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Cells

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  1. Cells Structure and Function Video

  2. Section 1: Introduction to the Cell

  3. Discovery of Cells • The invention of the lens • Robert Hooke (1665): observed a thin slice of cork (dead plant cells) with a microscope. He described what he observed as “little boxes” (cells). • @First to discover cells@

  4. The Cell Theory • @What is the cell theory? 1. All living things are composed of one or more cells. 2. Cells are organisms’ basic units of structure and function. 3. Cells come only from existing cells.@

  5. Cell Diversity • Size • Shape • Internal Organization

  6. Cell Diversity- Size

  7. Smallest Cells: Cell Diversity- Size Biggest Cells: Longest Cells: 6 inches long, 5 inches wide, 3 pounds Ostrich Egg

  8. Cell Diversity- Shape • Cells differ widely in shape. • Most cells are roughly cuboidal or spherical.

  9. Cell Diversity- Internal Organization • Nucleus: contains DNA which directs the activity of the cell • Organelle: a cell component that performs specific functions in the cell • Eukaryotes: cells that contain a nucleus and membrane-bound organelles • Prokaryotes: cells that lack nuclei and membrane-bound organelles

  10. Eukaryotes vs. Prokaryotes

  11. What are the 3 parts of the cell theory? • Cells are the smallest units of life • Living things are made of cells • All cells are made from other preexisting cells

  12. What is the main difference between Prokaryotes and Eukaryotes? • Eukaryotes are bigger and have a nucleus • Prokaryotes are smaller and do not have a nucleus

  13. Section 2: Parts the Cell

  14. The Parts of the Cell • Each living cell carries out the tasks of taking food, transforming food into energy, getting rid of wastes, and reproducing. • Most eukaryotic cells have three main components: • Cell Membrane • Cytoskeleton • Nucleus

  15. Structure and Function of Organelles • Many cellular structures act as if they are specialized organs. @These structures are known as organelles, literally “little organs.”@ : • Mitochondria • Lysosomes • Vacuoles • Cell Membrane • Nucleus • Cell Wall • Cytoplasm • Cytoskeleton • Ribosomes • Endoplasmic Reticulum • Golgi Apparatus

  16. Comparing the Cell to a Factory • The eukaryotic cell is much like a living version of a modern factory. • The specialized machines and assembly lines of the factory can be compared to the different organelles of the cell. • Cells, like factories, follow instructions and produce products.

  17. Cell Membrane • Structure: @phospholipidbilayer with proteins that function as channels, markers, and receptors@ • Function: selectively permeable boundary between the cell and the external environment

  18. Nucleus • Structure: the nucleus is a sphere that contains another sphere called a nucleolus • Function: -storage center of cell’s DNA-manages cell functions

  19. Cell Wall • Structure: rigid wall made up of cellulose, proteins, and carbohydrates • Function: boundary around the plant cell outside of the cell membrane that provides structure and support

  20. Cytoplasm • Structure: gelatin-like fluid that lies inside the cell membrane • Function: -contains salts, minerals and organic molecules -surrounds the organelles

  21. Cytoskeleton • Structure: a network of thin, fibrous elements made up of microtubules (hollow tubes) and microfilaments (threads made out of actin) • Function: -acts as a support system for organelles-maintains cell shape

  22. Ribosomes • Ribosomesare small particles of RNA and protein found throughout the cytoplasm in all cells. • @Ribosomes produce proteins by following coded instructions that come from DNA. @ • Each ribosome is like a small machine in a factory, turning out proteins on orders that come from its DNA “boss.”

  23. Endoplasmic Reticulum • Structure: a system of membranous tubules and sacs • Function: intercellular highway (a path along which molecules move from one part of the cell to another) • Two types: • Rough Endoplasmic Reticulum • Smooth Endoplasmic Reticulum

  24. Rough Endoplasmic Reticulum • Rough Endoplasmic Reticulum (rER): @prominent in cells that make large amounts of proteins to be exported from the cell @or inserted into the cell membrane • Covered with ribosomes

  25. Smooth Endoplasmic Reticulum • Smooth Endoplasmic Reticulum (sER): @involved in the synthesis of lipids and breakdown of toxic substances@ • Not covered with ribosomes

  26. Golgi Apparatus • Structure: stacked flat sacs • Function: receives proteins from the rER and distributes them to other organelles or out of the cell (receiving, processing, packaging, and shipping)

  27. Golgi Apparatus • The Golgi apparatus modifies, sorts, and packages proteins and other materials from the ER for storage in the cell or release outside the cell. It is somewhat like a customization shop, where the finishing touches are put on proteins before they are ready to leave the “factory.”

  28. Golgi Apparatus • From the Golgi apparatus, proteins are “shipped” to their final destination inside or outside the cell.

  29. Mitochondria • Structure: folded membrane within an outer membrane • @Powerhouse of the cell @ • Function: -converts energy stored in food into usable energy for work • cellular respiration

  30. Lysosomes • Structure: spherical organelles that contain hydrolytic enzymes within single membranes • Function: breaks down food particles, invading objects, or worn out cell parts

  31. Vacuoles • Structure: a sac of fluid surrounded by a membrane • Very large in plants • Function: used for temporary storage of wastes, nutrients, and water

  32. Chloroplasts • Structure: stacked sacs (thylakoids) that contain chlorophyll surrounded by a double membrane • Function: photosynthesis (conversion of light energy to chemical energy stored in the bonds of glucose)

  33. Secretory Pathway

  34. Plant Cells vs. Animal Cells • Animal cells are very similar to plant cells except for the following major differences: • Animal cells do not contain chloroplasts • Animal cells are not surrounded by cell walls • The vacuoles in plants are much larger than those of animals

  35. Animal Cell

  36. Plant Cell

  37. Which organelle provides energy for the cell? • Mitochondria

  38. What’s the difference between rough and smooth ER? • Rough involved with making proteins • Smooth involved with making lipids

  39. What’s the difference between plant and animal cells? • Animal cells do not contain chloroplasts • Animal cells are not surrounded by cell walls • The vacuoles in plants are much larger than those of animals

  40. THE END!

  41. Hierarchy of Biological Order