Sex-Linked Traits Worksheet
Explore the principles of sex-linked inheritance, analyze pedigree charts, and understand the implications of X and Y chromosomes in trait expression for Grade 11 Biology students.
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Sex-Linked Traits: Understanding Inheritance
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Read each question carefully and answer to the best of your ability. Show all your work for calculations and Punnett squares.
1. Traits that are determined by genes located on the sex chromosomes are called traits.
2. In humans, females have two chromosomes, while males have one and one chromosome.
3. A female who carries a recessive sex-linked allele but does not express the trait is called a .
1. Which of the following is an example of a common X-linked recessive disorder?
Cystic Fibrosis
Huntington's Disease
Color Blindness
Down Syndrome
2. Why are X-linked recessive traits more commonly observed in males than in females?
Males have two X chromosomes.
Males only need one copy of the recessive allele to express the trait.
Females cannot be carriers of X-linked traits.
The Y chromosome carries dominant alleles.
1. A color-blind father (X^bY) and a mother who is a carrier for color blindness (X^B X^b) have children. What is the probability that they will have a color-blind daughter? Show your work using a Punnett square.
2. Explain the difference between X-linked and Y-linked inheritance. Provide an example for each.
Examine the pedigree chart below, which traces the inheritance of a particular trait. Assume the trait is sex-linked.
1. Is the trait shown in the pedigree chart dominant or recessive? Justify your answer.
2. Is the trait X-linked or Y-linked? Explain your reasoning.
1. All genes on the X chromosome are expressed in males, regardless of whether they are dominant or recessive.
True
False
2. Females can be carriers for Y-linked traits.
True
False