BIOL 1411 1st Edition Lecture 6 Outline of Last Lecture I Lipids Continued II III Cells Organelles Outline of Current Lecture I Cells II Membranes Current Lecture I Cells Endoplasmic reticulum highest fraction of a cell s membranes and fluid Rough ER contains many ribosomes for manufacture of proteins that will be part of endomembrane system or exported Smooth ER site of protein modification glycogen degradation lipid synthesis and chemical detox no ribosomes The Golgi flattened sacs of membranes receives modifies and packages proteins from RER manufacture of cell wall polysaccharides plant cells Lysosomes membrane vesicles that contain digestive enzymes animal cells secondary lysosomes digest food particles brought into cell phagosomes also digest old organelles Food particles brought in by phagocytosis Free vs bound ribosomes bound are found on the RER to package things out of the cell while free are located in the cytoplasm and help with producing proteins for the cell Mitochondria site of the chemical reactions of cellular respiration that supple cell with energy ATP have its own DNA Many folds Chloroplasts site of chemical reactions of photosynthesis have DNA These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Prokaryotic endosymbiosis Inner and outer membranes Stacked membranes called thylakoids Granum stack of thylakoids Plant Cells have unique organelles Vacuole for storage fluids responsible for turgor pressure Cell wall made of sugars gives rigidity Cytoskeleton supports and maintains cell shape moves organelles in cytoplasm Microfilaments made of the protein actin often interact with strands of other proteins Intermediate filaments anchoring cell structures Microtubules responsible for movement of organelles inside the cell framework for motor proteins made of protein tubulin a dimer polar can change length my adding or subtracting dimers o One of main jobs intercellular movement of DNA into 2 daughter cells o Can use their length and polarity for trafficking purposes kinesins move towards the plus end to move cargo kind of like little roadways o Microtubules line cilia and flagella 9 outer 2 inner microtubules doublet arrangement interactions with the motor protein dynein causes bending and movement o Microtubules bend cilia and flagella o Nextin can cross link the doublets and prevent from sliding II Membranes Boundaries between cells and surrounding environment Which molecules can make it through the cell membrane Nonpolar hydrophobic small molecules Phospholipids form a fluid bilayer Occurs spontaneously in water A variety of proteins float within the bilayer Carbohydrates attach to lipids or proteins Fluid mosaic model of Cell Membranes All trans membrane proteins are also integral membrane proteins Lipids composition phospholipids vary in fatty acid chain length Percentage of cholesterol up to 25 Membrane composition can vary Membrane Proteins are mostly independent of the lipids most lipids and proteins have weak hydrophobic interactions Lateral movement of membrane components occurs Plasma membrane involved in cell adhesion and recognition 3 types of Cell Junctions 1 Tight junctions prevents leaking between cells ex Stomach Cells 2 Gap Junctions allow cell to cell communication pores communicate with another cell 3 Desmosomes are like spot welds
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