Genetic Mutations Exam With Correct
Detailed Answers 2025.
Substitution mutation - ANSWER- An incorrect nucleotide (base) is put in place of
another nucleotide in the DNA sequence.
Insertion and deletion mutations are said to cause shifts in the "reading frame" (the sets
of three nucleotides) of the mRNA. Substitution mutations do not cause these so-called
𝙛𝙧𝙖𝙢𝙚𝙨𝙝𝙞𝙛𝙩𝙨. Explain why insertions and deletions are called frameshift mutations, using
the terms reading frame, codons, and amino acids in your answer. - ANSWER- The
mRNA is read in groups of three nucleotides, called codons. You start reading in groups
of three when you see a start codon (AUG). This start codon sets the reading frame,
(i.e., the view through which you read groups of three). If a nucleotide is inserted into
the mRNA or removed from it, the groups of three are redefined from that point onward.
In other words, the reading frame shifts. Because there is now a new sequence of
codons, there will be a new sequence of amino acids, since each codon codes for a
specific amino acid.
A gene mutation is a change in the sequence of nucleotides that occurs during cell
replication (mitosis and meiosis) within a single coding section of DNA. Mistakes can
also occur in the transcription of mRNA or the translation of a polypeptide. However,
these changes are not considered to be mutations, because they are not permanent
changes to the cell. Explain why "mistakes" in transcription or translation are not as
serious as mutations in a gene. - ANSWER- A mutation in DNA would be passed on to
any daughter cells that are produced from that cell. The polypeptides produced from the
mutated mRNA are not replicated in the daughter cells, so a mistake in translation
would not be carried into the daughter cells.
Why is only a tiny subset of these mutations passed on to our children? - ANSWER- In
order to be passed on to the next generation, mutations must be present in egg or
sperm. Errors that accumulate in skin or liver cells of a parent will not be passed on to
the child.
If each cell has multiple mutations, why do most of us have normally-functioning tissues
and organs? - ANSWER- Most of us have normally-functioning tissues and organs
because one, proofreading enzymes catch these mutations. But when they don't catch
them, the mutations are so small it is unlikely that they will affect anything. To add on,
not all mutations are bad. There are positive, negative and neutral mutations so not all
of these will harm you. Furthermore, the only way mutations can be passed on due to
sexual reproduction is mutations in the reproductive cells.
Detailed Answers 2025.
Substitution mutation - ANSWER- An incorrect nucleotide (base) is put in place of
another nucleotide in the DNA sequence.
Insertion and deletion mutations are said to cause shifts in the "reading frame" (the sets
of three nucleotides) of the mRNA. Substitution mutations do not cause these so-called
𝙛𝙧𝙖𝙢𝙚𝙨𝙝𝙞𝙛𝙩𝙨. Explain why insertions and deletions are called frameshift mutations, using
the terms reading frame, codons, and amino acids in your answer. - ANSWER- The
mRNA is read in groups of three nucleotides, called codons. You start reading in groups
of three when you see a start codon (AUG). This start codon sets the reading frame,
(i.e., the view through which you read groups of three). If a nucleotide is inserted into
the mRNA or removed from it, the groups of three are redefined from that point onward.
In other words, the reading frame shifts. Because there is now a new sequence of
codons, there will be a new sequence of amino acids, since each codon codes for a
specific amino acid.
A gene mutation is a change in the sequence of nucleotides that occurs during cell
replication (mitosis and meiosis) within a single coding section of DNA. Mistakes can
also occur in the transcription of mRNA or the translation of a polypeptide. However,
these changes are not considered to be mutations, because they are not permanent
changes to the cell. Explain why "mistakes" in transcription or translation are not as
serious as mutations in a gene. - ANSWER- A mutation in DNA would be passed on to
any daughter cells that are produced from that cell. The polypeptides produced from the
mutated mRNA are not replicated in the daughter cells, so a mistake in translation
would not be carried into the daughter cells.
Why is only a tiny subset of these mutations passed on to our children? - ANSWER- In
order to be passed on to the next generation, mutations must be present in egg or
sperm. Errors that accumulate in skin or liver cells of a parent will not be passed on to
the child.
If each cell has multiple mutations, why do most of us have normally-functioning tissues
and organs? - ANSWER- Most of us have normally-functioning tissues and organs
because one, proofreading enzymes catch these mutations. But when they don't catch
them, the mutations are so small it is unlikely that they will affect anything. To add on,
not all mutations are bad. There are positive, negative and neutral mutations so not all
of these will harm you. Furthermore, the only way mutations can be passed on due to
sexual reproduction is mutations in the reproductive cells.
