Tag: biochemical techniques

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Questions Related to biochemical techniques

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

A mixture containing DNA fragments, A, B, C and D, with molecular weights of A + B = C, A > B and D > C, was subjected to agarose gel electrophoresis. The positions of these fragments from cathode to anode sides of the gel would be 

  1. D, C, A, B

  2. A, B, C, D

  3. C, B, A, D

  4. B, A, D, C.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Shorter lengths of DNA move faster than longer lengths so move further in the time the current is run. So, since D has the heaviest weight (implying it has the longest strand), it will tend to remain far from the anode. B being a lightest fragment moves farthest from the cathode.
  • Hence The positions of these fragments from cathode to anode sides of the gel would be D, C, A, B,
  • So,the correct answer is 'D,C,A,B'.
Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

DNA probe is used in:

  1. Gel electrophoresis

  2. Northern blotting

  3. DNA finger printing

  4. Interferon synthesis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

DNA probes are essential in DNA fingerprinting to identify specific variable number tandem repeats (VNTRs) or other markers after they have been separated by electrophoresis and transferred to a membrane.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by

  1. Polymerase chain reaction

  2. Electrophoresis

  3. Restriction mapping

  4. Centrifugation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A restriction enzyme (or restriction endonuclease) is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. The DNA fragments are separated by electrophoresis, a process that involves application of an electric field to cause the DNA fragments to migrate into an agarose gel. The gel is then stained with a methylene blue stain to visualize the DNA bands and may be photographed. 

Thus, the correct answer is option B.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna
Read the passage and answer the following question.
Bacterial plasmid sequence: ATCCCA...1000 more nucleotides..... ..ATTAAGGCCTTACAGGACCCCGGAATGAGAGTA ATGGGCTATTCAGGTA... 2000 more nucleotides
Human DNA sequence: ATATCGTAATGTTGGTG..500 more nucleotides.. ..GTGTCAGGACGGGTGAAAGCCAGGACGCCGAATCG...5000 more nucleotides
The underlined DNA signifies the gene of interest were trying to clone Restriction enzyme sequences:
          ERA  I      GTAATG
          CRO  I     CAGGAC
           MEM II    GCCG
How many bands would show up on a 1 percent agarose gel if the plasmid was cut with both ERA I and CRO I?

  1. 1

  2. 2

  3. 3

  4. 100

  5. 1,000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CRO I has restriction sequence CAGGAC and ERA I has the restriction sequence GTAATG. When both the enzymes are used to cleave the bacterial and the human DNA, there are three fragments produced. So, only three bands will show up on the agarose gel as the restriction enzymes will cut very close. Thus, the correct answer is option C.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Which of the following is correct for hydbridization of C-atom?

  1. $CH _{4}-SP^{3}$
  2. $C _{2}H _{4}-sp^{2}$
  3. $C _{2}H _{2}-sp$

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

CH4− Alkane SP3

C2H4- Alkene SP2
C2H2- Alkyne SP

Hence all hybridization of carbon are correct

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Steam distillation is used for the extraction of_____________.

  1. essential oil

  2. higher alkynes

  3. mineral oils

  4. fatty acids
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Steam distillation is used to separate essentials oils so that the temperature goes nowhere near their boiling points,
which minimises the risk of decomposition.
Steam distillation is used and not simple distillation for separating essential oils.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

How will you separate mixture of two gases? 

  1. Fractional distillation technique

  2. Grahams law of diffusion technique

  3. Osmosis

  4. Chromatography
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A mixture of two gases can be separated by fractional distillation technique. Fractional distillation is a process by which components in a chemical mixture are separated into different parts called fractions according to their different boiling points.

Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

___________ is a separation process for temperature sensitive materials like natural aromatic compounds.

  1. Vacuum distillation

  2. Steam distillation

  3. Fractional distillation

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
True (2)
Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds. It once was a popular laboratory method for purification of organic compounds but has become obsolete by vacuum distillation.
In steam distillation, steam is used to lower the distillation temperatures of high boiling organic compounds that are immiscible with water. In the process, steam is charged to the matrix to volatilise the hydrophobic liquid and carry it across to a chilled condenser for subsequent liquefaction and separation from water. Variations in temperature, pressure and distillation time are used to control the process. 
Multiple choice chemistry organic chemistry : some basic principles and techniques methods of purification of organic compounds methods of purification - organic compounds biochemical techniques

Simple distillation can be used to separate:

  1. a mixture of benzene (b.pt. $80^{o}$C) and toluene (b.pt. $110^{o}$C)
  2. a mixture of ether (b.pt. $35^{o}$C) and toluene (b.pt. $110^{o}$C)
  3. a mixture of ethanol (b.pt. $78^{o}$C) and water (b.pt. $100^{o}$C)

  4. solid substances
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Simple distillation is used to separate volatile liquids from non-volatile impurities having sufficient difference in their in their boiling points.
A mixture of ether (B.P $35^{0}$) and toluene (B.P $110^{0}$) since they have large boiling point difference.