Font size
WorksheetsBiochemistry Lab Quiz
Total questions: 49
Worksheet time: 27mins
In Benedict's test ___ colour precipitate was obtained with reducing sugars
Violet
Red
Orange
Purple
___ test indicates the absence of monosaccharides
Barfoed's
Fehling's
Molisch's
Selivanoff's
Phenyl hydrazine test yield ___ shaped crystal for Galactose
Rod
Cylinder
Petal
Round
In Selivanoff's test, if there is no characteristic change it indicates the
Absence of ketose sugar
Presence of ketose sugar
Absence of monosaccaride
Presence of monosaccaride
In Fehling's test for maltose, ___ colour precipitate was obtained
Violet
Orange
Red
Reddish brown
In Molisch's test, (test solution + Molisch's reagent + ____) is added
Con. Sulphuric acid
Dil. Sulphuric acid
Con. Hydrochloric acid
Dil. Hydrochloric acid
In phenyl hydrazine test, yellow sunflower shaped crystal indicates the ___
Absence of maltose
Absence of ketose sugar
Presence of ketose sugar
Presence of maltose
In Molisch's test, violet ring indicates the presence of
Ketose sugar
Carbohydrate
Reducing sugar
Monosaccharide
___ test is used to identify reducing sugar
Barfoed's
Fehling's
Selivanoff's
Osazone
Which test would indicate the presence or absence of starch in a sample?
Barium Chloride Test
Biuret Solution Test
Iodine Test
Glucose Test
Which among the following carbohydrates will give blue color at the end of Benedict's test?
Glucose
Galactose
Lactose
Sucrose
Which is a non-reducing sugar?
Maltose
Sucrose
Lactose
None of the above
Reducing sugars are differentiated from non-reducing sugars
Iodine test
Molisch's test
Seliwanoff's test
Benedict's test
The general test for detection of cabohydrates is
Iodine test
Molisch's test
Barfoed's test
Osazone test
Olive oil is tested with iodine.
What result is to be expected?
Iodine turns from yellow to dark blue
Iodine turns from dark blue to yellow
Iodine turns from yellow to purple
Iodine remains yellow
What is the reagent to test for reducing sugars?
Bial's reagent
Iodine
DNS reagent
Biuret reagent
Which of the following sugars will not test positive in Molisch's test?
Triose
pentose
ketohexose
aldohexose
Fructose tests positive in Fehling's test as it is a/an
ketohexose
alpha- hydroxy ketohexose
aldohexose
pentose
Which one of the following will test negative for Iodine test?
glycogen
starch
cellulose
amylose
Which part of starch is responsible for testing positive in Iodine test?
Amylose
Amylopectin
Rochelle's salt is used in which of the following solutions?
Fehling's
Benedict's
Seliwanoff's
Molisch's
What is the role played by sodium bicarbonate in Benedict's solution?
Chelate copper sulfate
Maintain pH
Supply carbon dioxide
An additive
Copper sulfate is an ingredient of
Molisch's Reagent
Benedict's Reagent
Seliwanoff's reagent
Iodine solution
After performing Benedict's test, which colour in the resulting solution corresponds to the highest concentration of reducing sugar present?
Light blue
Green
Orange
Red
Which one of the following is present in Seliwanoff's reagent?
Conc Sulfuric acid
Conc Nitric acid
5N Hydrochloric acid
Conc Hydrochloric acid
The copper sulfate in Fehling's solution specifically reacts to reducing sugars as
it is in a chelate form with Rochelle's salt
it can interact with free aldehyde groups only
it can not act with other reducing groups
all of these
The red coloured precipitate formed in Fehling's test is due to the presence of
Rochelle's Salt
cuprous oxide
cupric oxide
copper sulphate
------------ method estimates the amount of total sugar in the sample
Nelson Somogyi method
Lane Eynon method
Anthrone method
Munson and Walker method
The color of the positive result for Iodine test
Blue - black
Yellow - orange
Pink
Reddish-violet
The following are the sugars that formed brick red precipitate during Barfoed test, EXCEPT:
Sucrose
Lactose
Glucose
Fructose
The following are the sugars that formed needle shaped or broomstick crystals during Osazone test, EXCEPT:
Galactose
Xylose
Glucose
Fructose
Primary element found in every Fehling's reagent
Iron
Copper
Sulfur
Magnesium
This test will give blue green colored complex as the positive result for the presence of pentoses.
Bial's orcinol test
Fehling's Test
Seliwanoff's Test
Barfoed Test
When preparing a blank for spectrophotometer, how do you choose the correct liquid?
Use the same liquid that is mixed with your substance of interest.
Use ethanol for proteins and water for starches.
Use distilled water whenever possible.
Use methanol whenever it is available.
What are some steps to follow when preparing a standard curve?
Measure several samples of known dilution at one specific wavelength and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure two samples of known dilution at one specific wavelength and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure several samples of known dilution at many wavelengths and plot their absorbance on a graph vs. concentration. Then add a line of best fit.
Measure several samples of known dilution and then use a line of best fit to determine their wavelength.
In spectrophotometer, the amount of light absorbed by a sample is called
Absorbance
Transmittance
Hue
Saturation
Q. chromatography separates the mixture of dyes on the basis of their ----------------------------
solubility
boiling point
boiling point
boiling point
A substance is soluble if it can be dissolved.
In paper chromatography, the most soluble solute _____________________ .
travels furthest away from the start point
does not move from the start point
stays closest to the start point
can be found in the middle of the chromatogram
.
What is chromatography?
A way to see pretty colors
A form of distillation
A laboratory technique used to separate a mixture.
In chromatography, the stationary phase can be ___________ supported on a solid.
Solid or liquid
Liquid or gas
Solid only
Liquid only
The Rf value for the red component is
0.3
0.7
10
7
The presence of more than one spot on the TLC plate shows that____
the Rf value is higher than it should be
the solvent used was too dilute
impurities are present
too much solvent was used
Thin layer chromatography is
partition chromatography
electrical mobility of ionic species
adsorption chromatography
none of the above
the number of milligrams of potassium hydroxide required to neutralize the free fatty acids in 1 g of the substance
Acid value
Iodine value
Saponification value
the number of milligrams of potassium hydroxide required to neutralize the free fatty acids and saponify the esters contained in 1 g of the substance
Saponification value
Acid value
Iodine value
It indicates the degree of unsaturation.
Iodine value
Saponification value
Acid value
What is electrophoresis?
a. The study of electrical properties of food
b. The separation of charged molecules based on their mobility in an electric field
c. The measurement of electrical conductivity in food samples
d. The production of electricity using food as a fuel source
Which of the following is true about polyacrylamide gel electrophoresis (PAGE)?
a. It is used to separate proteins based on size and charge
b. It is exclusively used for DNA analysis
c. It requires the use of agarose gel as a matrix
d. It is used for the separation of lipids
What is the purpose of sodium dodecyl sulfate (SDS) in SDS-PAGE?
a. To denature proteins
b. To enhance protein binding to the gel matrix
c. To visualize protein bands
d. To neutralize the charge of proteins
