Tag: biochemical techniques

Questions Related to biochemical techniques

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 

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

  1. D, C, A, B

  2. A, B, C, D

  3. C, B, A, D

  4. B, A, D, C.

Show answer
Correct Option: A
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'.

DNA probe is used in:

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

  1. Gel electrophoresis

  2. Northern blotting

  3. DNA finger printing

  4. Interferon synthesis

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Correct Option: C

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

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

  1. Polymerase chain reaction

  2. Electrophoresis

  3. Restriction mapping

  4. Centrifugation

Show answer
Correct Option: B
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.

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

  1. 1

  2. 2

  3. 3

  4. 100

  5. 1,000

Show answer
Correct Option: C
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.

Fractional distillation is used to separate liquids which differ in their boiling point by :

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

  1. $5$

  2. 10 to 20

  3. $30-80$

  4. $3$

Show answer
Correct Option: B,C

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

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

  1. $CH _{4}-SP^{3}$

  2. $C _{2}H _{4}-sp^{2}$

  3. $C _{2}H _{2}-sp$

  4. All of these

Show answer
Correct Option: D
Explanation:

CH4− Alkane SP3

C2H4- Alkene SP2
C2H2- Alkyne SP

Hence all hybridization of carbon are correct

Steam distillation is used for the extraction of_____________.

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

  1. essential oil

  2. higher alkynes

  3. mineral oils

  4. fatty acids

Show answer
Correct Option: A
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.

How will you separate mixture of two gases? 

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

  1. Fractional distillation technique

  2. Grahams law of diffusion technique

  3. Osmosis

  4. Chromatography

Show answer
Correct Option: A
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.

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

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

  1. Vacuum distillation

  2. Steam distillation

  3. Fractional distillation

  4. None of the above

Show answer
Correct Option: B
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. 

Simple distillation can be used to separate:

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

  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

Show answer
Correct Option: B
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.