Unit 3 Target 5: Mutations

2.

Mutations can

Change the shape of the protein.
Change the function of the protein.
Both A and B.
Only B.

Correct Answer

A. Both A and B.

Explanation

Mutations can change the shape of the protein and also change its function. Mutations are alterations in the DNA sequence, which can lead to changes in the amino acid sequence of a protein. This change in the sequence can result in a different folding pattern of the protein, altering its shape. Additionally, mutations can affect the active site or binding site of a protein, leading to a change in its function. Therefore, both A and B are correct.

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3.

Which of the following is NOT a gene mutation?

Inversion
Insertion
Deletion
Substitution

Correct Answer

A. Inversion

Explanation

Inversion is not a gene mutation because it involves the rearrangement of genetic material within a chromosome, rather than a change in the DNA sequence itself. In an inversion, a segment of the chromosome is flipped in orientation, but the actual DNA sequence remains unchanged. This can affect the expression of genes by disrupting their normal regulation or by altering the way they interact with other genes, but it does not involve a change in the DNA sequence itself. Therefore, inversion is not considered a gene mutation.

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4.

Which of the following would have no affect on the amino acid in the protein that is produced?

Insertion
Silent
Deletion
Frameshift
None of these

Correct Answer

A. Silent

Explanation

A silent mutation is a type of mutation that does not result in any change in the amino acid sequence of the protein. It occurs when a nucleotide substitution happens in the DNA sequence, but the new codon still codes for the same amino acid. Therefore, a silent mutation would have no effect on the amino acid in the protein that is produced.

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5.

An error in DNA replication can cause

Mutations.
Genetic variation.
Cancer
All of the above.

Correct Answer

A. All of the above.

Explanation

An error in DNA replication can cause mutations, which are changes in the DNA sequence. These mutations can lead to genetic variation, as they introduce new genetic information into the population. In some cases, these mutations can also result in the development of cancer, as certain mutations can disrupt the normal regulation of cell growth and division. Therefore, all of the above options are correct.

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6.

Which of the following would affect the entire amino acid sequence in the protein that is produced?

Frameshift
Substitution
Point
Silent
All of these

Correct Answer

A. Frameshift

Explanation

A frameshift mutation occurs when nucleotides are inserted or deleted in the DNA sequence, causing a shift in the reading frame during translation. This shift alters the codons and results in a completely different amino acid sequence in the protein that is produced. Therefore, a frameshift mutation would indeed affect the entire amino acid sequence in the protein.

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7.

Which of the following is NEVER a frameshift mutation?

Substitution
Insertion
Deletion
All of the above

Correct Answer

A. Substitution

Explanation

A frameshift mutation occurs when nucleotides are inserted or deleted in a DNA sequence, causing a shift in the reading frame. This alters the way the genetic code is read, leading to a different amino acid sequence being produced. However, a substitution mutation involves the replacement of one nucleotide with another, without changing the reading frame. Therefore, a substitution mutation does not cause a frameshift and is NEVER a frameshift mutation.

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8.

Which of the following would only affect one amino acid in the protein that is produced?

Silent
Point
Frameshift
Deletion
All of these

Correct Answer

A. Point

Explanation

A point mutation is a type of genetic mutation that affects only a single nucleotide base pair in the DNA sequence. This change in a single base pair can result in the substitution of one amino acid for another during protein synthesis. Therefore, a point mutation would only affect one amino acid in the protein that is produced. Silent mutations do not change the amino acid sequence, frameshift mutations cause a shift in the reading frame, and deletions remove a portion of the DNA sequence, all of which can have more significant effects on the protein structure and function.

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9.

The mRNA sequence ACUGCUUGG codes for the amino acids Thr-Ala-Trp. A mutation occurs, and the resulting mRNA sequence is AUCUGCUUGG. What type of mutation would this be?A) frameshift mutation caused by deletion because the removal of one nucleotide changed the entire sequence of amino acids after the mutation B) silent mutation because it has no affect on the amino acid sequence C) frameshift mutation caused by insertion because the addition of one nucleotide changed the entire sequence of amino acids after the mutation D) point mutation because it only affects one amino acid

A
B
C
D

Correct Answer

A. C

Explanation

The correct answer is C) frameshift mutation caused by insertion because the addition of one nucleotide changed the entire sequence of amino acids after the mutation. In this case, the original mRNA sequence codes for the amino acids Thr-Ala-Trp, but due to the insertion of one nucleotide, the reading frame is shifted, resulting in a completely different sequence of amino acids.

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10.

Which of the following is NOT true about gene mutations?

A gene mutation may be cause by exposure to radiation.
Gene mutations can change the shape of the protein that is produced.
Gene mutations can change the function of the protein that is produced.
A gene mutation is a permanent change in the sequence of the DNA nucleotides.
Gene mutations only occur during DNA replication.

Correct Answer

A. Gene mutations only occur during DNA replication.

Explanation

Gene mutations can occur due to various factors, including exposure to radiation. These mutations can lead to changes in the shape and function of the protein produced by the gene. A gene mutation is a permanent alteration in the DNA nucleotide sequence. However, it is not true that gene mutations only occur during DNA replication. Mutations can also occur due to errors in DNA repair mechanisms or as a result of exposure to mutagenic agents such as radiation or certain chemicals.

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11.

Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGAUACUAAGGGCUGAUse the genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.

Persons A and B have identical amino acid sequences.
Lys in Person A is replaced with Glu in Person B.
Val in Person A is replaced with Glu in Person B.
Val in Person A is replaced with Asp in Person B.

Correct Answer

A. Val in Person A is replaced with Asp in Person B.

Explanation

The given mRNA sequences differ by only one nucleotide. According to the genetic code chart, AUG codes for the amino acid Methionine (Met). The difference occurs at the 6th nucleotide, where U is present in Person A and A is present in Person B. UGU in Person A codes for the amino acid Cysteine (Cys), while AGU in Person B also codes for Cysteine (Cys). Therefore, the amino acid sequence for the first six amino acids (Met-Cys) is the same in both Person A and Person B. After the 6th amino acid, the sequences diverge. The 7th and 8th nucleotides in Person A are GU, which codes for the amino acid Valine (Val), while the corresponding nucleotides in Person B are AU, which codes for the amino acid Aspartic Acid (Asp). Therefore, Val in Person A is replaced with Asp in Person B.

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12.

The mRNA sequence CAGAAAGAU codes for the amino acids Gln-Lys-Asp. A mutation occurs, and the resulting mRNA sequence is CAGAAGGAU. What type of mutation would this be?A) frameshift mutation caused by deletion because the removal of one nucleotide changed the entire sequence of amino acids after the mutation B) point mutation because it only affects one amino acid C) frameshift mutation caused by insertion because the addition of one nucleotide changed the entire sequence of amino acids after the mutation D) silent mutation because it has no affect on the amino acid sequence

A
B
C
D

Correct Answer

A. D

Explanation

The given mRNA sequence CAGAAGGAU differs from the original sequence CAGAAAGAU by a single nucleotide substitution. This type of mutation is known as a point mutation, as it only affects one amino acid in the resulting sequence. In this case, the amino acid Asp is changed to Gly due to the substitution of a single nucleotide. Therefore, the correct answer is B) point mutation because it only affects one amino acid.

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Unit 3 Target 5: Mutations

Changes in the DNA sequence that affect genetic information is known as:

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Mutations can

Which of the following is NOT a gene mutation?

Which of the following would have no affect on the amino acid in the protein that is produced?

An error in DNA replication can cause

Which of the following would affect the entire amino acid sequence in the protein that is produced?

Which of the following is NEVER a frameshift mutation?

Which of the following would only affect one amino acid in the protein that is produced?

Which of the following is NOT true about gene mutations?

Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGAUACUAAGGGCUGAUse the genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.