1. Unit 4: Cell Structure and Function

2. The Discovery of Cells
In the 1660’s scientist Robert Hooke was also studying small objects using magnifying lenses
He was the first to coin the term “cell” as the basic unit of life
Developed a compound microscope: a microscope with a series of lenses to magnify an object in steps.

3. The Discovery of Cells
In the 1660’s scientist Anton Van Leeuwenhoek was the first to observe living cells under a simple microscope.
Considered the “Father of microbiology” because he was the first to magnify and study bacteria

4. The Electron Microscope
The newest development in microscopy first used in (There have been several upgrades over the years)
Capable of magnifying up to 500,000x the size of an object.
Allows us to see structures inside a cell!

5. Electron Microscope Images
Pollen
Dust Mite
Bacteriophage Virus
Common mouth bacteria
Bird Flu

6. Scientists Contributing to the Cell Theory
Mattias Schleiden (1838)
discovers that plants are made of cells
Theodor Schwann (1839)
discovers that animals are made of cells
Rudolf Virchow (1855)
stated that cells come only from other cells

7. The Cell Theory
Basic theory of “requirements to be a cell” developed by Schleiden, Schwann and Virchow
Rules:
All organisms are made of one or more cells
The cell is the basic unit of organization
All cells come from pre-existing cells

8. Cell Types 2 major cell types: Prokaryotes Simple
No membrane-bound organelles
No nucleus
Found only in unicellular forms

9. Cell Types Eukaryotes Complex Have membrane-bound organelles
Have a nucleus
Found in both uni- and multicellular forms

10. Cell Types
ALL cells have:
Cell membrane
Cytoplasm
DNA
Ribosomes

11. Prokaryote vs. Eukaryote

12. Eukaryotic Cells Examples: plant and animal cells
Internal structures act as specialized organs with specific functions
Divided into cytoplasm and nucleus
Cytoplasm: the area of
the cell outside of the
nucleus

13. Eukaryotic Cells 2 main types:
Animal cells: have a flexible cell membrane
Plant cells: have a rigid cell wall in addition to the cell membrane

14. Plant vs. Animal Cells
Animal Cell
Plant Cell

15. Eukaryotic Cell Parts The Nucleus
contains almost all of the cell’s DNA
called the “control center” of the cell
surrounded by a nuclear envelope(similar to the cell membrane)

16. Eukaryotic Cell Parts The Nucleus (cont.) nuclear envelope has
2 membranes
pores allow movement
into and out of the cell
contains chromatin
(protein wrapped with DNA)
- contains the nucleolus (little nucleus) where ribosomes are made

17. Eukaryotic Cell Parts Ribosomes Acts as a protein producing machine
Found in the cytoplasm
Look like small dots in the cell
Ribosomes

18. Eukaryotic Cell Parts Endoplasmic Reticulum (ER)
Internal membrane where
lipids, proteins and other
materials are assembled and
exported out of the cell
2 types:
Rough ER- with ribosomes
Smooth ER- without ribosomes

19. Eukaryotic Cell Parts Golgi Apparatus
sorts and packages proteins from the ER
stores or sends packages out of the cell

20. Eukaryotic Cell Parts Lysosomes
small cell structures that break down lipids, carbohydrates and proteins in the cell
filled with enzymes
act as the clean up centers
in the cell

21. Eukaryotic Cell Parts Vacuoles
storage centers in the cell (water, salt, proteins, etc.)
Found in plants and some animal cells
Vacuole

22. Eukaryotic Cell Parts Mitochondria
where food molecules (glucose) are broken down and turned into energy
Powerhouses of the cell
Inner folds called cristae

23. Eukaryotic Cell Parts Chloroplasts
Only found in plant cells and a few unicellular organisms
Turn light energy into food molecules (glucose) through photosynthesis
Chloroplasts

24. Eukaryotic Cell Parts Microtubules: Thin, hollow cylinders of protein.
Cytoskeleton
A network of thin, fibrous elements that provide support for organelles and helps the cell maintain its shape.
Microtubules: Thin, hollow cylinders of protein.
Microfilaments: Thin, solid protein fibers.
- Both work together to provide support.

25. Eukaryotic Cell Parts
Cytoskeleton

26. Structures for Locomotion
Cilia: short, numerous, hair- like projections from the plasma membrane of the cell
Often beat together to produce motion
Flagella: long projections that move in a whip-like motion to produce movement
Used by unicellular organisms

27. Cell Boundaries All cells are surrounded by a cell membrane
Thin flexible barrier
Lets things in and out of the cell to promote homeostasis (selectively permeable)

28. Cell Boundaries
Composed of a phospholipid bilayer (double layered sheet of lipids)
Form the main structure of the plasma membrane
Also contains proteins

29. Cell Boundaries
Cell Walls are rigid cellulose layers surrounding the plasma membrane of plant, fungi, and most bacterial cells
Provide support and protection

30. Cell Diversity Unicellular Organisms
Single celled organism with all the ability to carry out all necessary functions for life
Examples: Yeast, Algae, Bacteria

31. Cell Diversity Multicellular Organisms
Made up of many cells working together
Cells must communicate and cooperate

32. Cell Diversity
Cell Organization
Cells Tissues Organs Organ System

33. Cell Diversity Cell specialization occurs in multicellular organisms
Cells develop different ways to perform different tasks
Examples: red blood cells, nerve cells

34. Cell Parts Review

35. Cell Parts Review