Biology

Molecular Genetics

917 Questions

Molecular genetics explores the mechanisms of genetic information transfer, including DNA replication, transcription, and translation. It is a core component of biology syllabi. These concepts frequently appear in general science sections of major competitive exams.

DNA replicationTranscription processTranslation processRNA typesCentral dogma

Molecular Genetics Questions

Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

Viruses that infects plants generally have

  1. ds DNA

  2. ssRNA

  3. ds RNA

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

  • Approximately around 70% of viruses infecting plant are ssRNA, 20% are ssDNA and rest are either dsRNA or dsDNA.
  • ssDNA is advantageous due to it's ability to infect and duplicate it's genome faster.

So, the correct option is 'ssRNA'.

Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

The latest view for the origin of viruses is?

  1. They have arisen from nucleic acid and proteins found in primitive soup

  2. They arose from bacteria as a result of the loss of the cell, ribosome etc

  3. They arose from some bacteria, which has developed a nucleus only

  4. They are modified plasmids, which are in-fact the fragments of the nucleic acids of host
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The current scientific consensus suggests that viruses may have originated from primitive nucleic acid and protein molecules that evolved to become self-replicating entities.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Which one of the following statements is TRUE about eukaryotic cells?

  1. Cycloheximide blocks elongation during translation

  2. Formulated ERNA is necessary for initiation of translation

  3. A single mRNA specifies for more than one gene product

  4. Erythyromycin inhibits elongation during translation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cycloheximide inhibits protein synthesis in eukaryotes by blocking the elongation phase during translation, making option A correct. Option D has a typo (erythromycin, not 'erythyromycin'). Formylated mRNA is for prokaryotic initiation, and single mRNA producing multiple products (polycistronic) is prokaryotic.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

Choose the incorrect statement 

  1. RNAi silencing takes place in all eukaryotic cells for cellular defence

  2. RNAi involves binding of dsRNA molecules with mRNA for silencing to occur.

  3. Complementary nucleic acid could be from mobile genetic elements (transposons).

  4. Ti plasmid with nematode specific genes have been used in RNAi
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gene silencing by dsRNA makes use of the naturally occurring cell machinery that is involved in the processing of miRNA in eukaryotic cells. It does not provide any defense mechanism. So the correct answer is ' RNAi silencing takes place in all eukaryotic cells for cellular defense'.

Multiple choice botany biotechnology and its applications biotechnology in agriculture gm crops transgenic organisms

(A) Source of sense &- Transposon 
      Antisense RNA gene
(B) Host of sense &- Tobacco 
      Antisense  RNA gene
(C)   Site of iRNA  - Tobacco 
        Production
(D) Site of pre RISC  - Meloidegyne     
      formation
(E) Site of pre RISC to RISC &- Meloidegyne     
      conversion
(F) Destruction  of- Gastric tract of      
      functional m-RNA    Meloidegyne      gene
In Nematode resistant plant formation, among
given combinations which are incorrect

  1. D & E

  2. D & F

  3. C & E

  4. A & F
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Transgenic plants are those plants whose genome is altered by the addition of one or more transgenes. Tobacco plant is the most common plant for expressing the transgenes. As the genome of tobacco plant is completely studied. The transgenic plants are transcribed in such a way that they develop tolerance against stress, salt, herbicide and also for vaccine productions. There are several transgenes which are inserted in tobacco plant like cry2Aa gene which gives resistance against any worms.
  • The Meloidogyne does not perform the conversion of sites like pre-RISC to RISC. The Meloidogyne gene is obtained by the species Meloidegyne incognita which are mainly responsible for causing root knot in plants.
  • Therefore the correct answer is option "A".
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

DNA polymerase enzyme is responsible for the synthesis of

  1. DNA from RNA

  2. DNA from DNA

  3. RNA from DNA

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

DNA polymerase is an enzyme used in DNA replication. It synthesizes DNA on a DNA template. Bacteria have three different DNA polymerases, i.e., DNA pol I, DNA pol II and DNA pol III; while eukaryotes have several DNA polymerase enzymes.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Ribozyme is

  1. RNA with enzyme activity

  2. RNA without sugar

  3. RNA without phosphate

  4. RNA with extra phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ribozymes are also known as ribonucleic acid enzymes. These are RNA molecules which helps in the catalysis of a particular reaction. It was discovered in the year 1982. The RNA can act as both genetic material and can act as a biocatalyst. It acts as a part of ribosome which attaches to the amino acid during protein synthesis. It increases the rate and specificity of peptide bond synthesis and phosphodiester bond. So, the correct answer is option A.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Ribozymes are 

  1. RNA acting as enzymes.

  2. Antibody acting as enzymes.

  3. Ribosomes acting as enzymes.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are biological catalysts which speed up the biological reactions. All metabolic reactions in a cell are catalyzed by enzymes. Almost all enzymes are proteins. There are some nucleic acids that behave like enzymes. These are called ribozymes. Ribozymes are molecules of ribonucleic acid with catalytic activity.