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Cell BIO LAB > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Which of these mathematical parameters associated with a protein standard curve are sufficient to determine the concentration of an “unknown” sample from its absorbance in the Bradford assay

A

Slope and y-intercept

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2
Q

Unknowns and standards have to be assayed at the same time for a comparison between the two to be valid T/F

A

True (bc environmental factors, temp, could be diff at diff times)

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3
Q

A standard curve is usually considered valid only if its correlation coefficient (R-squared) is

A

greater than 0.90

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4
Q

The reducing agent beta mercaptoethanol

A

Breaks disulfide bonds in proteins which ensures that all proteins will have a uniform linear shape

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5
Q

The dye Coomassie Blue G-250 forms colored complexes with

A

proteins

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6
Q

1 x 10^6 uL

A

1L

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7
Q

1000 mL

A

1L

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8
Q

1kda

A

1000 Da

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9
Q

An SDS-coated protein has a positive/negative charge

A

negative

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10
Q

Unpolymerized acrylamide monomer is toxic but polymerized acrylamide is ______

A

nontoxic

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11
Q

What is the function of bisacrylamide in an SDS-PAGE gel?

A

Crosslinker “bridges” between the linear acrylamide chains

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12
Q

Why is it important that there are no leaks from the inner chamber when loading an SDS PAGE gel? What will happen if the buffer is too low?

A

incomplete circuit

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13
Q

If the cilia of a Tetrahymena cell are damaged or their function is inhibited, the rate of food vacuole formation will increase/decrease/remain the same

A

decrease

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14
Q

True or False. The cilia found on Tetrahymena cells have the same fundamental structure as cilia found on human cells

A

True

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15
Q

Why is phase contrast microscopy useful for viewing Tetrahymena cells?

A

It does not require use of toxic chemical stains and uses changes in refractive index to play on light so cells are visible with more detail.

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16
Q

Tetrahymena food vacuoles fuse with an organelle called a _______ where the food particles are digested.

A

lysosome

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17
Q

True or False. Eukaryotic cells must be stained with chemical dye before they can be seen by phase contrast.

A

false

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18
Q

Describe 2 potential health concerns about e-cig use:

A

Metal nanoparticles in the vape get in lungs and cause damage in lungs
Cancerous ingredients in vapor that can cause cancer with sustained use

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19
Q

The use of e-cigs doubled between 2011 and 2012- True/False

A

True

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20
Q

Explain why metal particles are found in e-cig vapor

A

Metal coil in vape heats up to vaporize nicotine, nanoparticles of metal get released as well- so small that can get in lungs

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21
Q

Are propylene glycol safe ingredients in e-cig liquid?

A

No- supposed to be eaten, not inhaled. The effects are still unknown

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22
Q

How long have e-cigs been available in the US?

A

Made by Chinese pharmacist in 2003, been around since 2010

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23
Q

Purpose of homogenizing and chopping up tissue-

A

increases surface area and breakdown cells

24
Q

Purpose of detergent in homogenization buffer

A

SDS is a detergent that binds to proteins, causing them to lose their normal 3-D shapes

25
Q

Purpose of 2 high speed centrifugation step

A

separates pellet with unwanted debris

26
Q

High yield

A

protein is extracted efficiently from the tissue

27
Q

High quality

A

protein is not degraded or contaminated

28
Q

how to get high yield

A

chop and homogenize tissue well to maximize surface area, and vortex thoroughly to ensure that most cells are lysed.

29
Q

how to get high quality

A

keep the samples on ice to inhibit proteases in the tissue, and avoid introducing external proteases

30
Q

In coomassie dye in bradford assay: More blue color =

A

more protein present

30
Q

In coomassie dye in bradford assay: More blue color =

A

more protein present

30
Q

SDS adds ______ charge to the proteins

A

negative

31
Q

Proteases =

A

enzymes that split protein molecules into fragments

32
Q

Larger proteins will move through the gel _________. Smaller proteins will move ______

A

slowly, quickly

33
Q

The ______-charged proteins move down the gel toward a _________charged electrode

A

negatively, positively

34
Q

(buffering compound that adjusts pH to 6.8)

A

Tris

35
Q

(reducing agent that breaks disulfide bonds)

A

Beta mercaptoethanol

36
Q

Protein mobility

A

Rf = band distance (mm) / dye front distance (mm)

37
Q

Destaining removes the excess Coomassie dye from the background polyacrylamide of the gel, allowing bands where Coomassie is bound to protein to be seen.
T/F

A

T

38
Q

The single greatest advantage of phase-contrast microscopy

A

does not require the use of toxic chemical stains, making it the best method for observing living cells and tissues

39
Q

Core of cilia is composed of

A

microtubules

40
Q

microtubules are connected by the motor protein

A

dynein

41
Q

dynein movement causes microtubules to slide past one another
T/F

A

T

42
Q

cytoproct

A

The vacuole then re-fuses with the cell membrane and its remaining contents are expelled by this

43
Q

In the Bradford assay, how does the light absorbance of Coomassie Blue change when the dye binds to protein?

A

The absorbance increases

44
Q

What was the purpose of the protein standard curve in your Bradford assay?

A

The standard curve provided a reference for determining the concentration of protein in the “unknown” samples, by establishing the relationship between protein concentration and absorbance

45
Q

Name two factors that must be controlled to ensure that you obtain a high-quality extract when extracting protein from tissue.

A

Temperature (keep the sample cold to slow protease activity)
Proteases (avoid introducing materials that might include them)
Contamination (centrifuge to remove undesired materials)

46
Q

Which piece of lab equipment would allow you to separate water soluble components of a suspension from insoluble components?
Vortex
Microcentrifuge
Micropipette
Spectrophotometer

A

microcentrifuge

47
Q

allows you to mix suspensions or solutions

A

vortex

48
Q

measures small volumes of liquid

A

micropipette

49
Q

measures light absorbance

A

spectrophotometer

50
Q

Before SDS-PAGE, protein samples must be heated in a solution containing SDS and a reducing agent. Explain the reason for this.

A

The procedure denatures proteins, breaks covalent disulfide bonds, and gives polypeptides a uniform ratio of negative charge to mass.

51
Q

Which one of these microscope parts is the first to produce a magnified image of the specimen?
Ocular
Condenser
Objective
Rheostat

A

objective

52
Q

further magnify the image produced by the objective.

A

Oculars

53
Q

focuses light on the specimen

A

The condenser

54
Q

controls lamp brightness.

A

rheostat

Cell BIO LAB (7 decks)

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