Biology

DNA and Genetics

985 Questions

DNA and genetics questions explore molecular biology, DNA replication, and genetic engineering techniques. These topics are essential for various competitive exams requiring a strong foundation in life sciences. Practice these questions to understand complex biological processes thoroughly.

DNA replication mechanismsGenetic engineering techniquesGene editing toolsPolymerase chain reactionDNA sequencing methods

DNA and Genetics Questions

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. electrophoresis

  2. restriction mapping

  3. centrigugation

  4. polymerase chain reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gel electrophoresis is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge. It is used in molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge.


Nucleic acid molecules are separated by applying an electric field to move the negatively charged molecules through a matrix of agarose or other substances. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving.

DNA Gel electrophoresis is usually performed for analytical purposes, often after amplification of DNA via polymerase chain reaction (PCR), but may be used as a preparative technique prior to use of other methods such as mass spectrometry, RFLP, PCR, cloning, DNA sequencing, or Southern blotting for further characterization.

So the correct option is 'Electrophoresis'.

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 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 zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Recombinant DNA bearing ampicillin resistance gene is passed in E. coli. The latter are spread on agar plates containing ampicillin. Then

  1. Both transformed and untransformed cells die

  2. Both transformed and untransformed cells grow

  3. Transformed recipient cells grow and untransformed cells die

  4. Transformed recipient cells die and untransformed cells grow
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ampicillin resistance gene acts as a selectable marker. Only cells that have taken up the recombinant plasmid (transformed cells) will survive and grow on the agar plates containing ampicillin, while untransformed cells will be killed.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Escherichia coli having plasmids for production of human insulin is cultured in medium containing __________.

  1. Glucose

  2. Maltose

  3. Lactose

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

In the production of human insulin using E. coli, the insulin gene is typically placed under the control of the lac promoter. Lactose (or its analog IPTG) is added to the culture medium to induce the expression of the gene.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Some of the steps involved in the production of humulin are given below. Choose the correct sequence
(i)   Synthesis of insulin gene artificially
(ii)  Culturing recombinant E. coli in bioreactors
(iii) Purification of humulin
(iv) Insertion of human insulin gene into a plasmid
(v)  Introduction of recombinant plasmid into E.coli
(vi) Extraction of a recombinant gene product from E. coli

  1. ii, i, iv, iii, v, vi

  2. i, iv, v, ii, vi, iii

  3. i, iii, v, vi, ii, iv

  4. iii, v, ii, i, vi, iv
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The correct sequence starts with synthesizing the gene (i), inserting it into a plasmid (iv), introducing the plasmid into E. coli (v), culturing the bacteria (ii), extracting the product (vi), and finally purifying the protein (iii).

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

In the technique of recombinant insulin production, the genes for $\alpha$- and $\beta$ - polypeptides were inserted into the plasmid by the side of __________.

  1. Antibiotic resistance gene

  2. Lac Z promoter gene
  3. $\beta$-galactosidase gene

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

In early recombinant insulin production, the insulin polypeptide genes were fused to the beta-galactosidase gene (lacZ) to ensure stable expression and to produce a fusion protein.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

Some of the steps involved in the production of humulin are given. Choose the correct sequence (i) Synthesis of gene (DNA) for human insulin artificially (ii) Culturing recombinant E.coli in bioreactors (iii) Purification of humulin (iv) Insertion of human insulin gene into plasmid (v) Introduction of recombinant plasmid into E. coli (vi) Extraction of recombinant gene product from E. coli.

  1. ii, i, iv, iii, v, vi

  2. i, iii, v, vi, ii, iv

  3. i, iv, v, ii, vi, iii

  4. iii, v, ii, i, vi, iv
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct sequence is

1.Synthesis of the gene for human insulin artificially.
2.Insertion of human insulin.
3.Introduction of recombinant plasmid into E.coli
4. Culturing recombinant E.coli in bioreactors.
5.Extraction of a recombinant gene product from E.
6.Purification of Humulin.
So, the correct option is 'i, iv, v, ii, vi, iii'.

Multiple choice zoology applications of biotechnology genetically engineered insulin application of biology in therapy and vaccine application of biotechnology in medicine

The first step in production of insulin using E.coli is

  1. Isolation of mRNA transcribing for insulin pancreas cell.

  2. Isolation of nucleotides transcribing for insulin from pancreas cell.

  3. Isolation of gene producing insulin from human DNA.

  4. Attachment of gene producing insulin from human DNA to plasmid using ligase.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Scientists synthesized in the laboratory genes for the two insulin "A" and "B" chains. This is accomplished by chemically linking together small pieces of DNA sequence and then joining them in a specific manner to form complete genes. Once the genes were synthesized, they are attached into circular DNA strands called as plasmids. The newly constructed plasmids containing the transplanted genetic material were introduced into a benign E. coli bacterial strain.

Multiple choice biology division for growth and reproduction cell division in embryo development structure of chromosome, cell cycle and cell division component of the cell different types of reproduction reproductive health of humans need of family planning tissues of animals mitosis reproductive health

In a culture of E.coli the cell population increased from $1.5 \times 10^6$ cells /ml to $ 12 \times 10^6$ cells/ml in 36 minute.The generation time is 

  1. 6 mt

  2. 9 mt

  3. 12 mt

  4. 18 mt
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At the start, the culture of E. coli has cell population of 1.5 X 10$^6$ cells/ml. After first generation, it will be doubled, that is 3 X 10$^6$ cells/ml. After second generation, it will be 6 X 10$^6$ cells/ml. After third generation, it will be 12 X 10$^6$ cells/ ml. It is given that for a cell population to increase from 1. 5 X 10$^6$ cells/ml to 12 X 10$^6$ cells/ml, it takes 36 minutes. It means, for 3 generation, it takes 36 minutes. So, its generation time is 36/3 = 12.

Thus, the correct answer option C.

Multiple choice commercial studies biotechnology: general introduction introduction to genetic engineering and production of insulin use of efficient and eco-friendly technology genetics of the future

The genes for antibiotic resistance are found in

  1. Chromosome

  2. Nucleus

  3. Cell wall

  4. Plasmid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Antibiotic resistance plasmids are bacterial extrachromosomal elements that carry genes conferring resistance to one or more antibiotics. Resistance genes are commonly found on plasmids, which are small extrachromosomal elements commonly found in bacteria. Plasmids are commonly able to move from one bacterial cell to another by a mechanism known as conjugation, which involves cell‐to‐cell contact followed by transfer of a copy of plasmid DNA from a donor to a recipient. 

Therefore, the correct answer is option D.

Multiple choice commercial studies biotechnology: general introduction introduction to genetic engineering and production of insulin use of efficient and eco-friendly technology genetics of the future

Restriction endonucleases are

  1. Synthesized by bacteria

  2. Present in cells for degradation of foreign DNA

  3. Used in genetic engineering

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Restriction enzyme is a protein produced by bacteria that cleaves DNA at specific sites along the molecule. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
The goal of genetic engineering is changing the genetic makeup of an organism. To achieve this goal, scientists must have a way of rearranging genes to create new combinations of DNA. Restriction enzymes are one tool that can be used to accomplish this goal. A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. To cut DNA, all restriction enzymes make two incisions, once through each sugar-phosphate backbone (i.e., each strand) of the DNA double helix.
Therefore, the correct answer is option D.
Multiple choice commercial studies biotechnology: general introduction introduction to genetic engineering and production of insulin use of efficient and eco-friendly technology genetics of the future

From the below list, which of the following is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium?
(i) Transformbacteria with recombinant DNA molecule.
(ii) Cut the plasmid DNA using restriction enzymes.
(iii) Extract plasmid DNA from bacterial cells.
(iv) Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments.
(v) Use ligase to seal plasmid DNA to nonplasmid DNA.

  1. (iv), (v), (i), (ii), (iii)

  2. (iii), (ii), (iv), (v), (i)

  3. (iii), (iv), (v), (i), (ii)

  4. (ii), (iii), (v), (iv), (i)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
1. A gene of interest ( DNA fragment) is isolated from cells that have been grown in laboratory culture. 
2. Both the human DNA and the plasmid are treated with the same restriction enzyme to produce identical sticky ends. 
3. The restriction enzyme cuts the plasmid DNA at its single recognition sequence, disrupting the antibiotic resistance gene. 
4. The DNA fragment are mixed together and the complementary sticky ends are attached to each other by base pairing. The enzyme DNA- ligase is added to bond the sticky ends. 
5. The recombinant plasmid or molecular clone, is introduced into a bacterial cell by adding the DNA to a bacterial culture. Under the right condition some bacteria will take up the plasmid from solution by the process transformation. 
Therefore, the correct answer is option B.
Multiple choice biology cell biology cell as structural and functional unit introduction to cell biology cell : the basis of life

Choose the correct answers from the alternatives given .
Evolution of the DNA $\rightarrow$ RNA $\rightarrow$ protein system was a milestone because the protocell could now

  1. be a heterotrophic fermenter

  2. passon genetic information

  3. use energy to grow

  4. take in preformed molecules
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The evolution of the DNA to RNA to protein system allowed for the storage and replication of genetic information, which is essential for biological inheritance and the continuity of life.