9.2 Mitosis and Cytokinesis

II. Stages of Mitosis A. Prophase Sister chromatids

Structures that contain identical copies of DNA

II. Stages of Mitosis A. Prophase Spindle apparatus in animal cell Spindle apparatus in plant cells

Animal cells- spindle fibers, centrioles, and aster fibers Plant cells- spindle fibers

Contrast the spindle apparatus in animal cells with taht of plabt

Animal- centrioles at the ends Plant- no centeiokes

cytokinesis in plant cells

Because of their cell wall covering their plasma membrane , cell plate by vesicles forms, divide daughter cells Cell wall then form on either side of the cell plate

9.8 compare a cell's equator to earth's equator

Cell -duplicated chromosomes at the equator -asters radiating from centrosome -spindle fibers connecting to centimeter Earth -most heat

II. Stages of Mitosis A. Prophase What is the structure at the center of the chromosomes that hold hold the sister chromatids?

Centromere

II. Stages of Mitosis D. Telophase What happens to chromosomes in telophase

Chromosomes arrive at the poles of the cell and begin to relax, or decondense

Figure 9.5- structure of chromosomes in prophase

Chromosomes in prophase are actually SISTER CHROMATIDS that are attached at the centromere

II. Stages of Mitosis D. Telophase Recount the major events in telophase

Chromosomes teach poles of cell Nuclear envelope reforms Nucleolus reappear Chromosomes decondense

Discuss the Role of microfilaments in Cytokinesis in Cytokinesis

Cleavage furrow

II. Stages of Mitosis A. Prophase 3. Aster fibers

Coming out of the centrioles are yet another type of microtubules called aster fibers

Cycles in real life

Cycle of the day Cycle of seasons Cycles of comets in spaces Cell cycle if Growth and reproduction

Explain he process of Cytokinesis

Division of the cytoplasm during cell division that results in genetically identical daughter cells

What occurs in mitosis?

Duplicated DNA is divided

II. Stages of Mitosis A. Prophase Structure of chromosomes during prophase

Each chromosome is X shaped. Each half is called a sister chromatids held by a centromere.

II. Stages of Mitosis A. Prophase Chromosomes in prophase as single structure

Each chromosomes is a single structure that contains the genetic material that was replicated in interphase Each half of the X is called a sister chromatid

Main Idea

Eukaryotic cells reproduce by mitosis, the process of nuclear division and cytokinesis, the process of cytoplasm definition

T or F. Centrioles migrate to the poles of the cell during telophase

F, anaphase

T or F: Chromosomes reach the poles of the cell during metaphase

F, anaphase

T or F: the first stage of mitosis is telophase

F, prophase

T or F. The nuclear envelope reforms during anaphase

F, telophase

The nucleus reappears during prophase. T or F

F, telophase

II. Stages of Mitosis A. Prophase

First stage of Mitosis Dividing cell spends the most time

I. Mitosis What is Mitosis used for

Growth and replace of damaged cells

II. Stages of Mitosis A. Prophase 2. Centrioles

In animal and protist cells Another PAIR of microtubules structures, migrate to the ends, or poles, of the cell

I. Mitosis Mitosis In growth. Give example

In multicellular organisms, the process of mitosis increases the number of cells as a young organism grows to its adult size

IV. Visualizing the Cell Cycle

Interphase Cell frowns and carrier DNA replucatedi Prophase-PREPARATION Condense chromosomes Nuclear membrane disintegrates Nucleolus disappear Chromosomes condense Mitotic spindle begins to form between the poles Metaphase- MIDDLE chromosomes attach to mitotic spindle and align along equator of cell Anaphase- AWAY Microtubules shorten; moving chromosomes to opposite pairs Telophase- TWO chromosomes reach piles of cell Nucleus envelop reforms Nucleolus reappears Chromosome decondense s Cytokinesis Plant-Cell plate forms, dividing daughter cells Animal-cleavage furrow forms at the equator of cell and punches inward until cell divides in two

II. Stages of Mitosis A. Prophase Why is the centromere important?

It ensures that a complete copy of the replicated DNA will become part of the daughter cells at the end of the cell cycle

II. Stages of Mitosis B. Metaphase Metaphase is the shortest phase of Mitosis. Why is it important?

It ensures that the new cells have accurate copies of the chromosomes

II. Stages of Mitosis C. Anaphase Recount major events of anaphase

Microtubules shorten This shortening is pulls at the centromere of each sister chromatids, causing the sister chromatids to separate into two identical chromosomes

II. Stages of Mitosis A. Prophase 1. Spindle fibers

Microtubules structures called spindle fibers form in he Cytoplasm

II. Stages of Mitosis A. Prophase Spindle apparatus importance

Moving and organizing the chromosomes before cell division

II. Stages of Mitosis A. Prophase Near the end of prophase

Nuclear envelope seems to disappear Spindle fingers attach to the sister chromatids oh each chromosome on both sides of the centromere and then attach to opposite poles of the cell

II. Stages of Mitosis A. Prophase Recount the major events that happen during prophase

Nuclear membrane disintegrates Nucleolus disappears Chromatin shortens/tightens and condenses to form chromosomes Mitotic spindle begins to form between the poles

Acronym for mitosis

PMAT

III. Cytokinesis What is the process of Cytokinesis and what the result?

Parent cell will divide Cytoplasm to form 2 daughter cells

II. Stages of Mitosis A. Prophase Plants v animals in prophase

Plants- only have spindle fibers Animal- have spindle fibers and an ADDITIONAL microtubules structure calls ASTER FIBERS

II. Stages of Mitosis What are he stages of Mitosis in order?

Prophase Metaphase Anaphase Telophase

II. Stages of Mitosis B. Metaphase Recount the Major events during metaphase

Sister chromatids pulled by MOTOR PROTEINS along the spindle apparatus toward the center of the cell. Line up in the middle, or equator In other words, chromosomes are attached to mitotic spindle and align at the equator

II. Stages of Mitosis A. Prophase What is the WHOLE structure with all the spindle fibers, centrioles, and aster fibers called?

Spindle apparatus

II. Stages of Mitosis D. Telophase What happens to the spindle apparatus in telophase? What about he microtubules in it?

Spindle apparatus disassembled Some of the microtubules are recycled by th cell to build various parts of the cytoskeleton

II. Stages of Mitosis A. Prophase Types of microtubules in prophase

Spindle fibers Centrioles Aster fibers

T or F. Chromatids are pulled apart during anaphase

T

T or F: Chromosomes attach to spindle fibers and line up along the equator of the cell during metaphase

T

T or F: Microtubules move chromatids to the poles of the cell during anaphase

T

T or F: The chromosomes decondense or unwind during telophase

T

T or F: The shortest stage of mitosis is metaphase

T

The cell's chromatin condenses into chromosomes during prophase. T or F

T

The nuclear membrane disintegrates during prophase. T or F

T

II. Stages of Mitosis A. Prophase Spindle fingers attach to the sister chromatids oh each chromosome on both sides of the centromere and then attach to opposite poles of the cell. What does this arrangement ensure?

That each new cell receives one complete copy of the DNA

I. Mitosis What is the key activity of Mitosis? What does this enable?

The accurate separation of the cell's replicated DNA The cell's genetic info to pass into the new cells intact, resulting in 2 daughter cells that are genetical identical

Figure 9.9 End of telophase

The cell has complete the work of duplicating the genetic material and dividing it into two "packages" but the cell has so complete divided (Cytokinesis is next)

I. Mitosis Process of mitosis

The cells genetic material separates Cell prepares to split into 2 Cells

II. Stages of Mitosis C. Anaphase Ending of anaphase

The microtubules, with the help of motor proteins, move the chromosomes toward the poles of the cell

II. Stages of Mitosis C. Anaphase True or False: all the sister chromtids separate simultaneously

True, the exact mechanism that controls this is unknown

II. Stages of Mitosis D. Telophase What happens to the two nuclear membrane and nucleoli?

Two nuclear membranes begin to form Nucleoli reappear

I. Mitosis Mitosis in replacing damaged cells. Give example

Under that scab, the existing skin cells divided by Mitosis and Cytokinesis to create new skin cells that filled the gap in the skin caused by the injury

Cytokinesis in animal cells

Uses microfilaments yo constrict a Cleavage furrow forms at the equator of cell and punches inward u til cell divides into two

III. Cytokinesis How do prokaryotic Cells finish cell division in binary fission?

When prokaryotic DNA is duplicated, both copies attach to the plasma membrane . As plasma membrane grows, the attached DNA are pulled apart The cell completes fission by producing two new prokaryotic Cells

life cycle

the sequence of growth and development stages that an organism goes through during its life