1. Cellular Structure and Function
Chapter 7
Cellular Structure and Function

2. CELLS!

3. Chapter 7.1 Cell Discovery and Theory
Robert Hooke observes the structures of cork (oak bark) and calls the units cells.

4. History of Cell Theory
What did Anton Van Leeuwenhoek see through his microscope?
He was surprised to find what looked like tiny animals.
He named these animals “animalcules”.

5. How do you develop a theory?

6. Cell Theory All living organisms are composed of one or more cells.
Cells are the basic unit of structure and organization of all living organisms.
Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.

7. Microscopes
Review Figure 7.1 on page , Microscopes in Focus Why were there long periods between significant discoveries about cells? How Big?

8. Types of Microscopes Compound Light Microscopes Electron Microscopes
Transmission Electron Microscope
Scanning Electron Microscope
Scanning Tunneling Electron Microscope
Based on the names of these microscopes, how do you think each type magnifies objects?

9. Compound Light Microscope
Uses series of glass lenses and visible light to produce a magnified image
Specimens must be thin
Specimens can be alive or dead
Maximum magnification is 1000x

10. Compound Light Microscope

11. Calculating Total Magnification
Compound light microscopes use a series of lenses to magnify; each lens magnifies the image
For example, if eyepiece lens magnifies at 10x and the objective lens magnifies at 10x, the total magnification is 100x (10 X 10)
What would the total magnification be if the eyepiece magnified at 10x and the objective lens magnified at 4x?
Answer = 40 x = 10 X 4

12. Helpful Hints: Diaphragm Usage Course Adjustor v. Fine Adjustor
Location and purpose
Movement of stage
Lowest power to highest power!
DON’T USE COURSE ADJUSTOR IN HIGH POWER!

13. Compound Light Microscope
Microscope Part
Function
Ocular (eyepiece)
Nosepiece
High Power Objective Lens
Low Power Objective Lens
Stage and Stage Clips
Diaphragm
Fine Adjustment
Course Adjustment
Base/Arm

14. Compound Light Microscope
Microscope Part
Function
Ocular (eyepiece)
Used for viewing object; hold lens with 10x magnification
Nosepiece
Holds objective lens
High Power Objective Lens
Lenses with magnification of 10x, 40x, 100x, or more
Low Power Objective Lens
Lens with magnification of 4x
Stage and Stage Clips
Hold microscope slide in place
Diaphragm
Controls the light entering the field of view
Fine Adjustment
Brings object into sharp focus
Course Adjustment
Brings object into focus
Base/Arm
Support for the microscope

15. Electron Microscopes – Uses beams of electrons to magnify images
Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)
Scanning Tunneling Electron Microscope (STM)
Aim a beam of electrons at a thin slice of cells
Electrons are passed through a specimen to a screen
Thick parts of the specimen absorb more electrons than thin parts forming a black-and-white shaded image of specimen
Can magnify up to 500,000x
Specimen must be dead, sliced thin, and stained
Directs electrons over the surface of the specimen
produces a three dimensional image
Specimen must be nonliving
Brings a charged tip of a probe extremely close to the specimen so that the electrons “tunnel” through the small gap between
Creates a three-dimensional image
Can use live specimens

16. Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)
Scanning Tunneling Electron Microscope (STM)

17. Transmission Electron Microscope
Bacteriophages (viruses that infect bacteria)

18. Scanning Electron Microscope

19. Human atrial (heart) muscle

20. Scanning Electron Microscopy
Stainless Steel Screen

21. Scanning Electron Miscroscopy
Table Salt

22. Scanning Electron Miscroscopy
Insect on the leg of a daddy long-leg spider

23. Scanning Electron Miscroscopy
Eye of an Ant

24. Scanning Electron Miscroscopy
Spider

25. Scanning Tunneling Microscope
STM of DNA molecule

26. Quiz Tomorrow History of Cell Theory Cell Theory Types of Microscopes
Hooke and Van Leeuwenhoek
Cell Theory
Types of Microscopes
Electron Microscopes
Compound Light Microscopes
Parts
Functions
Calculating total magnification
(NOT Basic Cell Types)

27. Basic Cell Types What do all cells have in common?
Plasma Membrane (barrier controls what moves in and out of cell)
Genetic material

28. Basic Cell Types Prokaryotic Cells Eukaryotic Cells Smaller Larger
Contain no organelles
Contain membrane-bound organelles – specialized structures that carry out specific cell functions
No nucleus
Contain nucleus to hold genetic material
Bacteria
Protists, Fungi, Plants, and Animals

29. Prokaryotic Cells

30. Eukaryotic Cells

32. Chapter 7.2

33. Function of Plasma Membrane
Thin, flexible boundary between the cell and its environment
Maintains homeostasis by controlling what enters and exits the cell
Allows nutrients to enter
Allows waste and other products to leave

34. Selective Permeability
The plasma membrane allows some substances to pass through while keeping others out
Controls how, when, and how much of these substances enter and leave a cell

35. Structure of the Plasma Membrane
Most molecules in the membrane are lipids
Phospholipids containing
Glycerol
2 fatty acids
Phosphate group

36. Phospholipids

37. Structure of Plasma Membrane

38. Structure of the Membrane
“Phospholipid bilayer”
TWO layers of phospholipids
Interior is hydrophobic (water fearing)
Non-polar fatty acid tails
Exterior is hydrophilic (water loving), polar
Polar phosphate groups

39. Structure of the Plasma Membrane
Phospholipids are arranged in a bilayer.
hydrophilic (polar) heads are on the outside
hydrophobic (nonpolar) tails are on the inside
© Glencoe Biology 2007

40. Other Components of the Plasma Membrane
Proteins are imbedded in the membrane.
Transmit signals to the inside of the cell.
Anchor the membrane to the internal support structure of the cell.
Transport proteins act as tunnels for substances to enter and leave the cell.
Cholesterol prevents fatty acid tails from sticking together.
Carbohydrates attach to the proteins.
Identify the cell
Identify chemical signals in the cell’s environment.

41. The Fluid Mosaic Model “Fluid Mosaic Model”
Phospholipids move sideways
Other molecules float in the phospholipids like apples bobbing in a barrel of water
© Glencoe Biology 2007

42. Cell Structures and Organelles
Chapter 7.3
Cell Structures and Organelles

43. Cell Organelles Cell Part Function Cytoplasm
Semfluid material that surrounds the organelles and provides a place for chemical reactions to take place.
Cytoskeleton
A network of long, thin protein fibers that form a framework and support system for the cell; anchors all the organelles
Nucleus
Control center of the cell; contains the cell’s DNA; surrounded by nuclear membrane (envelope)
Ribosomes
Produces proteins
Nucleolus
Produces ribosomes
Endoplasmic reticulum
Folded membrane system that is the site for protein and lipid production
Smooth ER
Area with no ribosomes attached; place where many carbohydrates and lipids are produced
Rough ER
Ribosomes are attached and produce proteins

44. Cell Organelles Cell Part Function Golgi Apparatus
Flattened membranes that modified, sorts, and packages proteins
Vacuoles
Temporary storage for the cell; used to store food, enzymes, and other materials needed for the cell
Lysosomes
Structure containing enzymes used to digest waste
Centrioles
Used in cell reproduction
Mitochondria
Produce energy by breaking down sugars
Chloroplasts
Capture light energy and convert it to chemical energy (food); found in plant cells
Cell wall
Thick, rigid fibers that surround the plasma membrane and protects the cell
Cilia and Flagella
Used for cell movement in some eukaryotic cells

45. Chapter 7 Test History of Cell Theory Microscopes
Hooke
Leeuwenhoek
Cell theory
Microscopes
Light microscopes
Electron microscopes
Prokaryotic & eukaryotic cells
Plasma membrane
Selective permeability
Phospholipid bilayer
Cell Organelles Function