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Unit Test — Unit test Answers

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Which is a purpose for which a pedigree chart might be prepared?

A
to determine the gender of a fetus
B
to determine if a fetus has the correct number of chromosomes
C
to identify chromosomal defects
D
to identify the pattern of inheritance of a particular trait
2
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Consider the diagram.Which chromosomal change is represented?

Question illustration
A
deletion
B
translocation
C
inversion
D
insertion
3

Consider the diagram. Which disorder is produced as a result of the final chromosomal change shown in the diagram?

Question illustration
A
Nondisjunction
B
Fragile X syndrome
C
DiGeorge syndrome
D
Robertsonian translocation
4

Which best matches a type of genetic material with its description?

A
Nucleotides form a helical structure that is called a gene.
B
Genes combine to form structures called nucleotides.
C
Chromosomes create genes.
D
DNA is located in the nucleus.
5

Which is a frameshift mutation?

A
substitution
B
nonsense
C
silent
D
deletion
6

Karyotypes can be studied to determine an organism’s chromosomal makeup and to detect genetic defects. Down syndrome is a genetic disorder that is also called trisomy 21. What would trisomy 21 look like in a karyotype?

A
missing chromosome 21
B
extra chromosome 21
C
missing sex chromosome
D
extra sex chromosome
7

Maria is concerned because she has been exposed to a small amount of radiation during an X-ray. What is her doctor most likely to tell her?

A
Radiations from X-rays is not a mutagen.
B
Mutagens have no effect on the body unless you have inherited them.
C
Small amounts of a mutagen often do not have an effect on health.
D
Severe mutations are usually caused by small amounts of a mutagen.
8

James is working with the lac operon of Escherichia coli (E. coli). He places the bacteria on a plate of growth media. Based on the current understanding of this operon, which hypothesis would be useful for James to test?

Question illustration
A
Addition of allolactose (inducer) to the bacterial growth media should increase the speed at which the bacteria metabolize the sugar lactose.
B
Removal of the RNA polymerase molecule should increase the amount of bacterial growth on the plate.
C
Decreasing the amount of allolactose (inducer) in the bacterial growth media should increase the rate of bacterial growth.
D
Increasing the rate at which RNA polymerase acts will inhibit bacterial growth.
9

Which best summarizes the process of protein synthesis?

A
RNA instructs DNA to make proteins.
B
DNA unzips, resulting in the formation of two protein molecules.
C
RNA moves the DNA code to the ribosomes for protein synthesis.
D
DNA makes proteins in the nucleus.
10

Which of the following correctly organizes these genetic terms in order from smallest to largest?

A
chromosome, gene, nucleotide, DNA molecule
B
nucleotide, gene, DNA molecule, chromosome
C
DNA molecule, nucleotide, gene, chromosome
D
DNA molecule, nucleotide, chromosome, gene
11

Which is an arrangement of genes consisting of an operator, a promoter, and a repressor?

A
RNA polymerase
B
anticodon
C
codon
D
operon
12

Which represents a strand of RNA bases?

A
CAAGGTCTC
B
AGGTTCACA
C
CAAGGUCUC
D
TGGAACTCA
13

What must occur for protein translation to begin?

A
A water molecule must be added to the protein chain.
B
A peptide bond must form between subunits of mRNA.
C
The amino acid Cys must be picked up by tRNA.
D
The codon AUG must be identified.
14

All of the following would be visible on a karyotype except

A
aneuploidy.
B
polysomy.
C
trisomy.
D
histones.
15

How many genes make up the human genome?

A
four: adenine, thymine, guanine, and cytosine
B
23 pairs of genes
C
20,000–25,000 genes
D
3 billion genes
16

Which chromosomal defect is caused when part of a chromosome breaks off at either end and attaches to another chromosome?

A
nondisjunction
B
translocation
C
deletion
D
insertion
17

Which best describes a centromere?

A
sister chromosomes that are held together by a chromatid
B
paired chromosomes that have genes arranged in the same order
C
the part of a chromosome that joins the sister chromatids
D
the material that makes up a chromosome
18

Which describes something that occurs during translation?

A
A DNA template is used to create an mRNA strand.
B
A tRNA template is used to create a DNA strand.
C
A tRNA template is used to create an mRNA strand.
D
An mRNA template is used to create an amino acid chain.
19

What can a person do to limit exposure to X-rays?

A
wear sunblock
B
avoid cigarette smoke
C
wear a protective lead vest
D
avoid chemicals
20

What was Friedrich Miescher's contribution to the discovery of the genetic code?

A
He created the first photograph of the structure of DNA.
B
He discovered how the DNA bases pair together.
C
He created the first accurate model of DNA's structure.
D
He extracted and observed DNA from white blood cells.

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