DR. RAMESH U2 L3. MITOSIS and Cell Cycle

DR. RAMESH U2 L3 MITOSIS and Cell Cycle

Do Now! Directions: Answer the following questions in complete sentences. 1. Describe how bacteria reproduce. Describe how cats reproduce.are there any similarities between the two? 2. What is DNA?

ENGAGE How do organisms grow?

ENGAGE The cells in an organism divide and increase in number, resulting in growth of the organism.

Objective! The student will (TSW) identify the purpose of cell division and illustrate the differences in the stages of mitosis. Benchmark/Standard LS-H-B2: Compare mitosis and meiosis

All life begins and continues through cell division, which is responsible for the growth and development of organisms. Without this process, organisms would die.

3.5A MITOSIS SWBAT determine the process for cellular growth and division. (Mitosis). SWBAT identify limiting factors on cell size.

MAIN IDEA All organisms grow by increasing their number of cells. Cell numbers increase when cells divide and multiply.

Pause- important questions to think about! 1. Why does mitosis happen in your body? (what is the point!) 2. Why is it important that you start with one cell but end with two? 3. Why would your body want to make make two IDENTICAL cells?

CELL DIVISION IS NECESSARY FOR GROWTH.

CELL DIVISION HELPS TO REPAIR DAMAGED TISSUES. IT IS NEEDED FOR HEALING.

REPRODUCTION: SIMBA IS A LION CUB

Functions of Cell Division: growth, repair and reproduction.

Eukaryotes have two types of cells: 1. Somatic (body cells) 2. Gamete (sex cells; sperm & egg)

Review Point #1 In order for an organism to grow, it must make more somatic (body) cells.

Key Point #1 The process of making more body cells is called MITOSIS. In mitosis one parent cell divides into two identical daughter cells. Start with one skin cell Mitosis happens End with TWO skin cells that are just like the original one

THE CELL CYCLE A cell s life consists of a repeating pattern of events called the cell cycle.

Key Point #2 The life cycle of a cell has two parts: Interphase and Cell Division. The cell spends most of its life in interphase. Cell division (mitosis) Interphase

Interphase- In between divisions 1. The cell grows. 2. The cell DOUBLES its DNA so it is ready to divide. 3. The cell replicates its centrioles. Human cell during interphase 46 chromosomes Human cell at the end of interphase 92 chromosomes, ready to divide!

Interphase centriole DNA (chromatin) nuclear envelope nucleus

STAGES OF THE CELL CYCLE STAGES OF THE CELL CYCLE 1.Interphase (G1, S, G2) 2.Mitosis (P,M,A,T) 3.Cytokinesis (Cytoplasm divides)

THE CELL CYCLE Cell cycle has 5 main stages- 1. Gap 1 (G1) 2. Synthesis (S) 2. Gap 2 (G2) 3. Mitosis (M) 4. CYTOKINESIS -Divides the cytoplasm into two cells

THE CELL CYCLE INTERPHASE Purpose: Grow, Carry out Job, Prepare for Cell Division G 1 - Cell growth S copies or synthesizes DNA G2 - Additional growth

Key Point #3 Once the cell has doubled its DNA, it is ready to divide in a process called mitosis. Think of mitosis like baking a cake. It is a process with many steps. The steps must happen in order or it will be a disasterrrrrrrr

Steps of mitosis Prophase Metaphase Anaphase Telophase Please Make Another Touchdown

THE CELL CYCLE MITOSIS Purpose: make two identical copies of the nucleus 4 STAGES PROPHASE METAPHASE ANAPHASE TELOPHASE

THE CELL CYCLE PROPHASE: CELL PREPARES FOR DIVISION chromosomes condense, nuclear membrane dissolves, centrioles form spindle fibers Centrioles: organelles that push and pull chromosomes during cell division

Prophase 1) DNA organizes into chromosomes 2) The nucleus breaks down. 3) The centrioles separate, and a spindle begins to form.

THE CELL CYCLE METAPHASE spindle fibers align sister chromatids in the middle of the cell (equator) Chromatid: single, identical chromosome strands

Metaphase-Middle 1) The chromosomes line up across the middle of the cell. Spindle 2) Each chromosome is connected to a spindle fiber at its centromere.

Metaphase Animal Cell Plant Cell Photographs from: h8p://www.bioweb.uncc.edu/biol1110/stages.htm

THE CELL CYCLE ANAPHASE spindle fibers retract and pull the sister chromatids away to the opposite sides of the cell (poles)

Anaphase- Apart The chromosomes (X s) separate into individual chromatids (v s) and are moved apart to opposite sides of the cell.

Anaphase Animal Cell Plant Cell Photographs from: h8p://www.bioweb.uncc.edu/biol1110/stages.htm

THE CELL CYCLE TELOPHASE: chromosomes uncoil, nuclear membrane reforms. A notch appears in preparation for two daughter cells to form.

Telophase- Two nuclei 1) Two nuclei start to form. 2) The cell begins to tear apart. 3) Chromosomes lose their distinct shapes.

Telophase Animal Cell Plant Cell Photographs from: h8p://www.bioweb.uncc.edu/biol1110/stages.htm

Key Point #4 Once mitosis is over, cytokinesis happens. Cytokinesis = splitting of cytoplasm

Cytokinesis Key information: - cyto = cell kinesis = movement - cell pinches in the middle. Cell splits into 2 new identical cells.

THE CELL CYCLE CYTOKINESIS -Divides the cytoplasm into two cells -2 cells separate -nucleus reforms

Cytokinesis- Cut The cytoplasm and cell membrane are cut in half. Two daughter cells are made with IDENTICAL DNA.

THE BOTTOM LINE 1. Mitosis happens so an organism can GROW. 2. Mitosis makes TWO daughter cells with IDENTICAL DNA 3. Mitosis makes more SOMATIC (body) cells.

THE CELL CYCLE 11 2 Daughter Cells are genetically identical to the parent cell and have the same number of chromosomes Start of Interphase End of Interphase/ End of Mitosis Beginning of Mitosis End of Cytokinesis

12 THE CELL CYCLE WHY DO CELLS DIVIDE? Cells divide to maintain size limit (surface area to volume ratio). A large cell will not have enough surface area to function efficiently.

CHECK FOR UNDERSTANDING Voices at a Level Zero Raise your hand to answer the following questions Pick one from the choices given for each question.

Answer the following question by picking one CELL DIVISION OR CELL THEORY? The function of this is growth, repair and reproduction. Cell Division

Answer the following question by picking one PROPHASE OR INTERPHASE? This is the first stage of Cell Division. Interphase

Answer the following question by picking one CYTOKINESIS OR TELOPHASE? During this stage of Cell Division, the celldivides into two identical cells. Cytokinesis

Answer the following question METAPHASE OR ANAPHASE? During this stage of mitosis, the chromosomes line up at the center of the cell. Metaphase

Answer the following question by picking one PROPHASE OR ANAPHASE? During this stage of mitosis, the chromosomes are pulled apart to opposite ends. Anaphase

Answer the following question by picking one CENTRIOLES OR CELL MEMBRANE? This organelle is responsible for pushing and pulling the chromosomes during cell division. Centrioles

Answer the following question by raisong your hand: Name the four phases of mitosis. Prophase, Metaphase, Anaphase & Telophase

Think Pair Share How is mitosis similar to asexual reproduction? The end product is identical to the starting cell.

GUIDED PRACTICE View the slide on the screen Silently identify the stage of mitosis (you have 10 secs), go. Raise your hand to respond

METAPHASE: spindle fibers align sister chromatids in the middle of the cell (equator)

TELOPHASE chromosomes uncoil, nuclear membrane reforms

PROPHASE chromosomes condense, nuclear membrane dissolves, centrioles form spindle fibers

ANAPHASE spindle fibers retract and pull the sister chromatids opposite sides of the cell (poles)

CYTOKINESIS -Divides the cytoplasm into two cells -2 cells separate -nucleus reforms

GUIDED Practice The following steps of mitosis and cell division are out of order. Place numbers 1-5 in the blanks provided to show the correct order. Correct order 1. 2. 3. 4. 5.

GUIDED Practice The following steps of mitosis and cell division are out of order. Place numbers 1-5 in the blanks provided to show the correct order, and name the stages. Correct order 1. C = PROPHASE 2. B = METAPHASE 3. A = ANAPHASE 4. E = TELOPHASE 5. D = CYTOKINESIS

Exit Ticket 1. Which of the following is not one of the 4 major stages of the cell cycle? a. Gap 2(G2) b. Sister chromatid c. Mitosis (M) d. Synthesis (S) 2. Gap 1 (G1), Synthesis (S) and Gap 2 (G2) together make up the a. interphase b. anaphase c. mitosis d. telophase 3. In the figure below which letter represents prophase? a. A b. B c. C d. D 4. In the above figure, what is happening in panel C? a. The sister chromatids are pulled apart b. the nuclear membrane begins to reform c. the sister chromatids line up at the equator d. two daughter cells have formed 5. In the above figure, the correct order of mitosis-prophase, metaphase, anaphase, and telophase, is. a. A B C D b. ACBD c. A C D B d. B D C A

Exit Ticket 1. Which of the following is not one of the 4 major stages of the cell cycle? a. Gap 2(G2) b. Sister chromatid c. Mitosis (M) d. Synthesis (S) 2. Gap 1 (G1), Synthesis (S) and Gap 2 (G2) together make up the a. interphase b. anaphase c. mitosis d. telophase 3. In the figure below which letter represents prophase? a. A b. B c. C d. D 4. In the above figure, what is happening in panel C? a. The sister chromatids are pulled apart b. the nuclear membrane begins to reform c. the sister chromatids line up at the equator d. two daughter cells have formed 5. In the above figure, the correct order of mitosis-prophase, metaphase, anaphase, and telophase, is. a. A B C D b. A C B D c. A C D B d. B D C A

HOMEWORK Read chapter 5.1, pages 134 137 Read 5.2, pages 138-142 FROM THE TEXT BOOK. Complete the Vocabulary words: Cell cycle, mitosis, chromatid, chromosome, centromere Prophase, metaphase, anaphase, telophase Cytokinesis.