Sex-Linked Genetic Disorders Flashcards

1️⃣ Familiarise yourself with the flashcards:

  • Look through all the flashcards to see what's on both sides.
  • Make sure you understand the information on each card. If something's unclear, click the link to the revision notes at the bottom of the page for more details.

2️⃣ Test yourself:

  • Look at the question or prompt on each card and try to remember the answer before flipping it over.
  • Check the answer and make a note of any cards you find challenging and need to go over more.

3️⃣ Consistently Review and Practice:

  • Use spaced repetition: spend more time on the cards you struggle with and go over them more often.
  • Regularly review all the flashcards to help you better understand and retain the information over time.

Note: We may include questions that have multiple correct answers. It's useful to remember specific examples to understand these concepts better.

PERSONALISED 1-TO-1 TUTORING

Need more help on this topic? Get 1-to-1 support

Get support with clear explanations, practice and feedback (Ages 5 to 16).

  • DBS-checked tutors
  • Flexible times
  • Parents can be updated
Book a free 10-min call See pricing

Want an ad-free experience? Subscribe to remove ads

What does sex-linked mean?

A gene is on a sex chromosome (X or Y) rather than on the other chromosomes.

Why are X-linked recessive disorders more common in males?

Males have one X chromosome. One faulty recessive allele on it causes the disorder.

What is a carrier of an X-linked disorder?

A female with one normal allele and one faulty allele on her two X chromosomes. She is not affected but can pass it on.

Name two X-linked genetic disorders studied at GCSE.

Haemophilia and red–green colour blindness.

Can males be carriers of X-linked recessive disorders?

No. With only one X, they are either affected or not affected.

Which parent passes an X-linked disorder to a son?

The mother. Sons get their X from their mother and their Y from their father.

If a carrier mother (X^N X^n) and an unaffected father (X^N Y) have a son, what is the chance he is affected?

50%. Half of her sons will inherit the faulty X.

In the same cross, what is the chance a daughter is affected?

0%. Daughters get a normal X from the father, so they are either normal or carriers.

If the father is affected (X^n Y) and the mother is not a carrier (X^N X^N), who is affected?

No children are affected. All daughters are carriers. All sons are unaffected.

How can a female be affected by an X-linked recessive disorder?

She must get two faulty alleles, one from each parent. This is rare.

Why are Y-linked disorders rare?

The Y chromosome has few genes. Most relate to male development, so few disorders are Y-linked.

Previous Topic
Back to Lesson
Next Topic