DNA Mutations — Unit test Answers

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1
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Which accurately describes the relationship between cancer risk and exposure to mutagens?

A
Cancer risk decreases when a person is exposed to mutagens because the risk of DNA mutation decreases as well.
B
Cancer risk increases when a person is exposed to mutagens because the risk of DNA mutations increases as well.
C
Cancer risk increases when a person is exposed to mutagens because the risk of DNA mutations decreases considerably.
D
Cancer risk decreases when a person is exposed to mutagens because the risk of DNA mutations increases considerably.
2
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Missense, nonsense, and silent mutations are examples of which type of mutation?

A
substitution
B
insertion
C
deletion
D
replication
3

Which statements describe the characteristics of an individual protein? Select two options.

A
It is specific to one biochemical reaction.
B
It increases the activation energy needed for a reaction.
C
It can catalyze many different reactions.
D
It increases the rate of a biochemical reaction.
E
It slows down the rate of a biochemical reaction.
4

Which flow chart correctly organizes the structures of heredity, from least to most complex?

A
codon ® gene ® DNA ® chromosome
B
gene ® chromosome ® codon ® DNA
C
DNA ® codon ® chromosome ® gene
D
chromosome ® DNA ® gene ® codon
5

Which base is found only in DNA?

A
adenine
B
guanine
C
cytosine
D
thymine
6

Photo 51 is a picture of the structure of DNA that was used to create a model of DNA. Who created the photo?

A
James Watson and Francis Crick
B
Erwin Chargaff
C
Rosalind Franklin
D
Friedrich Miescher
7

What does a karyotype show?

A
genetic abnormalities
B
relationships among family members
C
carriers of a genetic disorder in a family
D
alleles on each chromosome
8

A scientist observes a pair of separate chromosomes that have genes for the same trait arranged in the same order. However, some of the alleles for the genes are different. What is the scientist most likely observing?

A
homologous chromosomes with heterozygous alleles
B
homologous chromosomes with homozygous alleles
C
heterozygous chromosomes with heterozygous alleles
D
heterozygous chromosomes with homozygous alleles
9

What will happen if RNA polymerase fails to attach to the promoter?

A
Translation will begin early.
B
Transcription will not begin.
C
RNA polymerase will unwind DNA strands.
D
An mRNA strand will be made before translation begins.
10

A mutation causes a sequence of DNA that has the nucleotides TTG to be changed to TCG. The resulting protein has a different sequence of amino acids. Which type of mutation is this?

A
missense
B
nonsense
C
silent
D
frameshift
11

What purpose does the peptide bond serve in protein synthesis?

A
It connects amino acids.
B
It adds a water molecule to the amino acid chain.
C
It releases the protein from the tRNA.
D
It makes a strand of mRNA.
12

Which diagram correctly shows how homozygous alleles are found on homologous chromosomes?

A
A chromosome is labeled Upper A a.
Option A
B
A chromosome is labeled a a.
Option B
C
2 chromosomes are labeled Upper A and a.
Option C
D
2 chromosomes are labeled a and a.
Option D
13

What does DNA provide the code for?

A
nitrogenous base pairing
B
protein synthesis
C
deoxyribose formation
D
nucleotide synthesis
14

Many different types of mutations can occur within the body. An individual experiences a mutation that changes a base in a mRNA strand, but during translation the mRNA strand still creates the same protein. Which type of mutation is responsible for the change in the mRNA base?

A
silent
B
missense
C
nonsense
D
insertion
15

Which carries the code for protein synthesis from the cell nucleus to the cytoplasm?

A
DNA
B
tRNA
C
rRNA
D
mRNA

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