Ch. 7 – Cells

1. Ch. 7 – Cells

2. I. Cells • A. What is a cell? • 1. Cell – the smallest unit of matter that can carry on all the processes of life

3. I. Cells • B. Who first discovered the cell? • 1. Anton van Leeuwenhoek– first to observe cells • 2. Robert Hooke– used the light microscope to observe cork • a. First person to call the shapes inside of organisms “cells”

4. I. Cells • 3. Rudolph Virchow – studied cell reproduction and discovered that all cells come from other pre-existing cells. http://www.youtube.com/watch?v=5fg3Q-hbSsI

5. I. Cells • 4. Mathias Schleiden – studied plants and discovered that all plants are made of cells • 5. Theodor Schwann – studied animals and discovered that all animals are made of cells

6. I. Cells • C. What is the cell theory? • 1. The cell theorywas developed by theories of Hooke, Virchow, Schleiden, and Schwann. • a. The cell is the basic unit of organization for organisms. • b. All organisms are made of one or more cells. • c. All cells come from other pre-existing cells.

7. I. Cells • 2. With better microscopes, scientists observed that cells contained specialized structures. • a. Organelles – cells parts that perform a specific jobor functionfor the cell

8. I. Cells • D. Cell Diversity! • 1. Your body alone contains 200 different cell types! • 2. CellsOrganisms can be classified by the number of • cellsthey are made up of. • a. Unicellular Organism – single celledorganism • Example: bacteria, yeast • b. Multicellular Organism – organism made up of many cells • Example: plants, animals

9. I. Cells • E. How are cells classified based upon the presence/absence of organelles? • 1. Eukaryotic Cells – cells with a membrane-bound nucleus and organelles • a. Examples: plant and animal cells 1. Nucleus 2. Nucleolus 3. Chromatin 4. Cell membrane 5. Organelles

10. I. Cells • 2. Prokaryotic Cells – cells with no membrane-bound nucleus or organelles(except ribosomes) • a. Examples: bacteria 3. Cell membrane 2. DNA 1. Ribosomes 4. Cell wall

11. I. Cells Left: Colorized micrograph of a prokaryotic cell of the bacterium. Right: Colorized micrograph of a eukaryotic cell of the green algae.

12. I. Cells 3. Review:

13. II. Cell Boundaries • Plasma (Cell) Membrane • Function: • Surrounds cell • Allows things in and out (homeostasis) • Fact: • Selectively permeable – allows water and nutrients in and waste out • Made of phospholipids • Found in: • Prokaryotes • Eukaryotes

14. II. Cell Boundaries • Cell Wall • Function: • Surrounds cell membrane to provide extra support and protection • Fact: • Made of cellulose in plants • Found in: • Prokaryotes • Eukaryotes (plants) 2. Cell wall 1. Cell membrane

15. Nucleus III. Cell Control • Nucleus • Function: • Controls the organelles • Contains DNA • Fact: • “Command center” or “brain” of the cell • Most prominent structure • Found in: • Eukaryotes Nucleus

16. III. Cell Control • Chromatin • Function: • Condense to form chromosomes in nucleus • Fact: • Strands of DNA that look like spaghetti • Found in: • Eukaryotes

17. Nucleolus III. Cell Control • Nucleolus • Function: • Makes ribosomes • Fact: • Found inside the nucleus • Found in: • Eukaryotes Nucleolus

18. III. Cell Control • Ribosomes • Function: • Makes proteins • Fact: • Made of RNA • Can be free or attached to ER • Found in: • Eukaryotes • Prokaryotes Ribosomes

19. III. Cell Control • Nuclear Envelope/Membrane • Function: • Controls what enters/exits the nucleus • Fact: • Surrounds the nucleus • Found in: • Eukaryotes

20. IV. Cell Assembly • Cytoplasm • Function: • Suspends/holds organelles • Site of chemical reactions • Fact: • Contains clear gel-like fluid called cytosol • Found in: • Eukaryotes • Prokaryotes

21. IV. Cell Assembly • Rough Endoplasmic Reticulum (ER) • Function: • Produces proteins • Fact: • Helps move molecules throughout the cell • Found in: • Eukaryotes

22. IV. Cell Assembly • Smooth Endoplasmic Reticulum (ER) • Function: • Produces lipids (steroids) • Detoxifies poisons • Fact: • Helps move molecules throughout the cell • Found in: • Eukaryotes

23. IV. Cell Assembly • Golgi Apparatus • Function: • Processes, packs, and secretes proteins and lipids • Fact: • Works closely with ER • Flattened stack of membranes • Found in: • Eukaryotes Golgi

24. IV. Cell Assembly • Vacuole • Function: • Stores food, water, waste, proteins, carbs • Fact: • Helps maintain homeostasis • Found in: • Eukaryotes (plants have a LARGE vacuole) Vacuole

25. IV. Cell Assembly • Lysosomes • Function: • Uses enzymes to digest old organelles and foreign objects (bacteria, viruses) • Fact: • “Suicide sacs” • Found in: • Eukaryotes Lysosome

26. IV. Cell Assembly • Ever wonder how a tadpole gets rid of its tail and grows legs???? • It’s lysosomes digest the cells in the tail, and these molecules are released to build different cells, like legs!

27. V. Energy Transformers • Chloroplast • Function: • Capture light (solar energy) and convert it to chemical energy during photosynthesis • Fact: • Glucose is the sugar made • Found in: • Eukaryotes (plants) Chloroplast

28. V. Energy Transformers • Mitochondria • Function: • Breaks down food into ATP energy during cellular respiration • Fact: • “Powerhouse” of the cell • Found in: • Eukaryotes Mitochondria

29. VI. Support & Locomotion • Cytoskeleton • Function: • Maintains the shape & supports the cell • Fact: • Made of microfilaments & microtubules • Found throughout the cytoplasm • Found in: • Eukaryotes • Prokaryotes

30. VI. Support & Locomotion • Cilia • Function: • Movement of cells or fluids • Fact: • Short hair-like fibers • Found in: • Eukaryotes • Prokaryotes

31. Cilia VI. Support & Locomotion • Flagella • Function: • Movement of cells • Fact: • Long hair-like fibers • Found in: • Eukaryotes • Prokaryotes Flagella http://www.youtube.com/user/ecrouch7#p/a/f/0/1IqsE8CVTms http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=related

32. VII. Levels of Organization • A. Organization: Organelles  Cells  Tissues  Organs  Organ systems Organisms

33. VIII. THE CELL MEMBRANE • A. A cell’s survival depends on the cell’s ability to maintain the necessary conditions inside itself. • 1. Maintaining these constant internal conditions is called homeostasis.

34. VIII. THE CELL MEMBRANE • B. Cell Membrane– flexible boundary between the cell and its outside environment • 1. Allows water and nutrients to enter the cell and wastes to leave the cell. Cell Membrane Water

35. VIII. THE CELL MEMBRANE • 2. Selectively Permeable– allowing some materials to pass while keeping others out • a. Example: A spaghetti strainer allows water, but not spaghetti to pass through

36. VIII. THE CELL MEMBRANE • C. What is the cell membrane made up of? • 1. Phospholipids – diglyceride with a phosphate group attached

37. VIII. THE CELL MEMBRANE • a. Phospholipid Bilayer– the cell membrane is TWO layers thick

38. VIII. THE CELL MEMBRANE • b. Phospholipids have a polar “head” and nonpolar“tail”. • - Polar “heads” are attracted to water, sugars, and proteins.

39. VIII. THE CELL MEMBRANE • - Non-polar “tails” repelwater, sugars, and proteins. • - Resulting in a selectively permeablemembrane.

40. VIII. THE CELL MEMBRANE • 2. Proteins are embedded in the cell membrane to recognize substances that can enter and exit the cell.

41. VIII. THE CELL MEMBRANE • 3. Cholesterol stabilizes the membrane by preventing lipids from sticking together.

42. VIII. THE CELL MEMBRANE • D. Fluid Mosaic Model- describes how phospholipids can move around like a fluid and the proteins make a pattern

43. VIIII. Cell Transport • A. What types of materials need to cross the cells membrane? Water, nutrients, oxygen, waste • B. In cells, particles always move to reach equal concentrations. • 1. Concentration Gradient– unequal distribution of particles

44. VIIII. Cell Transport • C. Types of Transport • 1. Passive Transport– movement of any substance across a membrane WITHOUT the use of chemical energy. • a. Occurs from high to low concentration, with the concentration gradient.

45. VIIII. Cell Transport • b. Types of Passive Transport • - Diffusion– movement of molecules across a selectively permeable membrane; occurs from high to low concentration, with the concentration gradient.

46. VIIII. Cell Transport • - Example: Oxygen diffuses into the bloodstream because of a high pressure in the lungs.

47. VIIII. Cell Transport • - Osmosis– movement of water across a selectively permeable membrane; occurs from high to low concentration, with the concentration gradient.

48. VIIII. Cell Transport • c. How are larger and strongly charged molecules, such as glucose, able to pass through the cell membrane more quickly than they should? • - Facilitateddiffusion – passive transport of large particles across a membrane with the help of proteins; occurs from a high to low concentration, with the concentration gradient • - Example: Sugars, Amino Acids Glucose molecules High Concentration Cell Membrane Low Concentration Protein channel

49. VIIII. Cell Transport

50. VIIII. Cell Transport • 2. Types of Solution – How does the water “know” which way to move? • a. Hypertonic Solution – (high solute concentration) more wateron the inside of the cell than the outside of the cell. • - Water moves OUT of the cell. • - Size of the cell = shrinks (plasmolysis) Over time Cell H2O + NaCl Solution