Drill #1Jan. 23, 2013 List the two parts that make up a chromosome. How many chromosomes do human cells contain?

Reviewing the Chromosome… Each chromosome (coiled DNA) consists of two identical “sister” chromatids. Each pair of chromatids are attached at an area called the centromere. Sister chromatids Centromere

Agenda Online Cell Cycle Lab Course recommendations

Homework Complete Cell Reproduction and Mitosis WS – due Friday

Drill #21/24/13 What is the difference between a prokaryote and eukaryote?

Drill #3: 1/25/13 Why does a cell need to go through cell division? If a cell has 3 chromosomes, how many chromosomes would there be at the end of mitosis?

SWBAT Identify and draw the steps of cell division in eukaryotes (cell cycle)

Agenda Turn in Cell Reproduction/Mitosis WS Notes on the Cell Cycle Course Recommendation Quiz – next week on DNA and the Cell Cycle

Cell Division in Prokaryotes Asexual reproduction Binary fission-one cell divides into 2 offspring cells

Cell Division in Eukaryotes 2 types: –Cell Cycle – Interphase & Mitosis-division of the nucleus Takes place in body cells (somatic cells) –Meiosis-reduces the number of chromosomes by half in new cells Takes place in sex cells (sperm and egg cells)

Your Turn ! Below are life spans of human cells: Red blood cell – less than 120 days Esophagus – 2-3 days Cardiac muscle – long-lived Neuron – long lived Based on this information, how are injuries to the heart and spinal cord similar to each other?

Cell Cycle –Cells grow, prepares for division, and divides to form 2 daughter cells.

Your Turn! Based on the image, what does a cell spend most of its time doing?

Phases of the Cell Cycle Interphase: G 1 phase-1st growth phase –Cell grows –Synthesize new proteins and organelles S phase-synthesis phase –DNA replication -- Chromosomes copied G 2 phase- 2nd growth phase –Cell continues to grow –Prepares to divide

4 Phases of the Cell Cycle cont. M – phase: –Mitosis - division of the nucleus –Cytokinesis – division of the cell

Cell Cycle cont. Cell spends 90% of its time in Interphase which includes the first 3 phases G 1, S, G 2 :

Mitosis The division of the nucleus 4 phases (PMAT) –Prophase –Metaphase –Anaphase –Telophase

Prophase Start of mitosis DNA coils into chromosomes Nuclear membrane disappears Spindle fibers form between centrioles Nuclear membrane Chromosomes (paired chromatids) Spindle fibers Centrioles

Metaphase Chromosomes line up in the middle of the cell Spindle fibers attach at the centromeres

Anaphase Spindle fibers pull chromatids away from each other toward opposite poles of the cell

Telophase Nuclear membrane forms around chromatids Cytokinesis starts.

Cytokinesis The division of the cytoplasm

Cytokinesis in Animal and Plant Cells In animal cells, the cell membrane pinches in and separates the dividing cell into 2 cells In plant cells, vesicles line up in the middle of the dividing cell –The vesicles fuse and form the cell plate –Cell plate separates the cell into 2 cells

Regulation of Cell Cycle Controlled by proteins to determine if the cell should go into the next phase If a protein does not work, cell growth and division will go out of control –Ex. Cancer-uncontrolled growth of cells that do not respond to the signals that regulate the growth of most cells. –Cancer Causes: DNA becomes damaged or changed (mutated) from smoking tobacco, radiation exposure, viral infections, etc.

Skin Cancer

CELL DIVISION A T THE CONCLUSION OF CELL DIVISION, EACH OFFSPRING WILL RECEIVE IDENTICAL COPIES OF THE CELL ’ S CHROMOSOMES.

Your Turn! How many chromosomes are in a human skin cell before mitosis? After?

Name the following stages of Mitosis:

Agenda DNA/Cell Division Concept Map Quiz Please hand in your cell division computer game questions.

Drill #17: Jan. 4 & 5, 2012 ID each stage of the cell cycle: –Sister chromatids line up on the midline –Spindle fibers begin to form –Sister chromatids separate and begin to move towards the poles –Cytoplasm division –DNA makes a copy of itself –Two new nuclei form

Drill #17: Jan. 4 & 5, 2012 ID each stage of the cell cycle: –Sister chromatids line up on the midline - metaphase –Spindle fibers begin to form - prophase –Sister chromatids separate and begin to move towards the poles - anaphase –Cytoplasm division - cytokinesis –DNA makes a copy of itself – S phase –Two new nuclei form - telophase

Agenda Notes on Cell Division – prokaryotes Notes on Cell Division - eukaryotes Short clip on Mitosis Cell cycle Worksheet Control of Cell Cycle Computer Game

Steps of Binary Fission 1.Circular DNA makes a copy of itself and attaches to the cell membrane 2.Cell grows and begins to divide (pinches in the middle) Splits into 2 new cells (each with own DNA) that are genetically identical.

Binary Fission