Structure of a Generalized Cell

Transcription

1 A Quick Tour Through A Cell BIO130 Lab 2 Exercise 4 The Cell: Anatomy Structure of a Generalized Cell -plasma membrane -cytoplasm: cytosol organelles -nucleus Play TourOfAnimalCell.mpg Plasma membrane Ribosomes -phospholipid bilayer -site of proteins synthesis -separates cell contents from environment -free in cytoplasm or -bound to endoplasmic reticulum Endoplasmic Reticulum (ER) Rough ER -membrane sacs studded with ribosomes -synthesizes proteins for use in plasma membrane or for secretion -membrane tubes and sacs -two types: RER & SER Amy Warenda Czura, Ph.D. 1 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

2 Smooth ER -membrane tubules -site of lipid synthesis, lipid metabolism, drug detoxification, & ion storage Golgi Apparatus -stack of membrane sacs -has associated vesicles -modifies, sorts, & packages proteins for export or use in plasma membrane Role of the Golgi Apparatus Lysosomes -membrane vesicles -contain digestive enzymes -break down old organelles, large molecules, & pathogens Peroxisomes -membrane sacs -contain oxidases -neutralize free radicals and toxins Mitochondria -double membrane wall -inner membrane folded into cristae -oxidize food to generate ATP - powerhouse of the cell Amy Warenda Czura, Ph.D. 2 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

3 Centrioles -paired cylindrical bodies -organize mitotic spindle during mitosis -form base of cilia and flagella -protein filaments -create internal framework of cell: for structure & support -important in cell mobility Cytoskeleton Figure 3.24 Nucleus -in center of cell -contains DNA: genetic material -double membrane Nuclear Envelope -separates nuclear contents from cytoplasm -has pores to allow molecule ex with cytoplasm Nucleoli -dense area in nucleus -site of ribosome production Chromatin -loose, thread-like DNA -open form of DNA found in cells that are not dividing Chromosomes -tightly wound DNA -dense, bar-like form of DNA that forms when cells begin mitosis for cell division (46 in humans) 10 objective (100) Pentagon cells with visible nuclei 4 objective (40) 40 objective (400) Amy Warenda Czura, Ph.D. 3 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

4 4 objective (40) 4 objective (40) Long, stringy cells with enlargements at nuclei Tiny cells with visible nuclei and long flagella 40 objective (400) 10 objective (100) 10 objective (100) 4 objective (40) 40 objective (400) BIO132 Lab 2 Exercise 5 or 5A The Cell: Transport Mechanisms and Cell Permeability The cell membrane: a selectively permeable barrier Tiny round cells: red blood cells lack nuclei, white blood cells have visible and often multi-lobed nuclei 10 objective (100) Play MembraneSelectivity.swf 40 objective (400) WBC Play MembraneBarrier.mov RBC Passive Transport: Diffusion Through the Plasma Membrane Passive Transport Diffusion Through the Plasma Membrane Diffusion: net movement of solutes from an area of high conc. to an area of low conc. Diffusion: net movement of solutes from an area of high concentration to an area of low concentration until equilibrium is reached. Occurs due to the constant and random motion of molecules. Play Diffusion.swf Play FatWaterSolu.mov Play Diffusion.mov Play FacilDiffusion.mov Amy Warenda Czura, Ph.D. 4 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

5 Passive Transport Diffusion Through the Plasma Membrane Diffusion: net movement of solutes from an area of high concentration to an area of low concentration: requires no energy from the cell Diffusion Through the Plasma Membrane Diffusion: net movement of solutes from an area of high concentration to an area of low concentration until equilibrium is reached Solutes move to bring the system to equilibrium. -Simple diffusion: through the phospholipid membrane -Facilitated diffusion: through a protein: a channel or a transport protein But what if the solutes are not free to move? Osmosis:! Occurs when the concentration of a solvent is different on opposite sides of a semipermeable membrane! Diffusion of water across a semipermeable membrane! Osmolarity total concentration of solute particles in a solution, a driving force of water movement Water molecules come to equilibrium Tonicity how a solution effects cell volume! Isotonic solutions with the same solute concentration as that of the cytosol: no net movement of water! Hypertonic solutions having greater solute concentration than that of the cytosol: net movement of water out of the cell (can cause crenation)! Hypotonic solutions having lesser solute concentration than that of the cytosol: net movement of water into the cell (can cause lysis) Water moves when the solutes cannot Active Transport Movement against the concentration gradient Requires work/energy input from the cell Play ActiveTransport.swf Play Exocytosis.swf Play Pinocytosis.swf Play Phagocytosis.swf Play OsmoticEffectsRBC.mpg Amy Warenda Czura, Ph.D. 5 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

6 Phagocytosis: cell eating, cell engulfs extracellular material via pseudopods and internalizes it in a vesicle for digestion in the lysosome Phagocytosis Pseudopods Play Neutrophil.mpg Play MO-phago.mov PlayAmoeba.mpg Play MO-phago2.mov 1 Water 2 1 Water 2 4 Water 4 Water 1 Water 2 yellow 1 Water 2 yellow + 4 Water 4 Water Amy Warenda Czura, Ph.D. 6 SCCC BIO130 Lab 2 The Cell Anatomy and Transport

7 1 Water 2 yellow same none + 1 Water 2 yellow same none + 4 Water 4 Water 1 Water 2 yellow same none + 1 Water 2 yellow same none + 4 Water cloudy 4 Water cloudy much big 1 Water 2 4 Water yellow same none cloudy much big blue _ sucrose + Amy Warenda Czura, Ph.D. 7 SCCC BIO130 Lab 2 The Cell Anatomy and Transport