Quiz 3 Flashcards
Tetrahymena need a lot of ____ to survive
O2
Most of the detail of living cells is undetectable by __________
bright-field microscopy,
Tetrahymena thermophila
Single celled organism, eukaryotic and belong to protozoans
Contain hair like structures called cilia
Cilia
Hair like structures that move in a wave like fashion
Create currents that propel nutrient material into the cytosome
Food vacuole
Food particles become enclosed in ____ and pinches off from cytosome and migrated to cell interior
Phagocytosis
Vacuole formation that occurs in many unicellular organisms
Cell mouth
Cytosome
Food vacuoles fuse with ____
Lysosomes
Undigested material is discharged from the cell at the ______
Cytoproct
Movement of cilia and formation and transport of food vacuoles are dependent on ____
Microtubules
Microtubules assembled from
Proteins alpha and beta tubulin
Motor protein
Dynein
What creates swimming pattern in cilia
Bending of the cilia in alternate rows
Tetrahymena have the same structure and function as cilia doing in specialized ____ cells
Human
bright-field microscopy
magnified images are created by passing light directly through a specimen and into a system of objective and ocular lenses
why is bright-field microscope hard to see things
little contrast between their internal structures and the surrounding water-based environment when they are observed with a bright-field microscope
Refractive index
n= c/v
why is phase contrast preferred?
Phase-contrast is preferable to bright-field microscopy when high magnifications (400x – 1000x) are needed and the specimen is colorless, or its details are so fine that color does not show up well
single greatest advantage of __________, however, is that it does not require the use of toxic chemical stains, making it the best method for observing living cells and tissues
phase-contrast microscopy
why are culture flasks marked ‘Tetrahymena’ with red tape never to be washed with soap?
The cells are sensitive to detergent and chemical residues on lab glassware.
Tetrahymena need a lot of ___ to survive
O2
When Tetrahymena cells are pelleted with a microcentrifuge, why must you resuspend them
soon afterwards
because if they are allowed to stand for any length of time (1 minute or more,)
cells in the center of the pellet will suffocate and die
-cells at the top will swim away into the supernate and will be lost
when it is poured or pipetted off
why must you pipette this particular cell gently
Larger cells must be pipetted gently to avoid rupturing their plasma membranes as cells pass through the small opening of the pipette tip
What does dynein do
Form multiple cross bridges to connect pairs of Microtubules
Why are tetrahymena cultures grown in small volumes in large flasks ?
to provide effective aeration of the media
need a lot of O2 to survive
Why fo you need to resuspend Tetrahymena soon after being in microcentrifuge?
Bc if allowed to stand any length of time (1minute or more), cells in the center of the pellet will suffocate and die
Why do you need to be gentle with pipetting Tetrahymena cells?
bc they are large cells and need to avoid rupturing plasma membrane as cells pass through small opening of the pipette tip
_____ is preferable when high magnifications are needed and specimen is colorless
Phase contrast
Greatest advantage of phase contrast
does not require the use of toxic chemical stains, making the best method for observing living cells and tissues
refractive index
ratio of the speed of light in a vacuum to its speed in a given medium and is
n=c/v
____ refractive structures bend light more than ___ refractive index
Highly, low
Phase contrast microscopy
uses variations in refractive index to produce differences in brightness that make transparent structures easy to see
Tetrahymena are sensitive to detergent and chemical residues on lab glassware
T/F
T
