Module 2 Flashcards
Ultrastructure
Everything inside a cell
Maginification equation
I AM
Magnification definition
How many times bigger an object appears than in real life
Resolution definition
The ability to distinguish 2 adjacent objects next to each other
Light microscope
Uses lights to see large organelles, max magnification x1500 but has low resolution and low magnification
transmission electron microscope (TEM)
Fires a beam of electrons through thin specimens, helps to visualise very small organelles inside a thin sample
Scanning electron microscope (SEM)
Scans a focussed beam of electrons over a surface to create a 3D image
Max res= 10nm
Max mag= x100,000
Laser scanning confocal microscope
Used on Thick samples of tissues that’s been stained with fluorescent dyes, shows organelles at different depths and layers
Sectioning and problems
Sample cut and preserved in wax
Problems= the cut could b too thick/ thin and not representative of a real cell
Staining and problems
Coloured chemicals that bind to certain pads of cells. Too much stain distorts image
Features of eukaryotic cells
Organelles are membrane bound, have a proper nucleus
Function of internal membranes
Sort and compartmentalise contents of a cell into organelles increasing efficiency
Nucleus
Contains chromatin- DNA wrapped around histone proteins and is surrounded by a nuclear envelope and contains nuclear pores
Nucleolus
Produces RNA and ribosomes which are passed thru nucl envelope and nucl pore to the ER
RER
Studded w ribosomes for protein synthesis
SER
Continuous with RER lacks ribosomes and is for lipid synthesis
Golgi apparatus
Stack of membrane bound sacs called cisternae receives proteins from ER thru transition vesicles and MODIFIES and PACKAGES them into secretion vesicles- exocytosis
Lysosomes
Contains enzymes- lysozyme which breaks down material
Mitochondria
Double membraned, site of aerobic respiration
Permanent vacuole
Membrane bound, maintains cell stability by pushing the cytoplasm against the membrane (turgid), filled w water/ sap