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

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
The Cell Theory TimelinePg. 370
Year of Discovery
Scientist
Contribution
1665
Robert Hooke
discovered the cellular composition of cork and introduced the word cell to science
1674
Anton van Leeuwenhoek
improved magnification of microscopes by polishing lenses
1676
"animacules" (meaning little animals) were discovered
1683
discovered bacteria from a sample of saliva from his mouth
1838
Matthias Schleiden
discovered the plants were made up of cells
1839
Theodor Schwann
discovered that animals were made up of cells
1855
Rudolph Virchow
stated that all living things come from other living things
“ ALL CELLS COME FROM CELLS”

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 Electron Light microscope

10. Pg. 373
r both P
A compound 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
Slide
Stage
Lens
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.