Genetics and Chromosomal Functions

What are genes?

• Long, coiled strands of DNA.

• Segments of DNA that tell cells to build proteins.

• Proteins that control cell identity.

• Pairs of chromosomes in the nucleus.

What combination of sex chromosomes do most women have?

• XY

• XX

• YY

• XO

Why do cells with two X chromosomes turn one of them off?

• To make sure the embryo develops correctly.

• To create different fur colors in animals.

• To allow for more mutations to occur.

• To help the cells divide faster.

Why was one identical twin colorblind for green light, even though both had a normal and a mutated gene?

• The normal gene was turned off in the cells that became her eyes.

• The mutated gene was turned off in the cells that became her eyes.

• She inherited two mutated genes.

• Her twin also had color blindness but it was less severe.