Brainscape's Knowledge GenomeTM

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


See full index

BC 2- > Labs > Flashcards

Labs Flashcards

1
Q

One of the most numerous protein-protein interactions are __

A

One of the most numerous protein-protein interactions are enzymes

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

How does the configuration of enzyme aid it in it’s function?

A

Each enzyme has a characteristic three-dimensional (3- D) shape
By their specific configuration, they hold the reactant molecules in close proximity and in the correct orientation for the reaction to occur
Their specificity is also due to their structure

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

What is lactose composed of?

A

monosaccharides glucose and

galactose

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

Where does lactase function in the body?

A

Small intestine

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

Describe lactose pathway in the body when lactase activity is low

A

With low lactase activity in the small intestine, undigested lactose is passed into the colon where bacteria ferment the sugar to hydrogen gas and organic acids.

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

Where is the gene for lactase found?

A

The gene for the production of lactase is located on chromosome two.

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

How do genomes of lactose intolerant and tolerant people differ? WHat does it allow to conclude?

A

there does not seem to be any difference in the DNA of individuals with or without lactase activity. Rather the differences
are in the messenger RNA (mRNA), which may indicate that the primary regulation of this enzyme occurs during translation.

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

Describe strip test for lactose

A
  1. Take a 1000 ul of milk sample and place it in a glass test tube + 500ul of Lactase
  2. dip the test area of the strip into the sample to test for the presence of free glucose.
  3. Remove any excess milk by gently tapping the strip against the side of the test
    tube.
  4. Place the test strip on a piece of paper towel and read after 30 seconds.
  5. Compare the colour to the chart on the side of the bottle and record the amount of
    free glucose in each sample
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the sugars in rice, soy and cow milks

A

Cow Lactose
Soy Sucrose
Rice Glucose

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

At what temp does lactase get denatured? pH?

A

Temp- above 57

pH- above 10 or 12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Fats readily dissolve in other fat solvents such as __ or __

A

Fats readily dissolve in other fat solvents such as hexane or acetone

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

What is saponification

A

When lipids are hydrolyzed with an alkali such as NaOH, it is split into glycerol and the fatty acid(s). This process is called saponification, and the sodium salt of the fatty acid produced is soap.

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

How can one determine the degree of bond saturation?

A

one can utilize a halogen solution such as
iodine or bromide. The extent of saturation can be demonstrated by the degree of
decolourization of these solutions after it comes in contact with the lipid.
Each type of lipid can be classified by its iodine number. The more double bonds a fat contains, the more halogen is required; thus, a high iodine number means a high degree of unsaturation. Generally, animal fats
are saturated and vegetable fats are unsaturated.

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

How can one determine the length of a lipid?

A

Differences in chain length can be distinguished by the differences in intensity of colour due to the absorption of a chemical known as Sudan III. Longer fatty acid chains give more intense and deeper colour.

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

What do you use in saponification number determination experiment?

A

non-polar solvent (50% isopropanol and 50% hexane)
KOH
phenolphthalein
titrating thing

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

Name monosaccharides

A

glucose, fructose and galactose

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

Name disaccharides and their constituents

A 
sucrose = glucose + fructose. 
lactose = glucose + galactose. 
maltose  = glucose + glucose.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

__ and __ are major sources of carbohydrates for humans

A

Starch and sucrose are major sources of carbohydrates for humans

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

__ is the most common carbohydrate in the human diet

A

Starch is the most common carbohydrate in the human diet

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

Glycogen synthesis happens mainly in the __.

A

Glycogen synthesis happens mainly in the liver.

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

Describe 1st step of glycogen synthesis

A

uradine triphosphate (energy source) is used to convert glucose-1-phosphate to a compound known as UDP-glucose.

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

Describe 2nd step of glycogen synthesis

A

The enzyme, glycogen synthase uses these UTP glucose monomers to form a chain of
glycogen (α (1→4) glycosidic bond)

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

Describe how does glycogen branching occur

A

A protein known as glycogenin and a second
enzyme (amylo (α1→4) to (α1→6) transglycosylase is needed to allow for
branching of the glycogen to occur. These
two compounds catalyze a transfer of last
several monomers residues from the nonreducing end of the chain to the C-6
hydroxyl group of a glucose molecule in the middle of the chain. This branching will only occur if a chain contains a sufficient number of residues

24
Q

Describe how does glycogenolysis occur

A

The enzyme, glycogen phosphorylase, attacks the Pi on the α 1 → 4 linkages between glucose units at one end and second enzyme attacks the branching points

25
Q

Describe benedict’s test

A

Benedict’s test is used to detect the presence of reducing sugars. Benedict’s is a clear blue solution of mainly copper sulphate.
Solution of benedict + sugar has to be boiled for 3 min
A positive test is the formation of a precipitate within 5 minutes. The colour of the solution should be brick red.

26
Q

Describe bial’s test

A

Bial’s reagent is used to test for pentoses. It contains orcinol, HCl, and FeCl3. The orcinol forms coloured condensation product. A positive test is indicated by the formation of a bluish product. All other colours indicate a negative
Sugar + reagent have to be in a hot water bath (almost boiling) for 5 minutes.

27
Q

Describe Seilwanoff’s test

A

Seilwanoff’s test is a test for ketoses. A positive test is the formation of orange to red/red wine colour within 5 minutes without the formation of a precipitate. Sucrose also tests positive with this assay.
Sugar + reagent have to be in a hot water bath (almost boiling) for 4 minutes.

28
Q

Describe what is a Molisch’s test

A

Molisch’s test is a test for all carbohydrates; however while monosaccharide react quickly to this test, disaccharides and polysaccharides react more slowly. A positive test is seen when a band of purple appears between the interface of the concentrated sulphuric acid and the sugar solution.

29
Q

What’s a reducing sugar?

A

reducing sugars have either a free aldehyde functional group or a free ketone functional group as part of their molecular structure.

30
Q

How’s molisch test done?

A
  1. In a test tube, place 2 ml. of glucose solution.
  2. Add 2 drops of Molisch’s solution.
  3. Mix gently
  4. VERY SLOWLY add 2 ml of concentrated sulphuric acid but dropper so 2 distinct
    layers form.
  5. A positive test is the formation a purple band at the interface of the two solutions.
31
Q

What is DNA gel electrophoresis?

A

Gel electrophoresis is a technique used for the separation of deoxyribonucleic acid, ribonucleic acid, or proteins using an electric current applied to a gel matrix

32
Q

How are DNA molecules separate in gel electrophoresis?

A

By placing the molecules in the gel and applying an electric current, the molecules will move through the matrix at different rates, usually based on size. Nucleic acids have a net negative change and move from negative electrodes located near the top of the gel to positive electrodes at the bottom of the gel. Movement is based on charge and size.

33
Q

What is rate of movement ofDNA particles related to

A

Migration of the fragments in an electrical field move at a rate that is inversely
proportional to the log10 of their size.

34
Q

What is the gel used in electrophoresis?

A

In most cases the gel is a cross linked polymer whose composition and porosity is chosen based on the specific weight and
composition of the target to be analysed.

35
Q

WHat is agarose?

A

Agarose is a gel used in electrophoresis
It is a long chain polysaccharide isolated from seaweed. It is heated in a buffer solution and then cooled it forms a matrix (gel) with buffer solution trapped inside. This
gives rise to a porous lattice in the buffer solution which enables nucleic acid molecules to slip through the lattice holes in order to move toward the positive pole. Larger molecules will be slowed down more than smaller molecules as they will be more
easily trapped in the pores while smaller molecules will pass through.

36
Q

What is another factor that can affect the

migration of the nucleic acid beside the size?

A

conformation (whether the nucleic acid is single or double stranded) and the charge are also important. As a result, a mixture of large and small fragments of nucleic acids that has been run through an agarose gel will be separated by size

37
Q

What is the influence of agarose % concentration?

A

Agarose concentration can be varied from 0.75 % to 2 %. As the concentration of the gel rises, the pore size changes. Higher percentage gels have smaller pores which retards nucleic acids movement. High percentage gels are excellent for allowing the separation of small fragments of nucleic acid and lower percentage gels are typically used to separate larger fragments.

38
Q

What is a comb?

A

A “comb” is used to create wells in the gel to allow for the loading of nucleic acids. These wells are small grooves in the gel where the nucleic acid is placed before running the gel to hold it in place. The well size determines how much of the nucleic acid sample can be loaded.

39
Q

what is the most common buffer in gel electrophoresis?

A

The most common buffer used in gel electrophoresis is Tris Borate EDTA (TBE)

40
Q

Describe Tris Borate EDTA

A

The Tris maintains a slightly basic condition (pH 7.3). EDTA prevents enzymatic degradation of nucleic acids as it chelates magnesium ions.

41
Q

How does the dye work in Tris Borate EDTA and what is the purpose

A

The dye moves more quickly than the nucleic acids and allows tracking the movement of the fragments. It is used as an indicator to alert the researcher to turn off Bovine Trypsin
the power on the electrophoresis chamber before the invisible nucleic runs off the end of the gel. The dye also makes the solution more visible, making it easier to work with during the initial phases of preparation and loading.

42
Q

What is a ladder?

A

It is a solution of known fragment sizes, which is a standard used to compare sizes of unknown nucleic acids. The ladder usually contains regularly spaced sized samplw

43
Q

What is Ethidium bromide used for?

A

It is commonly used in molecular biology laboratories for visualizing nucleic acids using electrophoresis and other gel-based nucleic acid separation methods.
Ethidium bromide fluoresces when exposed to ultraviolet light and exhibits a vivid red-orange color when bound to nucleic acids. UV-transilluminator are used to visualize the nucleic acid bands after running the gel

44
Q

What is a downside of Ethidium bromide?

A

Ethidium Bromide however is quite dangerous to use as it is a carcinogen and a
mutagen

45
Q

What is an alternative for Ethidium bromide?

A

Today, other products can be used such as SafeView™. These dyes were developed to
replace the more toxic Ethidium Bromide because they appear to be non-carcinogenic. However, most of these alternative are quite expensive so many labs still utilize the more toxic dye.

46
Q

Describe DNA base bonding

A

Cytosine always bonds with Guanine and Adenine always bonds with Thymine

47
Q

Instead of containing _, RNA contains a different base known of __

A

Instead of containing thymine, RNA contains a different base known of uracil

48
Q

How can gel electrophoresis results be visualized and identified?

A

Results can be analysed quantitatively by visualizing the gel with UV light and a gel
imaging device. The image is recorded with a computer operated camera, and the intensity of the band or spot of interest is measured and compared against standards or markers loaded on the same gel.The measurement and analysis are mostly done with specialized
software.

49
Q

What is used to make a gel for DNA electrophoresis . Describe the process

A
  1. Weigh out 2.0 g of agarose into a 250mL conical flask.
  2. Add 100mL of 1X TAE
  3. Heat for around 30s – 1 min in the microwave to melt. Swirl.
  4. Add 2 µL of Ethidium Bromide. Swirl
  5. Pour the gel into the gel tray when the conical flask is warm. Be very careful to prevent any air bubbles. Use tips to remove bubbles..
50
Q

What is the voltage for gel electrophoresis?

A

70 -100 V

51
Q

Describe the principle of chromatography

A

They all have a stationary phase (a solid and/or a liquid supported on a solid) and a mobile phase (a liquid or a gas). The mobile phase flows through the stationary phase and carries the components of the mixture or chemical with it.
Different components travel at different rates.

52
Q

It is important that the solvent level is _ the line with the spots(amino acids) on it

A

It is important that the solvent level is below the line with the spots(amino acids) on it

53
Q

Describe solvent used for amino acid detection?

A

solvents are polar binary, ternary or more complex mixtures of water, alcohols, and acids or bases

54
Q

How are amino acids made visible on the paper?

A

At 100°C, ninhydrin reacts with α-amino acids to form a purple colour, allowing the amino acids to be visualized

55
Q

What is the formula for Rf value?

A

distance travelled by compound/ distance travelled by solvent

56
Q

How is the distance traveled by a compound measured?

A

The distance travelled by the compound is measured by measuring from the start line to the middle of the coloured spo

BC 2- (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions