Bellwork: Identify the following biomolecules

Science Fact of the Day: If the entire DNA from all nuclei in the human body were to be arranged lengthwise, it would measure 1,000 times greater than the distance

from the Earth to the Sun.

Objective: TLW understand the purpose of meiosis.

Language Objective: TLW take notes about meiosis and make a

Venn diagram of meiosis and mitosis.

Chromosomes

Chromosomes are coiled DNA located in the cell

nucleus.

An organism inherits one chromosome from each

parent.

How many parents do you have?

So you have ____ sets of each chromosome.

2 copies of each chromosome = homologous

chromosomes

A cell that contains 2 sets of homologous chromosomes is said to be diploid.

2N = diploid cell.Because N = number of chromosomes

Sexual Reproduction & Our Cells

On a cellular level, what happens during sex?

Biologically speaking, what’s the point of sex?

Sexual reproduction combines DNA from 2

parents.

Gametes are sex cells, also known as the sperm and

the egg.

When each parent forms gametes (egg, sperm) in their body, they can only

have 1 set of chromosomes instead of 2.

During fertilization, 1 + 1 = 2 sets of chromosomes.

When gametes (sex cells) are formed, there must be a process that separates the two sets of genes so that each gamete ends up with just one set.

Because gametes contain only 1 set of chromosomes they are said to be haploid.

N = haploid N= number of sets of chromosomes in the cell

Meiosis

Meiosis is a process in which the number of chromosomes per cell is cut in half through

the separation of homologous chromosomes in a diploid

cell.

** Meiosis is how gametes are produced**

Meiosis usually involves two divisions.

By the end of meiosis, the 1 diploid cell that entered meiosis has become four haploid cells.

During Prophase I of meiosis, chromosomes line up to form homologous pairs.

When crossing over occurs genetic material is exchanged between the maternal and paternal sets of chromosomes

present in the cell. Crossing over results in genetic variation.

Color and label the diagram

Dad’s chromosome

Mom’s chromosome

Crossing over

Result = genetic variation

Results of Meiosis

In male animals, the haploid gametes produced by meiosis are called sperm.

In female animals, the haploid gametes produced by meiosis are called eggs.

Mitosis vs. Meiosis

Mitosis results in two genetically identical diploid cells. Mitosis is used for growth.

Meiosis results in four genetically different haploid cells.

Meiosis is used for gamete production and increased genetic variation.

Title the next section of your journal, “Mitosis vs. Meiosis”.

Create a Venn diagram comparing and contrasting the processes of mitosis and meiosis. Consider the # of divisions, # of cells, haploid/diploid, function in the body, etc.

Now let’s talk about it…

Make sure your diagram

contains these

ingredients: