1. Chapter7
Looking at cells

2. Where does cork come from?
The bark of an oak tree that grows in Spain and Portugal
The bark is dead
All that is left are the cell walls enclosing air

3. Microscopes reveal cell structure
Robert Hooke , an English scientist, invented the microscope in the 1600’s to view cork
He named the “little boxes” he saw, “cells”

4. Anton van Leeuwenhoek 10 years after Hooke’s findings
Used a microscope to view pond water
He named the single-celled organisms he discovered “animalcules”

5. The Cell Theory All living things are made of cells
Cells are the basic units of structure and function in organisms
All cells arise from existing cells

6. Measuring the size of cell structures
Measurements are in metric units
International System of Measurements (SI)
Based on powers of 10
Micrometers are one-millionth of a meter ( the size of a bacterial cell)

7. Cells must be small Small is good! Big is bad!
Lower surface area to volume ratio = inability to move substances across the membrane in large enough numbers
Higher surface area to volume ratio = greater ability to exchange substances
Small is good!
Big is bad!

8. Common features of all cells
Cell membrane
Cytoplasm
Cytoskeleton
Ribosomes
Genetic material

9. Prokaryotes do not contain internal compartments
No nucleus
Smaller
Ex: bacteria

10. Characteristics of bacteria
Prokaryotes
All have a cell wall surrounding the cell membrane
Some have flagella for movement
DNA is circular instead of linear
Some have a capsule for clinging

11. Eukaryotic cells are organized
Have a nucleus
Have other membrane enclosed organelles
Some have flagella or cilia for movement

12. Eukaryotes Larger More complex Many are highly specialized
Plants, animals, fungi, and many protists

13. Cell Organization Two divisions: Nucleus- eukaryotes only
Cytoplasm- fluid portion of the cell outside the nucleus
Eukaryotes and prokaryotes

14. Organelles
Specialized structures
“Little organs”

15. Nucleus Controls cell functions
Surrounded by a double membrane with nuclear pores
Contains DNA wound around proteins
Wind up into chromosomes before division takes place

16. Nucleus Nucleolus- where ribosomes are made
Nuclear pores- allow materials in and out

17. Vacuoles
Large, saclike, membrane-enclosed structures that store materials such as water, salts, proteins, and carbohydrates

18. Vacuoles
Plants- large central vacuole, helps keep leaves and flowers rigid
Found in some unicellular organisms and animals
Contractile vacuole in paramecium

19. Vesicles
In almost all eukaryotic cells
Used for storage and movement

20. Lysosomes Small organelle filled with enzymes
Digest old organelles, cellular “junk,” lipids, proteins, and carbohydrates
Type of vesicle, found in animal and some plant cells

21. Ribosomes Made of RNA and protein Produce proteins
Found in the cytoplasm (free) and rough ER (attached)

22. Endoplasmic Reticulum (ER)
A system of internal membranes that moves proteins and other substances through the cell
Rough ER- has ribosomes on the surface that create exported proteins
Smooth ER- no ribosomes, makes lipids for the cell membrane
Detoxifies drugs

23. Golgi Apparatus Stack of flattened sacs
Modifies, sorts, and packages proteins made from the rough ER
Sent into or out of the cell

24. Sources of Energy Mitochondria- animal and plant cells
Chloroplasts- plant cells

25. Chloroplasts
Converts sunlight into food energy in a process called photosynthesis
Double membrane
Contains a green pigment called chlorophyll

26. Mitochondria In eukaryotic cells Power plant of the cells
Converts food energy into smaller units the cell can more easily use
Double membrane

27. Mitochondria Inherited only from your mother
A way to trace the maternal lines of animals

28. Endosymbiotic Theory
Chloroplasts and mitochondria have their own DNA and double membranes
Theory states:
These may have been independent organisms at one time
Create their own energy
May have been beneficial once absorbed and found to be beneficial

29. Unique features of plant cells
Cell wall -surrounds the cell membrane, supports and protects the cell
Chloroplasts- green structures that absorb sunlight and produce glucose
Central vacuole- stores water and other substances, when full makes a cell rigid

30. Cytoskeleton Network of protein filaments
Gives cells their shape and internal organization
Helps to transport materials inside the cell
Protein filaments
Microtubules
Microfilaments

31. Microfilaments Threadlike structures made of protein called actin
Make up a tough flexible framework that helps support the cell
Help cells move
Amoebas- assemble and disassemble to help them move

32. Microtubules Hollow structures Made of protein tubulin
Maintains cell shape
Centrioles
Makes spindle during mitosis to separate chromosomes

33. Microtubules Make up cilia and flagella Arranged in a 9+2 pattern
Used for swimming
Arranged in a 9+2 pattern
Small bridges between aid in movement

34. Cell Boundries
Cell wall
Cell membrane

35. Cell Wall Prokaryotes, plants, algae, fungi Outside the cell membrane
Animal cells do not
Outside the cell membrane
Strong supporting layer
Porous- allows water, carbon dioxide and oxygen to pass through

36. Cell Membrane Protects and supports cell
Regulates what enters and leaves
Phospholipid bilayer- to layers of lipids