DNA Mutations — Unit test Answers

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1
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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
2
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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.
3

A forensic scientist is trying to find out the number of adenine bases in the DNA sample that he obtained from a crime scene.What can he assume about the number of adenine?

A
The number of adenine bases will be equal to the number of guanine bases.
B
The number of adenine bases will be equal to the total of all the other bases.
C
The number of adenine bases will be equal to the number of thymine bases.
D
The number of adenine bases will be half of the number of cytosine bases.
4

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
5

All of the following would be visible on a karyotype except

A
aneuploidy.
B
polysomy.
C
trisomy.
D
histones.
6

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.
7

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
8

What is the role of RNA?

A
to provide the original blueprint for protein production
B
to move information from the ribosomes to the nucleus for protein synthesis
C
to break down proteins into amino acid monomers
D
to move information from the nucleus to the ribosomes for protein synthesis
9

Based on scientific research, which statement best describes mutations?

A
Mutations are rare occurrences.
B
Mutations are always harmful.
C
Mutations cannot be inherited.
D
Mutations cannot be acquired.
10

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.
12

Which is a frameshift mutation?

A
substitution
B
nonsense
C
silent
D
deletion
13

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
14

Which represents a strand of RNA bases?

A
CAAGGTCTC
B
AGGTTCACA
C
CAAGGUCUC
D
TGGAACTCA
15

Many different types of mutations can occur within the body. Cystic fibrosis is a genetic disorder that is caused by different mutations within the CFTR gene. One mutation in the CFTR gene that leads to cystic fibrosis causes translation to end earlier in the gene sequence. Which type of mutation causes this translation error that leads to cystic fibrosis?

A
silent
B
missense
C
nonsense
D
deletion
16

Which of these is the primary site of protein synthesis?

A
mitochondria
B
cytoplasm
C
nucleus
D
ribosomes
18

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
19

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.
20

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
21

A single strand of DNA helix has the code ATAGGC. Which would be the complementary code on the other strand of the helix?

A
AUACCG
B
CGCTTA
C
GCGAAT
D
TATCCG
22

Which statement about sister chromatids is true?

A
One sister chromatid is inherited from each parent.
B
Sister chromatids are always in every cell.
C
Sister chromatids are only present during cell reproduction.
D
Each sister chromatid forms a lobe of a chromosome.

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