Biology Lab 3 Flashcards
what is the smallest and most simple biological structure
the cell
what is a prokaryotic cell
the earliest known cell that lacks a nuclei and membrane bound organelles
what is a eukaryotic cell
cells that have a nuclei and membrane bound organelles
what are groups of cells that have specific and different functions
tissues
what are the four types of microscopes used in lab
- compound microscope
- stereoscopic microscope
- scanning electron microscope (SEM)
- transmission electron microscope (TEM)
what are some of the various light microscopes
- phase contrast
- dark field
- polarizing
- UV
how do light microscopes usually differ
by the source and manner in which light is passed through the specimen to be viewed
what microscopes did we use in exercise 3.1
compound binocular light microscopes
what does compound mean in a compound binocular microscope
the scopes have a minimum of 2 magnifying lenses (ocular and objective lenses)
what does the binocular microscope mean in a compound binocular light microscope?
have 2 eyepieces
what kind of light does a compound binocular light microscope use
visible light from a lamb
When should you place or remove a slide onto the stage
when the 4X objective is in in place
what is parfocal lenses
little refocusing is required when moving from one lens to another
what should you never focus with when on intermediate or high power objective
coarse adjustment
what is the working distance
distance between specimen and the objective lens
what is a more common unit of measure in microscopy
micrometer
1 millimeter is equal to how many micrometers
1,000 micrometers
what is depth of field
the thickness of the specimen that may be seen in focus at one time; this is very short in the compound microscope so you will need to focus up and down to clearly view all planes of the specimen
what are the 2 types of electron microscopy
- transmission electron microscopy
- scanning electron microscopy
how does transmission electron microscopy work
allows researchers to examine very thin sections of cells at extremely high magnification; 1,000,000X
how does scanning electron microscopy work
provides an image of the surface of the cell at a lower magnification; 100,000X
what is the main difference between electron and light microscopes
resolving power; allows the user to see 2 objects of comparable size that are close together and still be able to recognize they are 2 objects rather than 1
what does resolving power depend on
wavelength of light (electrons) passed through a specimen; shorter the wavelength, the greater resolution
how do electron microscopes work
they focus a beam of electrons through a specimen to illuminate it; shorter wavelength as well
which is better, the resolving power of electron or light microscopes
electron microscope
what is the source of illumination in the electron microscope
beam of electrons
what are organelles
structures found within the cytoplasm that preform specific functions in the cell
what makes up the cytoplasm
a semifluid substance; fills the cell
what are unicellular organisms and how do they function
single celled; all living functions handled by that 1 cell
what do cells form that act as temporary clusters of cells
aggregates
what are colonies
clusters composed of consistent and predictable number of cells
what are multicellular organisms
- consist of 2 or more types of cells with specialized structure and function
- any one of the cell types of the organisms are isolated, then it is not capable of perpetuating the species in nature
what are the 2 types of unicellular eukaryotic organisms
- autotrophic (photosynthetic)
- heterotrophic (get food from other organisms or their by-products)
what specimen was used in part 3.4
amoeba
how was the amoeba transferred to the slide
use a pipet and transfer a drop with several amoebas to your slide by squeezing the pipet bulb before you place the tip under the surface of the water . Pipette a drop of water with debris from the bottom of the dish.
what specimen was studied in lab study b
- protococcus; terrestrial green algae know as moss
- Scenedesmus; aquatic green algae that is common in polluted water
when completing lab c, what was used to look at plant cells
a wet amount of Elodea
what structures are you trying to identify in the plant cell
- cell wall
- cytoplasm (does not fill nucleus)
- central vacuole
- chloroplasts
- nucleus
where is the central vacuole located in a plant cell and what is its function
membrane bound sac within cytoplasm; serves to store metabolic wastes and gives the cell support through turgor pressure
what is the purpose of the chloroplasts in plant cells
carry the pigment chlorophyll that is involved in photosynthesis; green in color and have a spherical shape; located within the cytoplasm
what is the purpose of the epithelial tissue in animal cells
protect from water loss, mechanical injury, and foreign objects
what structures in the animal cell are you trying to identify
- cell membrane
- nucleus
- cytoplasm
