Chapter 6 Section 3 Mitosis and Cytokinesis Objectives Describe the structure and function of the spindle during mitosis. Summarize the events of the four stages of mitosis. Differentiate cytokinesis in animal and plant cells.

New Vocabulary Spindle Prophase Metaphase Anaphase Telophase Cell plate

Growth and normal activities Review What occurs in the following three phases of interphase…. G1 S G2 Growth and normal activities DNA synthesis synthesis or replication of organelles needed for division

copied two mitosis spindle Once cells pass the G1, DNA is ________________ Each copy of the DNA is then separated into _____ new cells through the process of _______________ Chromosomes are actually pulled apart with the help of a ________________ two mitosis spindle

Spindle Structure centrioles fibers microtubules A spindle consist of ________________ and individual ____________ which are made up of _______________ centrioles fibers microtubules

9 Centrioles consist of ____ triplets of microtubules that arranged in a circle Animal ___________ cells always contain ____ pair of centrioles, but they are replicated during the ______ phase of interphase 1 G2

At the beginning of mitosis, the centrioles move to areas on the opposite poles of the cell called __________________ centrosomes The centrosome organizes the formation of the ____________ spindle

As the centrioles move, the spindle fibers begin to form and _____________ towards the chromosomes extend

Scientists are unclear about the role of centrioles in cell division, because they are not necessary for spindle _________________ Plant cells, which do not have centrioles, form a spindle that is almost _________________ to those in animal cells formation identical

Chapter 6 chromatids reel dragged chromosome Section 3 Mitosis and Cytokinesis Separation of Chromatids The two _______________ that make up a chromosome are moved to each pole of the cell in a manner similar to bringing in a fish with a fishing rod and ___________ When the microtubule “fishing line” is “reeled in,” the chromatids are ______________ to opposite poles. When the chromatids separate, you may call each one a _________________ chromatids reel dragged chromosome

4 Prophase Metaphase Anaphase Telophase Mitosis actually occurs in ______ continuous phases… _______________________ (P) _______________________ (M) _______________________ (A) _______________________ (T) Prophase Metaphase Anaphase Telophase

Prophase chromosomes dissolves poles spindle Chromatin condenses into visible _______________ Nuclear envelope _________________ dissolves Centrioles move towards opposite ______________ and the ____________ forms poles spindle

Interphase Slide Image Prophase Slide Image nucleoli Spindle fibers

Metaphase equator chromatids kinetochore Chromosomes line up along the middle or ____________ of the cell equator Spindle fibers attach to the centromere region that hold the sister _______________ together Specifically, they attach to a protein complex called a ________________ chromatids kinetochore

Metaphase Slide Image

Anaphase Centromeres chromosomes _________________ divide as spindle fibers pull the chromatids apart The chromatids can now be called ________________ chromosomes

Anaphase Slide Image

Telophase reforms dissolves chromatin prophase Nuclear envelope ______________ Spindle __________ Chromosomes begin to uncoil and stretch back into ______________ Reverse of ______________ dissolves chromatin prophase

Telophase Slide Image

Chapter 6 Cytokinesis half separate 2 Section 3 Mitosis and Cytokinesis Cytokinesis As mitosis ends, cytokinesis occurs. During cytokinesis… the cytoplasm of the cell is divided in __________ and the cell membrane grows to __________ each cell ____, identical separate cells are formed half separate 2

Chapter 6 anaphase fibers furrow Section 3 Mitosis and Cytokinesis In animal cells, cytokinesis actually begins during _______________ A belt of protein __________ pinches the cell in half This indentation is called a ___________ anaphase fibers furrow

cellulose membrane wall In plant cells, vesicles containing ____________ begin to congregate between the two nuclei These vesicles begin to fuse, forming a cell _______________, while the cellulose is used to form a cell __________ cellulose membrane wall

As the new cell wall forms in between the cell membranes, this structure is called a cell _________ plate

Golgi apparatus Recall Question? What cell part actually makes the vesicles? Hint…it is the packager and shipper Golgi apparatus

diploid G1 End result of mitosis? A diploid parent cell has been divided into two, identical ____________ daughter cells These new cells are small and will begin to grow during the _____ phase of interphase diploid G1

The spindle consists of fibers that attach to and move chromosomes Objective 1 Describe the structure and function of the spindle during mitosis. The spindle consists of fibers that attach to and move chromosomes

Objective 2 Summarize the events of the four stages of mitosis. Prophase Metaphase Anaphase Telophase Breakdown of nucleus, chromosomes condense, spindle forms Chromosomes line up at the middle or equator Chromatids are split Nucleus reforms…2 new cells have been formed, chromosomes uncoil, spindle dissolves

Objective 3 Differentiate cytokinesis in animal and plant cells. Protein belt pinches in the dividing cell forming a cleavage furrow Vesicles containing cellulose create a cell plate