English scientist Robert Hooke built this microscope in the 17th century and used it to conduct pioneering research. He discovered the cell structure of plants by observing a thin slice of cork under his microscope.
Important Tools in Biology Microscopes – is an instrument that uses lenses to produce an enlarged and focused image of a specimen. Two properties: 1. Magnification – is the ratio between the image size and the object size. 2. Resolution (Resolving power) – refers to the smallest degree of separation at which two objects are viewed as distinct from one another, rather than as a blurry, single image.
Micron (µ)- unit of measurement used in microscope study. Conversion of Units: 1µ = 0.000001m 1µ = 0.001mm Examples: Range of Bacteria = 0.5 to 2µ Range of some nerve cells = 1000µ
Types of Microscopes 1. Compound Light Microscope – focuses and bends visible light through a specimen to produce a magnified image. *Magnification = up to 1500x *Resolution = 0.1 to 0.2µ
Computation for the size of specimen TM =OLM x OL Where: TM = Total Magnification OLM = Objective Lens Magnification OL = Ocular Lens
Types of Microscopes 2. Stereomicroscope (Dissecting Microscope) – consists of two eyepieces and two objective lenses. - used for dissecting small specimens. Magnification = ranging from 4x to 50x
Types of Microscopes 3. Electron Microscope – uses a beam of electrons instead of light to create image. - the beam of electrons is focused using magnetic lenses. Resolution power = about 1,000 times
Types of Electron Microscopes a. Transmission Electron Microscope (TEM) – uses a magnetic field beam to focus a beam of electrons through a thin section of the specimen. Magnification = about 100,000 times
Types of Electron Microscopes b. Scanning Electron Microscope (SEM) – gives a surface view of a three- dimensional specimen by bouncing electrons off its surface. Magnification = about 10,000 times
Types of Electron Microscopes c. Scanning Tunneling Microscope (STM) – allows viewing of atoms on the surface of a solid. Magnification = over 1 million times
OTHER SCIENTIFIC TOOLS 1. Ultracentrifuge – a machine used to separate suspended particles in a mixture.
OTHER SCIENTIFIC TOOLS 2. Chromatography – used in separating substances in a mixture. Types: a. Paper Chromatography b. Column Chromatography
OTHER SCIENTIFIC TOOLS 3. Electrophoresis – used to separate substances in a mixture according to how fast they move when subjected to an electric current. - commonly used to purify proteins based on their sizes and shapes.
OTHER SCIENTIFIC TOOLS 4. X-ray Diffraction – useful for analysis of protein crystals using X-rays of a single wavelength.
OTHER SCIENTIFIC TOOLS 5. Spectrophotometer – used to determine the amount of proteins or nucleic acid present in a solution. - measures the amount of light absorbed by the solution at specific wavelength.
OTHER SCIENTIFIC TOOLS 6. Computer – useful in storing vast amounts of information. - also used to organize data, make long and complex calculations and make graphs to summarize results.