Warm ups:

1. What is a mutation?

2. Can you inherit mutations from your parents?

Human genetics

Genes and Health

1. Sometimes, genes undergo mutations that can be harmful and cause disorders or diseases.

2. Sickle cell anemia, cystic fibrosis and down syndrome are examples of disorders that result from mutations

Recessive genetic disorders

1. Recessive disorders – the disorder is a recessive gene

a. If you have one gene – you are a carrier (you carry the gene but you don’t have the actual disease)

b. If you have both recessive genes – you will have the disorder

2. Sickle cell disease – blood cells are sickle shape (half moon) instead of round

a. Can’t carry oxygen correctly

b. Need blood transfusions

3. Cystic Fibrosis – body produces more mucus in lungs and digestive tract

a. Hard to breath and causes lung damage

b. Digestive tract problems

c. Helped with antibodies and physical therapy to break up the thick mucus

1. A father is a carrier of sickle cell disease and the mother has the disease. (R = round blood cells, r = sickle shaped blood cells) Complete a Punnett square to determine the offspring of these parents.

Father = _____

Mother = ____

Rr

rr

r r

r

R R r

r r

R r

r r

____ % carrier

____ % have sickle cell anemia

____ % homozygous

____ % heterozygous

50

50

50

50

2. A father is the carrier of the gene for sickle cell anemia but the mother is purebred for normal red blood cells. (R = round blood cells, r = sickle shaped blood cells) Complete a punnett square to determine the offspring of these parents.

Father = _____

Mother = ____

Rr

RR

R R

r

R RR

Rr

R R

Rr

____ % carrier

____ % have sickle cell anemia

____ % no disease

____ % homozygous

____ % heterozygous

50

0

100

5050

3. A father and mother both carry the gene for cystic fibrosis. Complete a punnett square to see how this will

affect their offspring. (C = normal , c = cystic fibrosis)

Father = _____

Mother = ____

Cc

Cc

C c

c

C CC

Cc

Cc

c c

____ % carrier

____ % have cystic fibrosis

____ % no disease

____ % homozygous

____ % heterozygous

50

25

75

50

50

4. A mother has cystic fibrosis and marries a man who is a carrier of the disease. Complete a punnett square

to see how this will affect their offspring. (C = normal , c = cystic fibrosis)

Father = _____

Mother = ____

Cc

cc

c c

c

C Cc

c c

Cc

c c

____ % carrier

____ % have cystic fibrosis

____ % no disease

____ % homozygous

____ % heterozygous

50

50

50

50

50

Sex Determination

1. Last pair of chromosomes determine the sex of a person

2. “X” = female chromosome, “Y” = male chromosome

3. XX = female sex, XY = male sex

A man and women get married and have children. What are their chances of having a boy? Complete a punnett square to see how this will affect their offspring. (X = female , y = male)

Father = _____

Mother = ____

Xy

XX

X X

y

X X X

X y

X X

X y

____ % female

____ % male

50

50

Exit slip questions

1. Explain the difference between being a carrier of a disease and actually having the disease.

2. If both parents are carriers for cystic fibrosis, what percent of children will also be carriers?