Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biomedical Lab > Lab 10 > Flashcards

Lab 10 Flashcards

1
Q

Amino acids have a ___ group and a ____ group

A

Carboxyl group (COO-) and an amino group (NH2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the isoelectric point?

A

The pH at which a protein carries no net charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Below the isoelectric point, proteins carry a net ___ charge

A

POSITIVE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

It is preferable that the polar and charged amino acids lie where on the protein? Why?

A

On the surface so that the protein can form hydrogen bonds by donating or accepting a proton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What lies in the MIDDLE of a folded protein?

A

A hydrophobic core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Chromatography is a procedure used to….

A

Separate individual compounds present in a sample based on the difference of their physical and chemical properties and to determine the relative concentration of the compound in the mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some physical properties that that chromatography can separate

A

Size, binding affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some chemical properties that chromatography can separate

A

Polarity, charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Before a sample is analyzed using chromatography, it must be….

A

Completely soluble in solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The technique of chromatography consists of 3 steps:

A
  1. Transfer of sample onto or into the chromatography device
  2. Movement/migration through the chromatography device
  3. Detection of the compounds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The 2 compounds present in all types of chromatography are the ___ phase and ___ phase

A

Stationary phase and mobile phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The higher the hydrophobicity value, the _____ the hydrophobicity

A

Greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name 4 very hydrophobic amino acids

A

Leucine, isoleucine, phenylalanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Detection of the compounds in chromatography is performed how?

A

Visually using colorimetric reagents or by spectrophotometric analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give an example of a compound that forms colored products with reagents

A

Amino acids with ninhydrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are colorless compounds detected in chromatography?

A

By measuring the absorbance of the elute using a spectrophotometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In some cases, a ________ is incorporated into the matrix to visualize spots under _____ uv (____nm)

A

In some cases, a FLUORESCENT COMPOUND is incorporated into the matrix to visualize spots under SHORT-WAVE uv (254nm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Stationary phase is also known as a “____”

A

Matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The stationary phase can be a ____ or _______

A

The stationary phase can be a THIN LAYER ON SOLID SUPPORT (glass/plastic) or PACKED IN A COLUMN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How are the compounds separated in chromatography?

A

Based on their relative affinity to the stationary and mobile phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

If the compound has a greater affinity for the mobile phase as compared to the stationary phase, the compounds will move with the ____ phase

A

Mobile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Each compound in the sample mixture moves _____ through the stationary phase

A

At different speeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

WHY does each compound in the sample mixture move at different speeds through the stationary phase?

A

Because of the relative affinity of each compound to the mobile phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Explain NORMAL PHASE chromatography

A

Normal phase chromatography has a relatively more POLAR stationary phase and is usually made of SILICA gel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
In normal phase chromatography, will polar or nonpolar compounds bind strongly to the matrix while ____ compounds will move quickly
In normal phase chromatography, the stationary phase is polar. THEREFORE, polar compounds will bind strongly to the matrix while hydrophobic compounds will move quickly
26
Is silica gel acidic or basic?
Acidic
27
Since silica gel is acidic….
It offers poor separation of basic samples and causes a deterioration of acid-labile colecules (easily destroyed by an acidic environment)
28
In reversed phase chromatography, the matrix particles (silica gel) have been coated with compounds with ______ side chains
HYDROPHOBIC
29
In reversed phase chromatography, the matrix particles have been coated with compounds with hydrophobic side chains. What does this mean?
The matrix has a higher affinity for hydrophobic compounds than polar compounds. Thus, the highly polar compounds are easily eluted using a polar mobile phase (eluding solvent)
30
Ion-exchange chromatography has a ____ matrix which binds to which molecules?
Ion-exchange chromatography has a CHARGED matrix which binds to molecules with an opposite charge
31
In ion exchange chromatography, negatively charged proteins will bind to a ____ charged column
Positively
32
The mobile phase can be a ___ or ____
Liquid or gas
33
The mobile phase moves through the ___ phase via…..
Stationary phase via capillary action or with the use of pressure
34
How many solvents can be mixed together in varying proportions to obtain the best polarity (or pH) for separation?
2 or more
35
What are some common mobile phases used in liquid chromatography?
Water (polar solvent), ethanol and methanol (less polar solvents)
36
For more sophisticated chromatographic separations, what kind of solvents are used?
Other organic solvents such as aniline and octane
37
Name 3 types of chromatography
Size exclusion chromatography, thin layer chromatography, high performance (or pressure) liquid chromatography SEC, TLC, HPLC
38
What kind of chromatography was used to separate DNA and proteins based on their size or molecular weight in previous labs
Size exclusion chromatography (SEC)
39
Which chromatography is a simple and rapid technique?
Thin layer chromatography
40
What chromatography is used in this last lab?
Thin layer chromatography
41
Explain the process of thin layer chromatography
The sample is spotted onto a stationary phase fixed onto the surface of a glass plate. The bottom edge of the plate is placed in a mobile phase. The mobile phase moves through the stationary phase by capillary action. A compound with GREATER AFFINITY TO THE MOBILE PHASE MOVES UP THE GLASS PLATE ALONG WITH THE MOBILE PHASE
42
After the separation is complete, the TLC plate is called a _____
Chromatogram
43
Most compounds in TLC are _____ and visualized how?
Colorless, visualized using UV light or by using a reagent which reacts with the compound to give a colored spot on the plate
44
What does RF value stand for?
Retardation factor
45
Rf values are used to….
Compare the movement of the individual compounds in the sample mixture
46
Rf value =
Distance traveled by the compound in the mixture/ distance traveled by the mobile phase
47
The vale for Rf is always between __ and ___
0-1
48
How can compounds with the same Rf values be compared?
They can be compared with a known standard to assist in identification of the compound
49
Amino acids are _____
Colorless and cannot be visualized by our eyes
50
How can amino acids be visualized?
By using a color reagent (ninhydrin)
51
Ninhydrin will react with most amino acids to give what color?
Purple
52
What test is commonly used to visualize TLC spots?
The Ninhydrin test
53
HPLC stands for….
High performance (or pressure) liquid chromatography
54
HPLC uses a ___ stationary phase packed in a ____
Solid stationary phase packed in a column
55
The mobile phase is also known as the ____
Eluent
56
In HPLC, what happens to the mobile phase?
It is pushed through the packed column under constant pressure using pressure pumps
57
How many pumps are often used in HPLC? WHY?
2 So that the polarity of the mobile phase can be automatically changed during the run
58
Reverse phase HPLC is most common in chromatographic analysis of what?
Drugs and body fluids
59
Many drugs are hydrophilic or hydrophobic?
Hydrophobic
60
Since many drugs are hydrophobic, ____ matrices must be used because…..
Hydrophobic matrices must be used so that they could retain hydrophobic compounds (such as drugs) and remove polar contaminants
61
In HPLC, a spectrophotometer continuously measures the absorbance of the _____
Eluent as it leaves the column
62
A CHROMATOGRAPH is a……
Recording of absorbance changes
63
When a compound is eluted, there is a ___ in absorbance
Increase
64
When a compound is eluted, there is an increase in absorbance, recorded as a ____ on the chromatograph
Peak
65
The chromatograph not only shows a peak, but also….
The time of the elution, and the area of the peak
66
The area of the peak is used to calculate……
The concentration of the compound (by measuring the area under the curve)
67
What is retention time? (Rt)
The time required for eluting the compound through the column
68
A compound attracted more strongly by the mobile phase will have a ____ retention time
Shorter, as it will move rapidly through the column
69
The identity and concentration of the saluted compounds is determined by comparing…
The retention times and the chromatographs with known standards
70
Salicylic acid has a small retention time, meaning it is relatively ____
Polar
71
Between lysine, glycine, and phenylalanine, which is the most hydrophilic (_____est Rf value)
Lysine is the most hydrophilic (lowest Rf value)
72
A higher retention time = the ____ spinning in the column
Longer

Biomedical Lab (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions