Chapter 4 Section 3Get book and Open to

page 124

Anticipatory Set

Cell DivisionBig Idea

California StandardsScience Standard 7.1.e:

Cells divide to increase their numbers through a process of mitosis, which results in two daughter cells with identical sets of chromosomes.

Science Standard 7.2.e:

DNA is the genetic material of living organisms and is located in the chromosomes of each cell.Paraphrase:

Cells divide and make identical copies of

themselves.

InputCell cycle: the regular sequence of growth

that cells undergoInterphase: The first stage of the cell

cycle(usually last the longest)replication: the process in which cells make

exact copies of the DNA and nucleusMitosis: The second stage of the cell cyclechromosomes: Double rod structures that

are created during prophasecytokinesis: The final stage of the cell cycle

Input Stage 1: Interphase Growing-

Cell grows to its full size and produces structures it needsEx: cell makes new ribosomes and produces enzymes;

copies are made of both mitochondria and chloroplasts.Copying DNA-

The cell makes an exact copy of the DNA in it’s nucleus (replication)

The chromatin appears as dense mass within a clearly defined nucleus.

At the end of DNA replication, the cell contains two identical sets of DNA.Preparing of Division-

Cells produce structures that it will need to divide into two new cells.

At the end of Interphase the cell in ready to divide.

Input Stage 2: Mitosis

The stage during which the cell’s nucleus divides into two nuclei.

During Mitosis on copy of the DNA is distributed into each of the two daughter cells.

Scientists divide Mitosis into four PHASES: PROPHASE, METAPHASE, ANAPHASE, AND TELOPHASE

Input Stage 2: MitosisProphase-

Chromatin in the nucleus condenses to form chromosomes.

The pairs of centrioles move to opposite sides of the nucleus.

Spindle fibers form a bridge between the ends of the cell.The nuclear envelope breaks down.

Metaphase-The chromosomes line up across the center of each

cell.Each chromosome attaches to a spindle fiber at its

centromere.

Input Stage 2: MitosisAnaphase-

The centromes splitThe Two chromatids separate, and each new chromatid

becomes a new chromosome. The new chromosomes move to the opposite ends of the

cell.The cell stretches out as the opposite ends are pushed

apartTelophase-

The chromosomes begin to stretch out and lose their rod like appearance.

A new nuclear is forms around each region of chromosomes.The DNA is once again separated from the cytoplasm by a

membrane.

Input Stage 3: CytokinesisThe cytoplasm divides. The organelles are

distributed into each of the two new cells.Usually starts about the same time as

telophase.When Cytokinesis is complete, two new cells,

or daughter cells, have formed.Each daughter cell has the SAME number of

chromosomes as the original parent cell.At the end of cytokinesis , each cell enters

interphase, and the cycle begins again.

Finish the Front of Notes on your ownAcross Disciplines: Math Patterns: Draw a picture of the stageQuestion: Write a question and

answer it.Different Perspectives: The differences

in cell division from an animal cell and plant cell

Summary: Write a summary of what you have learned.