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Ch. 5.1 At the end of this lesson, students will be able to… • List the main stages of the cell cycle in order • Explain the main function of each stage • Describe factors that determine division rate and cell size. Prokaryotes Eukaryotes Nucleus No Yes Chromosomes Single, circular More than one Membrane bound organelles No Yes Mitochondria No Yes Microtubules No Yes Mitosis No (Binary fission) Yes Examples Bacteria Animals, plants… The cell nucleus is where eukaryotes store their DNA DNA is what carries the instructions for how to build a new cell down to every detail – like the blueprints for a house The nucleus is surrounded by a membrane called the nuclear envelope Inside the nucleus is the nucleolus which is the site of rRNA transcription Fig 2.2, Pg. 131 DNA is in the form of double helix strands • If we stretched out human DNA strands from ONE cell it would be 6.5 feet long In order to organize these strands of DNA, they are wrapped around proteins called histones. Wrapping DNA around histones isn’t enough DNA/histone strands are twisted into coils called chromatin Chromatin is twisted tighter and tighter until it forms a neatly packed chromatid Chromatids duplicate during the cell cycle to form the X shaped chromosomes we generally see The centromere is the pinched region of the chromosome that holds the sister chromatids together The kinetochores are the attachment point for spindle fibers Definition: The cell cycle is the regular pattern of growth, DNA duplication, and cell division that occurs in EUKARYOTIC cells. Interphase includes: • G1 (Gap 1) • S (Synthesis) • G2 (Gap 2) Mitosis includes: • M (Mitosis) • Cytokinesis The cell spends most of its time in G1 This is when the cell carries out its normal functions Cells also GROW in size Organelles replicate The cell gets ready for the S stage Synthesis only begins if the cell passes the checkpoint at the end of G1 During the synthesis stage, DNA is duplicated At this point, DNA is still loosely organized in the nucleus G2 is another period of cell growth and normal function G2 also includes a checkpoint that the cell must pass to enter mitosis Definition: the division of the cell nucleus and its contents (DNA) • Mitosis is broken in 4 phases we will learn about later Cytokinesis is the actual separation of the cell into two identical daughter cells Literally means “splitting of the cytoplasm” What are the 2 major phases of the cell cycle? What percentage of time do most cells spend in interphase? What is the non-dividing state called? • Why do cells enter this state? What is the function of histones? How many chromosomes do human cells have to duplicate? Catch up: Section 5.1 • **FAQ #5 – Page 129** • Fill in missing notes (powerpoints on website) For tomorrow: Section 5.2 • FAQ #2 – Page 134 Ch. 5.2 At the end of this lesson, students will be able to… • Describe what happens to DNA during cell division • List the phases of mitosis and cytokinesis in order • Explain major events in each phase The M-Phase, mitosis, can be broken down into four stages FIRST: Number off from 1 – 5 SECOND: Find the table in the back with your number and become the “expert” on that phase. THIRD: Mingle with your classmates until you have information on each phase of the worksheet LAST: Once your worksheet is filled in, return to your seats Prophase Metaphase Anaphase Telophase Cytokinesis http://www.youtube.com/watch?v=C6hn3s A0ip0 How long does mitosis typically last? Where do spindle fibers come from? T or F: The nucleolus breaks down in prophase. Where do spindle fibers/microtubules attach to? In what phase are sister chromatids separated? T or F: new nuclear membranes form during telophase. What does the contractile ring cause? Pee MAT Parties (on) Mondays Aren’t That Cool Presidents May Admire The Cabinet Please Make A Taco Cake Please Make A Tasty Chicken Play Makes A Toddler Crazy! Personal Money And Time Care Parties Make Aaron Totally Crazy Purple Monkeys Attack The Cat Play Mates Are Totally Cute Prokaryote cells divide faster than eukaryotes Cells that have a short “life span” need to divide faster to replace dead cells • What types of cells die quickly? • What types live a long time? DNA Cell packaging (1.75 mins) signals, Growth factors, and Healing (13 min) Hand Blue in mitosis activity packet mitosis packets – Thursday 2/21 Powerpoints Test and flashcards online – probably on Friday 3/1 • Note packet will be collected on test day Page 128 - Figure 1.2 Cell Life Span CELL TYPE APPROXIMATE LIFE SPAN Skin cell 2 weeks Red blood cell 4 months Liver Cell 300 – 500 days Intestine – Internal lining 4 – 5 days Intestine – muscle and other tissues 16 years Would a skin cell have a long or short G1 stage compared to other cell types? Explain. Cells must be BIG enough to include all of the necessary parts, but SMALL enough to have the correct ratio of membrane surface area to volume Membrane surface area allows diffusion and osmosis to take place See fig 1.3 on page 129 Demo – How does size affect the cell?? Catch up: • 5.1 – FAQ #5 and 5.2 – FAQ #2 • Fill in missing notes (powerpoints on website) For tomorrow: • Read 5.3 and do FAQ #5 page 139 What limits the maximum size of a cell? The minimum size? Ch. 5.3 At the end of this lesson, students will be able to… • Identify factors that regulate the cell cycle • Explain cancer in terms of the cell cycle The cell cycle is like an assembly line at a factory – Quality checks need to be made along the way to make sure everything is being made correctly • Three major checkpoints occur during the cell cycle: at the end of G1, G2, and metaphase • If the cells fail any of these checkpoints they will move into the NON-dividing phase called G0 Other things that can regulate cell division are: • Cell to cell contact – when cells come into contact with each other, cell division stops • Apoptosis – programmed cell death. Cells that are defective or no longer needed are shut down and destroyed • Growth factors – proteins and hormones that stimulate growth and division External factors – Available nutrients, chemicals from environment Internal factors – Genetics, stress (causes release of chemicals and hormones inside the body) Cell signals, Growth factors, and Healing (13 min) If any methods of regulation become dysfunctional – cell division can run out of control • Uncontrolled cell division is called cancer CANCER = UNCONTROLLABLE CELL DIVISION!!!!!!!!!!!!! Define: • Benign – • Malignant – • Metastasize• Carcinogens – Why are tumors harmful? What are Oncogenes? What is the difference between radiation and chemotherapy? Tumor Growth Oncogenes – genes that have the ability to cause cancer Normally these genes are inactive or expressed at healthy levels • BUT – if a mutation occurs, even a single base pair, the function of this gene can change to produce cancerous cell division Genes that keep cancer turned off • If these genes mutate, their normal function changes and they can’t keep cancer away P53 – tumor suppressor on chromosome 17 When normal it keeps damaged cells from replicating – Damaged DNA is a major cause of cancer so if these cells aren’t stopped, cancer can develop About 50% of human cancer is associated with this gene – these cancers are generally the most aggressive Human chromosomes – Cancer related genes written in red 1920 - 1951 North County High School freshman Jack Andraka earned the grand prize at the Intel International Science and Engineering Fair for creating a test that can detect early-stage pancreatic cancer with 90% accuracy and at a cheaper rate than other tests. “It detects an abnormal protein that you find in the blood when you have a pancreatic cancer,” Dr. Anirban Maitra, professor of pathology, oncology and chemical and biomolecular engineering at Johns Hopkins School of Medicine, told CBS affiliate WJZ-13. “He conceived this idea, and I think the fact that he is 15 makes this whole story more remarkable.” Discuss: • If a child was born with defective growth hormone receptors, how would development be affected? Catch up: • 5.1-5.3 with FAQs • Fill in missing notes (powerpoints on website) For tomorrow: • Re - read Pg 138-139 and the “career” box on pg. 276 For Monday: • Read 5.4 and do FAQ # 3 page 142 Ch. 5.4 At the end of this lesson, students will be able to… • Identify at least one organism that uses asexual reproduction • Explain the outcome of asexual reproduction • Explain the advantages and disadvantages of asexual reproduction Requires a male and female to donate sperm and eggs • Sperm and eggs are specialized cells called gametes • Gametes carry the genetic information of each parent • When these gametes come together, the genetic information is combined to create a UNIQUE genetic combination and therefore a unique individual Definition: The creation of offspring from a single parent and does not involve the joining of gametes. • These offspring are genetically identical to each other AND to the single parent. Prokaryotes (no nuclei) use asexual reproduction Most bacteria only have a single, circular chromosome – makes reproduction very fast! • Bacteria The chromosome is replicated, separated and the cell divides in half • This is called BINARY FISSION (pg. 140) We normally think of asexual reproduction as a prokaryotic trait – But there are some eukaryotes that use it too Three examples of eukaryotic asexual reproduction are: • Budding • Fragmentation • Vegetative reproduction In budding, the single celled organism grows a “clone” that eventually breaks off and becomes an individual Yeast (a fungus), hydra (a multicellular aquatic organism) Fig 4.3, Pg. 142 Fragmentation, the parent splits into pieces and each piece can become its own individual • Certain worms can do this, starfish Vegetative Reproduction – the plant version of fragmentation • Plant cuttings, runners Asexual Pros: • Fast • Don’t need a partner • Less energy input than sexual Cons: • No genetic diversity – Risky in a changing environment Sexual Pros: • Offspring are genetically unique – have a better chance at adapting Cons: • Slower • Need partner Some organisms have the ability to switch between sexual and asexual reproduction. • What might cause the organism to do this? • How does this benefit the organism? Catch up: • 5.1-5.4 with FAQs • Fill in missing notes (powerpoints on website) For tomorrow: • Read 5.5 and do FAQ #5 page 147 Ch. 5.5 At the end of this lesson, students will be able to… • Explain how cells differentiate in terms of genetics and specialized cells • Identify different types of stem cells and why they are important in terms of function and medical possibilities If we all start out as a single cell that multiplies by MITOSIS, how do we develop skin, muscles, bones, hair?? Cellular Differentiation! As the body forms and cells divide and grow, certain genes within the DNA are switched on or off causing the cell to commit to a specific function • This function determines which tissue, organ, and system that the cell will be a part of • Fig 5.2 Pg. 145 The book uses the example of your DNA being like a cookbook and genes are like all of the different recipes • When a cell is ready to differentiate it “reads” a specific gene that changes its development Video Tissues: are groups of cells that work together to perform a similar function Organs: are groups of tissues that work together to perform a specific function or related functions Organ systems: are organs that carry out similar functions Stem cells are a unique type of body cell that have the ability to: • Divide and renew themselves for long periods of time • Remain undifferentiated • Develop into a variety of specialized cell types Stem cells are classified by their potential to develop into differentiated cell types • Totipotent: can grow into ANY other cell type • Pluripotent: can grow into any cell type EXCEPT a totipotent stem cell • Multipotent: can develop into cells within a specific range (ex: if the range is blood cells, it cannot become a brain cell) See fig. 5.3, Pg 146 The potential of these stem cells depends on where they come from • Embryonic – These cells have the ability to become any cell or tissue type in the body, pluripotent • Adult – These cells can become the tissue they were taken from (liver, brain, blood etc.), multipotent Diseases and trauma that could benefit from stem cell research: • Parkinson's disease, • Diabetes, • Traumatic spinal cord injury, • Duchenne's muscular dystrophy, • Heart disease • Vision and hearing loss • Burn victims • Cancer patients • Liver disease This is the END OF THE UNIT! • Finish missing readings and FAQs • 5.1#5 - 5.2#2 - 5.3#5 - 5.4#3 - 5.5#5 • Fill in missing notes (powerpoints on website) • Be sure to have: blue mitosis packet, cancer test, stem cell packet A. The order of the cell cycle phases B. The major events of the cell cycle phases C. Things that affect the rate of division D. Cell size E. The FAQs F. Regulation of the cell cycle G. Cancer and the cell cycle H. Asexual reproduction in prokaryotes I. Asexual reproduction in eukaryotes J. Differentiation of cells K. Stem cells L. Mitosis