Presentation on theme: "The Endoplasmic System"— Presentation transcript:
1 The Endoplasmic System Chapter 4.5The Endoplasmic SystemAP BiologyFall 2010
2 Endoplasmic Reticulum Endoplasmic Retculum (ER): collection of interconnected tubes and flattened sacs that begin at the nucleus and ramble throughout the cytoplasmFlattened channel, starts at nuclear envelope and folds back on itself repeatedly in cytoplasm
4 Endoplasmic Reticulum Inside the channel polypeptide chains become modified into final proteins and lipids are assembledTwo types distinguished by presence or absence of ribosomes:Smooth ERRough ER
5 Endoplasmic Reticulum Rough ERConsists of stacked, flattened sacs with many ribosomes attachedOligosaccharide groups are attached to polypeptides as they pass through on their way to other organelles or to secretary vesiclesCells that make, store and secrete proteins have a lot of rough EREx. Pancreas
7 Endoplasmic Reticulum Smooth ERHas no ribosomesIs the area from which vesicles carrying proteins and lipids are buddedInactivates harmful chemicals and breaks down fatty acidsMakes lipid molecules that become part of cell membrane
9 Golgi BodiesGolgi Bodies: proteins and lipids undergo final processing, sorting, and packagingAttach sugar side chains to proteins and lipids they received from the ERFinished products are packaged in vesicles
10 Golgi BodiesMembranes of Golgi are arranged in flattened sacs whose edges break away as vesicles
11 VesiclesVesicles: commonly used by the cell as transporters to and from plasma membraneTiny sacs that form as buds from ER, Golgi bodies, and plasma membraneSome transport substances to or from other organellesFuse and form larger membranous sac, or vacuoles
13 Lysosomes Lysosomes: vesicles that bud from Golgi Carry powerful enzymes that can digest contents of other vesicles, worn out cell part, or bacteria and foreign particlesEnzymes activated when another vesicle moves through the cytoplasm and fuses with the lysosomesContents are digested into bits
15 PeroxisomesPeroxisomes: hold enzymes that digest fatty acids, amino acids, and hydrogen peroxide (a toxic metabolic product)Convert H2O2 to water and oxygen or use it in reactions that degrade alcohol and other toxins
16 Review What are the main differences between the rough and smooth ER? What is the function of the golgi body?Distinguish between a lysosome, peroxisome, and vesicle.
17 AnswersRough ER has ribosomes and smooth ER does not. Rough ER is where oligosaccharide groups are attached to polypeptides. Smooth ER is the area from which vesicles carrying proteins and lipids are budded, inactivates harmful chemicals and breaks down fatty acids.The golgi bodies are where proteins and lipids undergo final processing, sorting, and packaging, they attach sugar side chains to proteins and lipids they received from the ER.Vesicles are commonly used by the cell as transporters to and from plasma membrane. Lysosomes are vesicles that bud from Golgi, contain digestive enzymes. Peroxisomes hold enzymes that digest fatty acids, amino acids, and hydrogen peroxide (a toxic metabolic product) .