Cell GrowthChapter 10

The method behind how YOU grow

By the end of this lesson you will be able to:

• Explain why cells must stay small• Describe the steps of the cell cycle• List the main events that occur during

each stage of mitosis (M phase)

Think about these…..

• How did you get from a single celled zygote (egg + sperm cell) to the size you are today?

• Could you be one big cell? Why or why not?

The key to your size….

• Cell growth by cell division• Reasons for cell division:

– Big cells have too many demands placed on the DNA

– Big cells can’t get enough nutrients in or wastes out by just using the cell membrane• What takes up a cell’s volume???• What takes up a cell’s surface area???

Cell volume: Surface area

If a cell became too large it would not be able to provide for itself because it couldn’t get enough nutrients through its limited surface area

Egg-speriment #2

The whole egg Piece of the egg

Represents?

How far inside did the dye travel?

If the dye represents important nutrients, what does this mean for the cell it represents?

In conclusion? Can a big cell survive? Why or why not?

The solution to growth is….

CELL DIVISION!!!!!

Two Main Stages of cell division or reproduction:

1) Mitosis – division of the nucleus2) Cytokinesis – division of the cytoplasm

WAIT!!!!!! FIRST the cell must prepare to divide its nucleus and its cytoplasm!!!!

Also called the M phaseHOW?!?!?!?!

INTERPHASEPreparation for Cell Division

3 parts of interphase:

1) G1 phase – the cell increases in size

2) S phase – DNA replication

3) G2 phase – cell preparation

Let’s take a closer look at this!

DNA vocabulary

• DNA – genetic information in the nucleus• Chromosomes – organized structures

made of DNA wrapped around proteins that condense and become visible before the M phase

• Chromatin – the unorganized strands of DNA

• Sister Chromatids – identical copies of a chromosome that form during the S phase

Pipe Cleaner Chromosomes

What does one pipe cleaner represent?

What does the second pipe cleaner represent?

What does the beaded center represent?

Centromere = the area of attachment for sister chromatids

http://www.cellsalive.com/cell_cycle.htm

Now lets look at the M phase

PMAT

P = Prophase

M = Metaphase

A = Anaphase

T = Telophase

Fill out your worksheets as we go through these steps

Prophase

Metaphase

Anaphase

Telophase & Cytokinesis

Genetics Related Vocabulary

• Diploid – 2n, refers to a normal human body cell that has to sets of chromosomes – one from the mother and one from the father

• Haploid – n, refers to a sex cell (gamete) that has only one set of chromosomes

Okay, then…

• How many chromosomes are in human body cells?

• How many chromosomes are in human gametes, or sex cells?

Haploid Cell

What is this?

Diploid Cell

What sex is this individual?