1. Chapter 7 Cellular Structure and Function

2. 7.1 Vocabulary Cell Cell Theory Plasma Membrane Organelle Eukaryotic Cell Nucleus Prokaryotic Cell

3. Section 1 Cell Discovery and Theory Standards: 2.1 - 2.3 Objectives: Relate advances in microscope technology to discoveries about cells. Compare compound light microscopes with electron microscopes. Summarize the principles of the cell theory. Differentiate between a prokaryotic cell and a eukaryotic cell.

4. History of Cells Robert Hooke in 1665 made the first light microscope and discovered cells. – Studied cork (oak bark)  “cells” Cell - basic structural & functional unit of life – Smallest unit of life

5. Cell Theory Cell Theory – one of the fundamental ideas of modern biology that describes the properties of cells. 3 Major Principles: 1.All living organisms are composed of one or more cells  unicellular/multicellular organisms 2.Cells are the basic unit of structure and organization of all living things. 3. All presently existing cells arose from previously existing cells  cells grow and then divide

6. Microscope Technology Microscopes allow scientists to study cells in great detail. Advancements in science = advancements in technology & better microscopes. Increases magnification Increases resolution

7. Compound Light Microscope Use glass lenses and visible light Each glass lens magnifies previous lens Cells are often stained with dye to see better

8. Electron Microscope Greater magnification Use magnets to aim a beam of electrons at thin slices of cells. – Electrons pass through and are absorbed leaving behind a black and white shaded image. Specimen must be dead, sliced very thin, and stained with metals.

9. Basic Cell Structure/Function All cells have a special boundary that helps control what enters/leaves the cell called a plasma membrane (or cell membrane). Most cells have genetic material. Cells break down molecules for energy.

10. Prokaryotic Cells No nucleus or membrane-bound organelles. – Have ribosomes  protein synthesis DNA is not completely separated by a nuclear membrane  exposed DNA is not arranged in chromosomes Obtain energy from sun or chemicals Most unicellular organisms  bacteria

11. Prokaryotic Cells

12. Eukaryotic Cells Contains many specialized structures that carry out specific cell functions called organelles. – Contains a nucleus – central organelle that contains the cell’s genetic material. Mostly multicellular organisms but can be unicellular ( algae and yeast).

13. Eukaryotic Cell

14. 7.3 Vocabulary Cytoplasm Cytoskeleton Ribosome Nucleolus Endoplasmic Reticulum Golgi Apparatus Vacuole Lysosome Centriole Mitochondrion Chloroplast Cell Wall Cilium Flagellum

15. Section 3 Structure and Organelles Standards: 2.2, 2.3, 4.3, 4.4 Objectives: Identify the structure and function of the parts of a typical eukaryotic cell. Compare and contrast structures of plant and animal cells.

16. Cytoplasm Semi-fluid material inside the plasma membrane. – Prokaryotes  all chemical processes occur here – Eukaryotes  all chemical processes occur in organelles found throughout this area; different processes can occur at the same time

17. Cytoskeleton Supporting network of long, thin protein fibers that form a framework for the cell. Provide anchor for organelles Cell movement  organelles do not float freely Made up of: – Microtubules – long, hollow proteins – Microfilaments – thin protein threads

18. Nucleus Cell’s managing structure Contains most of the cell’s DNA (info used to make proteins for growth, function, & reproduction). Nuclear Envelope (Nuclear Membrane)  Double membrane that surrounds nucleus; has PORES to allow substances to enter/exit the nucleus

19. Ribosomes Manufacture a variety of proteins  protein synthesis Non membrane bound Some float freely in cytoplasm & some are attached to the endoplasmic reticulum (ER) Made up of: 1.RNA 2.Protein Nucleolus Site of ribosome production Found in the nucleus

20. Endoplasmic Reticulum (ER) System of folded sacs and interconnected channels that serves as the site for protein and lipid synthesis. – Transports materials – High surface area = more room for functions to occur Two types: 1.Rough ER – attached ribosomes; produce proteins for export to other cells 2.Smooth ER – no ribosomes; synthesizes carbohydrates and lipids.

21. Golgi Apparatus Flattened stack of membranes that modifies, sorts, & packages proteins into sacks called vesicles. – Vesicles fuse to plasma membrane  release proteins outside of the cell.

22. Vacuole Membrane bound vesicle for temporary storage of materials within the cytoplasm. – Store food, enzymes, waste. Plant Cells  large vacuole Animal Cells  none or have very small vacuoles

23. Lysosomes Membrane bound vesicles that contain enzymes that digest excess or worn-out organelles and food particles. Digest bacteria and viruses Fuse with vacuole  dispense enzymes  digest waste. Animal cells only

24. Centrioles Organelles made of microtubules that function during cell division  organizes chromosomes for division. Located in the cytoplasm near nucleus Animal and Protists cell

25. Mitochondria “Powerhouse” Convert fuel particles (mainly sugars) into usable energy  cellular respiration Outer membrane and highly folded inner membrane  increase surface area for breaking down sugar.

26. Chloroplasts Capture light energy and convert it to chemical energy  photosynthesis Plant cells only Thylakoids  disk-shape compartments inside the inner membrane. – Contains chlorophyll  pigment that traps sunlight; gives plants green color

27. Cell Wall Thick, rigid, mesh of fibers that surrounds the outside of the plasma membrane. Made of cellulose (carbohydrate)  protects the cell and gives extra support. Plant and Fungi cells

28. Cilia and Flagella Hair-like structures that project outside of the plasma membrane  allow for movement. Composed of microtubules. – Cilia  many & short hairs  Animal & Protists Cells – Flagella  less and longer; whip-like motion  Animals & Plant cells

29. Protein Synthesis 1.Begins in nucleus; DNA  RNA 2.RNA and ribosomes leave nucleus through the pores of the nuclear membrane. 3.RNA and ribosomes make proteins on rough ER and/or free floating in the cytoplasm. Each protein has a function 4.Proteins sent to Golgi and packaged in vesicles to be transported in or out of cell. Lysosome use proteins  enzymes Mitochondria use proteins  energy

30. Animal Cell

31. Plant Cell

32. 7.2 Vocabulary Selective Permeability Phospholipid Bilayer Transport Protein Fluid Mosaic Model

33. Section 2 The Plasma Membrane Standards: 2.2, 2.5, 3.5 Objectives: Describe how a cell’s plasma membrane functions. Identify the roles of proteins, carbohydrates, and cholesterol in the plasma membrane.

34. Homeostasis Maintaining balance internally = constant & stable. Essential for cell to survive. Structure responsible  plasma membrane

35. Plasma Membrane’s Functions Selective Permeability (or Semipermeable)- allows some substances to pass through while keeping others out. – Controls what, how, when, and how much of each substance to enter/exit the cell Water O 2 Glucose Waste CO 2 Waste Outside Membrane Inside

36. Plasma Membrane Structure Mostly made up of phospholipids Polar Head Hydrophilic  “water loving” attracted to water Nonpolar Tails Hydrophobic  “water fearing” repel water

37. Phospholipid

38. Plasma Membrane Structure Phospholipid Bilayer – 2 layers of phospholipids are arranged tail-tail  make a sandwich. – Exists in watery environment (inside & outside cell) – Many phospholipids  create barrier

39. Plasma Membrane Structure

40. Proteins – Outside proteins  surface receptors transmit signals to the inside of the cell. – Inside proteins  anchor the membrane to support structures  gives cell its shape – Transport Proteins – embedded tunnels in membrane; move needed substances or waste material through  “selective permeability”

41. Plasma Membrane Structure Cholesterol – Helps prevent the tails of the phospholipid bilayer from sticking together  allowing fluidity. – Affects stiffness – More cholesterol = more rigid – Less Cholesterol = more fluid

42. Plasma Membrane Structure Carbohydrates – Attach to proteins and stick out to define the cell’s characteristics and help cells identify chemical signals.

43. Fluid Mosaic Model Plasma membrane with components constantly in motion, sliding past one another within the lipid bilayer. Creates a “sea” in motion & a pattern (mosaic)

44. Plasma Membrane

45. 7.4 Vocabulary Diffusion Dynamic Equilibrium Facilitated Diffusion Osmosis Isotonic Solution Hypotonic Solution Hypertonic Solution Active Transport Endocytosis Exocytosis

46. Section 4 Cellular Transport Standards: 2.5 Objectives: Explain the processes of diffusion, facilitated diffusion, and active transport. Predict the effect of a hypotonic, hypertonic, or isotonic solution on a cell. Discuss how large particles enter and exit cells.

47. Passive Transport Passive Transport – process by which substances move across a cell membrane but do not require energy; follow concentration gradient (H  L) 3 Types: 1.Diffusion 2.Facilitated Diffusion 3.Osmosis

48. Diffusion Diffusion – net movement of particles from area of many particles  area with fewer particles. – High  low concentration – Requires no additional energy needed because particles already in motion

49. Diffusion Dynamic Equilibrium – condition of continuous, random movement of particles but no overall change in concentration. – Particles spread equally out – Increase rate of diffusion by increasing: 1.Concentration 2.Pressure 3.Temperature

50. Diffusion in a Cell

51. Facilitated Diffusion Facilitated Diffusion – uses transport proteins to move other ions and small molecules across the plasma membrane. – Requires no additional energy – Channel Proteins  opens/closes – Carrier Proteins  can change shape

52. Osmosis Osmosis – diffusion of water across a selectively permeable membrane from an area of high  low concentration of water. – Water moves freely in/out of cell – Important in maintaining homeostasis – Solute (substance being dissolved) is dissolved in the solvent (substance doing the dissolving)

53. Osmosis Isotonic Solution – same concentration of water and solutes outside as inside the cell. – Retains normal shape – Equilibrium = no net water movement – Water enters & exits at the same rate – Most cells in the body

54. Osmosis Hypotonic Solution – lower concentration of solute outside than inside the cell. – More water outside cell  water flows into – Increases osmotic pressure & cell SWELLS Animal cells could burst (lyse) because to much pressure Plant cells will not burst because of cell wall; vacuole fills up with water  more firm

55. Osmosis Hypertonic Solution – higher concentration of solute outside than inside the cell. – More water inside cell  water flows out of cell – Decreases osmotic pressure & cell SHRIVELS Plant cells lose water from vacuole causing wilting

56. Active Transport Active Transport – movement of substances across the membrane against a concentration gradient. – Low  high concentration – Requires energy – Uses pumps (carrier proteins) to transport substances – Important in maintaining homeostasis

57. Sodium-Potassium Pump Active transport pump found in animal cells Maintains sodium (Na + ) and potassium (K + ) ions Enzyme that catalyzes the breakdown of an energy-storing molecule.

58. Transport of Large Particles  Vesicles Endocytosis – energy- requiring process by which large substances from the outside environment can enter a cell. Exocytosis – energy- requiring process by which a cell expels wastes and secretes substances at the membrane.

59. SNBK 7.4

62. Pictures on Test