Worksheets7.1 Chromosomes and Phenotype
Total questions: 5
Worksheet time: 5mins
Most of the traits expressed in a person’s phenotype are determined by
Y chromosomes.
X chromosome inactivation.
autosomal genes.
sex chromosomes.
Which of the following phrases is true of X chromosome inactivation?
affects fewer genes than Y chromosome expression
occurs in cells of female mammals
disables some chromosomes in cells of male mammals
determines phenotype in male mammals
A person who is heterozygous for a disorder caused by recessive alleles is a carrier of the disorder. A carrier is a person who
does not have the disorder but can pass it on to offspring.
can develop the disorder later in life but cannot pass it on.
has a dominant normal allele that has been inactivated.
passes the disorder to offspring on the Y chromosome only.
Genes that are located on sex chromosomes are called
alleles.
recessive.
XY.
sex-linked.
Which statement is true of a sex-linked recessive gene?
In an XY male, this recessive gene is always expressed.
In an XY male, one copy is always inactivated.
In an XX female, only one copy is needed for expression.
In an XX female, it is always passed to offspring.
