Lab 2

Question 1

Base

Answer 1

the bottom of the microscope; provides a sturdy flat surface to support and steady the microscope

Question 2

Substage Light

Answer 2

located in the base; the light from the lamp passes directly upwards through the microscope

Question 3

Light Control

Answer 3

located on the base or arm; this dial allows you to adjust the intensity of the light passing through the specimen

Question 4

Stage

Answer 4

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

Question 5

Mechanical Stage

Answer 5

holds the slide in position for viewing and has two adjustable knobs that control the precise movement of the slide

Question 6

Condenser

Answer 6

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

Question 7

Iris Diaphragm Lever

Answer 7

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

Question 8

Coarse Adjustment Knob

Answer 8

this knobs allows you to make large adjustments to the height of the stage to intially focus your specimen

Question 9

Fine Adjustment Knob

Answer 9

this knob is used for precise focusing once the intial coarse has been completed

Question 10

Head

Answer 10

attaches to the nosepiece to support the objective lens system; also provides for attachment of the eyepieces which house the ocular lenses

Question 11

Arm

Answer 11

vertical portion of the microscope that connects the base and the head

Question 12

Nosepiece

Answer 12

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

Question 13

Objective Lenses

Answer 13

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

Question 14

Ocular Lenses

Answer 14

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

Question 15

What does the objective lens do?

Answer 15

magnifies the specimen to produce a real image that is projected to the ocular

Question 16

What does the ocular lens do?

Answer 16

real image is magnified by the ocular lens to produce the virtual image that your eye sees

Question 17

Total Magnification

Answer 17

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

Question 18

Resolution

Answer 18

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

Question 19

Parfocal

Answer 19

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)

Question 20

Chromatin

Answer 20

when the cell is not dividing, the genetic material is loosely dispersed throughout the nucleus in a threadlike which is chromatin

Question 21

Chromosomes

Answer 21

when the cell is in the process of dividing to form daughter cells, the chromatin coils and condenses, forming dense, rodlike bodies called chromosomes

Question 22

Nucleoli

Answer 22

spherical bodies; composed primarily of proteins and ribonucleic acid (RNA); the nucleoli are assembly sites for ribosomes that are particulary abundant in the cytoplasm

Question 23

Nuclear Envelope

Answer 23

double layered porous membrane; similar in composition to other cellular membranes but has large nuclear pores

Question 24

Nuclear Pores

Answer 24

spanned by protein complexes that regulate what passes through, and they permit easy passage of protein and RNA molecules

Question 25

Plasma Membrane

Answer 25

separates cell contents from the surrounding environment, providing a protective barrier; mainly phospholipids and globular protein molecules

Question 26

Selective Permeability

Answer 26

plasma membrane is selective about what passes through it; it lets some stuff in/out and doesnt let some stuff in/out

Question 27

Microvilli

Answer 27

greatly increase the surface area of the cell available for absorption or passage of materials and for the binding of signaling molecules

Question 28

Cytoplasm

Answer 28

consists of the cell contents between the nucleus and plasma membrane

Question 29

Ribosomes

Answer 29

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

Question 30

Endoplasmic Reticulum

Answer 30

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

Question 31

Golgi Apparatus

Answer 31

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

Question 32

Lysosomes

Answer 32

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”

Question 33

Peroxisomes

Answer 33

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

Question 34

Mitochondria

Answer 34

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)

Question 35

Centrioles

Answer 35

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

Question 36

Cytoskeletal Elements: Microfilaments, Intermediate Filaments, and Microtubules

Answer 36

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

Question 37

Inclusions

Answer 37

stored foods, pigment granules, crystals of various types, water vacuoles, and ingested foreign materials; cell cytoplasm may or may not contain it

Question 38

What happens when you move the slide left?

Answer 38

image through microscope goes right

Question 39

What happens when you move the slide right?

Answer 39

image through microscope goes left

Question 40

What happens when you move the slide up?

Answer 40

image through microscope goes downW

Question 41

What happens when you move the slide down?

Answer 41

image through microscope goes up

Question 42

As you increase magnification working distance…

Answer 42

decreases

Question 43

As you increase magnification the image size…

Answer 43

increases

Question 44

As you increase magnification the field diameter…

Answer 44

decreases

Question 45

As magnification increases you should dim or brighten the light?

Answer 45

brighten