Which sequence shows a substitution mutation?
A substitution mutation is a type of genetic mutation that involves the replacement of one nucleotide with another in the DNA sequence. This can cause a change in the amino acid sequence during protein synthesis. To identify a substitution mutation, we compare two DNA sequences and look for differences at specific positions.
Here's an example DNA sequence showing a substitution mutation:
Original DNA sequence: ACTGACCGTATG
Mutated DNA sequence: ACTGATCGTATG
In this example, the nucleotide "C" at position 5 in the original sequence is replaced by "A" in the mutated sequence. This substitution mutation can result in a different amino acid being incorporated into the protein.
Gene Expression Quick Check
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Question
Look at the DNA sequence.
C G T T A C T G C A A T
G C A A T G A C G T T A
Which sequence shows a substitution mutation?
(1 point)
Responses
C G T T A C T G C A A T
G C A A T G A C G T T AC G T T A C T G C A A T G C A A T G A C G T T A
C G T A C T G C A A T
G C A T G A C G T T AC G T A C T G C A A T G C A T G A C G T T A
C G T C T A C T G C A A T
G C A G A T G A C G T T AC G T C T A C T G C A A T G C A G A T G A C G T T A
C G T G A C T G C A A T
G C A C T G A C G T T AC G T G A C T G C A A T G C A C T G A C G T T A
The correct sequence that shows a substitution mutation is:
C G T C T A C T G C A A T
G C A G A T G A C G T T AC G T C T A C T G C A A T G C A G A T G A C G T T A
Which of the following best describes how a liver cell and skin cell have the exact same DNA sequence and yet look different and perform different functions?(1 point)
Responses
The cells discard the DNA that is not in use.
The cells discard the DNA that is not in use.
The tRNA uses a different sequence in each cell during transcription.
The tRNA uses a different sequence in each cell during transcription.
The cells mutate during transcription.
The cells mutate during transcription.
The proteins are expressed differently in each cell.
The correct answer is: The proteins are expressed differently in each cell.
Stella described protein synthesis as a process that makes the necessary proteins for the human body to function. She explained the process in the following steps.
DNA is transcribed into mRNA.
Amino acids form a chain.
The amino acid chain is folded into a protein in the endoplasmic reticulum.
What step did Stella miss in her explanation?
(1 point)
Responses
tRNA delivers the DNA to the ribosome.
tRNA delivers the DNA to the ribosome.
mRNA is translated into amino acids.
mRNA is translated into amino acids.
DNA is replicated into two daughter cells.
DNA is replicated into two daughter cells.
Polypeptide chains express gene traits.