This document includes complete solutions for all chapters. The
chapters are arranged in reverse order (Ch 19 to 1), beginning
19 Biochemistry with the final chapter. Please scroll through the document to
access every
chapter.
Questions
1. The goal of the Human Genome Project was to map all of the genetic material
(genome) of a human being. One of the surprises from the Human Genome Project
results was that humans have only 20,000-25,000 genes; scientists had always
predicted that there would be many more.
2. The benefits of the Human Genome Project are expected to include the ability to
identify persons who are genetically predisposed to contracting certain diseases and
the ability to design new drugs to fight diseases.
3. The cell is the smallest structural unit of living things that has the properties
associated with life. The main chemical components of the cell can be divided into
four classes: carbohydrates, lipids, proteins, and nucleic acids.
4. Carbohydrates are organic compounds having the generic chemical formula (CH20)n
. Carbohydrates are used for short-term energy storage and are the main structural
components of plants.
5. Glucose is soluble in water because of the many OH groups that allow water to
hydrogen-bond to glucose. This is important because glucose needs to be
transported by blood to the cells and then through the cell wall into the aqueous
interior of the cell.
6. A monosaccharide is a carbohydrate unit that cannot be broken down into simpler
carbohydrates. A disaccharide is a carbohydrate unit that can be broken down into
two simpler monosaccharides. A polysaccharide is a carbohydrate unit that is
composed of many monosaccharides.
7. During digestion, the links in disaccharides and polysaccharides are broken,
allowing individual monosaccharides to pass through the intestinal wall and enter
the bloodstream.
8. Monosaccharides and disaccharides are collectively known as simple sugars.
Polysaccharides are also referred to as complex carbohydrates.
9. Starch and cellulose are both polysaccharides, but the difference is the bond angles
that form between saccharide units. Because of the difference in bond angle,
humans can digest starch and use it for energy, while cellulose cannot be digested
and passes directly through humans.
10. Lipids are chemical components of a cell that are insoluble in water but are soluble
in nonpolar solvents. Lipids include fatty acids, fats, oils, phospholipids, glycolipids,
and steroids. The main functions of lipids are as structural units of cells, long-term
energy storage, and insulation.
11. A fatty acid is a carboxylic acid with a long hydrocarbon chain. The general
structure of a fatty acid is shown below, where R is a carbon chain ranging from 3 to
19 atoms long.
0
II
R-C-OH
Genericfatty acid structure
12. A saturated fatty acid has no double bonds between carbon atoms in the R group.
An unsaturated fatty acid has at least one (possibly more) double bond.
13. Triglycerides are tri-esters composed of glycerol and three fatty acids. Oils and fats
are triglycerides.
,14. A saturated fat is a triglyceride containing saturated fatty acids (no double- or triple-
bonded carbons) and is usually a solid at room temperature. An unsaturated fat is a
triglyceride containing unsaturated fatty acids (double-bonded carbons) and is
usually a liquid at room temperature.
15. Phospholipids are molecules having the same generic structure as triglycerides in
which one of the fatty acid esters has been replaced with a phosphate ester.
Glycolipids have similar structures and properties as phospholipids, but the polar
phosphate group has been replaced by a sugar molecule such as glucose.
16. The main function of phospholipids and glycolipids in the body is as components of
cell walls.
17. Steroids are lipids containing a four-ring structure. Examples include cholesterol,
testosterone, and estrogen. Cholesterol is a steroid that is part of cell membranes
and also serves as a starting material for the body to synthesize other steroids. Also,
steroids serve as male and female hormones in the body.
18. Proteins are polymers consisting of long chains of amino acids linked together by
peptide bonds.
19. Proteins have many roles in the body such as catalysts, structural unit of muscle,
skin and cartilage, transportation of oxygen, disease-fighting antibodies, and
hormones.
20. Amino acids are compounds that contain an amine group, a carboxylic acid group,
and an R group. The general structure for amino acids is:
0
II
f½N-CH-C-OH
I
R
21. Amino acids differ from each other by the nature of the R group.
22. A peptide bond is formed from the reaction between the amine end of one amino
acid and the carboxylic acid end of another amino acid.
23. The formation of a peptide bond:
0 0 0 0
II II II II
HN-CH-C-OH +HN -CH-C-OH~ H~-CH-C-NH-CH-C-OH+Hp
2 I 2 I I I
R R R R
► Extended Figure Description for Chapter 19 Problem 23 Figure 1
24. The shape of proteins is determined by the sequence of amino acids and by the
short-range and long-range interactions between the amino acids in the protein
chain. The shape of the protein is important because it determines biological
function.
25. The primary protein structure simply refers to the sequence of amino acids in the
protein chain. The primary protein structure is maintained by the peptide bonds
formed between the amino acids.
26. The short-ranged periodic or repeating patterns along a protein chain are referred to
as secondary protein structure. The secondary protein structure is maintained by
interactions between individual amino acid R units that are fairly close to each other
in the linear sequence.
27. The tertiary protein structure refers to the large-scale bends and folds in the protein
structure. The tertiary protein structure results from interactions between individual
, amino acid R units that are separated from each other by a large distance along the
linear sequence of amino acids.
28. The quaternary protein structure is the shape that occurs when several proteins
interact with one another to form a larger protein structure. The quaternary protein
structure is maintained by interactions of individual amino acid R groups between
different chains.
29. The a-helix structure occurs when the amino acid chain is wrapped into a tight coil,
much the same as a spring, with the R groups extending outward. The ~-pleated
sheet structure has an extended chain that is in a zigzag pattern.
30. Nucleic acids are polymers in which the individual units are called nucleotides. Each
nucleotide is made up of a phosphate, a sugar, and a base.
31. Nucleic acids contain a chemical code that specifies the correct amino acid
sequences for the creation of proteins.
32. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and
ribonucleic acid (RNA).
33. The four bases found within DNA are adenine (A), cytosine (C), guanine (G), and
thymine (T).
34. A codon is a sequence of three nucleotides and their associated bases that form the
code for a single amino acid in a protein.
35. The genetic code links a specific codon to an amino acid.
36. The genetic code is identical for all living organisms.
37. A gene is a sequence of codons within a DNA molecule that codes for a single
protein. Genes vary in length from fifty to thousands of amino acids.
38. There are three nucleotides needed to specify a single amino acid; therefore, the
gene would have to consist of 3 x 300 = 900 nucleotides.
39. A chromosome is the structure within a cell that contains the genes.
40. Most cells in the human body contain a complete set of genes for all the proteins
needed by the human body, although all cells do not synthesize every protein
specified by the DNA in the cell.
41. No, cells only produce those proteins that are critical to the cell type and function.
42. DNA replication begins with the DNA uncoiling and separating into individual
strands. Enzymes then aid in the creation of new strands that are the complements
of the opposite strands. The hydrogen bonding re-forms the strands, and the result
is two complete copies of the original DNA.
43.
a. thymine (T)
b. adenine (A)
c. guanine (G)
d. cytosine (C)
44. The synthesis of a protein involves the DNA code for the protein unraveling and the
creation of a complementary copy of the gene of interest using m-RNA. The m-RNA
leaves the nucleus of the cell and proceeds to the ribosome, where protein synthesis
occurs. The ribosome then follows along the m-RNA and reads each codon, which
specifies the amino acid sequence in the new protein. Many of the amino acids used
in protein synthesis come from digested protein in your diet.
Problems
chapters are arranged in reverse order (Ch 19 to 1), beginning
19 Biochemistry with the final chapter. Please scroll through the document to
access every
chapter.
Questions
1. The goal of the Human Genome Project was to map all of the genetic material
(genome) of a human being. One of the surprises from the Human Genome Project
results was that humans have only 20,000-25,000 genes; scientists had always
predicted that there would be many more.
2. The benefits of the Human Genome Project are expected to include the ability to
identify persons who are genetically predisposed to contracting certain diseases and
the ability to design new drugs to fight diseases.
3. The cell is the smallest structural unit of living things that has the properties
associated with life. The main chemical components of the cell can be divided into
four classes: carbohydrates, lipids, proteins, and nucleic acids.
4. Carbohydrates are organic compounds having the generic chemical formula (CH20)n
. Carbohydrates are used for short-term energy storage and are the main structural
components of plants.
5. Glucose is soluble in water because of the many OH groups that allow water to
hydrogen-bond to glucose. This is important because glucose needs to be
transported by blood to the cells and then through the cell wall into the aqueous
interior of the cell.
6. A monosaccharide is a carbohydrate unit that cannot be broken down into simpler
carbohydrates. A disaccharide is a carbohydrate unit that can be broken down into
two simpler monosaccharides. A polysaccharide is a carbohydrate unit that is
composed of many monosaccharides.
7. During digestion, the links in disaccharides and polysaccharides are broken,
allowing individual monosaccharides to pass through the intestinal wall and enter
the bloodstream.
8. Monosaccharides and disaccharides are collectively known as simple sugars.
Polysaccharides are also referred to as complex carbohydrates.
9. Starch and cellulose are both polysaccharides, but the difference is the bond angles
that form between saccharide units. Because of the difference in bond angle,
humans can digest starch and use it for energy, while cellulose cannot be digested
and passes directly through humans.
10. Lipids are chemical components of a cell that are insoluble in water but are soluble
in nonpolar solvents. Lipids include fatty acids, fats, oils, phospholipids, glycolipids,
and steroids. The main functions of lipids are as structural units of cells, long-term
energy storage, and insulation.
11. A fatty acid is a carboxylic acid with a long hydrocarbon chain. The general
structure of a fatty acid is shown below, where R is a carbon chain ranging from 3 to
19 atoms long.
0
II
R-C-OH
Genericfatty acid structure
12. A saturated fatty acid has no double bonds between carbon atoms in the R group.
An unsaturated fatty acid has at least one (possibly more) double bond.
13. Triglycerides are tri-esters composed of glycerol and three fatty acids. Oils and fats
are triglycerides.
,14. A saturated fat is a triglyceride containing saturated fatty acids (no double- or triple-
bonded carbons) and is usually a solid at room temperature. An unsaturated fat is a
triglyceride containing unsaturated fatty acids (double-bonded carbons) and is
usually a liquid at room temperature.
15. Phospholipids are molecules having the same generic structure as triglycerides in
which one of the fatty acid esters has been replaced with a phosphate ester.
Glycolipids have similar structures and properties as phospholipids, but the polar
phosphate group has been replaced by a sugar molecule such as glucose.
16. The main function of phospholipids and glycolipids in the body is as components of
cell walls.
17. Steroids are lipids containing a four-ring structure. Examples include cholesterol,
testosterone, and estrogen. Cholesterol is a steroid that is part of cell membranes
and also serves as a starting material for the body to synthesize other steroids. Also,
steroids serve as male and female hormones in the body.
18. Proteins are polymers consisting of long chains of amino acids linked together by
peptide bonds.
19. Proteins have many roles in the body such as catalysts, structural unit of muscle,
skin and cartilage, transportation of oxygen, disease-fighting antibodies, and
hormones.
20. Amino acids are compounds that contain an amine group, a carboxylic acid group,
and an R group. The general structure for amino acids is:
0
II
f½N-CH-C-OH
I
R
21. Amino acids differ from each other by the nature of the R group.
22. A peptide bond is formed from the reaction between the amine end of one amino
acid and the carboxylic acid end of another amino acid.
23. The formation of a peptide bond:
0 0 0 0
II II II II
HN-CH-C-OH +HN -CH-C-OH~ H~-CH-C-NH-CH-C-OH+Hp
2 I 2 I I I
R R R R
► Extended Figure Description for Chapter 19 Problem 23 Figure 1
24. The shape of proteins is determined by the sequence of amino acids and by the
short-range and long-range interactions between the amino acids in the protein
chain. The shape of the protein is important because it determines biological
function.
25. The primary protein structure simply refers to the sequence of amino acids in the
protein chain. The primary protein structure is maintained by the peptide bonds
formed between the amino acids.
26. The short-ranged periodic or repeating patterns along a protein chain are referred to
as secondary protein structure. The secondary protein structure is maintained by
interactions between individual amino acid R units that are fairly close to each other
in the linear sequence.
27. The tertiary protein structure refers to the large-scale bends and folds in the protein
structure. The tertiary protein structure results from interactions between individual
, amino acid R units that are separated from each other by a large distance along the
linear sequence of amino acids.
28. The quaternary protein structure is the shape that occurs when several proteins
interact with one another to form a larger protein structure. The quaternary protein
structure is maintained by interactions of individual amino acid R groups between
different chains.
29. The a-helix structure occurs when the amino acid chain is wrapped into a tight coil,
much the same as a spring, with the R groups extending outward. The ~-pleated
sheet structure has an extended chain that is in a zigzag pattern.
30. Nucleic acids are polymers in which the individual units are called nucleotides. Each
nucleotide is made up of a phosphate, a sugar, and a base.
31. Nucleic acids contain a chemical code that specifies the correct amino acid
sequences for the creation of proteins.
32. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and
ribonucleic acid (RNA).
33. The four bases found within DNA are adenine (A), cytosine (C), guanine (G), and
thymine (T).
34. A codon is a sequence of three nucleotides and their associated bases that form the
code for a single amino acid in a protein.
35. The genetic code links a specific codon to an amino acid.
36. The genetic code is identical for all living organisms.
37. A gene is a sequence of codons within a DNA molecule that codes for a single
protein. Genes vary in length from fifty to thousands of amino acids.
38. There are three nucleotides needed to specify a single amino acid; therefore, the
gene would have to consist of 3 x 300 = 900 nucleotides.
39. A chromosome is the structure within a cell that contains the genes.
40. Most cells in the human body contain a complete set of genes for all the proteins
needed by the human body, although all cells do not synthesize every protein
specified by the DNA in the cell.
41. No, cells only produce those proteins that are critical to the cell type and function.
42. DNA replication begins with the DNA uncoiling and separating into individual
strands. Enzymes then aid in the creation of new strands that are the complements
of the opposite strands. The hydrogen bonding re-forms the strands, and the result
is two complete copies of the original DNA.
43.
a. thymine (T)
b. adenine (A)
c. guanine (G)
d. cytosine (C)
44. The synthesis of a protein involves the DNA code for the protein unraveling and the
creation of a complementary copy of the gene of interest using m-RNA. The m-RNA
leaves the nucleus of the cell and proceeds to the ribosome, where protein synthesis
occurs. The ribosome then follows along the m-RNA and reads each codon, which
specifies the amino acid sequence in the new protein. Many of the amino acids used
in protein synthesis come from digested protein in your diet.
Problems
