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

The cis-trans test can determine whether a gene codes for

  1. an activator or a repressor

  2. an RNA or a protein

  3. a protein with the same or different amino acids

  4. a diffusible or non-diffusible product
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cis-trans (complementation) test determines whether two mutations are in the same gene, which functionally tests whether a genetic unit encodes a single functional, diffusible product. If mutations in trans fail to complement, they affect the same functional product.

Multiple choice biology organisation of the organism introduction to cell what are the living organisms made of component of the cell

Which of the following is codons codes for proline.

  1. CCC, CCU, CCG

  2. UCC, UGU, CCU

  3. CUG, CUU, CUA

  4. CGC, CGG, CCA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Proline is encoded by four codons: CCU, CCC, CCA, and CCG. Option A lists three of these four codons correctly. The other options contain codons for different amino acids or incorrect combinations.

Multiple choice biology caskets of life the cell structure cytoplasm unicellular and multicellular organisms number and shape of cells

Nucleolus contains

  1. Genetic instructions

  2. Ribosome assembly line

  3. Protein synthesis machinery

  4. Enzymes for polysaccharide formation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The nucleolus, whose primary function is to assemble ribosomes is the largest structure in the cell nucleus. The nucleolus takes up around 25% of the volume of the nucleus. It is made up of proteins and ribonucleic acids (RNA). Its main function is to synthesize ribosomal RNA (rRNA) which helps in the synthesis of proteins. It has a ribosome assembly line.
So the correct answer is 'Ribosome assembly line'.
Multiple choice biochemical polymers polymerisation chemistry

RNA is ?

  1. single helix strand

  2. double helix strand

  3. right hand twisted double helix strand

  4. triple helix strand
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
RNA is a single-stranded molecule in many of its biological roles and consists of a much shorter chain of nucleotides. 
Multiple choice biochemical polymers polymerisation chemistry

RNA molecules are of three types which are based on their different functions. These are:

  1. messenger RNA, translational RNA, structural RNA

  2. cytosine RNA, nucleoside RNA, nucleotide RNA

  3. messenger RNA, ribosomal RNA, transfer RNA

  4. primary RNA, secondary RNA, tertiary RNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
There are 3 types of RNA, each encoded by its own type of gene:
mRNA - Messenger RNA $\rightarrow$ Encodes the amino acid sequence of a polypeptide.
tRNA - Transfer RNA $\rightarrow$ Brings amino acids to ribosomes during translation.
rRNA - Ribosomal RNA $\rightarrow$ With ribosomal proteins, makes up the ribosomes, the organelles that translate the mRNA.
Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

A sequential expression of a set of human genes occurs when a steroid molecule binds to the

  1. Transfer RNA

  2. Messenger RNA

  3. DNA sequence

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

Steroid hormone are chemical messengers that interact or bind with the DNA inside the nucleus

For example, Oval albumin synthesis in oviduct of chick is influenced by estrogen (steroid) (Transcriptional control) 

Multiple choice zoology cell and cell organelles one gene - one enzyme hypothesis component of the cell molecular genetics

Who propounded the theory, 'one gene-one enzyme one chemical reaction'?

  1. Watson & Crick

  2. George Beadle and Edward Tatum

  3. Abraham Trembley

  4. T.H. Morgan
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The one gene-one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. The concept was proposed by George Beadle and Edward Tatum in an influential 1941 paper.  Beadle and Tatum noted that it was "entirely tenable to suppose that these genes which are themselves a part of the system, control or regulate specific reactions in the system either by acting directly as enzymes or by determining the specificities of enzymes".

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

Which of the following regulates the activities integrator gene?

  1. Sensor site

  2. RNA

  3. Producer gene

  4. Receptor site
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Sensor sites are signal receiving genes. They are very sensitive for specific signals from the cell and its environment. 
A sensor site regulates activity of an integrator gene which can be transcribed only when the sensor site is activated. 
So, the correct option is 'Sensor site'.
Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

Which of the following sequence helps in modification but not in protein synthesis?

  1. Integrator site

  2. Sensor site

  3. Producer site

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

Producer site produces pre mRNA, which after processing becomes mRNA. Its expression is under the control of many receptor sites. mRNA later takes part in protein synthesis during translation. 

Integrator gene is responsible for the synthesis of an activator RNA molecule that activates the receptor site. A sensor site regulates the activity of an integrator gene which can be transcribed only when the sensor site is activated.
So, the correct option is 'Both A and B'.

Multiple choice biology selection and evolution phylogeny cladistics speciation

Which of the following is sequenced during study of phylogeny?

  1. mRNA

  2. rRNA

  3. tRNA.

  4. DNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ribosomal RNA groupings contrast between species, because of change. Through variety in r RNA groupings, we can recognize living beings on around the species level and follow developmental connections.
So, the correct option is 'r RNA'.
Multiple choice botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

rDNA is

  1. Genomic RNA of virus

  2. Genomic RNA that produces DNA through reverse transcription

  3. DNA found in ribosome

  4. DNA segment speciaiised to form rRNA
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA. Ribosomes are assemblies of proteins and rRNA molecules that translate mRNA molecules to produce proteins. In the nucleus, the rDNA region of the chromosome is visualized as a nucleolus which forms expanded chromosomal loops with rDNA.

So, the correct answer is 'DNA segment speciaiised to form rRNA.'

Multiple choice evs - i growth and personality development heredity and other supporting factors for development all together community work and its importance

What is called the unit of heredity?

  1. Genes

  2. Alleles

  3. Cells

  4. Chromosomes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A. Genes are the unit of heredity.
B. Alleles are the alternate form of the gene.
C. Cells are fundamental structural and functional unit of living organisms.
D. Chromosomes carry genetic information in the form of genes.

So, the correct option is 'Genes'.
Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Find the correct statement with respect to function or properties of RNA polymerase.

  1. Bacteria have $3$ different types of RNA polymerase

  2. RNA polymerase binds to promoter and initiate transcription

  3. It uses nucleoside monophosphate as substrate

  4. RNA polymerase polymerizes in a template independent manner
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

RNA polymerase is the primary enzyme responsible for transcription, locating and binding to promoter regions on DNA to initiate RNA synthesis. Bacteria have a single type of RNA polymerase with multiple subunits, use nucleoside triphosphates as substrates, and require a DNA template.