Mutations And Molecular Evolution

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| By Biology16100
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Biology16100
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Quizzes Created: 7 | Total Attempts: 5,849
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  • 1/17 Questions

    DNA mutations are random

    • True
    • False
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About This Quiz

In the normal being of a person, we have genetics, which dictates among other things, how our bodies develop. At times, the normal never happens. Mutations and molecular evolution quiz below has more on the subject.

Genetics Quizzes & Trivia

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  • 2. 

    Proof-reading by DNA polymerases occurs through 'backing-up' and removal of incorrect nucleotides

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The statement is true because proof-reading by DNA polymerases involves a process called "backing-up" where the polymerase enzyme moves backwards on the newly synthesized DNA strand to remove any incorrect nucleotides that were added. This proof-reading mechanism helps to ensure the accuracy of DNA replication by correcting any errors that may have occurred during the synthesis process.

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  • 3. 

    DNA polymerase fixes 100% of incorrect bases

    • True

    • False

    Correct Answer
    A. False
    Explanation
    DNA polymerase does not fix 100% of incorrect bases. While DNA polymerase does have proofreading capabilities and can correct some errors during DNA replication, it is not perfect. It can still make mistakes and introduce errors into the newly synthesized DNA strand. Additionally, there are other DNA repair mechanisms in the cell that help to fix any errors that DNA polymerase may have missed. Therefore, the statement that DNA polymerase fixes 100% of incorrect bases is false.

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  • 4. 

    The addition of a single nucleotide to the DNA sequence causes a frameshift mutation

    • True

    • False

    Correct Answer
    A. True
    Explanation
    A frameshift mutation occurs when the addition or deletion of a nucleotide shifts the reading frame of the DNA sequence, resulting in a completely different amino acid sequence being produced during protein synthesis. In this case, the addition of a single nucleotide would disrupt the correct reading frame, leading to a frameshift mutation. Therefore, the statement is true.

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  • 5. 

    Random mutations occur due to:

    • Radiation

    • Chemicals

    • External facors

    • All of the above

    Correct Answer
    A. All of the above
    Explanation
    Random mutations can occur due to radiation, chemicals, and external factors. Radiation, such as UV rays, can cause changes in DNA structure, leading to mutations. Chemicals, such as certain carcinogens, can also damage DNA and cause mutations. Additionally, external factors like viruses or environmental toxins can contribute to random mutations. Therefore, all of the mentioned factors can lead to random mutations.

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  • 6. 

    In a frameshift mutation, all of the amino acids before the shift are changed.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    In a frameshift mutation, the insertion or deletion of nucleotides causes a shift in the reading frame of the genetic code. This means that the codons are read incorrectly, leading to a change in the sequence of amino acids in the resulting protein. However, not all of the amino acids before the shift are necessarily changed. Only the amino acids after the shift are affected, while the amino acids before the shift remain the same. Therefore, the statement that all of the amino acids before the shift are changed is false.

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  • 7. 

    If a frameshift mutation causes a stop codon to be inserted into the DNA sequence...

    • The resulting protein will not be affected

    • The phenotype will change but not the genotype

    • The resulting protein will be too short and non-functional

    • The resulting protein will be too long and non-functional

    Correct Answer
    A. The resulting protein will be too short and non-functional
    Explanation
    A frameshift mutation causes a shift in the reading frame of the DNA sequence, altering the way the sequence is translated into a protein. If a stop codon is inserted into the DNA sequence as a result of the frameshift mutation, it will prematurely terminate the translation process. This means that the resulting protein will be truncated and shorter than normal. Additionally, the premature stop codon may disrupt the normal folding and function of the protein, rendering it non-functional. Therefore, the correct answer is that the resulting protein will be too short and non-functional.

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  • 8. 

    Point mutations have different effects because of the redundancy of the genetic code

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Point mutations can have different effects because of the redundancy of the genetic code. The genetic code is degenerate, meaning that multiple codons can code for the same amino acid. Therefore, a point mutation in the DNA sequence may not always result in a change in the amino acid sequence of the protein. This can lead to different effects, such as no change in the protein function or a slight alteration in its structure or function. Thus, the statement that point mutations have different effects due to the redundancy of the genetic code is true.

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  • 9. 

    Which of the following would be responsible for an increased rate of mutation?

    • Ultrasound

    • Ultraviolet light

    • Infra-red light

    • Ultraviolent light

    Correct Answer
    A. Ultraviolet light
    Explanation
    Ultraviolet (UV) light would be responsible for an increased rate of mutation. UV light is a form of electromagnetic radiation that can cause damage to the DNA molecule. When UV light interacts with DNA, it can lead to the formation of covalent bonds between adjacent pyrimidine bases, particularly thymine. This can result in the formation of thymine dimers, which disrupt the normal structure of DNA and can lead to errors during DNA replication. These errors can manifest as mutations, altering the genetic code and potentially leading to genetic disorders or diseases.

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  • 10. 

    Of the following terms, which one is likely to be the MOST common?

    • Point mutation

    • Missense mutation

    • Base-pair substitution

    • Nonsense mutation

    • Frameshift mutation

    Correct Answer
    A. Point mutation
    Explanation
    Point mutation is likely to be the most common term among the given options because it refers to a change in a single nucleotide base in the DNA sequence. This type of mutation can occur frequently during DNA replication and can lead to various genetic variations. On the other hand, missense mutation, base-pair substitution, nonsense mutation, and frameshift mutation are also types of mutations, but they may occur less frequently compared to point mutations.

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  • 11. 

    Addition or deletion of a nucleotide base pair involves

    • Point mutation

    • Silent mutation

    • Nonsense mutation

    • Frameshift mutation

    Correct Answer
    A. Frameshift mutation
    Explanation
    Frameshift mutation occurs when a nucleotide base pair is either added or deleted from the DNA sequence, causing a shift in the reading frame during translation. This results in a completely different amino acid sequence being produced, leading to a nonfunctional or truncated protein. Therefore, frameshift mutation is the correct answer as it accurately describes the consequence of addition or deletion of a nucleotide base pair.

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  • 12. 

    A nucleotide deletion in DNA replication...

    • Causes one amino acid of the protein to be incorrect

    • Causes all of the amino acids of the protein to be incorrect

    • Causes the amino acids inserted after the deletion to be incorrect

    • Causes the amino acids inserted before the deletion to be incorrect

    • Has no effect on the resulting protein

    Correct Answer
    A. Causes the amino acids inserted after the deletion to be incorrect
    Explanation
    A nucleotide deletion in DNA replication causes the amino acids inserted after the deletion to be incorrect. This is because a nucleotide deletion shifts the reading frame of the DNA sequence, leading to a change in the codons that specify the amino acids. As a result, the subsequent codons and amino acids will be altered, leading to incorrect protein synthesis.

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  • 13. 

    What mutational outcome leads to the placement of a different amino acids in a protein?

    • Back mutation

    • Silent mutation

    • Nonsense mutation

    • Missense mutation

    • Point mutation

    Correct Answer
    A. Missense mutation
    Explanation
    A missense mutation is a type of point mutation that leads to the placement of a different amino acid in a protein. In this mutation, a single nucleotide change in the DNA sequence results in the substitution of one amino acid with another during protein synthesis. This change can alter the structure and function of the protein, potentially leading to a variety of effects on the organism.

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  • 14. 

    A base substitution that causes regular codon to change in to another codon that codes for a different amino acids is said to be?

    • Nonsense mutation

    • Silent mutation

    • Missense mutation

    • None of the above

    Correct Answer
    A. Missense mutation
    Explanation
    A missense mutation is a type of base substitution that causes a regular codon to change into another codon that codes for a different amino acid. In other words, it leads to a change in the genetic code, resulting in the incorporation of a different amino acid into the protein being synthesized. This mutation can have varying effects on the protein's structure and function, depending on the specific amino acid substitution and its location within the protein.

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  • 15. 

    Sickle-cell disease is probably the result of which kind of mutation?

    • Point only

    • Frameshift only

    • Nonsense only

    • Nondisjunction only

    • Both B and D

    Correct Answer
    A. Point only
    Explanation
    Sickle-cell disease is caused by a specific point mutation in the gene that codes for hemoglobin, the protein responsible for carrying oxygen in red blood cells. This mutation results in a single nucleotide change in the DNA sequence, leading to the production of abnormal hemoglobin molecules. Therefore, the correct answer is "Point only" as the disease is not caused by frameshift mutations, nonsense mutations, or nondisjunction.

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  • 16. 

    Using the molecular record to determine phylogenetic relationships is based on the assumption that

    • Nucleotide sequences do not change over time

    • Nucleotide sequences change at a fairly constant rate over time

    • Nucleotide sequences change randomly and erratically over time

    • Evolutionary changes occur in phenotypes but not in genotypes

    • All mutations are harmful

    Correct Answer
    A. Nucleotide sequences change at a fairly constant rate over time
    Explanation
    The correct answer is that nucleotide sequences change at a fairly constant rate over time. This assumption is the basis for using the molecular record to determine phylogenetic relationships. By comparing the differences in nucleotide sequences between different organisms, scientists can estimate how long ago they diverged from a common ancestor. This assumes that the rate of nucleotide sequence change is relatively constant over time, allowing for the estimation of evolutionary relationships.

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  • 17. 

    Which of the following does not apply when discussing the molecular evidence for evolution:

    • Related organisms share a greater portion of their DNAs

    • The haemoglobin gene is less similar between humans and dogs than between humans and chimpanzees

    • Only DNA can be examined for establishing evolutionary differences

    • Molecular evolution progresses more quickly when there is no selection for the gene

    • Phylogenetic trees can be established using molecular evidence

    Correct Answer
    A. Only DNA can be examined for establishing evolutionary differences
    Explanation
    The statement "Only DNA can be examined for establishing evolutionary differences" is incorrect because molecular evidence for evolution can also be obtained by examining other molecules such as RNA and proteins. These molecules can provide valuable information about evolutionary relationships and patterns.

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  • Current Version
  • Mar 19, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Apr 25, 2016
    Quiz Created by
    Biology16100
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