Microscope Lab Quiz

parts and function of a microscope, microscope mechanics, prokaryotic and eukaryotic cells

eye piece/ocular lens

picks up the magnified image and magnifies it for viewing

coarse adjustment knob

moves body tube and body tube extension up and down to find the specimen

fine adjustment knob

moves the lenses very little to focus the image

low power objective

lens of the lowest power (4x)

high power objective

lens of the highest power (40x)

arm

handle to hold and tilt microscope

inclination joint

allows microscope to tilt

body tube extension

connects eyepiece to body tube

body tube

passes the image from objective through body tube toward eye piece

revolving nose piece

rotates objectives around

stage clips

holds slide onto the stage

stage

platform that the slide is placed onto

condenser

condenses light from wide beam to narrow strong beam

diaphragm

modifies the amount of light that is allowed through the stage

light

allows light to pass through specimen for viewing

cord

power supply

base

bottom of the microscope, must be held when carried

How do you hold the microscope?

put one hand around the arm and one on the base

Which knobs can you use on each power objective?

low/medium power objective: coarse and fine

high power objective: fine only

How do you find the total magnification?

multiply the magnification of the eye piece and the magnification of the objective lens

How do you prepare a wet mount?

1. place the specimen on the slide

2. add liquid (usually water)

3. hold the cover slip at a 45 degree angle and slowly lower it down

What power objective should you always start on?

low power objective

What do you have to make sure the specimen is before zooming in?

centered

How do you estimate the length of cells?

diameter of the field of view / number of cells

How do you find the field of view length on high power?

measure the length with a ruler on low power, then use this formula:

diameter (LP) X magnification of LP objective / magnification of HP objective

What happens to the field of view when the magnification is increased?

it shrinks

How does the image appear/move in the microscope?

opposite (the image is flipped)

What’s the main difference between a prokaryotic and eukaryotic cell?

prokaryotic does not have a nucleus (free-floating DNA - aka nuceloid region), eukaryotic has a nucleus

membrane-bound organelles

in eukaryotic cells, don’t move around

example of prokaryotic cells

bacteria

types of eukaryotic cells

plant and animal cells

shape of animal cell

irregular

shape of plant cell

rectangular

difference in organelles

plant cells have a cell wall, large vacuole, and chloroplast

animal cells have small vacuoles

What causes the shape difference between plant and animal cells?

cell wall in plant cells

indicator purpose (when looking at cells)

to stain the cells since they are transparent

onion cell indicator and why

iodine; cellulose (polysaccharide) in the cell wall reacts with the iodine which accentuates the cell wall of the onion cell

cheek cell indicator and why

methylene blue, stains the cell blue