Think About This… • What is this? • What IS cancer?? What are some causes? • What are some reasons for cell division? • How do you think a cell would accomplish this task?
SO WHY LEARN ABOUT CELL DIVISION?? • Growth • Cancer- uncontrolled growth • Cells have given life spans; need to replace! • Lining of esophagus 2-3 days • Lining of small intestine 1-2 days • Skin 2-4 weeks • Stem Cells
All Cells Come From Cells • One concept of the cell theory we just learned about! • All organisms reproduce their own kind… • Asexual Reproduction • Sexual Reproduction
Types of Cell Division We Will Learn About • Mitosis- Division of somatic cells (body cells) • Meiosis- Creation of gametes (sex cells)
Lab- You Are a 19th Century Cell Biologist • In this lab, you will assume the role of a biologist in the mid-1890s. You are fascinated by the power of the microscope to reveal the inner workings of living cells. The invention of the compound microscope, along with new stains, make it possible for you to see cell structures that no one has ever seen before. You plan to collaborate with your colleagues to discover the events of cell division.
Lab- You Are a 19th Century Cell Biologist • Things you know right now: • 1) The cell has many organelles. • 2) The nucleus seems to be pretty important. • 3) There seem to be “structures” inside the nucleus that undergo changes during cell division (chromosomes).
Lab- You Are a 19th Century Cell Biologist • 1) Obtain a microscope and a slide of onion root tip. • 2) Focus under low power.
MITOSIS-ONION ROOT TIP • 3) Move to high power; only adjust here with the fine focus.
Lab- You Are a 19th Century Cell Biologist • 4) Select one cell whose chromosomes are clearly visible & sketch in the box. • 5) Look around and select 4 other cells whose internal appearances are differentand sketch them as well. • 6) Try and place your sketches in order from 1-5. • 7) Check your answers with Mrs. Romano… how many did you get right??
Lab- You Are a 19th Century Cell Biologist • 8) Identify the phases of cell division. • 9) Count the number of cells in your slide in each stage of cell division. • 10) Answer the analysis questions.
TERMS TO KNOW: Nucleus Nuclear envelope Centriole Spindle Fiber Chromatin Chromatid Chromosome Centromere Review- Cell Parts
Do All Cells Divide?? • NO!! • Muscles, neurons, red blood cells, white blood cells generally DO NOT go through mitosis.
Orderly sequence of cell division INTERPHASE- Cell grows, DNA replicates, gets ready to divide; LONG MITOSIS (cell divides) 4 parts Cell Cycle
MITOSIS- Step 1 of 4 • Prophase- chromosomes condense, nuclear membrane disappears, spindle forms
MITOSIS- Step 2 of 4 • Metaphase- chromosomes move to center of the cell and attach to spindle fibers
MITOSIS- Step 3 of 4 • Anaphase- Chromosome strands move towards opposite ends
MIATOSIS- Step 4 of 4 • Telophase- Chromosomes reach ends; nuclear envelope reforms; cytoplasm divides (CYTOKINESIS)
ANIMALS- cleavage furrow PLANTS- cell plate Plant vs. Animal Cell Mitosis
Movie • Mitosis Video
Review- Mitosis • Animation
Out-of-control cell reproduction TUMOR- mass of cells Benign Malignant Breast Cancer cells Cancer
Metastasis • Most dangerous property of cancer cells is their ability to spread beyond their original site
Detection • Visual • Radiation Imaging (spot glows under UV light) • Biological or chemical test (spot changes color when exposed to a chemical)
Treatment • Radiation Therapy • Chemotherapy
Getting older Genetics Tobacco UV radiation (sunlight) X-rays Certain chemicals (asbestos, vinyl chloride, nickel) Certain viruses/ bacteria (HPV, Hepatitis C, HIV) Certain hormones (excess estrogen) Alcohol Poor diet/ lack of exercise Causes
Video • The Genetics of Cancer