- Slides: 30
Happy Tuesday! – 10/22 **Put these warm ups on back of old sheet** One arctic food chain consists of polar bears, fish, seaweed, and seals. Which sequence demonstrates the correct flow of energy between these organisms? A B C D seals seaweed fish polar bears fish seaweed polar bears seals seaweed fish seals polar bears fish seals seaweed
Schedule for the week: § Tuesday: Notes over Cell Cycle (Interphase) § Wednesday: Benchmark (meet in computer lab § § § next door) Thursday: Finish notes over Cell Cycle (Mitosis) Friday: Cell Cycle Foldable (for a grade) Monday: Cell Cycle QUIZ ** Be attentive and respectful. Remember you are an extension of me so make me proud!
CELL CYCLE Click here to watch brief video over cell cycle
Why do cells divide… A. One-celled organisms § i. ii. for reproduction Asexual reproduction (clones) Binary fission (bacteria only) amoeba B. Multi-celled organisms § for growth & development - from fertilized egg to adult § for repair & replacement - replace cells that die from normal wear & tear or from injury starfish
Stages of Cell Cycle § The cell cycle is the sequence of growth and division. 1. INTERPHASE: a. G 1 Phase b. S Phase c. G 2 Phase 2. M Phase (MITOSIS)
The Cell Cycle Interphase § The majority of a cells life is spent in Interphase. § Interphase is broken into 3 phases: G 1, S, and G 2 § During Interphase 2 things happen: 1. A cell grows in size. 2. Chromosomes (DNA) are duplicated in preparation for cell division.
3 Phases of Interphase: 1. G 1 Phase (Growth) Ø First growth stage Ø Cell increases in size Ø Cell prepares to copy its DNA
2. Synthesis Phase (S Phase) Ø Copying of all of DNA’s instructions Ø Chromosomes duplicated Ø DNA repairs any errors/damage
3. G 2 Phase (Growth) ØTime between DNA synthesis & mitosis ØCell continues growing ØNeeded proteins produced
Why do cells copy their DNA? § A dividing cell duplicates its DNA creates 2 copies of all DNA u separates the 2 copies to opposite ends of the cell u splits into 2 daughter cells u DNA cell nucleus § But the DNA starts loosely wound in the nucleus § If you tried to divide it like that, it could tangle & break
Organizing & packaging DNA cell nucleus DNA in chromosomes in everyday “working” cell DNA has been “wound up” cell nucleus 4 chromosomes in this organism DNA in chromosomes in cell getting ready to divide
Copying & packaging DNA When cell is ready to divide… 1. 2. copy DNA first, then… coil up doubled chromosomes like thread on a spool… § now can move DNA around cell without having it tangle & break Copying DNA Coil DNA into compact chromosomes
double-stranded human chromosomes ready for mitosis
DNA must be duplicated…before division chromosomes in cell DNA in chromosomes cell nucleus 4 single-stranded chromosomes duplicated chromosomes 4 double-stranded chromosomes cell nucleus
Stop for today. Yay!!!
Happy Thursday! – 10/24 The graphic shows the processes involved in the cell cycle. The cell cycle is necessary in order for new cells to replace damaged or dead cells. In which part of the cycle is DNA repaired to prevent errors such as cancer? A B C D Growth DNA Synthesis Preparation for Division Mitosis
MITOSIS: Making New Cells Making New DNA
The next five slides of the stages of Mitosis. You need to know what happens in each stage and be able to recognize a picture. **So draw the pictures in your notes as well as the words.
5 Stages of MITOSIS: 1. Prophase § DNA is wound up into chromosomes to keep it § § organized Nuclear membrane disappears Centrioles migrate to poles duplicated chromosomes **Different colors of DNA represent what you got from MOM & DAD cell centrioles nucleus
5 Stages of MITOSIS: 2. Metaphase § § chromosomes line up in middle attached to protein “cables” that will help them move M=M Metaphase = Middle duplicated chromosomes lined up in middle of cell
5 Stages of MITOSIS: 3. Anaphase § chromosomes split, separating pairs § start moving to opposite ends A=A Anaphase = Away chromosomes split & move to opposite ends
5 Stages of MITOSIS: 4. Telophase § Cell starts to divide nucleus forms again u Plant cells form CELL PLATES u Animal cells form CLEVAGE FURROWS u
5 Stages of MITOSIS: 5. Cytokinesis § DNA unwinds again cells separate u now they can do their every day jobs u
***End result of mitosis: TWO identical “daughter” cells § Get 2 exact copies of original cells same DNA u “clones” u Every cell in your body has the same DNA (except sperm & eggs).
Overview of CELL CYCLE interphase prophase I. P. M. A. T. C. prophase Make an acronym to remember the steps: Individual: Please Make Another Two Cells cytokinesis metaphase anaphase telophase
Cell Cycle in Plant Cells Interphase Prophase Metaphase Anaphase Telophase
What stage is shown here? Anaphase
And now for the world’s creepiest song about cell division MITOSIS SET TO MUSIC
My Sophia… Yay!! I’m finally here!