DNA segment has base order CCC ATA GCT. Which copy exhibits a deletion in the first codon triplet and then a substitution mutation?(1 point)

Question

Responses

CCA ATA GCT
CCA ATA GCT

CCA TAA CT
CCA TAA CT

CCC TAG CT
CCC TAG CT

CCA TAG CT
CCA TAG CT
Skip to navigation

Answer 1

To analyze the original DNA segment (CCC ATA GCT) and determine which copy exhibits a deletion in the first codon triplet followed by a substitution mutation, we need to first establish what mutations entail:

1. Deletion Mutation: This involves the removal of one or more nucleotide bases in the DNA sequence.
2. Substitution Mutation: This implies that one base is replaced by another, changing the original sequence.

Now, let's evaluate the responses:

1. Response: CCA ATA GCT

   • Here, the first codon (CCC) has been changed to (CCA) which indicates a substitution.

2. Response: CCA TAA CT

   • The first triplet CCC has changed to CCA (substitution), and there appears to be a deletion because there are only five nucleotides instead of nine (the original had three codons).

3. Response: CCC TAG CT

   • The first codon appears unchanged (CCC) but we see TAG replacing A in the second codon, followed by deletion of G, making this a substitution with a partial deletion of the last codon.

4. Response: CCA TAG CT

   • The first codon has still undergone a substitution (CCC to CCA) but doesn’t fully represent the original length.

Given that the question states it specifically requires a deletion in the first codon triplet followed by a substitution, Response 2 (CCA TAA CT) is the correct answer as it shows deletion of the original triplet to a two-nucleotide sequence along with the observed substitutions.

Answer 2

Which type of mutation causes cystic fibrosis?(1 point)
Responses

silent
silent

deletion
deletion

substitution
substitution

insertion
insertion
Skip to navigation

Answer 3

Cystic fibrosis is primarily caused by a deletion mutation in the CFTR gene, specifically the deletion of three nucleotides that results in the loss of a phenylalanine amino acid at the 508th position (F508del). This type of mutation leads to the production of a faulty protein that affects salt and water transport in cells, resulting in the symptoms associated with cystic fibrosis.

Therefore, the correct response is:

deletion

Answer 4

Which statement about chromosomes is true?(1 point)
Responses

DNA contains chromosomes.
DNA contains chromosomes.

The same number of chromosomes appears in haploid and body cells.
The same number of chromosomes appears in haploid and body cells.

Chromosomes are found in sets of three.
Chromosomes are found in sets of three.

Chromosomes contain DNA.

Answer 5

The statement that is true about chromosomes is:

Chromosomes contain DNA.

This statement accurately describes the relationship between chromosomes and DNA, as chromosomes are structures composed of DNA and proteins that organize and package genetic material in cells.

Answer 6

Which modification affects an organism’s expressed characteristics while leaving its DNA sequence unchanged?(1 point)
Responses

deletion mutation
deletion mutation

epigenetic change
epigenetic change

insertion mutation
insertion mutation

substitution mutation
substitution mutation
Skip to navigation

Answer 7

The correct response is:

epigenetic change.

Epigenetic changes affect how genes are expressed without altering the underlying DNA sequence. These changes can involve modifications to the DNA or associated proteins that influence gene activity, which in turn can impact an organism's characteristics.