Wake-up (Presentation Mode)1. There are 40 chromosomes in a cell.

a. How many would be present in a cell after meiosis?

b. How many would be present in a cell after mitosis?

2. Explain the difference in the cells produced in meiosis from those produced in mitosis.

3. How many chromosomes do humans have?a. What is our diploid number?b. What is our haploid number?

Meiosis and Punnett Squares

Make sure PowerPoint is in Presentation mode

Christopherson

Punnett Square

Tool used to predict the genotypes and

phenotypes of offspring

Brief summary of MeiosisProcess in which gametes (sex cells) are made

Need to split apart the homologous pairs; reduce # of chromosomes by 1/2

What does Meiosis have to do with Punnett Squares?

Meiosis separates the alleles of a parent into different sex cells (gametes).

A heterozygous male has a child with a female with dimples. Dimples are a recessive trait.

What are the predicted results?

Male Genotype

Dd

Go grab a plastic container of markers/colored pencils. You should have one per table. I would

like the diagram to be in color in your notes.

Homologous Pairs

DNA is ReplicatedMale: Dd D d

Process: Meiosis

Meiosis IHomologous

Pairs are separated

Meiosis IISister

Chromatids are

separated

d dD D

D D d d

ddD D

A heterozygous male has a child with a female with dimples. Dimples are a recessive trait.

What are the predicted results?

Female Genotype

dd

Homologous Pairs

DNA is ReplicatedFemale: dd d d

Process: Meiosis

Meiosis IHomologous

Pairs are separated

Meiosis IISister

Chromatids are

separated

d dd d

d d d d

ddd d

FertilizationCombination of the egg and sperm to form a zygote

Process: Fertilization

Homologous Pairs

Egg Sperm Zygote

d D d D

Pick any egg and any sperm and draw them in your notes.

A heterozygous male has a child with a female with dimples. Dimples are a recessive trait. What are the

predicted results? Complete the Punnett Square.

Female Genotype

ddMale Genotype

Dd

A heterozygous male has a child with a female with dimples. Dimples are a

recessive trait. What are the predicted results? Complete the Punnett Square.

Dd x ddd d

D

d

Dd Dd

dd dd

Results 50% with Dimples

50% without Dimples

Genetic Disorder ProjectPick up the Genetic Disorder Project description from the

substitute.

Take your time and read the directions VERY clearly!

When complete reading, I have linked two sites on the Wiki to help you with picking project ideas.

Once you have decided on your topic, you need to post it on the class boards I created (links on Wiki). The disorders are first come first serve. Everyone will have a different topic.

Check the board to see what your classmates are doing. The boards are also linked to the Wiki.