AP Bio: Friday, 3/2/12Cell Cycle & Mitosis

Homework: Work on PS 14

Do Now: Take out your Mitosis worksheet Get back your test and look it over

Today’s Goals: Describe the purpose and steps of the cell cycle Describe the anatomy of a chromosome and explain

how it changes during the cell cycle Agenda:

Review Test 8 Lecture/Discussion: Cell Cycle & Mitosis

Cell Cycle & MitosisAP Biology - 3/1/11

The Cell Cycle: Overview

One cell grows and divides into two new cells

Purpose: Growth Replace dead cells Repair tissues after

injury Asexual

reproduction (in single-celled organisms)

Amoeba reproducing

Animation of the Cell Cycle:

• Stages of Mitosis Video: Mitosis.mpg

Major Steps of the Cell Cycle

Interphase: growth; copying of chromosomes & organelles G1 phase: Cell grows S phase: DNA replicates G2 phase: More growth;

cell prepares to divide

Mitosis: Chromosomes separate to form two new nuclei

Cytokinesis: Cell splits to form two new identical cells

What do you notice about the chromosomes in G1 versus G2?

Chromosome Replication During the Cell Cycle

G1 Phase: Chromosomes are un-

replicated - each contains one copy of its DNA

G2 Phase: Chromosomes are

replicated - each contains two exact copies of its DNA

Un-Replicated Chromosome

Centromere – a small spot in the center of a chromosome

Replicated Chromosome

Sister Chromatids– two halves of a replicated chromosome– exact copies of each other

Centromere

S Phase:DNA Replication

creates replicated chromosomes

DNA Replication = Chromosome Replication

Why do Chromosomes Replicate?

So they can split during mitosis and separate into two new cells

Each cell gets an exact copy of each chromosome!Objectives for Class:

Describe the purpose and steps of mitosis and cytokinesis.Draw diagrams showing how mitosis/cytokinesis separate chromosomes into two new cells.

• .

Mitosis Animation

                                                                                                                                                                   

Interphase(can’t see difference between G1, S, G2)

Animal cell:

Plant Cells:

Stages of Mitosis

Prophase

Anaphase

Telophase/Cytokinesis

Metaphase

Mitosis Stages: Prophase Chromosomes condense

(become thicker and visible under the microscope)

Nuclear membrane begins to distintegrate

Centrosomes/centrioles move towards poles, and spindle apparatus forms

Objectives for Class:• Explain how mitosis separates the cell’s DNA into two different nuclei to create two new cells.

Mitosis Stages: Metaphase Spindle is fully assembled, with centrosomes at

opposite poles Chromosomes lined up along middle of cell

Objectives for Class:• Explain how mitosis separates the cell’s DNA into two different nuclei to create two new cells.

Mitosis Stages: Anaphase

Sister chromatids separate into two unreplicated chromosomes and begin to move to opposite ends of the cell

Objectives for Class:• Explain how mitosis separates the cell’s DNA into two different nuclei to create two new cells.

Mitosis Stages: Telophase Two new nuclei form (membranes re-form) Chromosomes de-condense (become thinner & less

visible)

Objectives for Class:• Explain how mitosis separates the cell’s DNA into two different nuclei to create two new cells.

AP Bio: Wednesday, 3/7/12Lab 3A – Mitosis

Homework: Analysis Questions for Lab 3A due tomorrow Transformation Lab Report due Friday

Do Now: Take out your Mitosis lab packet and turn to page 2 Find the region of the root tip in which you think the

cell cycle will be happening fastest Today’s Goals:

Identify stages of the cell cycle under the microscope

Determine the length of time that onion root tip cells spend in each phase of the cell cycle

Agenda: Lab!

Do Now: (1) Identify the stage of each numbered cell.(2) Put them in sequential order.

1

11

10

65

987

432

Pre-Lab…

Which phase do you think takes the longest? Why?

How can we figure this out using prepared slides like the one in the Do Now?

AP Bio: Thursday, 3/8/12Mitosis Wrap-up; Embryonic Development

Homework: Completed Transformation Lab Report due tomorrowDo Now:

Take out your Mitosis lab packet and turn to your results

Be ready to read out your data for each stageToday’s Agenda and Goals:1. Mitosis Wrap-up:

Confirm and explain the results of the lab Explain cytokinesis and plant/animal cell

differences2. Introduction to Embryology:

Brainstorm Video

Lab Results…

Cytokinesis

Cell splits to create two daughter cells – each with its own nucleus with identical chromosomes

Animal cells: cell membrane pinches inward to separate the two cells

Plant cells: new cell wall built by cellulose-containing vesicles aligning and fusing along the middle of the cell

Objectives for Class:• Explain how mitosis separates the cell’s DNA into two different nuclei to create two new cells.

Cell Division in Mitosis

• Animal Cell Mitosis under the Microscope: 12_06AnimalMitosis_SV.mpg

Shifting Gears…Embryonic DevelopmentPass your Mitosis Lab forward…

Brainstorm:What comes to mind when you think of embryonic

development? What do you know about this process? What are some of the things that happen in this

process? What questions do you have?

Starts w/ fertilized egg (zygote) Zygote divides and divides (mitotic cell

cycle) Cell differentiation/specialization Development of different organs Growth

Embryonic Development involves…

Goals for Today: Describe and illustrate key terms relating to

embryonic development Describe the key stages in early embryonic

development Describe the origins and development of the three

embryonic germ layers

Embryonic Development

AP Bio: Friday, 3/9/12Embryonic Development

Homework: Problem Set 14 will be due next WEDNESDAY. Over the weekend, you should:

Do Section A and Section B Be ready to present on your assigned question from

Section CDo Now:

1. Take out the Embryonic Development packet and spend a few minutes answering #4 on page 2.

2. Take out PS 14 and read questions 6-8. Choose one you want to work on.

AP Bio: Friday, 3/9/12Embryonic Development

Today’s Goals: You will be able to: Describe the development from zygote to

embryo to fetus, and Identify key stages and processes in embryonic

development

Agenda:In groups:1. Complete Part 2 of the Embryonic Development

packet2. Take notes on your assigned question from PS

14.

Review Mitosis Worksheet #5

a) Interphaseb) Cytokinesisc) S phased) Anaphasee) G1f) G2g) Metaphaseh) Prophasei) Telophasej) Prophasek) Mitosis