Topic 3 study cells Flashcards
Explain components of a light microscope (illumination, lenses, techniques, magnification, resolution.
Illumination: light (sun, light bulb, lasers)
Lenses: quarts, glass, plastics
Techniques: oil immersion, staining, fluorescence, confocal
Magnification: 100-1000x
Resolution: .5 micrometers (500 nanometers)
Dissecting scope:
Light is reflected off the specimen and produced a 3D image, the stage is large enough to manipulate the specimen, lower magnification than compound scope.
Compound light microscope.
Had an ocular and objective lense, light passes through the specimen and the image is inverted, oil immersion can be used to reduce refraction at high magnification
Quality of a microscope image depends on 3 things what are they?
Magnification, resolution, contrast
The ratio of an object’s image size to its real size is?
Magnification
Resolution?
The measure of the clarity of the image, or the minimum distance of two distinguishable points
Contrast?
The visible difference in parts of the sample
What can you stain with vital stains?
Live cells
What does mordant do?
Used to fix the stain or coat the specimen
Fluorescence microscopy use?
Fluorescent dyes, markers, stains to increase resolution and contrast
Confocal microscopy
A special type of fluorescent microscopy that used lasers to focus light or to excite fluorescent dyes at precise depths
What do electron microscopes do??
Electrons waves pass through or bounce off a specimen, are magnified/ focused by magnets and the image is recorded on film or computerized.
Explain a scanning electron microscope (SEM)
Specimens are coated with heavy metals
Electrons are bounced off of the specimen resulting in a 3D image
SEM images are often enhanced by adding colours
Explain a transmission electron microscope (TEM)
Electrons pass through the specimen
Specimens are stained with heavy metals
TEMs are used mainly to study the internal structure of cells
Scanning probe microscopy (SPM)
A probe makes a molecular contact with the atoms of a surface of a specimen and measures its contours creating a 3D digital image.
Another type of scanning probe microscopy is?
Atomic force microscopy (AFM)
What are the chemical requirements for growth and what each does
Carbon: all organisms require carbon
Nitrogen: amino acids and nucleotides
Sulfur: amino acids, thiamine, biotin
Phosphorous: DNA,RNA,ATP and phospholipids
Oxygen: required for cellular respiration but can be lethal to some organisms
Microscope from highest to lowest magnification
AFM/SPM, TEM, SEM, fluorescent, compound then dissecting
Why do we grow cells in the labs?
To study them, clinical diagnosis, vaccines
Physical requirements for cell growth?
Temperature, PH, osmotic pressure
Magnification of a SEM
Up to 250,000x
Magnification of TEM
Up to 1,000,000x
Electron microscopy illumination?
Electrons
Lenses for an electron microscopy
Magnetic fields
Resolution of electron microscopy
Approximately 1 nanometer
Culturing microbes - liquid media what are the cells suspended in
Liquid nutrient broth containing nutrients such as sugar, amino acids, salts that the microbe needs to grow
Liquid media can be used for both…
Small scale and large scale cultures
Culturing media- solid media what is the liquid media turned to…
Liquid media is solidified using agar (a carbohydrate extracted from seaweed)
On a given media, microbes will grow with specific….
Colony morphologies
What is solid media often used for
Streaking
Explain the purpose of streaking
Used to isolate a pure stain from a single species of microorganisms, and the sample is diluted so that a single bacterium will grow as a colony
Why are animal cells for difficult to culture
They require more complex nutrients and often only grow when attached to specially coated surfaces.
Explain culturing viruses
They are routinely cultured to produce viral particles for study or for vaccine production. Since viruses lack the cellular machinery to reproduce they must culture in host cells
Explain cell fractioning
Fractioning breaks cells apart and separates the major organelles from one another
What does ultracentrifuging do?
Fractionates cells into their component parts
What does cell fractionation enable scientists to determine?
The functions of organelles
