Bioprinciples Exam 2 Questions With Correct Answers

Cytology - the study of cells Robert Hooke - - observed cork could float - discovered a honeycomb-like structure in a cork slice using a primitive compound microscope - only saw cell walls as this was dead tissue - coined the term "cell" for these individual compartments he saw Two types of microscopes: - 1. Light Microscope 2. Electron Microscope Light Microscope - - light is focused on specimen by a glass condenser lens - the image is magnified by an objective lens and an ocular lens - projection on photographic film Electron Microscope - - a beam of electrons is used instead of light - bombards object with electrons to see small, precise images - electromagnets are used instead of glass lenses - the electron beam is focused on the specimen by a condenser lens - the image is magnified by an objective lens and projector lens - projection on a screen or on photographic film Two Types: 1. Transmission Electron Microscope 2. Scanning Electron Microscope Transmission Electron Microscope (TEM) - - magnet lens focus on electron beam - the image can be viewed through a viewing lens - cuts thin slices with a microtome made of diamonds - displays different colors depending on electrons absorbed Scanning Electron Microscope (SEM) - - a scanning coil moves the beam back and forth - electrons reflected from the specimen are analyzed by a computer to reconstruct a 3D image