UNIT _____:  Cell Division                                   Name:  _____________________

The cell cycle consists of interphase, mitosis and cytokinesis.  

• Distinguish between interphase, mitosis and cytokinesis.

During interphase, many metabolic reactions occur, including DNA replication and protein synthesis.

• List example metabolic reactions occurring during cell interphase.
• Outline events of G1, S, G2 and G0 phases of interphase.

Supercoiling of the DNA prevents DNA replication and transcription and allows duplicated DNA to condense.

• Explain the levels of supercoiling.
• Explain why chromosomes must condense during mitosis.

Proteins called histones are associated with DNA and assist in the supercoiling during prophase.

• Describe the structure of eukaryotic DNA and associated histone proteins during interphase (chromatin).
• Describe the structure of a replicated chromosome, including the centromere and sister chromatids.
• Draw and label the structure of a nucleosome, including the H1 protein, the octamer core proteins, linker DNA and two wraps of DNA.
• Identify nucleosome structures using molecular visualization software.
• Outline the mechanism of histone-DNA association

Mitosis is the division of the nucleus into two genetically identical daughter cells.

• State the function of mitosis.
• List four processes which involve mitosis.
• State the names of the four phases of mitosis.
• Draw typical eukaryotic cells as they would appear during the interphase and the four phases of mitosis.
• Outline four events that occur during prophase.
• Outline the process of metaphase, inclusive of the role of microtubules and the kinetochore.
• Outline the process of anaphase.
• Outline four events that occur during telophase.
• Determine the phase of mitosis of a cell viewed in a micrograph or with a microscope.

Cytokinesis is the division of the cell and occurs after mitosis.

• Define cytokinesis.
• State the difference between mitosis and cytokinesis.
• Contrast cytokinesis in plant and animal cells.
• Describe the formation of the cleavage furrow in animal cell cytokinesis.
• Describe the formation of the middle lamella and cell wall in plant cell cytokinesis.

The eukaryotic cell cycle.

Definition:

Three phases of the cell cycle:

1.

2.

3.

Interphase is a very active phase of the cell cycle with many processes occurring in the nucleus and cytoplasm.

Cells spend __________________________ in interphase.  

There are three stages of interphase:

• _____________________
• _____________________
• _____________________

In G1, the cell grows and carries out its specialized functions by performing…

In S phase:

In G2 the cell prepares to divide by:

Both binary fission and mitosis are types of asexual cell reproduction.

Mitosis is the division of the nucleus into two genetically identical daughter nuclei.

Processes which involve mitosis.

Mitosis is divided into four major phases:

Phases of Mitosis

Chromosomes condense by supercoiling during mitosis.

____________________  is a linear molecule associated ____________________ .  The ____________________  around the ________________________ to form a ____________________ .  The ____________________  coil and stack together to form fibers called ____________________ .

During  _____________________________________, the DNA is in _______________________ form. This allows the DNA to be easily accessible for _______________________ .

In _________________________________________, the DNA _______________________ creating  _______________________  _______________________ that are attached to each other at the  _______________________, a region of the DNA  that does  ___________________________________________________________.

Each of the identical strands of DNA is called a  ____________________________.  The now replicated DNA is still in  _______________________ form.

During mitosis, the DNA is separated into _____________________________.   The DNA needs to further condense, “______________________,” so that it can more easily be _______________________________________________________.  To "condense" means to make DNA __________________________________________________________________.

During ____________________________ of mitosis replicated DNA, in chromatin form, condenses to become ____________________________, which is thousands of times more compact.  Each chromosome is seen as a pair of ________________________________________ joined by the ____________________________.

Nucleosomes

DNA During the Cell Cycle

Cytokinesis occurs after mitosis and is different in plants and animal cells.

Cytokinesis is different than mitosis

Cytokinesis is different in plant and animal cells

In Plant Cells:  the cytoplasm is divided by the formation of a cell plate between the two daughter cells.

In Animal Cells:  cytokinesis is achieved through the constriction of the cell by a ring of contractile proteins (actin and myosin).