Lab 5 – Mitosis10/13/15

Cell cycle: sequence of events that begins when a cell first arises to the time that it replicates and divides.

Interphase: includes G1, S, G2. Cell is in this phase 90% of the

time!Growth and maintanence!

Mitosis: This is what we will look at

today.DNA division. Cell in this phase 10% of the

time!

The purpose of the cell cycle is to make new cells and ensure that each new cell has the same genetic information

Terms and Definitions:

Mitosis: Division of single nucleus into two genetically identical daughter nuclei.

chromosome: Gene carrying structure in nucleus. Consists of DNA and proteins.

chromatid: 1 of the 2 identical copies of DNA in duplicated chromosome, ½ of the “X”.

centromere: Small protein, center of the “X”.

The 4 Phases of Mitosis:

videoInterphase (90% of the time)

early prophase-late prophase metaphase anaphase telophase

DNA: basics of structure and replication

DNA contains genetic instructions that govern the development and functioning of living organisms.

DNA is a double helix made up of two strands of nucleotides.

Replication – happens in S phase!•two strands are unzipped by Helicase

•and each strand is copied individually by DNA polymerase and other enzymes

•At the end two double helices exist!

video video 2!

Mitosis: implications (or) why do we care?1. When division goes wrong

No Cell Division -cell death – necrosis and unregulated apoptosis - bad

Happy Medium

The Spectrum of Cell Division

Constant cell division– Cancer - bad

Mitosis: implications (or) why do we care?

Cloning: production of genetically identical cells or organisms.We manipulate cell cycle to get what we want.

Plants:• Clones created from meristem tissue – undifferentiated tissue in plant.• horticulture and propagating plants - many plants descendent of one plant

Examples: bananas, apples, hybrid poplarsAnimals:• stem cells

Dolly the sheep (1996-2003

Embryonic Stem Cells: derived from an early embryonic state called the blastocyst (~100 cells). A blastocyst is just a few days old and has not yet implanted into the uterus.

Adult Stem Cells: cells in adult tissues that generate replacements for non-dividing differentiated cells. More differentiated than ES cells.

Umbilical Cord Blood: Another source of stem cells collected from the umbilical cord and placenta at birth. Partially differentiated, but less so than adult stem cells.

Mitosis: implications (or) why do we care?

Stem Cells – undifferentiated animal cell that can divide via mitosis and produce daughter cells with a specific function for for a specific tissue.

TODAY:

Don’t do part C

FOR QUIZ:

1. Know cell cycle!!2. Know the following definitions:• Chromosome• Sister chromatid• Centromere• DNA replication• Clone

3. Know phases of Mitosis and what happens in each phase. Be able to produce the drawings required in the manual! I might ask you to draw “Metaphase” or something.

4. Know products of mitosis (2 identical daughter cells)

5. Know the consequences of unregulated cell division (cancer) and no cell division (necrosis and apoptosis)