than starch because of differences in the link
between the glucose units in the polysaccharide.
18) Lipids are soluble in aqueous solutions such as blood and cytoplasm.
19) Lipids are considered to be more soluble in water than in other solvents.
20) The term hydrophilic indicates a substance is repelled by water.
21) The polar section of a phospholipid is said to be hydrophobic.
22) The nonpolar part of a phospholipid is repelled by water and is said to be hydrophilic.
23) Fatty acids differ only in their “R” group.
24) A fatty acid has a long chain of carbon atoms that ends with a carboxylic acid.
25) A triglyceride is a fat or oil that contains a fatty acid bonded to three glycerol molecules.
26) Saturated fats tend to be solid at room temperature.
27) Enzymes that act as catalysts are called proteins.
28) Proteins are polymers of amino acids.
29) Amino acids are molecules that contain a side chain, a main chain, an amine group, a
carboxylic acid group and a protein group.
30) Amino acids link together to form a peptide bond because the amine end of one amino acid
reacts with the carboxylic acid of another amino acid.
31) A tripeptide consists of three steroids linked together.
32) Protein structures are expressed in terms of amino acid sequence, the short-term repeating
pattern, the long-term bend and folds and finally how proteins structures interact with
themselves.
33) Peptide bonds are responsible for the primary protein structure.
34) In the formation of a secondary protein structure, the primary protein structure is destroyed.
35) The exact shape that a protein takes depends on the types of amino acids and their sequence
in the protein chain.
36) Pleated sheet is a tertiary protein structure.
37) Quaternary protein structure is simply the sequence of amino acids in that protein’s chain.
38) The pattern Gly-Val-Gln-Cys-Cys-Ala-Ser-Val is an example of a primary protein structure.
39) Nucleic acids contain a chemical code that ensures the correct amino acid sequence for
proteins.
40) DNA and RNA are the two types of nucleic acids.
41) Nucleotides contain a phosphate, a sugar and an amino acid.
42) A gene is a portion of DNA that codes for a single protein.
43) DNA contained within the nucleus of most cells contains a complete set of instructions to
make all of the proteins in the human body.
44) Protein synthesis occurs at the ribosome.
45) Humans must synthesize some of the proteins they need because they cannot obtain them
from the foods they eat.
46) The complementary strand of DNA to the pattern GAATC is TCCGA.
47) The bases on one strand of DNA pair with bases on the other strand of DNA through
hydrogen bonding.
48) A codon is a section of DNA that specifies a single amino acid.
19.2 Multiple Choice Questions
1) The human genome project showed that humans have approximately ________ genes.
A) 46
B) 20,000
C) 36,000
D) 3 Million
E) none of the above
2) A roundworm has approximately ________ genes.
A) 46
B) 20,000
C) 32,000
D) 3 Million
E) none of the above
3) The human genome project is expected to:
A) help identify people who are susceptible to certain diseases.
B) produce important drugs in the lab by using the blueprint our body provides.
C) help develop new drugs to fight genetic diseases.
D) help understand the genetic basis for intelligence.
E) all of the above
4) The portion of the cell that contains the genetic information is called ________.
A) cytoplasm
B) membrane
C) nucleus
D) mitochondria
E) none of the above
5) The region of the cell that contains specialized structures that carry out the cell’s work is
called ________.
A) nucleus
B) cell wall
C) cell membrane
D) cytoplasm
E) none of the above
6) The region of the cell that holds the contents of the cell together is called ________.
A) nucleus
B) mitochondria
C) cell membrane
D) cytoplasm
E) none of the above
7) Which sequence below lists the order of the components of a cell, listed in order from inside
to outside?
A) nucleus, cell membrane, cytoplasm
B) cytoplasm, nucleus, cell membrane
C) nucleus, cytoplasm, cell membrane
D) cell membrane, nucleus, cytoplasm
E) cell membrane, cytoplasm, nucleus
8) The main chemical components of the cell are ________.
A) carbohydrates, alcohols, proteins and amines
B) alcohols, proteins, amines and nucleic acids
C) proteins, nucleic acids, lipids, and carbohydrates
D) amines, lipids, nucleic acids and proteins
E) none of the above
9) An example of a monosaccharide is ________.
A) glucose
B) sucrose
C) cellulose
D) glycogen
E) both C and D
10) A seven-carbon sugar is known as:
A) tetrose.
B) sevose.
C) hexose.
D) heptose.
E) none of the above
11) An example of a disaccharide is:
A) glucose.
B) sucrose.
C) cellulose.
D) glycogen.
E) both C and D
12) Which of the following is NOT true regarding disaccharides?
A) The disaccharide link is so strong that it cannot be broken during digestion.
B) The link between the monosaccharides is called a glycosidic linkage.
C) Water is eliminated when two monosaccharides react to form a disaccharide.
D) A disaccharide is a carbohydrate composed of two simpler carbohydrates.
E) none of the above
13) During digestion, sucrose breaks down into ________.
A) glucose and galactose
B) galactose and fructose
C) fructose and lactose
D) glucose and fructose
E) none of the above
14) An example of a polysaccharide is:
A) glucose.
B) sucrose.
C) cellulose.
D) glycogen.
E) both C and D
15) Which of the following statements is FALSE about polysaccharides?
A) They are long chain structures containing large number of repeating monosaccharide units.
B) Starch, cellulose, and glycogen are polysaccharides.
C) Table sugar is a polysaccharide.
D) They break down to produce monosaccharides during digestion.
E) none of the above
16) All of the following carbohydrates can be digested by humans EXCEPT:
A) glucose.
B) sucrose.
C) cellulose.
D) glycogen.
E) both C and D
17) Which of the following is a complex carbohydrate?
A) monosaccharide
B) disaccharide
C) polysaccharide
D) all of these
E) none of these
18) All of the carbohydrates below are hexoses EXCEPT:
A) glucose.
B) fructose.
C) galactose.
D) both A and B
E) Glucose, fructose and galactose are all hexoses.
19) The only difference between starch and cellulose is:
A) starch is a linear arrangement of glucose units and cellulose is a branched arrangement of
glucose units.
B) starch is a linear arrangement of sucrose units and cellulose is a linear arrangement of glucose
units.
C) starch is a linear arrangement of fructose units and cellulose is a branched arrangement of
fructose units.
D) starch is a linear arrangement of glucose units with alpha linkages and cellulose is a linear
arrangement of glucose units with beta linkages.
E) none of the above
20) A lipid is a chemical component of the cell that is:
A) insoluble in water but soluble in methanol.
B) soluble in nonpolar solvents and insoluble in water.
C) soluble in water and insoluble in nonpolar solvents.
D) soluble in both water and nonpolar solvents.
E) none of the above