Table of Contents

1. Table of Contents • Discovering Cells • Looking Inside Cells • Chemical Compounds in Cells • The Cell in Its Environment

2. What is a Cell? • *A cell is the basic • unit of life. • *All life activities • take place inside • cells.

3. Discovery of Cells • *Robert Hooke—first man to see cells (1663) • -looked at thin slices of cork • -saw empty boxes and called them cells • -never realized that cells are living things

4. *Anton van Leeuwwenhoek • -father of microbiology • (1600’s) • -improved and developed • many types of microscopes • -discovered microscopic, one • celled organisms and called • them “animalcules”, • meaning “little animals”.

5. *Matthias Schleiden (1838) • -stated all plants are • made of cells • *Theodor Schwann (1839) • -stated all animals are • made of cells

6. *Rudolph Virchow (1855) • -stated all cells come • from other cells. • *The work of these men • led to the “Cell Theory”

7. - Discovering Cells • The cell theory states: • 1. All living things are • made of cells. • 2. Cells are the basic units of • structure and function in • living things. • 3. All cells come from other • cells.

8. - Discovering Cells Sequencing • Construct a flowchart showing how the work of Hooke, Leeuwenhoek, Schleiden, Schwann, and Virchow contributed to scientific understanding of cells. Discovering Cells Hooke sees cells in cork. Leeuwenhoek sees many one-celled organisms. Schleiden concludes that all plants are made of cells. Schwann concludes that all animals (and all living things) are made of cells. Virchow proposes that new cells form only from cells that already exist.

9. - Discovering Cells Links on Cell Theory • Click the SciLinks button for links on the cell theory.

10. End of Section:Discovering Cells

11. Eukaryotic vs. Prokaryotic • *All cells are either eukaryotic or prokaryotic. • -Eukaryotic cells —complex cells with a nucleus. All animal and plant cells are eukaryotic. • -Prokaryotic cells—simple cells without a nucleus. All bacteria and cyanobacteria (blue-green bacteria) are prokaryotic.

12. Structure of Animal CellsAnimal cells are typical eukaryotic cells. Most contain the following structures: • *Cell Membrane • -Surrounds the cell • -Has pores • -Controls what gets • in and out

13. - Looking Inside Cells • *Nucleus—control center of cell • -directs all of the cell’s activities Chromatin Pores Nucleolus Nuclear Envelope

14. *Cytoplasm—gel-like material inside the cell. • *Organelles—many tiny structures inside the cell. Each has its own job to do. • -Organelles include:

15. - Looking Inside Cells • Mitochondria—“powerhouses” of the cell because they convert energy in food molecules to energy the cell can use to carry out its functions.

16. - Looking Inside Cells • 2.Endoplasmic reticulum —folded tube • like membranes that move materials • throughout the cell. • 3.Ribosomes—small protein factories • found on the “er” or in the cytoplasm Ribosomes Endoplasmic reticulum

17. - Looking Inside Cells • 4.Golgi bodies —packaging centers • that wrap up and package proteins • and send them to other parts of the • cell or out of the cell. Golgi Body

18. 5.Lysosomes—garbage • collectors that contain • enzymes used to break down • large molecules and old cell • parts.

19. 6.Vacuoles—sacs that store water, dissolved material or waste products. They are larger in plant cells than in animal cells.

20. Structure of Plant Cells • *Plant cells contain all the same structures and organelles as animal cells plus a few more. Plant cells can do everything that animal cells can do plus make food.

21. -Cell wall—a ridged structure outside the cell membrane made of cellulose. It supports and protects the plant cell. • -Chloroplasts—tiny disks that contain chlorophyll. Photosynthesis takes place here. • -Larger Vacuoles—to store water

22. - Looking Inside Cells Plant and Animal Cells

23. Cell Variety • *Cells differ in size, shape, and • function. They will not all look like the • diagrams.

24. *Examples: • -Nerve cell—0ne meter long with many extensions: carries impulses to the brain. • -Red Blood Cell—microscopic, round and flexible: carries oxygen throughout the body.

25. Structure of Bacteria Cells • *Bacteria cells have no nucleus and no membrane-bound organelles. • -They are prokaryotic. • -Their parts include: • Capsule • Cell wall • Cell membrane • Cytoplasm • DNA floating in cytoplasm • Ribosomes Some have flagella

26. Diagram of a Bacteria Cell Cytoplasm DNA Capsule Cell wall Cell Membrane Ribosomes Flagella

27. - Looking Inside Cells Plant and Animal Cells Activity • Click the Active Art button to open a browser window and access Active Art about plant and animal cells.

28. - Looking Inside Cells Previewing Visuals • Before you read, preview Figure 12. Then write two questions you have about the illustrations in a graphic organizer like the one below. As you read, answer your questions. Plant and Animal Cells Q. How are animal cells different from plant cells? A. Plants cells have a cell wall and chloroplasts, which animal cells to not have. Q. What do mitochondria do? A. Mitochondria convert energy in food molecules to energy the cell can use.

29. - Looking Inside Cells The Cytoplasm and Organelles • Click the Video button to watch a movie about cytoplasm and organelles.

30. - Looking Inside Cells Specialized Cells • Click the Video button to watch a movie about specialized cells.

31. End of Section:Looking Inside Cells

32. What are Cells Made Of? • *Cell Chemistry begins with atoms: • -Atom—basic units of matter • -Elements—any substance that • cannot be broken down into • simpler substances (made of • only one type of atom)

33. -All known elements are listed on • the Periodic Table of the Elements

34. -The elements found in living cells • include mostly carbon, hydrogen, • nitrogen, oxygen, phosphorus • and sulfur: (CHNOPS)

35. Molecules and Compounds • *Atomscombine to formmolecules. • -Molecules—two or more atoms • bonded together (different or • same) Ex: H2O O2 NaCl • -Special molecules made of different • elements only are called • compounds Ex: H2O CO2

36. - Chemical Compounds in Cells • Carbon dioxide, which is found in gas bubbles, is a chemical compound. So is water.

37. -When just the right molecules and • compounds get together in just • the right way, cells are formed. • -Compounds in living organisms • are classified as either organic or • inorganic.

38. *Organic compounds contain the • elements; carbon and hydrogen. • *They make up foods and cell membranes. • *Four basic groups:

39. Carbohydrates—make up 1% of a cell; contain carbon, hydrogen, and oxygen; used for energy; examples are sugars and starches; most important carbohydrate for living things is glucose.

40. 2. Lipids—make up 10% of a cell; • contain carbon, hydrogen and • oxygen; store and release • energy; found in cell membranes; • examples are fats, oils and waxes.

41. 3. Proteins—make up 15% of a cell; • made of amino acids that contain • carbon, hydrogen, oxygen and • nitrogen; used to build cell parts • and for growth and repair of cell; • examples are enzymes.

42. 4. Nucleic Acids—make up 4% of a • cell; contain carbon, hydrogen, • oxygen, nitrogen, and phosphorus; • carry genetic information; found • in chromosomes, mitochondria, • chloroplasts, and nucleus; • examples are DNA and RNA

43. - Chemical Compounds in Cells Compounds in Bacteria and Mammals • All cells contain carbohydrates, lipids, proteins, and nucleic acids, as well as water and other inorganic compounds. But do all cells contain the same percentages of these compounds? The graph compares the percentage of some compounds found in a bacterial cell and a cell from a mammal.

44. Red bars represent percentages of compounds in bacterial cells; blue bars represent percentages of compounds in mammalian cells. Reading Graphs: What do the red bars represent? What do the blue bars represent? - Chemical Compounds in Cells Compounds in Bacteria and Mammals

45. About 70%; the percentages are the same. Interpreting Data: What percentage of a mammalian cell is made up of water? How does this compare to the percentage of water in a bacterial cell? - Chemical Compounds in Cells Compounds in Bacteria and Mammals

46. Proteins Interpreting Data: Which kind of compound–proteins or nucleic acids–makes up the larger percentage of a mammalian cell? - Chemical Compounds in Cells Compounds in Bacteria and Mammals

47. They are similar, though mammalian cells have a lower percentage of nucleic acids, and bacterial cells have a lower percentage of lipids and fewer proteins. Drawing Conclusions: In general, how do a bacterial cell and mammalian cell compare in their chemical composition? - Chemical Compounds in Cells Compounds in Bacteria and Mammals

48. - Chemical Compounds in Cells • *Most inorganic compounds • are made from elements • other than carbon. • Example: Water • -water makes up two-thirds • of your body • -70% of a cell’s cytoplasm • is water • -many substances must • be dissolved in water in • order to be used by cells.

49. - Chemical Compounds in Cells Comparing and Contrasting • As you read, compare and contrast carbohydrates, proteins, and lipids in a table like the one below. Type of Compound Elements Functions Store and provide energy and make up cellular parts Carbon, hydrogen, oxygen Carbohydrate Make up much of the structure of cells and speed up chemical reactions Carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur Protein Carbon, hydrogen, oxygen Lipid Store energy

50. - Chemical Compounds in Cells Links on Proteins • Click the SciLinks button for links on proteins.