Discovering Cells 10.2 What are Cells? What is the Cell Theory?

1. Cells and Life Processes Ms. De Los Rios 6th Grade Discovering Cells 10.2 What are Cells? What is the Cell Theory? How do Microscopes Work? Pgs. 368-375

2. Vocabulary 10.2 • Microscope: instrument that makes small objects look larger, and the discovery of cells. • Cell Theory: explains the relationship between cells and living things HeLa cells stained for the cell nucleus DNA

3. What are Cells? Pg. 368 • Mushroom, tree, spider, and bird= Living organisms • Cells are the basic units of structure and function in living things. • Cells--- form the parts of an organism ---- carry out functions. • Organism= are made of one or more cells • Cells carry out basic functions that let it: • Live • grow • Reproduce • Cell functions can include: • obtaining food, water, and oxygen, getting rid of waste, and reproducing by division.

4. Fig. 1 Discovering Cells pg. 369 Needs of Cells A single cell has the same needs as an entire organism. What material moves in the direction shown by each blank arrow? Assess your Und.

5. The Cell Theory TimelinePg. 370

6. Growth of Cell Theory pg. 370-371 Leeuwenhoeek Microscope Hooke’s drawings of cork Dog Cell Cell Reproducing Hooke’s Microscope

7. What is The Cell Theory? Pg. 371 • The cell theory explains the relationship between cells and living things. • The cell theory was developed about two hundred years after the invention of the microscope, an instrument that makes small objects look larger, and the discovery of cells. • The cell theory states the following: • All living things are composed of cells. • Cells are the basic units of structure & function in living things. • All cells are produced from other cells. • Assess your Understanding

8. How Do Microscopes Work? Pg 372 • Most cells are too small= can not be seen by the human eye • The development of the cell theory depended on observations made through microscopes. • Some microscopes focus light through lenses to produce a magnified image. Other microscopes use beams of electrons. • Microscopes 2 important jobs: • magnify & have good resolution • r. 2 P • Fig. 3

9. Microscope Beam ElectronLight microscope

10. Pg. 373 • r both P • Acompound microscope uses two lenses and focuses light from a lamp or reflected from a mirror. This type of microscope is often used in classrooms. • Fixed lens • 2nd lens is chosen from group of 2 or 3 lenses revolving

11. How Do Microscopes Work? • You can estimate the true size of an enlarged object by measuring the width of the circular field visible through the microscope and comparing the size of the object to the width of the field. • Objects viewed through a microscope are also more detailed than when viewed with the naked eye. • Microscopes improve resolution: the • Ability to distinguish separate structures that • are close together. • Electron microscopes have better resolution • and magnification than light microscopes.

12. Fig. 4 Compound Microscope Eyepiece lens Revolving nosepiece Lenses Lens Slide Stage Light rays Light source • A Compound Microscope • This microscope has a 10x lens in the eyepiece. The revolving nosepiece holds three different lenses: 4x, 10x, and 40x. • Find the three total magnification possible for this microscope. • __________________________________________________________ • 2. What would happen if the object on the slide were too thick for light to pass through it? • __________________________________________________________

13. Discovering Cells Resolution The images in colorful photographs actually consist of only a few ink colors in the form of dots. This circle has been enlarged to show a tiny section of a picture of a bird's wing.