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Chapter 3 The Cell (part 1)

Chapter 3 The Cell (part 1). The Cell Theory. Three Principles All organisms are composed of cells Cells are the smallest living units of life All cells arise from pre-existing cells (by cell division). Cells Are Highly Structured.

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Chapter 3 The Cell (part 1)

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  1. Chapter 3The Cell (part 1)

  2. The Cell Theory • Three Principles • All organisms are composed of cells • Cells are the smallest living units of life • All cells arise from pre-existing cells (by cell division)

  3. Cells Are Highly Structured • Eukaryotic (“with nucleus”) cells are highly “compartmentalized” • plasma membrane • nucleus: information center • cytoplasm: fluid within membrane • organelles: structures with specialized functions • Prokaryotes have no nucleus or true organelles

  4. Prokaryotes have no nucleus or true organelles

  5. The Plasma Membrane • Structure of the plasma membrane

  6. Structural Features of the Plasma Membrane • Lipid bilayer • Phospholipids: polar head and nonpolar tail • Cholesterol: makes membrane a bit more rigid • Proteins: provide means of transportation through membrane • Carbohydrates: provide recognition for cells and organisms

  7. Movement Across the Plasma Membrane • Diffusion • Movement from area of highconcentration to low • Passive transport: no energy required

  8. Facilitated Diffusion • Diffusion that uses transport (carrier) proteins in membrane to assist moving molecules across the membrane both: • Down the concentration gradient • Without expending energy

  9. Active Transport • Active transport uses proteins andenergy to move substances from an area of lower concentration to an area of higher concentration

  10. Active Transport Proteins Use Energy

  11. Osmosis • Osmosis: net diffusion of water across a semi-permeable membrane

  12. Osmosis and Tonicity

  13. Endocytosis (Phagocytosis) Moves Materials in Bulk • Endocytosis moves material into cell • Example: WBC engulfs bacteria

  14. Exocytosis Moves Materials in Bulk • Exocytosis moves material out of the cell • Example: secretion of hormones

  15. Structure and Function of the Nucleus • Functions: • Contains the genetic information of the cell • Controls the function & the operations of the cell • Structural features: • Double-layered nuclear membrane • Nuclear pores • Chromosomes/chromatin • Nucleolus (synthesizes ribosomes)

  16. Our Cells Are Highly Structured • Chromosomes contained in the nucleus are made of DNA

  17. Endoplasmic Reticulum (ER)

  18. Endoplasmic Reticulum (ER) and Ribosomes • Ribosomes: used in synthesis of proteins • Free and membrane bound • Endoplasmic Reticulum (ER): packages the proteins • Smooth ER: no ribosomes, lipid synthesis & detoxifies alcohol and drugs • Rough ER: has ribosomes, protein synthesis

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