Cells “The basic unit of life”

1. Cells“The basic unit of life”

2. Levels of Organization

3. Levels of Organization • Cell: specialized to obtain food & oxygen, and carry out specific functions • Tissue: a group of similar cells that perform a particular function • Four types of tissue in living things: epithelial (skin), muscle, nerve, & connective (bone, blood, cartilage & lymph) • Organs: many tissues working together to perform a function • Organ systems: group of organs working together to perform a specific task

4. Section 7- 4 Levels of Organization Muscle cell Smooth muscle tissue Stomach Digestive system Go to Section:

5. Cells • Cells = basic unit of life • Can be many different sizes (always very small) • Discovered by Anton Van Leeuwenhoek (1600s)

6. The Cell Theory • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.

7. Exceptions to the Cell Theory • Within the cell there are structures that can reproduce themselves • Not all parts of living things are composed of “normal” cells. • Ex. Skeletal muscle contains many nuclei within one cell. • Viruses are often thought of as living cells, but they can’t reproduce on their own and they do not contain any organelles.

8. Unicellular vs. Multicellular • Unicellular (one-celled) organism • Multicellular (many-celled) organisms

9. Multicellular Organisms • The cells in a multicellular organism are interdependent (can not live on their own) (they depend on each other like players on a team) • Cell specialization = each type of specialized cell performs separate roles or functions within the organism, has a different number of each organelle depending on function

10. Plant vs. Animal Cell

11. Unicellular organisms Paramecium Euglena

12. Prokaryotes vs. Eukaryotes Cells ProkaryotesEukaryotes No nucleus Have a Nucleus Smaller and simpler Larger and complex Have cell membranes Have organelles Have cytoplasm Single or Multi- celled Ex. Bacteria Ex. Plants, animals & fungi

13. Cell membrane Cytoplasm Cell membrane Cytoplasm DRAW these Prokaryotic and Eukaryotic Cells Section 7-1 Prokaryotic Cell Nucleus Eukaryotic Cell Organelles Go to Section:

14. Cell Functions

15. Structures • Cells have particular structures that perform specific jobs. These structures perform the actual work of the cell. Just as systems are coordinated and work together, cell parts must also be coordinated and work together. • These structures are called organelles.

16. Cell Organelles • What is an organelle? • They are specialized microscopic structures within cells • They are contained within the cytoplasm • exception- nucleolus is contained within the nucleus • They have characteristic structures and functions.

17. Section 7-2 Cell Structures • A. Cell Wall • B. Cell Membrane • C. Nucleus 1. Chromatin and Chromosomes 2. Nucleolus 3. Nuclear Envelope Go to Section:

18. Section 7-2 Cell Structures • D. Cytoskeleton • E. Organelles in the Cytoplasm 1. Ribosomes 2. Endoplasmic Reticulum 3. Golgi Apparatus 4. Lysosomes 5. Vacuoles 6. Chloroplasts 7. Mitochondria Go to Section:

19. STRUCTURE OF ORGANELLES • TWO TYPES: • MEMBRANE BOUND ORGANELLES • CELL PARTS NOT SURROUNDED BY A MEMBRANE

20. Cell parts not bound by a membrane • 1. Cell wall 2. Cell membrane 3. Cytoplasm 4. Cytoskeleton

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22. Cell Wall • Strong layer on the outside of plant and many prokaryotic cells (not in animal cells) • Support and protect the cell • Allow water, oxygen, carbon dioxide and other substances to pass through • Made from fibers of carbohydrates and proteins, for example, cellulose

23. Cell Membrane • Thin, flexible barrier around cells (inside cell wall on plant cells) • Helps maintain the chemical balance between materials inside and outside the cell by removing wastes from the cell • Selectively permeable = allows only certain material in or out of the cell • Made up of a lipid bilayer with some proteins scattered throughout

24. Cytoplasm • The gel-like material inside the cell (not including the nucleus and organelles) • Transports materials throughout the cell • Holds organelles • Constantly moving or flowing

25. Cytoskeleton • Network of protein filaments that helps keep the cell’s shape • Involved in many forms of cell movement • Microtubules – hollow tubes of protein that serve as “tracks” for moving organelles, form centrioles in animal cells to help separate chromosomes during cell division, form cilia or flagella to move • Microfilaments – long, thinner fibers functioning in support and movement within the cell

26. Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Michondrion Cytoskeleton Section 7-2 Go to Section:

27. Membrane Bound Organelles • Specialized structures that perform cellular functions 1. Nucleus 2. Ribosomes 3. Endoplasmic Reticulum 4. Golgi Apparatus 5. Lysosomes 6. Vacuoles 7. Chloroplasts 8. Mitochondria

28. Nucleus • Large structure that contains the cell’s genetic material or hereditary information (DNA) & instructions for making proteins (RNA) • Controls the cell’s activities • Chromatin – granular material visible with nucleus made up of DNA bound to protein • Chromosomes – formed by chromatin during cellular reproduction • Nucleolus – small, dense region within the nucleus where ribosome assembly begins • Nuclear Envelope – double membrane around the nucleus with nuclear pores

29. Ribosomes • Made of RNA and protein • Build proteins on ribosome from proteins and RNA (coded instructions from the nucleus)

30. Endoplasmic Reticulum • Internal membrane making parts of the cell membrane and modifying proteins • Rough ER – with ribosomes to make proteins, has a rough appearance through the electron microscope • Smooth ER – lacks ribosomes and appear smooth under the electron microscope

31. Golgi Apparatus • Stacked membranes with enzymes to package proteins by attaching carbohydrates and lipids

32. Lysosomes • Small spheres filled with enzymes to break down lipids, carbohydrates, and proteins from food into smaller particles to be used by the rest of the cell, as well as worn-out organelles and wastes

33. Vacuoles • Sac-like structure to store materials including water, salts, proteins, and carbohydrates • Plant cells contain a large central vacuole • Animal cells contain smaller vesicles that transport substances within the cell

34. MEMBRANE FLOW Proteins are made at ribosomes Proteins sent through ER to Golgi nucleus Secretory vessicles remove protein from cell by exocytosis. GOLGI

35. Chloroplasts • Use energy from sunlight with carbon dioxide and water to make food (carbohydrates) and oxygen through photosynthesis in plant cells and some other cells (not in animal/fungi cells) • Double envelop membrane • contain the green pigment chlorophyll

36. Mitochondria • Use food to makeenergy (ATP) for growth, development, and movement • “Powerhouse” • Contain some of its own genetic information (DNA)

37. Smooth endoplasmic reticulum Vacuole Ribosome (free) Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparatus Nucleus Mitochondrian Rough endoplasmic reticulum Section 7-2 Plant Cell Go to Section:

38. Ribosome (attached) Ribosome (free) Nucleolus Nucleus Cell Membrane Nuclear envelope Mitochondrian Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus Section 7-2 Animal Cell Go to Section:

39. Onion Cells

40. Cheek Cells

41. Cell Wall Chloroplasts Compare/ Contrast Section 7-2 Prokaryotes Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall Cytoplasm Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Lysosomes Go to Section: