The History and Organelles of Cells

1. The Historyand Organelles of Cells

2. 7.1 Section Objectives – page 171 Section Objectives: • Relate advances in microscope technology to discoveries about cells and cell structure. • Compare the operation of a microscope with that of an electron microscope. • Identify the main ideas of the cell theory.

3. Section 7.1 Summary – pages 171-174 The History of the Cell Theory • Before microscopes were invented, people believed that diseases were caused by curses and supernatural spirits. • As scientists began using microscopes, they quickly realized they were entering a new world–one of microorganisms. • Microscopes enabled scientists to view and study cells, the basic units of living organisms.

4. Section 7.1 Summary – pages 171-174 Development of Light Microscopes • The inventor of the microscope was Anton van Leeuwenhoek in the 1600’s.It was based on Galileo’s telescope • He looked at organisms living in water. • The microscope van Leeuwenhoek used is considered a simple light microscope because it contained one lens and used natural light to view objects.

5. Section 7.1 Summary – pages 171-174 Development of Light Microscopes Compound light microscopes use a series of lenses to magnify objects in steps. These microscopes can magnify objects up to 1 500 times.

6. Section 7.1 Summary – pages 171-174 The Cell Theory • Robert Hooke was an English scientist who lived at the same time as van Leeuwenhock. • Hooke used a compound light microscope to study cork, the dead cells of oak bark. He saw many small boxes or chambers that he called “CELLS”.

7. Click the button below to watchthe video: A Brief History of Cells

8. Section 7.1 Summary – pages 171-174 The cell theoryis made up of three main ideas: All organisms are composed of one or more cells. The cell is the basic unit of organization of organisms. All cells come from preexisting cells.

9. Section 7.1 Summary – pages 171-174 Development of Electron Microscopes • The electron microscope was invented in the 1940s. • This microscope uses a beam of electrons to magnify structures up to 500 000 times their actual size.

10. Section 7.1 Summary – pages 171-174 Development of Electron Microscopes There are two basic types of electron microscopes. The scanning electron microscope scans the surface of cells to learn their three dimensional shape. • The transmission electron microscope allows scientists to study the structures contained within a cell.

11. Section 7.1 Summary – pages 171-174 Two Basic Cell Types Cells that do not contain internal membrane-bound structures are called prokaryotic cells. Click here • The cells of most unicellular organisms such as bacteria do not have membrane bound structures and are therefore called prokaryotes.

12. 7.1 Section 7.1 Summary – pages 171-174 Two Basic Cell Types Cells containing membrane-bound structures are called eukaryotic cells. Click here • Most of the multi-cellular plants and animals we know are made up of cells containing membrane-bound structures and are therefore called eukaryotes.

13. Section 7.1 Summary – pages 171-174 Two Basic Cell Types The membrane-bound structures within eukaryotic cells are called organelles. • Each organelle has a specific function that contributes to cell survival.

14. Section 7.1 Summary – pages 171-174 Two Basic Cell Types • Separation of organelles into distinct compartments benefits the eukaryotic cells. The nucleus is the central membrane-bound organelle that manages cellular functions.

15. Summary Section 2 – pages 175-178 Basic Cell Structure

16. Section 3 Objectives page 179 Section Objectives • Understand the structure and function of the parts of a typical eukaryotic cell. • Explain the advantages of highly folded membranes. • Compare and contrast the structures of plant and animal cells.

17. Section 3 Summary – page 179-187 Cellular Boundaries The plasma or cell membrane acts as a selectively permeable membrane to control what goes in and out of the cell.

18. Section 3 Summary – page 179-187 The cell wall The cell wall is a fairly rigid structure located outside the plasma membrane that provides additional support and protection for plant cells.

19. Section 3 Summary – page 179-187 Nucleus and cell control Nucleolus Chromatin Nuclear Envelope

20. Section 3 Summary – page 179-187 Assembly, Transport, and Storage The endoplasmic reticulum (ER) is an organelle that is suspended in the cytoplasm and is the site of cellular chemical reactions.

21. Section 3 Summary – page 179-187 Assembly, Transport, and Storage Endoplasmic Reticulum (ER) Ribosomes

22. Section 3 Summary – page 179-187 Assembly, Transport, and Storage Golgi Apparatus

23. Section 3 Summary – page 179-187 Vacuoles and storage Vacuolesare membrane-bound spaces used for temporary storage of materials. Notice the difference between vacuoles in plant and animal cells. Plant Cell Vacuole Animal Cell

24. Section 3 Summary – page 179-187 Lysosomes and recycling Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

25. Section 3 Summary – page 179-187 Energy Transformers: Chloroplasts and energy Chloroplastsare cell organelles that capture light energy and produce food to store for a later time.

26. Section 3 Summary – page 179-187 Chloroplasts and energy The chloroplasts belongs to a group of plant organelles called plastids, which are used for storage. Chloroplasts contain green pigment called chlorophyll. Chlorophyll traps light energy and gives leaves and stems their green color.

27. Section 3 Summary – page 179-187 Mitochondria and energy Mitochondria are membrane-bound organelles in plant and animal cells that transform energy for the cell.

28. Section 3 Summary – page 179-187 Mitochondria and energy A mitochondria, like the endoplasmic reticulum, has a highly folded inner membrane. Energy storing molecules are produced on inner folds.

29. Section 3 Summary – page 179-187 Structures for Support and Locomotion Cells have a support structure called the cytoskeleton within the cytoplasm. The cytoskeleton is composed of microtubules and microfilaments. Microtubules are thin, hollow cylinders made of protein and microfilamentsare thin solid protein fibers.

30. Section 3 Summary – page 179-187 Cilia and flagella Some cell surfaces have cilia and flagella, which are structures that aid in locomotion or feeding. Cilia and flagella can be distinguished by their structure and by the nature of their action.

31. Section 3 Summary – page 179-187 Cilia and flagella Cilia Cilia are short, numerous, hair-like projections that move in a wavelike motion.

32. Section 3 Summary – page 179-187 Cilia and flagella Flagellaare long projections that move in a whip-like motion. Flagella and cilia are the major means of locomotion in unicellular organisms. Flagella

33. Check for Understanding Answer the following questions on your paper

34. Section 3 Check Question 1 What is the primary function of the cell wall? A. act as selectively permeable membrane B. provide support C. control activity of organelles D. acquire nutrients from environment

35. Section 3 Check Question 2 Describe the control center of a prokaryotic cell. Plasma membrane Ribosomes DNA Cell wall

36. Question 3 Section 1 Check How did the invention of the microscope impact society’s understanding of disease? A. Scientists were able to view microorganisms that were previously unknown. B. Microscopes were invented after the development of the cell theory. C. It was once believed that viruses, not bacteria, caused diseases. D. Scientists could view membrane-bound organelles of prokaryotes.

37. Section 1 Check Question 4 Which of the following uses a beam of light and a series of lenses to magnify objects in steps? A. compound light microscope B. scanning electron microscope C. transmission electron microscope D. simple light microscope

38. Question 5 Section 1 Check What makes this cell eukaryotic? A. Because it has a cell wall. B. Because it contains DNA. Nucleus C. Because it has membrane-bound organelles. Nucleolus Chromosomes Organelles Plasma membrane D. Because it does not have DNA.

39. Section 3 Check Question 6 Which of the following structures is the site of protein synthesis? A. Golgi apparatus B. Ribosome C. Vacuole D. Lysosome

40. Question 7 Section 3 Check What is the advantage of having numerous folds in the ER? A. It enables the ER to lie snugly against the nucleolus. B. It can create more vesicles in a smaller space. C. It can capture more light energy with more folds. D. A large amount of work can be done in a small space.

41. Section 3 Check Question 8 What could you predict about a plant cell that contains fewer chloroplasts than other plant cells? A. It contains less chlorophyll. B. It contains a greater number of plastids. C. It will have an increased rate of light energy capture. D. It will appear darker green in color.

42. Question 9 Section 3 Check A mutation results in the inner membranes of a liver cell’s mitochondria being smooth, rather than folded. Which of the following would you expect? A. more efficient storage of cellular energy B. it can create more vesicles in a smaller space C. decreased energy available to the cell D. fewer ribosomes available for protein synthesis

43. Chapter Assessment Question 10 Which of the following is a main idea of the cell theory? A. All organisms are composed of one cell. B. The organelle is the basic unit structure and organization of organisms. C. All cells come from two parent cells. D. All cells come from preexisting cells.

44. Chapter Assessment Question 11 In what type of cell would you find chlorophyll? A. prokaryote B. animal C. plant D. fungus

45. A. B. C. D. Chapter Assessment Question 12 Which of these structures packs proteins into membrane-bound structures?

46. Chapter Assessment Question 13 Cell wall What is the difference between the cell wall and the plasma membrane? Inside cell Outside cell Plasma membrane

47. Chapter Assessment Question 14 Which of the following organelles is not bound by a membrane? A. ribosome B. Golgi apparatus C. vacuole D. lysosome

48. Chapter Assessment Question 15 In which of the following pairs are the terms related? A. cell wall – selective permeability B. prokaryote – mitochondria C. microfilaments – locomotion D. plastid – storage

49. Chapter Assessment Question 16 Which of the following structures is found in both plant and animal cells? A. chloroplast B. cell wall C. mitochondrion D. thylakoid membrane

50. Chapter Assessment Question 17 Compare the cytoskeleton of a cell to the skeleton of the human body.