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Cell Structure and Function

Cell Structure and Function. The Cell Theory. All living things are composed of cells. Cells are the basic units of structure and function in living things. All cells come from pre-existing cells. Cell Structure. Most cells have three basic structures. cell membrane (outer boundary)

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Cell Structure and Function

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  1. Cell Structure and Function

  2. The Cell Theory • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • All cells come from pre-existing cells.

  3. Cell Structure • Most cells have three basic structures. • cell membrane (outer boundary) • cytoplasm (filling) • nucleus (control center)

  4. All cells have a cell membrane and cytoplasm.

  5. However some do not have a nucleus. These are called Prokaryotes.(bacteria)

  6. Cells with a nucleus are called eukaryotes. (plant, animal, fungus and protists) Nucleus

  7. Cell Membrane • Separates and protects the cell from its surroundings. • Regulates what enters and leaves the cell. • Made of two lipid layers: (Phospholipidbilayer)

  8. The Cell Membrane Phospholipid Bilayer Hydro-phobic (Fatty acids) Hydro-phyllic (Phos-phates)

  9. Cytoplasm • The area between the cell membrane and nucleus. • Contains structures called organelles and each one performs a specific job.

  10. Cytoplasm

  11. Nucleus (Control center) • Contains DNA which are the instructions for making molecules the cell needs.

  12. Nucleus (Control center) • Directs the activities of the cell. • Surrounded by a membrane called the nuclear membrane or nuclear envelope.

  13. Nucleus

  14. Nucleolus

  15. A small region of the nucleus made up of RNA and proteins. • The nucleolus makes ribosomes.

  16. Nucleolus Nucleus

  17. Ribosomes • Found in prokaryotic and eukaryotic cells • Protein factories. • Some ribosomes are attached to the endoplasmic reticulum.

  18. Ribosomes • Others are free in the cytoplasm. • Smallest organelle.

  19. Ribosomes Rough ER

  20. Endoplasmic Reticulum • Two forms Rough ER Smooth ER

  21. Endoplasmic ReticulumSmooth ER: no ribosomes are attached. Special enzymes and chemicals are stored here. Lipids (fats) are produced

  22. Endoplasmic ReticulumSmooth ER: also resp. for prod. of phospholipids for cell membrane.

  23. Endoplasmic Reticulum Rough ER: has ribosomes attached. After proteins are made in the ribosomes they are inserted in the rough ER where they can be modified.

  24. Endoplasmic Reticulum Rough ER: from the ER, proteins are sent to the Golgi Apparatus

  25. Golgi Apparatus (UPS) • modifies, collects, and packages molecules in the cell. • Also distributes the molecules to where they need to be in the cell.

  26. Golgi Apparatus

  27. Lysosomes • Cleanup crews for the cell. • Lysosomes are formed in the Golgi apparatus.

  28. Lysosomes • Contain chemicals and enzymes that digest and breakdown waste particles.

  29. Lysosome in action:

  30. Vacuoles (Warehouse) • Storage tanks in the cell. • Store materials like water, salts, proteins, and carbohydrates. • Plants have only one big vacuole filled primarily with water.

  31. Vacuoles (Warehouse)

  32. Cytoskeleton • The framework of the cell. • Made of microfilaments and microtubules • Provide support and are often involved in cell movement.

  33. Mitochondria(Generator) • Generator of the cell. • Changes chemical energy stored in food (sugar) into compounds easier for the cell organelles to use (ATP).

  34. Mitochondrion

  35. Chloroplast (Solar Panel) • Where photosynthesis takes place • Found only in plant cells and algae.

  36. Chloroplast (Solar Panel) • Traps energy from sunlight and changes it into chemical energy (makes sugars).

  37. Plant Cell Chloroplast

  38. Cell Wall • In addition to the cell membrane, plant (& fungus) cells have a cell wall. • Provides extra support. • Made up of cellulose and lignin

  39. Cell WallFound outside the cell membrane

  40. Movement of materials through the cell membrane. • Cells must take in materials, and release waste products. • Molecules must be able to move in and out of the cell.

  41. Movement of materials through the cell membrane. • They do this by diffusion.

  42. Diffusion • The process by which molecules move from areas of higher concentration to areas of lower concentration. (spread out)

  43. Diffusion • Driven by the random movement of molecules.

  44. Diffusion • Two factors determine if diffusion takes place equilibrium and permeability.

  45. Diffusion membrane higher conc. lower conc.

  46. Equilibrium • Equilibrium is when the concentrations on both sides of the membrane are equal.

  47. Equilibrium Semi-permeable membrane

  48. Permeability • If a molecule can diffuse across a membrane, the membrane is permeable.

  49. Permeability • If a molecule cannot diffuse across a membrane, the membrane is impermeable to that membrane.

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