4 - Plasma membrane-made of phospholipids(polar head...

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Plasma membrane -made of phospholipids (polar head) antipathetic inside -proteins nucleus -encased by nuclear envelop -holes to transport RNA -nucleolus- make ribosomes RNA -nuclear alima- structure, ridigity, shape nuclear proteins -DNA polymerase -RNA poymerase -DNA binding proteins -RNA binding/processing portiens etc Nucleouplasm -fluid inside nucleus is a suspension of DNA RNA, proteins, fibers, nucleotides etc. ribosomes- make proteins; composed of protein and RNA a. Free (free floating in membrane) b. Bound c. pro- 70s (subunits) 50s + 30s d. euk 80s (subunits) 60s+ 40s Which of the following has membranes? -nucleus and bacteria _RIBOSOMES DO NOT HAVE MEMBRANE!!! Chapter 6: Part 2 The endomembrane system -nuclear envelop -ER -golgi apparatus -lysososmes -vaculues -plasma membrane Endoplasmic reticulum
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-LOTS of foldings cisternal space Space inside cisternal = LUMEN -Rough ER- ribosomes are attached -Smooth ER- no ribosomes attached Functions of smooth ER 1. in lumen proteins chemically modified 2. synthesis of lipids and steriods 3. in liver- detoxify drugs and poisons 4. site of hydrolysis of glycogen 5. storage of calcium ions- muscles cell- sacroplasmic reticulum Functions of rough ER 1. production of secretory proteins-insulin 2. covalently bound carbohydrates (glycoslavation) to protiens 3. membrane factory for cell in which cell would you expect to find the most bound ribosomes? -pancreatic cell that manufactures and secretes digestive enzymes (SECRETE PROTIENS!!!! Goes outside the cell requires rough ER) in which would you expect to find the most SMOOTH ER? -muscle cell in the thigh muscle of a long distance runner (PRESENT IN MUSCLE CELLS) -ovarian cell that produces estrogen (PRODUCES STERIODS) relationships among organelles of the endomembrane system 1. protein enters the ER 2. in ER goes through modificatiosn (folding, chemically, etc) 3. exits ER to golgi (think postal office. ..gives zip codes to tell where to go) 4. can go back to ER or outside the membrane, different locations How do proteins the endomembrane system? -the signal hypothesis `1. Ribosome is synthesized on protein. Knows to enter because of amino acids (SIGNLA SEQUENCE or SIGNAL PEPTIDE) on N terminals of protein. Signal sequence attaches to complex on membrane Receptor changes its structure and allows protein to enter membrane. *hydrophobic 1. proteins spoils off ribosomes 2. 2. N terminals signal sequence of amino acids 3. interacts with SRP 4. recognizes amino acid
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5. the complex unlock receptor helps protein get inside ER 6. protein stays on ER membrane thru signal sequence 7. enzyme chops of protein *Signal peptidase role of signal sequence in protein sorting -cytosolic protein (no signal sequence) ER protein has N terminal signal sequence, cytosolic protein does not Signal sequence results in its import into the ER ER function Quality control (properly folded) Modification of proteins in rER lumen: 1. signal sequence cleaved off 2. poypeptide … 3. protein glycoslylation
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4 - Plasma membrane-made of phospholipids(polar head...

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