BELL WORK01/20/15

• Read article “From Stem Cell to Any Cell”• Highlight the main idea• Underline 3 supporting facts and write in the margin how

these facts support the main idea. • On a separate piece of paper, write the following

questions and answer:• 1. What are stem cells?• 2. Where are stem cells found?• 3. What are three important uses for stem cells?

BELL WORK 01/21/15WRITE QUESTIONS AND

ANSWER•Name two organs that are easy to repair using stem cells. •What are two organs that are difficult to repair using stem cells?

BELL WORK 01/22/15WRITE QUESTION AND ANSWER

Why are embryonic stem cells more useful than other stem cells?What makes the new technique called “somatic cell nuclear transfer” appealing to doctors?

BELL WORK 01/23/15WRITE QUESTION AND ANSWER

How are scientists trying to get around ethical concerns about the use of embryonic stem cells in research and medicine?

CELLULAR DIVISION AND GROWTH

OBJECTIVES FOR CHAPTER 10 SECTION 1

•Explain the problems that growth causes for cells.•Describe how cell division solves the problems of cell growth. •Read Chapter 10 Section 1 Page 241-243

2 MAIN REASONS WHY CELLS DIVIDE

•1. The larger the cell becomes, the more demands the cell places on its DNA.•2. The larger the cell, the more trouble the cell has moving enough nutrients in and wastes out of the cell membrane.

DNA “OVERLOAD”

•Genetic material•Found in the nucleus of the cell•Stored information to control all of cell’s needs•Only is copied when cell is dividing. Does NOT make more DNA just because the cell is growing.

EXCHANGING MATERIALS

•Cell membrane: allows food, water, and oxygen to enter into cell and allows wastes to leave. •Surface area of the cell membrane determines how effectively this exchange takes place. •Determine Surface Area of cell:

Length x width x 6

EXCHANGING MATERIALS

•Cell’s Volume determines how fast food and oxygen are used up by the cell. •To determine volume of the cell:

Length x width x height

RELATIONSHIP BETWEEN SURFACE AREA AND VOLUME

•As the cell grows, the cell’s volume increases faster than its surface area. •This causes the surface area to volume ratio to decrease which causes problems for the cell.

DIVISION OF THE CELL

• The cell will divide into two “daughter” cells through a process called cell division• Cell will copy its DNA so that each new cell receives its own copy• Cell division reduces the cell’s volume therefore increasing the surface area to volume ratio and making the exchange of materials more efficient.•Which means that each daughter cell has a higher surface area/volume ratio than the parent cell

SECTION 1 REVIEW

•What determines how fast food and oxygen are used up and wastes are produced by the cell?•Compared to small cells, large cells have more trouble doing what?•The process by which a cell divides into two daughter cells is called what?•What happens as the cell becomes larger?

SECTION 1 REVIEW

•What determines how fast food and oxygen are used up and wastes are produced by the cell?• volume

• Compared to small cells, large cells have more trouble doing what?•Moving needed materials in and waste out

• The process by which a cell divides into two daughter cells is called what? Cell division•What happens as the cell becomes larger?• Volume increases faster than surface area

CHAPTER 10 SECTION 2 OBJECTIVES

•Name the main events of the cell cycle.•Describe what happens during the four phases of mitosis.

CHROMOSOMES

•Made up of genetic material (DNA) and proteins•Found in nucleus•Each organism has a specific number of chromosomes•Humans (46), Drosophilia (8), Carrots (18)

CHROMOSOMES

•DNA is not visible except during mitosis (cell division)•DNA strands coil up around histone proteins to form a structure called a chromosome•Before a cell divides it is replicated forming 2 identical sister chromatids

CHROMOSOMES

•Sister chromatids are held together by a structure called a centromere. •The chromatids will move away from each other during cell division.

CELL CYCLE GRAPHIC ORGANIZER

CELL CYCLE – SERIES OF EVENTS THAT CELLS GO THROUGH AS THEY GROW AND

DIVIDE

• Interphase (longest)•G1•S•G2

•Cells that do not divide are always in interphase

•M phase (cell division)•Prophase•Metaphase•Anaphase•Telophase•Cytokinesis

INTERPHASE - G1 PHASE – CELL GROWTH

•Cell does most of its growing/increases in size•Synthesize new proteins and organelles•New cytoplasm forms

INTERPHASE - S PHASE - REPLICATION

•DNA replicates forming sister chromatids•Key proteins (histone proteins) are synthesized•Usually will complete rest of cycle once DNA is replicated.

INTERPHASE - G2 PHASE – PREPARE FOR MITOSIS

•Shortest of the three phases•Organelles and molecules required for cell division are produced

REVIEW CELL CYCLE

•What are the 3 parts of interphase and what occurs in each part?•Draw and label a chromosome. •When during the cell cycle are chromosomes visible?

M PHASE – CELL DIVISION

•May take a few minutes or several days•Consist of two parts:• 1. mitosis• Prophase•Metaphase• Anaphase• Telophase

• 2. cytokinesis

MITOSIS - PMAT

•Produces 2 daughter cells from one parent cell• Identical to each other and to the parent cell•Asexual reproduction•Most body (somatic) cells reproduce this way•Used to grow and replace old damage cells

PROPHASE

•Nuclear membrane disappears•DNA begins to shorten and thicken (becomes visible) – chromosomes/chromatids•Centrioles move to opposite ends of the cell•spindle fibers (aster fibers)form at the end of cell around the centrioles•Takes ~an hour

Prophase:

P = Primary (first)

P = Pair

METAPHASE “MIDDLE”

•Chromosomes line up along the equator “middle” of the cell•Centromeres connect the chromosomes to the spindle fibers•Take about 15 minutes

Metaphase

M = Middle

ANAPHASE – ADIOS AMIGOS

•Chromosomes divide into chromatids•Chromatids move to opposite ends of the cell•Takes about 10 minutes

Anaphase

A = Away

A = Adios Amigos

TELOPHASE – TWO

•Spindle fibers disappear•Nuclear membrane forms around each group of chromatids creating 2 new nuclei•Chromatids unwind and become long and thin again•Cytokinesis begins

Telophase

T = Two (nuclei)

Chromosomes finish journey at opposite ends of cell

Nuclear membrane re-forms around new groups of chromosomes

CYTOKINESIS

•Cytoplasm divides•One cell becomes two individual cells•Different in plants and animals•Plants – cell plate forms•Animals – cell membrane pinches in two

Cytokinesis (cy·to·ki·ne·sis)

Cyto = cell

Cell membrane pinches original cell into two new cells separating the cytoplasm

End Results of Mitosis:

Two cells

Identical to each other

Identical to parent cell (original cell)

Remember PMAT!!!!

MITOSIS REVIEW

•What are the phases of cell division? Name them in order. State what occurs in each phase. •What is the role of the spindle during mitosis?•What is one difference between plant cell division and animal cell division?

BELL WORK

•Review notes for section 2 quiz

SECTION 3 OBJECTIVES

• Identify a factor that can stop cells from growing.•Describe how the cell cycle is regulated.•Explain how cancer cells are different from other cells.

REGULATING CELL CYCLE

•Cell growth and cell division are controlled•By internal regulators •By external regulators

INTERNAL REGULATORS

•Proteins within the cell determine if the cell can go on to the next phase of the cell cycle•Cyclins – regulate timing of cell cycle in eukaryotic cells

EXTERNAL REGULATORS

• Proteins that respond to events outside the cell•Speed up or slow down the cell cycle• Includes growth factors which speed up• Prevent excessive growth:•When cells come into contact with other cells, they stop growing. When there is an empty space (from cut or injury) the cells are stimulated to divide rapidly and will continue to do so until the area is returned to normal.

CONTROL OF CELL DIVISION

Section 10-3

Cells grow until they touch other cells

If center cells are removed,cells near the space will start to grow again.

SHOWS: Cell division genes can be turned on and off

Cancer cells don’t stopwhen they touch nearbycells. . . they just keep growing!

That’s what makesa tumor.

NO CONTACT INHIBITION

http://www.exn.ca/news/images/2000/08/02/20000802-cancer.jpg

CANCER CELLS• Like a “car with no brakes”• Can spread to new places (METASTASIS)

• Carcinogens are substances that can damage DNA and cause cancer

Ex: Cigarette smoke (OR CHEW), Radiation, chemicals in environment,

even viruses

http://www.dfci.harvard.edu/abo/news/publications/pop/fall-winter-2004/images/metastasis_1.jpg

UNCONTROLLED CELL GROWTH

•LOST ALL CONTROL!!!!•Affects multicellular organisms•Cancer cells do NOT respond to the internal or external protein signals that regulate cell growth.•Defect in a gene called p53 causes chromosomal damage in cells

CHAPTER 10 SECTION 3 REVIEW

•Right after a bone breaks, what do the cells do at the edge of injury?•What is an external factor that can stop a normal cell from growing?•The timing of the cell cycle is regulated by?•Cancer cells form masses of cells called?•Cancer affects…?

CHAPTER 10 SECTION 3 REVIEW

•Right after a bone breaks, what do the cells do at the edge of injury? Begin to divide rapidly•What is an external factor that can stop a normal cell from growing? Contact with other cells•The timing of the cell cycle is regulated by? cyclins•Cancer cells form masses of cells called? tumors•Cancer affects…? Multicellular organisms

• Opening paragraph. Have a HOOK!!!

• Inform audience of stem cells.

• Many believe that using stem cells is morally and ethically wrong while others believe that it is not an issue. Those who do not believe in using stem cells but have a child diagnosed with a disease turn to another option of having a second child to use as a tissue donor. Put yourself in the position of that parent, would you want to use stem cells from a research lab to save your dying child or would you chose to have another child to use as a tissue donor? Be sure to back up your decision with at least three reasons as to why you chose this decision and provide evidence from the text that supported your decision making process.

• Close!!!

• Cite evidence from both articles in second and third paragraphs.