Test Bank for Essentials of Biological Anthropology, 4th Edition, Clark Spencer Larsen,
CHAPTER 03: Genetics: Reproducing Life and Producing
... [Show More] Variation
MULTIPLE CHOICE
1. Somatic cells include all of the following EXCEPT:
a. lung cells.
c. skin cells.
b. gametes.
d. neurons.
ANS: B
DIF: Easy
OBJ: Explain the difference between the two types of eukaryotic cells
TOP: The cell MSC: Remembering
2. Prokaryotes first appeared:
a. 10,000 years ago.
c. 3.5 bya.
b. 1 mya.
d. 65 mya.
ANS: C
DIF: Easy
OBJ: Describe the major parts of a cell and the function of the organelles
TOP: The cell MSC: Remembering
3. _______ DNA is heteroplasmic, meaning it can differ among different parts of a person’s body.
a. Nuclear
c. Ribosomal
b. All
d. Mitochondrial
ANS: D
DIF: Easy
OBJ: Explain what mtDNA is and why it is important in research about both modern and ancient
humans
TOP: The DNA molecule
MSC: Remembering
4. Nucleotide bases in nuclear DNA include all of the following EXCEPT:
a. thymine.
c. uracil.
b. adenine.
d. cytosine.
ANS: C
DIF: Easy
OBJ: Identify the four nitrogen bases of DNA and explain how they combine
TOP: DNA: the blueprint of life
MSC: Remembering
5. The following are complementary bases in DNA:
a. adenine and thymine.
c. guanine and thymine.
b. adenine and cytosine.
d. guanine and uracil.
ANS: A
DIF: Easy
OBJ: Identify the four nitrogen bases of DNA and explain how they combine
TOP: The DNA molecule
MSC: Remembering
6. DNA replication produces:
a. four identical daughter cells.
c. two single strands of DNA.
b. two identical copies of itself.
d. four single strands of DNA.
ANS: B
DIF: Easy
OBJ: Explain how DNA reproduces itself
TOP: The DNA molecule
MSC: Remembering
7. In mammals, the male parent’s gametes determine the sex of his offspring because:
a. the X chromosome originates only from females.
b. sperm are more powerful than eggs./
c. the Y chromosome is present in males only.
d. the X chromosome determines sex.
ANS: C
DIF: Moderate OBJ: Describe the human karyotype
TOP: The cell: its role in reproducing life and producing variation
MSC: Remembering
8. Gametes are:
a. diploid.
c. produced during mitosis.
b. haploid.
d. somatic.
ANS: B
DIF: Easy
OBJ: Describe and/or draw the process of meiosis
TOP: The cell: its role in reproducing life and producing variation
MSC: Remembering
9. Haplotypes are:
a. not likely to recombine during crossovers.
b. likely to recombine during crossovers.
c. genes that code for similar things.
d. genetic material that come from one parent only.
ANS: A
DIF: Moderate OBJ: Describe and/or draw the process of meiosis
TOP: Meiosis: production of gametes MSC: Remembering
10. Down syndrome can occur:
a. as a result of translocation during mitosis.
b. because of nondisjunction, which yields an extra chromosome.
c. most frequently in the offspring of women under the age of 40.
d. most frequently in the offspring of men under the age of 40.
ANS: B
DIF: Moderate
OBJ: Describe and/or draw the process of meiosis | Describe the human karyotype
TOP: Meiosis: production of gametes MSC: Remembering
11. In his work on pea plants, Mendel found that plant height was inherited independently of the type or
color of the seed coat. This finding:
a. applies only to genes on the same chromosome.
b. demonstrates the law of independent assortment.
c. explains gene linkage.
d. explains inheritance only in simple organisms.
ANS: B
DIF: Moderate
OBJ: Define Mendel’s law of segregation and law of independent assortment and explain their
importance to the study of genetics
TOP: Polymorphisms: variations in specific genes
MSC: Remembering
12. DNA is important for protein synthesis because it:
a. is the biological code for the production of hormones and enzymes.
b. serves as a template to which amino acids are attached in protein production.
c. provides the code to produce proteins.
d. transfers information from RNA to proteins.
ANS: D
DIF: Easy
OBJ: Describe the process of protein synthesis and the roles that DNA and RNA play
TOP: Producing proteins: the other function of DNA
MSC: Remembering
1. Use what you know about meiosis to explain Mendel’s law of segregation and law of independent
assortment.
ANS:
Although Mendel did not know about chromosomes, he recognized that what we now know to be
alleles segregate predictably. He demonstrated with garden peas that the father contributes one
physical unit and the mother the other; this is what is known as his law of segregation. For example, a
child with blood type AB has received the A allele from one parent and the B allele from the other
parent. This discovery was critical in explaining what Darwin was unable to account for, namely how
new variation arises with reproduction.
Mendel’s law of independent assortment refers to the discovery that each physical unit
(gene) passes from parent to offspring independently of other genes. In the case of the pea
plant, plant height was inherited independently from the type or color of the seed coat. We
now know that this principle applies only to genes from different chromosomes; because
meiosis involves separation of homologous chromosomes, genes on the same chromosome
(especially if near each other) have a greater chance of being inherited together. They are less
subject to recombination. Gene linkage refers to a group of genes from the same chromosome
being inherited together and is an exception to Mendel’s law of independent assortment.
DIF: Difficult
OBJ: Define Mendel’s law of segregation and law of independent assortment and explain their
importance to the study of genetics
TOP: Meiosis: production of gametes
MSC: Analyzing
2. Describe the steps involved in protein synthesis.
ANS:
DNA serves as a template for protein synthesis. Proteins can be structural or regulatory, meaning they
either make up tissues or serve in cell function or repair and growth of tissues. Proteins consist of
chains of amino acids. Of the twenty amino acids, eleven are made by the body and nine (the essential
amino acids) come from particular foods. Protein synthesis is a two-step process. Transcription is the
first step; it occurs in the cell’s nucleus. The second step, translation, takes place in the cytoplasm
outside the nucleus. Transcription starts out just like the first step of DNA replication: a double strand
of DNA unzips. But instead of producing daughter strands of DNA identical to the original parent (as
in replication), the exposed bases in the unzipped DNA molecule serve as a template for ribonucleic
acid (RNA). RNA has the same nitrogen bases as DNA, except uracil replaces thymine. In RNA, uracil
always matches with adenine while guanine continues to pair with cytosine. The single strand of
unzipped DNA attracts free-floating RNA nucleotides. The strand of RNA produced is called
messenger RNA (mRNA). Messenger RNA splits off from the DNA template and leaves the nucleus,
moving into the cytoplasm and attaching itself to ribosomes in the cytoplasm outside the nucleus. The
mRNA is a messenger because it carries the code for the protein being synthesized from the nucleus to
the ribosome.
In the second step of protein synthesis (translation), strands of transfer RNA (tRNA),
which occur as triplets (or anticodons), are built off the mRNA template. The tRNA triplets
seek complementary triplet strands of mRNA with which to pair (for example, a triplet of
AUC mRNA would pair with complementary UAG tRNA). The three bases of the tRNA
triplet represent a specific amino acid. Amino acids are chemically linked by peptide bonds. A
chain of these peptide bonds is called a polypeptide. In most cases, multiple polypeptides must
bind together and fold into a three-dimensional structure to form a functional protein (for
example, hemoglobin is composed of two pairs of polypeptide chains). Once the protein is
formed, it breaks away from tRNA and begins its work.
DIF: Difficult
OBJ: Describe the process of protein synthesis and the roles that DNA and RNA play
TOP: Producing proteins
MSC: Understanding
3. What is the evolutionary significance of meiosis?
ANS:
Adaptation by natural selection depends on inherited variability. If individuals were genetically
identical, there could be no evolutionary change by natural selection. Darwin was never able to
pinpoint the source of the variation or how it was inherited. This was one of the major barriers to
acceptance of natural selection by Darwin’s peers during his lifetime. Mendel’s work and the newer
science of genetics provide the missing information. Owing to meiosis and sexual reproduction,
genetic variation increases in populations. Each gamete contains just one chromosome from a
homologous pair, and during reproduction each parent contributes only half of his or her genetic
material. The random assortment of chromosomes in cells during the first meiotic division can result in
millions of genetically different gametes. Crossover (exchange of pieces of maternal and paternal
homologous chromosomes, or recombination) occurs during the reduction division, further increasing
variability. This provides the essential genetic diversity required for natural selection to occur.
DIF: Difficult OBJ: Describe and/or draw the process of meiosis
TOP: Meiosis: production of gametes MSC: Evaluating
4. Define polygenic and pleiotropic traits and explain their significance for researchers’ efforts to link
human genotypes to phenotypes.
ANS:
The relationship between most genes and their phenotypes is complex and does not follow simple
patterns of Mendelian inheritance (one gene for one trait). Polygenic traits are determined by genes at
two or more loci, but the genes cannot be identified individually and the phenotypes are also
influenced by environmental factors. In humans, the many polygenic traits include height, skin color,
and eye color. Children’s skin color and eye color may be very different from their parents’. Pleiotropy
refers to the fact that a single allele can have multiple effects and affect more than one trait. The PKU
allele affects mental abilities and the coloration of hair and skin. A person who inherits this allele will
have the disease phenylketonuria, characterized by a missing enzyme that leads to mental retardation
as well as reduced hair and skin pigmentation. One trait can be affected by more than one gene, and
each of those genes may also affect several other traits. Most complex traits in humans are polygenic
and pleiotropic, complicating our efforts to link genes to phenotypes.
DIF: Difficult
OBJ: Explain why the “one gene-one protein” model of genetics is [Show Less]