cell reproduction (part 2)
TRANSCRIPT
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?