Biology

Molecular Genetics

851 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 zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Griffith effect is

  1. DNA transcription

  2. RNA translation

  3. Bacterial transformation

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

The Griffith effect refers to the discovery of bacterial transformation, where non-virulent bacteria were converted into virulent ones by a 'transforming principle' from dead virulent bacteria.

Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Correct sequence of code transfer during polypeptide formation is

  1. DNA, mRNA, tRNA and amino acids

  2. DNA, tRNA, rRNA and mRNA

  3. mRNA, tRNA, DNA and amino acids

  4. rRNA, DNA, mRNA and tRNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The central dogma of molecular biology describes the flow of genetic information: DNA is transcribed into mRNA, which is then translated into a polypeptide chain using tRNA and amino acids.

Multiple choice botany mendel's law of inheritance genetics terminology similarities and dissimilarities in organisms introduction to genetics features of human body and sign language

A gene is

  1. Synonym of chromosomes

  2. Composed of mRNA

  3. A specific segment of nucleotides of DNA

  4. Having only those nucleotides required to synthesize a protein
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A gene is a sequence of nucleotides along a DNA strand - with 'start' and 'stop' codons and other regulatory elements - that specifies a sequence of amino acids that are linked together to form a protein.


So, the correct answer is 'A specific segment of nucleotides of DNA'.

Multiple choice biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

Transcription and translation occur in the cytoplasm in a/an

  1. Prokaryotic cell

  2. Eukaryotic cell

  3. Unicellular organism only

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

Transcription is the process of formation of RNA from DNA. Transcription takes place inside the nucleus, where the DNA of a cell is stored. Since eukaryotes have a defined membrane bound nucleus, therefore transcription always takes place inside the nucleus in eukaryotic cells.
Translation, on the other hand is the process of production of proteins from messenger RNA. Production of proteins require ribosomes and ribosomes are found in cytoplasm. Thus, translation always occurs inside cytoplasm, whether it is a prokaryotic or eukaryotic cell.
In prokaryotes, however there is no define membrane bound nucleus. The DNA or the genetic material of prokaryotes lie inside cytoplasm only. Therefore, prokaryotic cells are the only cells where transcription and translation both occurs inside cytoplasm.
Hence, the correct option 'Prokaryotic cell'.

Multiple choice biology organization of life comparison of prokaryotic vs eukaryotic cells prokaryotic cell and eukaryotic cell types of cell

Assertion:  Initiation step of protein synthesis in prokaryotes and eukaryotes has several differences.

Reason:  They both form mRNA - tRNA complex with smaller subunit of ribosome.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The differences between initiation step of protein synthesis in eukaryotes and prokaryotes are : 

(i) In prokaryotes initiation factors are three - IF1, IF2 and IF3. Eukaryotes have at least ten initiation factors - eIF1, eIF2, elF3, eIF4A, eIF4B, eIF4C, eIF4D, eIF4F, eIF5 and eIF6. 
(ii) In eukaryotes, formylation of methionine does not take place. In prokaryotes tRNA is charged with formylated methionine.
 (iii) The larger subunit of ribosome combines with 40S - mRNA - tRNAMet (in case of prokaryotes, 30S) complex to form intact ribosome. It requires initiation factor IF1 in prokaryotes and factors eIF1, eIF4 (A, B, C) in eukaryotes.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

The first genes may have developed when

  1. Protobionts grew and divided

  2. Short RNA strands self-replicated

  3. DNA molecules produced RNA molecules

  4. Polypeptides became catalytic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

RNA is capable of catalyzing a number of chemical reactions, including the polymerization of nucleotides. RNA is uniquely able both to serve as a template for and to catalyze its own replication. Consequently, RNA is generally believed to have been the initial genetic system, and an early stage of chemical evolution is thought to have been based on self-replicating RNA molecules—a period of evolution known as the RNA world.

So the correct option is 'short RNA strands self-replicated'.

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 drug streptomycin inhibits the process of

  1. Prokaryotic translation

  2. Eukaryotic translation

  3. Prokaryotic transcription

  4. Eukaryotic transcription
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When purifying protein from a biological extract, streptomycin sulfate is sometimes added as a means of removing nucleic acids. Since it binds to ribosomes and precipitates out of solution, it serves as a method for removing rRNA, mRNA, and even DNA if the extract is from a prokaryote
So, the correct answer is 'Prokaryotic translation'
Multiple choice zoology mutation dna fingerprinting human genome project and dna fingerprinting instruments in biotechnology

Satellite DNA contains

  1. Repetitive DNA

  2. Segments forming sn RNA

  3. Segments forming sc RNA

  4. Both B and C.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Satellite DNA consists of arrays of tandemly repeating sequences that are widely present (>30%) in the genome. Satellite DNA is mainly present in heterochromatin or the tightly packed regions of chromosomes in centromeres, telomeres, and sometimes even in the euchromatin region (active region of the genome).

So, the correct answer is 'Repetitive DNA.'

Multiple choice zoology mutation dna fingerprinting human genome project and dna fingerprinting instruments in biotechnology

Repeated genes are useful

  1. Against mutations

  2. Formation of pseudogenes

  3. Formation of multiple copies of a product

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

Repeated DNA sequences can act as more or less discrete elements in the genome. They can vary in the number of copies of repeat units from one chromosome to the next (polymorphism). The repeat copy number can expand through a unique form of mutation process referred to as ‘dynamic mutation.’ They are useful in the formation of pseudogenes and also in making multiple copies of a product.

So, the correct answer is 'All of the above.'

Multiple choice common laboratory equipments common laboratory apparatus and equipments laboratory equipments know about some common gases chemistry

 Which type of splicing reaction requires a guanine nucleoside or nucleotide cofactor that is not used as a source of energy?

  1. Group IV

  2. Group I

  3. Group II

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

Group I type of splicing reaction requires a guanine nucleoside or nucleotide cofactor that is not used as a source of energy. Self splicing group 1 intorns share number of different properties with enzymes which increases tthe reaction rate. The intorns excition the reactiion due to the internal guide sequence.

Multiple choice zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

Genetic code translates the language of __________________.

  1. Amino acids into that of RNA

  2. RNA into that of protein

  3. Protein into that of DNA

  4. RNA into that of DNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The genetic code describes the relationship between the sequence of nucleotides in mRNA and the sequence of amino acids in a protein. It is the mechanism by which the information stored in RNA is translated into functional proteins.

Multiple choice zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

According to finding from the Human Genome Project, there are about 25000 genes but there are amny more different polypeptides. Which of the following processes might explain the discrepancy between number of genes and polypeptides?
(1) Mutations
(2) Post-translational modifications
(3) Crossing over during meiosis
(4) Alternating splicing of RNA transcripts

  1. 1 & 2
  2. 2 & $

  3. 1,3 & 4

  4. 3 & 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

Which of the following statements is correct?

  1. The product of transcription is DNA

  2. The product of transcription is mRNA

  3. The product of transcription is a protein

  4. The product of translation is mRNA

  5. The product of translation is DNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transcription is the process of synthesizing mRNA from a DNA template. Translation is the process of synthesizing proteins from an mRNA template.