Cellular Reproduction

Mitosis

I) Cell Division in EukaryotesA) Eukaryotes use Mitosis to produce

identical daughter cells by means of Asexual Reproduction

B) Eukaryotes use Meiosis to produce a new mix of genes by means of Sexual Reproduction

II) Interphase (blue arrows)A) G1: Gap 1

1) Normal housekeeping

2) Basic cell functions

3) Is usual “stopping point” for cells

B) S: Synthesis (copying) of DNA1) Centrioles copied too

C) G2: Gap 2

1) Preparation to divide before mitosis begins

III) M Phase (pink arrow)

A) Prophase

B) Metaphase

C) Anaphase

D) Telophase

E) Cytokinesis (yellow)

IV) Mitosis: Early Stages

IV) Mitosis: Early StagesA) Prophase:

1) Early: nuclear envelope degrades, chromatin start to condense

2) Late: chromatin thickens (now called chromosomes) & matching chromosome pair-up (sister chromatids)

3) Spindle apparatus forms between the centrioles

IV) Mitosis: Early StagesB) Metaphase:

1) Spindle fibers attach to chromosomes at centromeres

2) Sister chromatids line up at cell equator

V) Mitosis: Late Stages

V) Mitosis: Late StagesA) Anaphase:

1) Sister chromatids separate (back into chromosomes) at their centromeres

2) Chromosomes move to the cell’s poles

V) Mitosis: Late StagesB) Telophase:

1) Nuclear envelope reforms in each daughter cell & chromosomes uncoil back into chromatin.

2) Cytokinesis: separates two new cells by division of the cytoplasm & organelles

V) Mitosis: Late StagesC) Interphase:

1) Daughter cells are genetically identical to each other and the original parent cell, but they are smaller

VI) Animal Cell Cytokinesis

A) Separation of the two daughter cells by the microtubules & microfilaments of the cytoskeleton

VII) Plant Cell Division & CytokinesisA) Spindle forms

without centriolesB) Golgi apparatus

forms vesicles over the equatorial plate, forming a cell wall while splitting into two cells

VIII) Controls of MitosisA) Reasons cells go through mitosis:

1) Growth

2) Repair

3) Replace old cells

4) Asexual reproduction

X) CancerA) Cancer cells do not have a

properly functioning cell cycle control system1) They divide excessively & can

invade other tissues of the body

B) Tumor – abnormal mass of cells1) Benign tumor – abnormal mass

of essentially normal cells

2) Malignant tumor – mass of cancer cells capable of spreading into neighboring tissues

C) Metastasis - spread of cancer cells beyond their original site

X) CancerA) Cancer cells do not have a

properly functioning cell cycle control system1) They divide excessively & can

invade other tissues of the body

B) Tumor – abnormal mass of cells1) Benign tumor – abnormal mass

of essentially normal cells

2) Malignant tumor – mass of cancer cells capable of spreading into neighboring tissues

C) Metastasis - spread of cancer cells beyond their original site

XI) Cell Division in ProkaryotesA) Prokaryotes undergo Binary

Fission, producing identical daughter cells — type of Asexual Reproduction

XI) Cell SizeA) Most cells are small

1) ~1-100 micrometers (μm)

2) Nerve cells may be a meter or more in length

3) Most egg cells are large

4) Prokaryotic cells are about 1-10 μm

5) Eukaryotic cells about 10-100 μm

XI) Cell SizeB) Cells are limited in size by the

ratio between their outer surface area (SA) & their inner volume (V).  1) Need sufficient (SA) to supply

the cell with its needs & remove its wastesa) As size increases, (V) increases faster

than (SA)

2) Larger the cell, longer it would take substances to reach organelles where they are needed