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A Tour of the Cell. Chapter 7. Objectives. Be familiar with the regions of the cell and the overall role of each region Be familiar with the basic organelles and their function. Cell Types. All living organisms are made of cells Two kinds of cells
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A Tour of the Cell Chapter 7
Objectives • Be familiar with the regions of the cell and the overall role of each region • Be familiar with the basic organelles and their function
Cell Types • All living organisms are made of cells • Two kinds of cells • Prokaryotic: lacks membrane bound structures other than plasma membrane • Bacteria • Eukaryotic: contains membrane bound organelles enabling compartmentalization leading to specialization • animals, plants, protists, fungi
Cell Size • Limits on cell size determined by ability to perform metabolic processes • Lower: can all necessary components fit • Upper: can we regulate supplies adequately (surface to volume ratio)
Regions of a Eukaryotic Cell • Nucleus: contains genetic material (DNA) necessary for cell regulation. Reference library • Cytoplasm: consists of cytosol (cell fluid) and organelles (specialized structures that carry out metabolic activities of cell) • PlasmaMembrane: contains the cell and regulates movement of materials into/out of the cell
Nucleus • Control center of cell • Dual membrane system that fuse to form nuclear pores • DNA and Protein complexes called Chromatin • Nucleolus: region of RNA within the Nucleus
Ribosomes • Sites of Protein synthesis • May be free or bound • Free make proteins typically used in the cell • Bound are attached to membrane (ER) and make proteins typically for export
Endoplasmic Reticulum (ER) • Part of the endomembrane system • Smooth ER: site of lipid synthesis, detox, carbohydrate metabolism • Rough ER: site of protein synthesis (contains bound ribosomes)
Golgi Apparatus“When it absolutely, positively, has to leave the cell” • Finishes, sorts, and packages manufactured products of the cell • cis: receives products from “ER” • trans: ships materials to other parts of cell (often the plasma membrane)
Lysosomes • Membrane bound structures responsible for the degradation of “spent” organelles and “food” items • Contain hydrolytic enzymes
Vacuoles • Membrane bound storage areas for resources • Named after the resource they contain
Mitochondria, Chloroplast • Mitochondria: site of most ATP synthesis • Chloroplast: site of carbohydrate synthesis
Peroxisomes • Modify molecules through redox reactions • Produce peroxide as a result (H2O2) • Split into two as they grow
Cytoskeletal elements • Provide structural framework for the cell • Movement of materials inside and on the surface of the cell • Microtubules • grow from centrosome • load bearing • Microfilaments • pulling forces • Intermediate filaments • load bearing
Organelles of Motility • Flagellum: moves the entire cell • Cilium (cilia): moves things along the surface of the cell
Extracellular Surfaces • Most cells have a combination of proteins, lipids and sugars that form an extracellular matrix • Plants have a cell wall
Communication is Critical • In order for many cells to function as a unit (as in multicellular organisms) there must be a minimal level of communication • Connections between cells are called junctions • Tight junctions: leak-proof connections between cells • Desmosomes: fasten cells together strengthening the tissue • Gap junctions: provide cytoplasmic channels between cells