Where it all began… You started as a cell smaller than a period at the end of a sentence…

Getting from there to here… Going from egg to baby…. the original fertilized egg has to divide… and divide…

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What types of cells divide? Prokaryotes: organisms include Bacteria Eukaryotes :Plants & animals copyright cmassengale

Key characteristics of Prokaryotes Lack a nucleus Have a single chromosome copyright cmassengale

Steps in Binary Fission Bacteria reproduce by BINARY FISSION 3 steps in Binary Fission: Cells increase their cell mass slightly DNA & cell components are replicated Each cell divides into 2 daughter cells copyright cmassengale

Binary Fission of Bacterial Cell copyright cmassengale

E. Coli Dividing by Binary Fission--SIMPLE copyright cmassengale

Remember this slide? Not so easy for Eukaryotes Going from egg to baby…. the original fertilized egg has to divide… and divide…

Why do cells divide… One-celled organisms for reproduction asexual reproduction (clones) 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 amoeba Unicellular organisms Cell division = reproduction Reproduces entire organism& increase population Multicellular organisms Cell division provides for growth & development in a multicellular organism that begins as a fertilized egg Also use cell division to repair & renew cells that die from normal wear & tear or accidents starfish

Cell Cycle: Seasons of a cell Stages in growth & division G1 Stage S Stage G2 Stage M Phase Cytokinesis Interphase (circle & label on notetaker) copyright cmassengale

copyright cmassengale G1 Stage G1 means first growth stage 2 processes that occur in G1: Cell increases in size Cell prepares to copy its DNA copyright cmassengale

copyright cmassengale S Stage: Synthesis: making more DNA is copied in this stage What is this process called? What enzymes are involved? copyright cmassengale

DNA must be duplicated… chromosomes in cell 4 single-stranded chromosomes nucleus cell DNA in chromosomes nucleus cell duplicated chromosomes duplicated chromosomes 4 double-stranded chromosomes

copyright cmassengale G2 Stage 2nd growth stage Time between DNA synthesis and mitosis Cell continues growing during G2 Makes proteins that will be needed for mitosis and cell division copyright cmassengale

Why do cells divide… for growth & development for repair & replacement from fertilized egg to adult for repair & replacement replace cells that die from normal wear & tear or from injury Unicellular organisms Cell division = reproduction Reproduces entire organism& increase population Multicellular organisms Cell division provides for growth & development in a multicellular organism that begins as a fertilized egg Also use cell division to repair & renew cells that die from normal wear & tear or accidents starfish

copyright cmassengale Interphase Resting Stage Cells carrying on normal activities Kidney cells filtering blood Skin cells replacing old skin cells Occurs before mitosis Chromosomes aren’t visible copyright cmassengale

copyright cmassengale Interphase copyright cmassengale

Do you get it? (aka: checking for understanding) Agree to Disagree Partner A prompt: “At first I thought cell division meant…now I know cell division’s function is…” Partner B in ONE MINUTE: Paraphrases (NOT repeats) 1st person’s idea Tells what they agree with Tells what they disagree with Tells their idea.

copyright cmassengale Stages of Mitosis Prophase Metaphase Anaphase Telophase copyright cmassengale

Cells Undergoing Mitosis copyright cmassengale

copyright cmassengale Steps in Prophase Nuclear membrane disappears Spindle fibers (rope-like proteins) begin to form from specialized organelles responsible for cell division DNA coils tightly & becomes visible as chromosomes copyright cmassengale

copyright cmassengale Prophase copyright cmassengale

copyright cmassengale Human Chromosomes copyright cmassengale

copyright cmassengale Steps in Metaphase Spindle fibers attach to each side of the copied chromosome Preparation for separating chromosomes Cell aligns its chromosomes in the middle of the cell copyright cmassengale

copyright cmassengale Metaphase copyright cmassengale

Do you get it? (aka: checking for understanding) Partner A: Explain what happens to a cell in Prophase (picture A) Partner B: Rephrase what your partner said for Prophase (picture A) and explain what happens to a cell in Metaphase (picture B) Partner A: Rephrase what your partner said for Metaphase (picture B)

copyright cmassengale Steps in Anaphase Cell chromosomes are separated (pulled apart) Spindle fibers (ropes) shorten so chromosomes pulled towards the sides of cell copyright cmassengale

copyright cmassengale Anaphase copyright cmassengale

copyright cmassengale Steps in Telophase Separation of chromosomes completed and found on either side of the 2 cells Nucleus reform Chromosomes uncoil Cell Plate forms in plants Cleavage furrow forms in animals copyright cmassengale

copyright cmassengale Telophase        Plant             Animal copyright cmassengale

copyright cmassengale Video THE BASICS OF BIOLOGY You tube video clip: Eukaryotic Cell Cycle copyright cmassengale

copyright cmassengale Cytokinesis Division of the Cytoplasm Follows mitosis Forms two, identical daughter cells copyright cmassengale

copyright cmassengale Cytokinesis Cell Plate Forming in Plant Cells copyright cmassengale

Mitosis in plant cell Partner A: summarize the cell cycle focusing on the chromosomes Partner B: summarize the cell cycle focusing on the everything but the chromosomes

copyright cmassengale THE CELL CYCLE!!!! copyright cmassengale

copyright cmassengale CONCEPT MAP copyright cmassengale

Amoeba Sisters Pt 1 & 2 (w/ Questions) copyright cmassengale