Biology

DNA and Genetics

1,095 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

Antibiotic resistant genes are located on

  1. chromosome

  2. cell wall

  3. nucleus

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

Plasmid contains antibiotic resistant genetic markers, which give resistance to bacteria against the antibiotics.

Multiple choice

Hypoxanthine is also used for selecting the hybridomas based on the following: P. Only hybridoma will grow since, it inherited the HGPRT genes from B cells and can synthesize DNA from Hypoxanthine. Q. Myeloma cells wil not grow in culture since, de novo synthesis is blocked by aminopterin and due to lack of HGPRT enzyme.

In hybridoma technology for monoclonal Ab production antibiotic is used to select hybridoma cell over myeloma cells.

  1. Only P is true

  2. Only Q is true

  3. Both P and Q are true

  4. P is true and Q is false

  5. Q is true and P is false
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both P and Q are true. In this procedure, myeoloma cells are engineered to be deficient enzyme HGPRT. After fusion of lymphocytes with HGPRT negative myeloma cells, aminopterin containing medium, supplemented with hypoxanthine and thymidine to ensure as adequate substrate supply for salvage pathway (HAT medium) is added, which kills myeloma cells but allows hybridomas to survive as they inherit HGPRT from lymphocyte parent.

Multiple choice

For which of the following is difference cloning useful?

  1. To isolate sequence of DNA that is expressed in specific tissue types.

  2. To detect the DNA sequence of a mutated gene.

  3. To detect biological activity of expressed polypeptide or protein.

  4. To isolate gene expressing antigenic peptides.

  5. To isolate specific DNA sequence from uncloned DNA fragments.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Difference cloning is used to isolate sequences that are expressed in specific cell types.

Multiple choice

One of the methods for finding common regulatory motifs present in a set of co–regulated genes is

  1. Prosite

  2. MEME

  3. Mat Inspector

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

PSSM (Position-Specific Scoring Matrix) is a statistical method used to identify and represent common regulatory motifs in co-regulated genes. Each position in the motif is assigned scores for each nucleotide based on its frequency in aligned sequences, allowing identification of conserved regulatory patterns. While Prosite is a database, MEME is a discovery algorithm, and MatInspector scans with known motifs.

Multiple choice

Match the following and choose the correct combination.

 
Group I Group II
A. blastx 1. Search protein database using translated nucleotide query
B. tblastn 2. Finding primers specific to your PCR template
C. tblastx 3. Search translated nucleotide database using a protein query
D. primer – BLAST 4. Search translated nucleotide database using a translated nucleotide query

  1. A - 3, B - 1, C - 2, D - 4

  2. A - 3, B - 1, C - 4, D - 2

  3. A - 1, B - 3, C - 4, D - 2

  4. A - 3, B - 4, C - 1, D - 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

blastx translates a nucleotide query in all six reading frames to search a protein database (A-1). tblastn uses a protein query to search a six-frame translation of a nucleotide database (B-3). tblastx performs six-frame translation on both query and database (C-4). Primer-BLAST is specifically designed for finding PCR primers unique to a template (D-2).

Multiple choice

Which of the following modes of DNA replication are found in bacteria?

  1. Rolling circle replication

  2. Bi directional replication

  3. Theta replication

  4. Only 1 and 2

  5. All 1, 2 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All 1, 2 and 3. Bacterial DNA replication by: Rolling Circle- multiple copies of a single circular DNA is achieved. Bi-directional- the synthesis of DNA is done in two directions; and Theta mode- it a type of bi directional replication, where “theta” (Θ) type structure is formed.