Unit 2: Chromosomes Genes and Alleles Ch.2

Question 1

How many DNA base pairs does Human Chromosome 13 have?

Answer 1

113 million DNA base pairs. ~800 genes.

Question 2

Name 3 genes located on Chromosome 13.

Answer 2

BRCA2, RB1, ATP7B (except for GJB2).

Question 3

What is the function of the protein coded for by BRCA2?

Answer 3

Important for DNA Damage repair.

Question 4

What is the function of protein coded by RB1?

Answer 4

Important for regulating cell growth and division.

Question 5

What is the function of the protein coded for by GJB2?

Answer 5

Forms channels between catering cells and is important for how we hear.

Question 6

What is the consequence of changes in the protein structure or function of GJB2?

Answer 6

Can causes differences in protein structure and function.

Question 7

What is the function of the protein coded by ATP1B?

Answer 7

Transports copper across membranes in certain cells.

Question 8

What is an alleles?

Answer 8

Different version of a gene.

Question 9

What is the relationship between a gene and its alleles in term of DNA sequence?

Answer 9

A gene is a DNA sequence. Different alleles of the same gene have (often slight) different DNA sequences.

Question 10

What are the possible consequences of having different alleles?

Answer 10

• Cause differences in protein structure and function.
• Cause expression of the gene to be regulated differently.

Question 11

What is the relationship between every version of a gene and its alleles?

Answer 11

Every version of a gene is an allele of that gene - even the most common version of that gene.

Question 12

What is the wildtype allele?

Answer 12

The most common allele of a gene.

Question 13

How is the wildtype allele often described?

Answer 13

Often called the “normal” allele for that gene.

Question 14

What is an important note about the genes BRCA2, RB1, ATP7B, and GJB2?

Answer 14

These genes don’t cause disease. We all have copies of these genes.

Question 15

What is the relationship between certain alleles of these genes and disease risk?

Answer 15

Certain alleles of these genes can increase disease risk.

Question 16

What is the specific disease associated with the GJB2 gene?

Answer 16

Congenital deafness.

Question 17

What is the specific disease associated with the ATP7B gene?

Answer 17

Wilson disease.

Question 18

What is Wilson disease?

Answer 18

A genetic disorder that prevents the body from removing extra copper, which can cause the liver, brain, eyes , and other organs.

Question 19

What is the specific disease associated with the BRCA2 gene?

Answer 19

Breast Cancer.

Question 20

What is the specific disease associated with the RB1 gene?

Answer 20

Retinoblastoma Risk.

Question 21

What can the high copper levels cause in Wilson disease if left untreated?

Answer 21

Life - threatening organ damage.

Question 22

Where does the ATP7B protein pump excess copper for removal?

Answer 22

Into bile for removal.

Question 23

Where does the ATP7B protein pump excess copper for storage?

Answer 23

Into vesicles for storage in intestinal cells.

Question 24

What is the consequence of certain alleles of the ATP7B gene?

Answer 24

A lack of functional ATP7B protein.

Question 25

What happens when there is a lack of functional ATP7B protein?

Answer 25

Copper builds up and causes damage.

Question 26

What is the most common ATP7B allele in Wilson disease and what does it cause?

Answer 26

It causes a single amino acid change in the protein.

Question 27

What is the result of the amino acid change caused by the common Wilson disease allele of ATP7B?

Answer 27

The protein is quickly broke down into cells.

Question 28

What did researchers find regarding HSP70-mediated degradation and Wilson disease?

Answer 28

They suggest that it can be safely targeted with clampericlone to counter the onset of Wilson disease.

Question 29

What is an important note about genes and alleles?

Answer 29

Most genes have multiple alleles that are not associated with diseases or disorders.