1. Cell Structure and Function
Chapter 7

2. Microscopes : windows to the world of the cell
Cells are the basic unit of life.
The invention and improvement of microscopes in the 17th century led to the discovery and early study of cells
Robert Hooke observed “cells” in a slice of cork

3. History of Cells 1800’s Schwann –Animal tissues are composed of cells
Schleiden – Plant materials are composed of cells
Virchow - All tissues from living organisms are composed of cells

4. The Cell Theory All living things are composed of cells
Cells are basic units of structure and function
All cells come from pre-existing cells

5. How Cells are Studied
Microscopy
Cell Fractionation

6. Microscopes An instrument used observe minute objects
Enlarges images of small objects

7. Types of Microscope Light: uses light and lenses to magnify image
Electron: uses magnets and electrons to magnify image

8. Parts of a Microscope
(Eyepiece)

9. Magnification To calculate:
Power of objective lens x Power of Eyepiece
Do these calculations:
Eyepiece = 10x
Objective = 10x; 40x; 100x

10. Electron Microscope Uses magnets and electrons to magnify images
Magnifies 1000x better than a light microscope
Specimen cannot be living

11. Types of Electron Microscopes
Transmission Electron Microscope: internal structures
Scanning Electron Microscope: surface structures

12. The Eukaryotic Animal Cell

13. The Eukaryotic Plant Cell

14. Major Type of Cells There are two basic types of cells
Prokaryotic & Eukaryotic
A major difference between prokaryotic and eukaryotic cells is the location of chromosomes.

15. Prokaryotic Cells Lacks a nucleus and most other organelles
DNA concentrated in nucleoid region
Bacteria and Archae
1-10 micrometers
Appear earliest in earth’s fossil record

16. Eukaryotic Cells Nucleus surrounded by its membrane
Internal organelles bounded by membranes
10 – 100 micrometers
Protists, Fungi, Plants, Animals

17. Cell Structure
Section 7.2

18. Cell Organization Cytoplasm Nucleus / Nuclear region
Cytoplasmic inclusions
Nucleus / Nuclear region
Cell Membrane/Wall

19. Cytoplasm Fluid portion of the cell
All cellular organelles are suspended in it
Organelles specialized structures that perform various functions

20. Nucleus & it’s Contents

21. Nucleus & it’s Contents
Chromosomes carry the cell’s genetic information
Always remain in the nucleus
RNA carries this message from the nucleus to the ribosomes moves through the nuclear pores

22. Storage, Cleanup and Support
Vacuolesstore water, salts, carbohydrates & proteins
Lysosomes filled with enzymes breakdown of macromolecules
Cytoskeleton  maintains shape & helps in movement

23. Microfilaments Threadlike structures made of actin
Forms an extensive network
Helps cells move

24. Microtubule Hollow structures made of  tubulin
Centriole
Hollow structures made of  tubulin
Maintain shape in many cells
Centrioles in animals cells  made of tubulin help organize cell division not present in plant cells
Project from the surface cilia & flagella movement
Cilia

25. Building Protein
Ribosomes
Endoplasmic Reticulum
Golgi Apparatus

26. Ribosome

27. Endoplasmic Reticulum (rough & smooth)

28. Protein Synthesis

29. Golgi Body

31. Capture and Release Energy
The cellular machinery constantly needs energy to function.
Supplied by two organelles the Chloroplasts & Mitochondria

32. Chloroplasts Sunlight to Chemical energy

33. Mitochondria
Convert chemical energy in food to a form that the cell can useATP
All mitochondria come from the cytoplasm of the egg cell inherited from the mother

34. Endosymbiosis Chloroplasts and mitochondria are similar to prokaryotes
Lynn Margulis in 1960 evidence that chloroplasts and Mitochondria evolved as endosymbionts
Both have DNA, RNA and Ribosomes that prokaryotic
They replicate their own DNA
Divide by binary fission

35. RNA World
Miller & Urey 1953, organic molecules necessary for life have arisen from simpler compounds
Origin of life RNA evolved before DNA

36. Cellular Boundaries Cell Walls Cell Membranes Provides support
Confers shape
Protects the cell
Present in plants and prokaryotes
Cell Membranes
Regulates what enters and leaves the cell
Selectively Permiable

37. Cell/Plasma Membrane Phospholipid Bilayer
Boundary that separates the interior of a living cell from it’s surroundings and regulates the traffic of chemicals into and out of the cell
Phospholipid Bilayer
Protein “icebergs” float in a “sea” of phospholipids

38. Phospholipid Molecule
Composed of proteins and a type of lipid called phosopholipid (glycerol+2 fatty acids)

39. Protein “icebergs” in a “sea” of phospholipids

40. Plasma Membrane

41. Cell Transport
Section 7.3

42. Function of Cell Membranes
Materials need to move in and out of the cell
Function like gatekeepers, letting some molecules through, but not others  “Selectively Permeable”

43. Passive Transport Active Transport Types of Transport Diffusion
Facilitated Transport
Active Transport

44. Diffusion
The spread of molecules from areas of high concentration, to areas of low concentration.
Equilibrium when the molecules are even throughout a space
Concentration Gradient  difference between concentrations in a space.

45. Passive Transport Diffusion Some substances are allowed to move freely
Facilitated diffusion transport proteins

46. Osmosis The diffusion of water (across a membrane)
Water will move in the direction where there is a high concentration of solute and low water concentration

47. Osmosis
Dissolved molecules ( ions, organic molecules, etc) are called solutes
Most solutes cannot cross membranes
As solute conc increases “free” H2O decreases
Hypertonic high [solute]
Hypotonic  low [solute]

48. Isotonic- means the same

49. Hypotonic- less solute

50. Hypertonic- high solute

52. Water Balance in Animal Cells
Net water flow into the cell which can burst (Hemolysis)
Water flow equal in both directions
Net water flow out of cell which shrinks
(Crenation)

53. Water Balance in Plant Cells
Turgid Flaccid

54. Plasmolysis
Shrinking of cytoplasm in both plant and animal cells

56. Active Transport
Cell expends energy to move molecules or ions across the membrane
A specific transport protein pumps solute across a membrane
The chemical energy is supplied by the mitochondria
Example Na+(Sodium) K+(Potassium) pump.

57. Active Transport

58. Transport of Large Molecules
Large molecules have to be packaged to be transported in and out of the cell
Vesicles (membranes sacs) are formed to move the substances
Exocytosis
Endocytosis

59. Exocytosis & Ednocytosis

60. More Exo & Endo