Read p.125 Rain Forest Rescue and

8.1, 8.2, 8.4, 8.5, 8.6

Asexual and Sexual Reproduction

• Cell Mitosis Lesson Objectives

• ∙We will understand the importance of

• cell reproduction (mitosis). ∙We will learn about all the stages of

• mitosis.

Why Mitosis?

• Growth. The number of cells within an organism increases by mitosis and this is the way multicellular organisms grow. ∙

• Cell Replacement. Cells are constantly dying and being replaced by new ones. The new cells must be exact copies of the cells being replaced. ∙

• Regeneration. Some animals can regenerate parts of their body, and production of new cells are achieved by mitosis.

• Red blood cells have short live spans of about 4 months and need to be replaced constantly by mitosis.

8.4 chromosomes

Draw figure 8.4b and 8.4c

Do question p. 128

Eukaryotes vs Prokaryotes—BODY CELLS (somatic cells)

Human cells (eukaryotes) have 25,000 genes

Bacterium (prokaryotes) have 3,000 genes

Chromatin—chromosome material, diffused mass of DNA and protein molecules. Long thin fibers

Found in Interphase of Cell cycle

Chromatin to chromosomes

During interphase chromatin doubles its material—information for 46 chromosomes in humans, duplicates material for 92 chromosomes

As chromatin coils up (prophase)Sister chromatids (two identical copies) are

formed--figure 8.4bCentromere—connection between sister

chromatids

Daughter cells

Fuzzy appearance—intricate twists and folds of chromatin fibers

P130

Create table comparing/contrasting stages of mitosis

Leave out prometaphase, include interphase and cytokenesis

Chromosome/

chromatin state

Alignment of chromatids

Beginning/end

Interphase

prophase

metaphase

anaphase

telophase

cytokenesis

CELL CYCLE

P.129

Interphase

Mitosis begins-Prophase(cell begins to divide)

• Chromatids (or pairs of chromosomes)

• attach to the spindle fibers

• Chromatids (or pairs of chromosomes)

• separate and begin to move to opposite ends of

• the cell.

• Title: Mar 25 8:

• 52 PM (6 of 9)

• Two new nuclei form, one for each cell. ∙Chromosomes appear as chromatin. ∙Mitosis ends.

• Title: Mar 25 8:

• 53 PM (7 of 9)

• The cell membrane moves inward to create two

• daughter cellseach

• with its own nucleus with

• identical chromosomes.

• ∙ Interphase ∙The Chromosomes are copied• (# doubles).• ∙ Prophase ∙The nuclear membrane disappears.• ∙ Metaphase ∙Chromatids (or pairs of• chromosomes) attach to the spindle• fiber. ∙ Anaphase ∙Chromatids (or pairs of chromosomes)• separate and begin to move to opposite• ends of the cell.• ∙ Telaphase ∙Two new nuclei form, one for each cell.• ∙ Cytokinesis ∙The cell membrane moves inward to create• two daughter cellseach• with itso wn nucleus• with identical chromosomes.• Title: Apr 6 6:• 47 PM (9 of 9)