Question

question 13
what is a chromosomal mutation?
a a change in the number or structure of chromosomes
b a temporary change that disappears after one cell division
c a mutation that never affects the phenotype
d a mutation involving only one nucleotide

question 14
what does a karyotype show?
a an individual’s chromosomes from one cell
b the nucleotide sequence of a single gene
c all the genes that are expressed in a cell
d an individual’s cellular proteins

Explanation:

Question 13

To determine the correct answer, we analyze each option:

• Option a: Chromosomal mutations involve changes in chromosome number (e.g., aneuploidy) or structure (e.g., deletions, translocations), which matches the definition.
• Option b: Chromosomal mutations are not temporary; they are heritable changes.
• Option c: Chromosomal mutations can affect phenotype (e.g., Down syndrome from trisomy 21).
• Option d: A mutation involving one nucleotide is a point mutation, not chromosomal.

Analyzing each option for the definition of a karyotype:

• Option a: A karyotype is a visual representation of an individual’s chromosomes from a cell, arranged by size, shape, etc.
• Option b: Karyotypes do not show nucleotide sequences (that’s DNA sequencing).
• Option c: Karyotypes don’t show expressed genes (that’s related to gene expression analysis).
• Option d: Karyotypes are about chromosomes, not proteins.

Answer:

a. A change in the number or structure of chromosomes

Question 14