BRAINCAKEComponents of Living Systems
Revision notes for Components of Living Systems in OCR Biology A (H020). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Development of Cell TheoryIn 1665 Robert Hooke observed the structure of thinly sliced cork under an early microscope.
- The Light MicroscopeA compound light microscope has two lenses - an eyepiece lens and an objective lens.
- Preparing SamplesDry MountSolid specimens can be viewed as they are or into very thin slices or sectioned using a very sharp blade.
- StainingStains increase the contrast and allow the components of the cell to become more visible.
- Gram StainAll bacterial cell walls are made of peptidoglycan.
- Acid-Fast TechniqueMycobacterium spp. are bacteria associated with TB and other infections.
- MagnificationMagnification is how many times larger the image is compared to the actual object.
- ResolutionThe resolution of a measuring instrument is the ability to see two individual objects that are close together as separate entities and determines…
- The Eyepiece GraticuleThe eyepiece graticule and stage micrometer are used to measure the actual size of specimens.
- Electron MicroscopyThe resolution of a microscope is about half its wavelength.
- Transmission Electron MicroscopeThe transmission electron microscope passes a beam of electrons through a thin specimen and focuses the electrons that have passed through the…
- Scanning Electron MicroscopeThe scanning electron microscope scans the surface of the specimen with a beam of electrons.
- Sample Preparation for Electron MicroscopesSpecimen preparation involves: fixation staining with heavy metals dehydration with solvents setting in resin further staining The steps to prepare…
- Differences Between Light and Electron Microscopeslight microscope electron microscope resolving power 200nm resolving power 0.5nm (TEM), 3-10nm (SEM) specimen can be stained black and white images…
- Scientific DrawingsInclude a title.
- ArtefactsArtefacts are features of the specimen that may be caused by the preparation process.
- Laser Scanning Confocal MicroscopyA laser is a very intense beam of light.
- Fluorescent TagsA fluorescence microscope is an optical microscope that uses fluorescence instead of, or in addition to, scattering, reflection, and attenuation or…
- Atomic Force MicroscopyIn atomic force microscopy, the surface of the specimen is scanned with a mechanical probe with a sharp tip to generate a 3D image of the specimen.
- Super Resolved Fluorescence MicroscopySuper resolved fluorescence microscopy can achieve a resolution of 0.2μm using visible light.
- Relative SizesA typical bacterium is about 1μm in length.