Lesson 7: Inherited dissorders/ sex determination

Question 1

What are inherited dissorders caused by?

Answer 1

• Inherited dissorders are caused by the inheritence of certain alleles.

Question 2

What is polydaylyl?
What type of allele is polydaylyl caused by?

Answer 2

• WHAT IS IT? - Having extra fingers/ toes.
• Caused by DOMINANT allele.

Question 3

What is cystic fibrosis?
What type of allele is cystic fibrosis caused by?

Answer 3

• WHAT IS IT? - A dissorder of cell membranes.
• Caused by RECESSIVE allele.

Question 4

What are the issues with embryo screening (screening embryos for the alleles for inherited dissorders?)

Answer 4

1.) It is expensive.
2.) Unethical (as some healthy- the one’s that aren’t implanted- embryos are destroyed.)
3.) In future, people may use it to produce offspring with “desirable features.” - unethical/ social issue.

Question 5

How many chromosomes do ordinary human body cells contain?

Answer 5

• Ordinary human body cells contain 23 pairs of chromosomes (so, 46 chromosomes IN TOTAL.)

Question 6

What are the 22 pairs of chromosomes in ordinary human cells for? What is one of the pairs in ordinary human cells for?

Answer 6

• The 22 pairs control characteristics only.
• One of the pairs carries the genes that determine sex.

Question 7

What are the sex chromosomes for men and women?

Answer 7

Men: XY (different chromosomes)
Women: XX (same chromosomes)

Question 8

If an inherited disease (ie. cystic fibrosis) is caused by a recessive alelle - how must’ve the person inherited it?

Answer 8

• One recessive allele from father, one recessive allele from mother.