Lab 2 Flashcards
Base
the bottom of the microscope; provides a sturdy flat surface to support and steady the microscope
Substage Light
located in the base; the light from the lamp passes directly upwards through the microscope
Light Control
located on the base or arm; this dial allows you to adjust the intensity of the light passing through the specimen
Stage
the platform that the slide rests on while being viewed; the stage has a hole in it to allow light to pass through the stage and through the specimen
Mechanical Stage
holds the slide in position for viewing and has two adjustable knobs that control the precise movement of the slide
Condenser
small nonmagnifying lens located beneath the stage that concentrates the light on the specimen; the condenser may have a know that reaises and lowers the condenser to vary the light delivery; generally, the best position is close to the inferior surface of the stage
Iris Diaphragm Lever
a shutter within the condernser that can be controlled by a lever to adjust the amount of light passing through the condenser; the lever can be moved to close the diaphragm and improve contrast; if your field of view it too dark you can open the diraphragm to let in more light
Coarse Adjustment Knob
this knobs allows you to make large adjustments to the height of the stage to intially focus your specimen
Fine Adjustment Knob
this knob is used for precise focusing once the intial coarse has been completed
Head
attaches to the nosepiece to support the objective lens system; also provides for attachment of the eyepieces which house the ocular lenses
Arm
vertical portion of the microscope that connects the base and the head
Nosepiece
rotating mechanism connected to the head; generally it carries three or four objective lenses and permits positioning of these lenses over the hole in the stage
Objective Lenses
these lenses are attached to the nosepiece; a compound microscope has four objective lenses: scanning (4x), low power (10x), high power (40x) and oil immersion (100x) lenses
Ocular Lenses
binocular microscopes will have two lenses located in the eyepieces at the superior end of the head; most ocular lenses have a magnification power of 10x; some microscopes will have a pointer and/or reticel (micrometer) which can be positioned by rotating the ocular lens
What does the objective lens do?
magnifies the specimen to produce a real image that is projected to the ocular
What does the ocular lens do?
real image is magnified by the ocular lens to produce the virtual image that your eye sees
Total Magnification
equal to the power of the ocular lens multiplied by the power of the objective lens used; ex) if the ocular lens magnifies 10x and the objective lens used magnifies 45x the total magnification is 450x
Resolution
the ability to discrimiate two close objects as separate; human eye can resolve at about 100 micrometers apart; compound microscope has a resolution of 0.2 micrometers under ideal conditions
Parfocal
the slide should be in focus (or nearly so) at the higher magnifications once you have properly focused at the lower magnification (you may have to adjust with the fine knobs not the coarse knobs)
Chromatin
when the cell is not dividing, the genetic material is loosely dispersed throughout the nucleus in a threadlike which is chromatin
Chromosomes
when the cell is in the process of dividing to form daughter cells, the chromatin coils and condenses, forming dense, rodlike bodies called chromosomes
Nucleoli
spherical bodies; composed primarily of proteins and ribonucleic acid (RNA); the nucleoli are assembly sites for ribosomes that are particulary abundant in the cytoplasm
Nuclear Envelope
double layered porous membrane; similar in composition to other cellular membranes but has large nuclear pores
Nuclear Pores
spanned by protein complexes that regulate what passes through, and they permit easy passage of protein and RNA molecules
Plasma Membrane
separates cell contents from the surrounding environment, providing a protective barrier; mainly phospholipids and globular protein molecules
Selective Permeability
plasma membrane is selective about what passes through it; it lets some stuff in/out and doesnt let some stuff in/out
Microvilli
greatly increase the surface area of the cell available for absorption or passage of materials and for the binding of signaling molecules
Cytoplasm
consists of the cell contents between the nucleus and plasma membrane
Ribosomes
tiny spherical bodies composed of RNA and protein; floating free or attached to a membranous structure (the rough ER) in the cytoplasm; actual sites of protein synthesis
Endoplasmic Reticulum
ER; membranous system of tubules that extends throughout the cytoplasm; two varieties: rough and smooth; rough ER is studded with ribosomes; tubules of the rough ER provide an area for storage and transport of the proteins made on the ribosomes to other cell areas; smooth ER (has no function in protein synthesis) is a site of steroid and lipid synthesis, lipid metabolism, and drug detoxification
Golgi Apparatus
stack of flattened sacs with bulbous ends and associated small vesicles; found close to the nucleus; plays a role in packaging proteins or other substances for export from the cell or incorporation into the plasma membrane and in packaging lysosomal enzymes
Lysosomes
various sized membranous sacs containing digestive enzymes including acid hydrolases; function to digest worn out cell organelles and foreign substances that enter the cell; have the capacity of total cell destruction if ruptured and are for this reason refered to as “suicide sacs”
Peroxisomes
small lysosome-like membranous sacs containing oxidase enzymes that detoxify alcohol, free radicals, and other harmful chemicals; they are particularly abundant in liver and kidney cells
Mitochondria
rod shaped bodies with a double membrane wall; inner membrane is shaped in folds or cristae; contain enzymes that oxidize foodstuffs to produce cellular energy (ATP)
Centrioles
Paired, cylindrical bodies that lie at right angles to each other, close to the nucleus,; internally each centriole is composed of 9 triplets of microtubules; as part of the centrosome, they direct the formation of the mitotic spindle during cell division; form the bases of cilia and flagella and in that role are called basal bodies
Cytoskeletal Elements: Microfilaments, Intermediate Filaments, and Microtubules
form an internal scaffolding called the cytoskeletong; provide cellular support; function in intracellular transport; microfilaments are formed largely of actin, a contractile proteing, and thus are important in cell mobility particularly in muscle cells; intermediate filaments are stable elements composed of a variety of proteins and resist mechanical forces acting on cells; microtubules form the internal structure of the centrioles and help determine cell shape
Inclusions
stored foods, pigment granules, crystals of various types, water vacuoles, and ingested foreign materials; cell cytoplasm may or may not contain it
What happens when you move the slide left?
image through microscope goes right
What happens when you move the slide right?
image through microscope goes left
What happens when you move the slide up?
image through microscope goes downW
What happens when you move the slide down?
image through microscope goes up
As you increase magnification working distance…
decreases
As you increase magnification the image size…
increases
As you increase magnification the field diameter…
decreases
As magnification increases you should dim or brighten the light?
brighten
