Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Proteolysis wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
Lipid signaling wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Paracrine signalling wikipedia , lookup
Magnesium in biology wikipedia , lookup
Magnesium transporter wikipedia , lookup
Polyclonal B cell response wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Cellular Level of Organization Introduction Two types of cells 1. Sex cells (haploid) 2. Somatic cells (diploid) Cell Membranes 4 main functions 1. Physcial Isolation Separates inside of cell from outside 2. Selectively Permeable Membrane Regulates exchange with the environment 3. Sensitivity Contains receptors 4. Structural Support The cell membrane can connect to other cells or extracellular proteins Cell Membrane Structure Hydrophilic head Hydrophobic tails Cell Membrane Structure Ions and water soluble compounds cannot cross the membrane Cell Membrane Structure This separates the extracellular fluid from the cytosol which is important for homeostasis What are in membranes? 1. Cholesterol What are in membranes? 2. Integral proteins What are in membranes? 3. Enzymes Catalyzes reactions What are in membranes? 4. Receptor proteins Protein – lock Ligand - key What are in membranes? 5. Carrier Protein Transports things across the membrane What are in membranes? 6. Channels Allows continuous movements of ions and water soluble materials What are outside cell membranes? 1. Peripheral proteins 2. Glycoproteins 3. Glycolipids Glycoprotiens and glycolipids Can tell if certain cells are normal or abnormal by their glycoproteins and glycolipids Organelles Components of cells 1. Cytoskeleton 1. 2. 3. Strength and flexibility Composed of 3 main structures Microfilaments ( actin ) Intermediate filaments ( collagen ) Microtubules ( tubulin ) 2. Microvilli Increase surface area Finger-shaped projections of cell membranes 3. Centrioles Their involved in cell division Not found in RBC, skel. muscle cells, cardiac muscle cells, and neuron cells 4. Cilia Long slim extensions of the cell membrane Found in trachea 5. Ribosomes Synthesize proteins Composed of two subunits ( one small and one large) Free ribosomes Fixed ribosomes 6. Endoplasmic Reticulum Network within the cytoplasm attached to the nucleus 6. Endoplasmic Reticulum Two types 1. SER 2. RER 6. Endoplasmic Reticulum SER Detoxifies drugs or toxins Synthesizes lipids and carbs 6. Endoplasmic Reticulum RER Transports materials and synthesizes proteins 7. Golgi Apparatus Proteins come from the ER into the golgi for modification 8. Lysosome Breaks down and recycles organelles Breaks down bacteria and foreign material 9. Peroxisomes Breaks down fatty acids and organic compounds 10. Mitochondria Powerhouse of the cell Produces ATP – energy Contains two membranes (outer and inner) 11. Nucleus Chromosomes are stored here Composed of DNA Membrane Transport Membranes are selectively permeable Membrane Transport Passive processes do not require energy Membrane Transport Active processes require energy Membrane Transport 3 major ways in which materials are transported 1. Diffusion 2. Carrier-mediated transport 3. Vesicular transport 1. Diffusion Hypotonic solution – less concentrated 1. Diffusion Hypertonic – more concentrated 1. Diffusion Isotonic solutions – equal concentration 1. Diffusion Solutes move from hypertonic solution to hypotonic solution Ions and Water Remember ions and water must pass through channels Lipid Soluble Substances Alcohol, fatty acids, and steroids are lipid soluble O2 and CO2 O2 and CO2 pass easily Glucose Glucose to big to cross cell membrane 2. Carrier-Mediated Transport Can be passive or active 2. Carrier-Mediated Transport Proteins carry substances across 2. Carrier-Mediated Transport Sometimes carries two things at once (cotransport) 2. Carrier-Mediated Transport Sometimes carries to things in opposite directions (countertrasnport) 2. Carrier-Mediated Transport 1. Fascilitated Diffusion 2. Active Transport 3. Secondary Active Transport Facilitated Diffusion Passive Facilitated Diffusion Carries substances such as glucose and amino acids Facilitated Diffusion Goes down conc. Gradient but limited to number of carrier proteins Active Transport Requires energy Active Transport Not dependent on concentration gradient Active Transport Ion pumps use active transport Active Transport Exchange pumps move two kinds of ions in different directions Example: Na+/K+ Pump Na+/K+ Pump Na higher in concentration outside cell K higher in cell Na+/K+ Pump Sometimes Na diffuses into cell and K leaves through leaky channels Na+/K+ Pump Na+/K+ pump puts things back into order Na+/K+ Pump Ejects on average 3Na+ and bringing in 2K+ ions Secondary Active Transport Does not require energy Secondary Active Transport Goes down a conc. gradient Secondary Active Transport It uses the concentration gradient of a molecule as the driving force to move another molecule against the concentration gradient 3. Vesicular Transport Requires energy 3. Vesicular Transport 1. Endocytosis 2. Exocytosis Endocytosis Imports substances into the cell Endocytosis 1. Receptor mediated endocytosis 2. Pinocytosis 3. Phagocytosis Receptor Mediated Endocytosis Extremely selective Receptor Mediated Endocytosis Plasma membrane proteins bind only with certain substances Pinocytosis Cell drinking Pinocytosis Dissolved proteins gather on the external surface of the plasma membrane, causing the membrane to invaginate and to incorporate a droplet of fluid Phagocytosis Cell eating Phagocytosis Parts of the plasma membrane flow around a relatively large or solid material and engulf it. Exocytosis Expels material out of the cell