Mr. Nettles

Biology I: Cell Growth and Reproduction (Part 2)

Today’s Objectives I will define: chromosomes,

sister chromatids, and centromere.

I will explore the stages of the cell cycle.

I will explore the phases of mitosis.

Agenda – Thurs., Sept. 22, 2011

Warm-Up

Presentations (Homework from last night)

Lesson

Wrap-Up

Warm-Up1. Mitosis is a form of

________________ reproduction.

2. Eukaryotes reproduce by _________________.

3. Prokaryotes reproduce by ________________.

Research: The Cell Cycle1. Choose one of the following stages of the

cell cycle: G1 phase, S phase, G2 phase, M phase, or Cytokinesis.

2. Use the internet to research information about the stage that you have chosen.

3. Write four interesting things about what you read: What is it? (The definition) What happens? How long does it happen? What’s used? (What special cell parts or

organelles are involved)

The Cell CycleA process by

which cells:

Grow

make copies of chromosomes

divide into new daughter cells

copyright cmassengale

The Cell CycleHas three parts:

Interphase

Mitosis

Cytokinesis

copyright cmassengale

InterphaseG1 Phase = “gap 1” phase

First growth stage

Cell gets bigger

Cell prepares to copy its DNA

Interphase

The set of 46 human chromosomes

Sister Chromatids = the two identical parts on a chromosome

Centromere = the middle part that holds the sister chromatids together

InterphaseG2 Phase = “gap 2” phase

Second growth stage

Organelles needed for Mitosis are formed

- Centrioles and Spindle Fibers

Interphase Summary

• G1: cell growth

• S phase: DNA is copied

• G2: cell prepares for division

M Phase (Mitosis)One division of the cell nucleus to

produce two new daughter cells

Has four phases (PMAT):- Prophase- Metaphase- Anaphase- Telophase

1. PROPHASEChromosomes appear

Centrioles move to opposite ends of the cell

Chromosomes attach to the spindle

Nucleolus and nuclear membrane breaks down

2. METAPHASE

Chromosomes line up at the center or (middle)

3. ANAPHASE

Centromeres split

Sister chromatids separate to form individual chromosomes

Anaphase ends when the movement of chromosomes stops

4. TELOPHASE

Chromosomes uncoil into chromatin

Nuclear membrane reforms

Spindle breaks apart

5. CYTOKINESIS

• The cytoplasm of the cell divides

• Forms two daughter cells that are exactly like the parent cell (each have one complete set of chromosomes)

Wrap-Up1. Which part of interphase involves

copying DNA?

1. Which stage of Mitosis involves chromosomes lining up at the middle?

2. What are chromosomes made up of?