Mitosis September (5*3)+2-9/3, 2009 Objectives: Describe the five phases of mitosis. Explain why...

MitosisSeptember (5*3)+2-9/3, 2009 Objectives:

Describe the five phases of mitosis. Explain why mitosis produces two identical

cells. Catalyst:

How do organisms grow? What happens in interphase?

Homework: Finish independent practice worksheet

Definitions – In case you missed them…

Sex cells = sperm and eggs Somatic cells = everything else

in your body DNA = instructions for how a cell

should run (it’s what makes you “you”)

Chromosome = coils of DNA. Look like Xs.

Catalyst Review

How do organisms grow? They create new cells! One cell divides into two The new cell is an exact copy of the previous cell

This process is called mitosis

Catalyst Review

What happens in interphase? Cells do their normal cell things

Heart cells beat Plant cells photosynthesizeEye cells let you seeSkin cells protect you from stuff

outside your body When cells are ready to divide, make

an exact copy of their DNA

Catalyst Review

Remember… Somatic (body) cells normally have 23 pairs of chromosomes2N = 2 PAIRS

When they are ready to divide, they make copies of their DNA4N = 4 PAIRS

Mitosis CHALLENGE! Are you up for it?

Arrange the four pictures in order that makes sense to you and your group!

There will be a prize for the group that gets the correct answer AND can explain why they chose this order.

Remember: In mitosis, a somatic cell creates an exact copy of itself.

Pull out the sheet you picked up this morning You can take notes on this sheet.

Stage #1: Interphase

Normally cells are 2N (two copies of each chromosome)

When cells are ready to divide, the cell’s DNA doubles Cell becomes 4N

(four copies of each chromosome)

Chromosome Pairs

In interphase, chromosomes duplicate and form pairs

When a chromosome is in a pair, it is called a chromatid

Stage #1: Interphase

Phase #2: Prophase

Chromatids attach to each other

Centrioles move to opposite ends of the cell Barrel-shaped organelle,

you’ll see what it does in a second

Nuclear membrane breaks Allows chromatids to

move freely

Sister chromatids line up in the center of the cell

Spindles shoot out of centrioles, and attach to sister chromatids

WHY would sister chromatids line up at the metaphase plate?!?!?!

Phase #3: Metaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Phase #3: Metaphase

Spindles pull sister chromatids apart to opposite ends of the cell

WHY would sister chromatids move to opposite ends of the cell?!?!?!

Phase #4: Anaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Phase #4: Anaphase

Nuclear membrane reforms

Spindle breaks apart Cleavage furrow

forms, “pinching” the cell in half

WHY would the cleavage furrow split the cell in half?!?!?!

Phase #5: Telophase

Phase #1: Interphase

Now we have two identical cells!!!

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Phase #5: Telophase

Animal Mitosis -- Review

Interphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Plant Mitosis -- ReviewInterphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

WOW MR. JHAVERI YOU RULE!!!

THANKS MR. JHAVERI FOR THE SWEET MOVIE!!!

IInterphasePProphaseMMetaphaseAAnaphaseTTelophase

II PPaintaint MMany any AAmazingmazing TT--shirtsshirts

WHO’S PAYING ATTENTION?

What type of cell does mitosis occur in?

What is the starting point of mitosis? What are the end products of mitosis?

What are the names of the stages of mitosis?

Guided Practice

Today, we will move around the classroom to answer questions on the board. You have 10 seconds to get to each spot.

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

Chromosomes line up in the middle of the cell

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

Cleavage furrow forms, pinching the cell in half.

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

In between cell divisions, when the cell does its thaaaaang.

What phase is this?

-In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

When chromosomes are pulled to opposite sides of the cell.

What phase occurs AFTER the following? -In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

Chromatids attach to each other and centrioles begin to move to opposite sides of the cell.

What phase occurs AFTER the following? -In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

Chromosomes line up in the middle of the cell.

What phase occurs AFTER the following? -In the middle of the classroom- Interphase -By the group folders- Prophase -By the computer- Metaphase -By Mr. McKnight’s room- Anaphase -By the door- Telophase

Chromatids are pulled apart to opposite sides of the cell.

Conclusion

I Paint Many Amazing T-shirts! Prophase- chromatids attach to each

other Metaphase- chromatids line up in the

middle of the cell Anaphase- chromatids are pulled to

opposite ends of the cell Telophase- cleavage furrow forms and

pinches off two cells Mitosis ends up with two identical cells!

Exit Question

What are the phases of mitosis in order? What must occur before mitosis (think

DNA)?