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How do you study molecular basis of inheritance for NEET?
Focus on understanding key concepts such as DNA replication, transcription, translation, and gene regulation. Use NCERT textbooks, reference books like "Molecular Biology of the Cell", study material by PW and practice solving past NEET papers to reinforce your understanding.
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Pursue undergraduate programs in molecular biology, genetics, or related fields. Explore universities offering bachelor's degrees in these areas. Engage in internships, research projects, or lab work to gain hands-on experience and deepen your understanding.
Is molecular biology hard?
Molecular biology can be challenging due to its complex and detailed nature. However, with consistent study, practical application, and a clear understanding of foundational concepts, it becomes more manageable. Practice problem-solving and seek additional resources if needed.
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Yes, molecular biology is in high demand, especially in fields like biotechnology, pharmaceuticals, and medical research. Advances in genetic technologies have increased the importance of molecular biology in understanding diseases, developing new therapies, and driving innovation in various industries.
Molecular Biology MCQ for NEET Biology with Answers
Molecular biology MCQ: Molecular biology is the study of biological molecules and their interactions within cells. Check Molecular biology MCQ for NEET.
Krati Saraswat16 May, 2024
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Molecular Biology MCQ Introduction
Molecular biology MCQ:
Molecular biology is the study of biological molecules and their interactions within cells. It involves analyzing and manipulating DNA, RNA, proteins, and other biomolecules to understand their functions in living organisms. Molecular biologists use advanced techniques such as PCR (polymerase chain reaction), gel electrophoresis, gene cloning, and sequencing to investigate the molecular mechanisms underlying various biological processes.
They also explore how genetic information is transmitted from one generation to another and how gene mutations can lead to diseases. The field of molecular biology has contributed significantly to our understanding of genetics, evolution, cell biology, biochemistry, and immunology, among others.
As technology advances at an unprecedented pace across all scientific fields today, discoveries are expected to continue revolutionizing our understanding of life's fundamental processes through this exciting multidisciplinary field: Molecular Biology!
Q 1. In eukaryotes, which of the following is removed from the primary transcribed RNA before being transported to the cytoplasm for translation?
Intron
3’Poly A tail
Ribosome binding site
5' cap
Answer:
a, Intron
Explanation:
Intron is a noncoding DNA section excised from the mRNA strand during post-transcriptional processing in eukaryotic cells. This process removes introns and leaves only the coding exons, which can then be translated into proteins.
Q 2. The process of splicing in eukaryotes :
is reminiscent of antiquity
represents the dominance of the RNA world
is an indicator of the complexity of the human genome
is a legacy of organic evolution
Answer:
d, is a legacy of organic evolution
Explanation:
Splicing is vital in eukaryotic gene expression, where non-coding introns are removed and coding exons are linked together to generate the final mRNA. This activity occurs in the nucleus of cells and is accomplished with the help of a sophisticated assembly called the spliceosome. The emergence of this process was instrumental in empowering gene regulation complexity and contributed to the diversification and progressive nature of eukaryotic organisms.
Q 3. In the Hershey and Chase experiment, which findings conclude that DNA is the genetic material?
The presence of radioactivity in bacteria when using 35S.
The presence of radioactivity in the supernatant when using 35S.
The presence of radioactivity in bacteria when using 32P.
The presence of radioactivity in the supernatant when using 32P.
Answer:
c The presence of radioactivity in the bacteria when using 32P.
Explanation:
The Hershey and Chase experiment used bacteriophages to investigate whether DNA or protein is the genetic material transferred into the bacterial host during infection. They marked the DNA of the bacteriophages with radioactive phosphorus-32 (32P) and the protein coat with radioactive sulfur-35 (35S) to distinguish them.
When they used 32P to label the DNA, they found radioactivity in the bacterial pellet after the infection. It is indicated that the bacteria took up the labeled DNA from the phages. In contrast, radioactivity was observed in the supernatant when 35S was used to label the protein coat, suggesting that the tagged protein was not incorporated into the bacterial cells.
Q 4. Which enzyme polymerizes RNA with defined sequences in a template-independent manner?
Peptidyl transferase
RNA polymerase
Reverse transcriptase
Polynucleotide phosphorylase
Answer:
d, Polynucleotide Phosphorylase.
Explanation:
Polynucleotide phosphorylase is an enzyme that can catalyze the synthesis of RNA molecules without requiring a DNA template. It is involved in non-templated RNA synthesis, also known as random RNA polymerization. This enzyme can add nucleotide monophosphates to the growing RNA chain in a sequence-independent manner, resulting in the synthesis of RNA with no specific template or predetermined sequence.
Q 5. What is the role of RNA polymerase Il in the transcription process in Eukaryotes?
Transcription of only snRNAs
Transcription of rRNAs (28S, 18S and 5.85)
Transcription of tRNA, five srRNA, and snRNA
Transcription of the precursor of mRNA
Answer:
d, Transcription of the precursor of mRNA
Explanation:
RNA Pol II is responsible for transcribing protein-coding genes into pre-mRNA molecules. Pre-mRNA undergoes further processing, including splicing to remove introns and adding a 5' cap and a poly-A tail before it is matured into functional mRNA. Afterward, mature mRNA is exported from the nucleus to the cytoplasm for translation into proteins.
While the other options mention transcription of other types of RNA, such as snRNAs, rRNAs, tRNAs, and 5S rRNA, these are transcribed by different RNA polymerases. RNA Pol II explicitly catalyzes the transcription of protein-coding genes to produce pre-mRNA, a crucial step in gene expression and protein synthesis in eukaryotes.
Q 6. E. coli bacteria with a mutated lac operon gene cannot grow in an environment that only has lactose to provide energy, why?
The lac operon is constitutively active in these cells
they cannot synthesize functional beta-galactosidase
in the presence of glucose, E. coli cells do not use lactose
They cannot transport lactose from the environment into the cell
Answer:
d, They cannot transport lactose from the medium into the cell.
Explanation:
Lactose metabolism is controlled by the lac operon in E. coli. The lacZ gene encodes beta-galactosidase, which hydrolyses lactose into glucose and galactose. The lacY gene encodes lactose permease, a transporter protein facilitating lactose uptake into the cell.
If there is a mutation in the lacY gene, the lactose permease function is impaired or non-functional. As a result, E. coli cells with this mutated gene cannot efficiently transport lactose from the medium into the cell. Therefore, they are unable to utilize lactose as a source of energy.
Q 7. Purines are found in both DNA and RNA...
Adenine and thymine
Adenine and guanine
Guanine and cytosine
Cytosine and thymine
Answer:
b, Adenine and Guanine.
Explanation:
In the purine group, adenine and guanine are nitrogenous bases. In both DNA and RNA molecules, adenine forms hydrogen bonds with thymine (T), while guanine forms hydrogen bonds with cytosine (C). As for RNA, adenine forms hydrogen bonds with uracil (U), while guanine forms hydrogen bonds with cytosine.
Q 8. Holoenzyme RNA polymerase binds to a DNA sequence during transcription, causing the DNA to be saddle-like. What is this sequence called?
AAAT box
TATA box
GGTT box
CAAT box
Answer:
b TATA box
Explanation:
The TATA box is the sequence that causes the DNA to assume a saddle-like structure and is recognized by the holoenzyme RNA polymerase during transcription.
The TATA box, also known as the TATA box element or the Goldberg-Hogness box, is a DNA sequence found upstream of the transcription start site in eukaryotic genes. It typically has the consensus sequence "TATAAA" or a variant. The TATA box plays a crucial role in the transcription initiation by providing a binding site for the TATA-binding protein (TBP), a subunit of the holoenzyme RNA polymerase. The holoenzyme binding to the TATA box helps to position RNA polymerase correctly and initiate transcription at the appropriate site.
Q 9. AGTCTACCGATAGT is a short sequence of bases on one strand of DNA. What would the corresponding base sequence in the new strand be if this sequence served as a template for forming the new DNA strand?
AGTCTACCGATAGT
TCAGATGGCTATCA
TGATAGCCATCTG
GACATCGATTCGAT
Answer:
b, TCAGATGGCTATCA.
Explanation:
If the sequence "AGTCTACCGATAGT" serves as a template for forming a new strand of DNA, the corresponding base sequence in the new strand would be the complementary sequence.
The complementary base pairing rules in DNA are as follows: adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
So, the complementary base is used to create the new strand for each base in the template strand.
In this case, the complementary sequence to "AGTCTACCGATAGT" would be "TCAGATGGCTATCA".
Q 10. The Okazaki fragments in DNA chain growth
polymerize in the 3’ — to — 5’ direction and form a replication fork
prove the semi-conservative nature of DNA replication
polymerize in the 5" — to — 3’ direction and explain 3’ — to — 5' DNA replication
result in transcription.
Answer:
c, polymerize in the 5" — to — 3’ direction and explain 3’ — to — 5' DNA replication
Explanation
: The new DNA strand is synthesized. In short, Okazaki fragments during DNA replication. These fragments are synthesized in the 5' — to — 3' direction. During DNA replication, the leading strand is synthesized continuously from 3' to 5', while the lagging strand is synthesized discontinuously using Okazaki fragments. The Okazaki fragments are joined together by DNA ligase to form a continuous strand.
Q 11. Taylor conducted experiments to demonstrate a semi-conservative mode of chromosome replication on _____
Vicia faba
Vinca rosea
coli
Drosophila
Answer:
a, Vicia Faba
Explanation:
Meselson and Stahl demonstrated that the semi-conservative replication of DNA takes place through their 1958 experiment involving Escherichia coli. It was preceded by Chase and Hershey's 1952 experiment involving bacteriophages, in which they labeled the DNA with radioactive phosphorus-32 (32P) to distinguish it from the protein coat, thus providing evidence for the genetic material being DNA. None of these is related to Taylor; therefore, Vicia Faba is the correct answer.
Q 12. The association of histone H1 with a nucleosome indicates ___
DNA is condensed into chromatin fibers
Transcription is in progress
DNA replication is in progress
DNA double helix is exposed
Answer:
a, DNA is condensed into chromatin fibers.
Explanation:
The association of histone H1 with a nucleosome indicates that the DNA is wrapped around an octameric complex of histones, forming a basic unit of chromatin known as a nucleosome. By condensing and compressing large segments of DNA, this process makes them easier to handle.
Q 13. Eukaryotic cells have a considerably larger nucleus than the DNA molecule. How is the DNA accommodated here?
super-coiling in nucleosomes
DNase digestion
by elimination of repetitive DNA
deletion of non-essential genes
Answer:
a, super-coiling in nucleosomes
Explanation:
Eukaryotic cells have a much larger nucleus than the DNA molecule, so the DNA must be folded and compacted into the nucleus. It is done through super-coiling, wounding the DNA around spool-like proteins called nucleosomes. It allows more DNA to fit in smaller spaces, making it much easier for the cell to store its genetic material.
Q 14. The core RNA polymerase can catalyze which steps of transcription?
Initiation only
Elongation only
Termination only
All of these
Answer:
b, Elongation only
Explanation:
The core RNA polymerase is responsible for the elongation process of transcription, catalyzing the addition of nucleotides to the growing RNA strand in a 5' to 3' direction. The core enzyme can do this lone step while initiation and termination require additional factors and signals.
Q 15. Where was semi-conservative replication of DNA first demonstrated?
Escherichia coli
Streptococcus pneumoniae
Salmonella typhimurium
Drosophila melanogaster
Answer:
a, E Coli
Explanation:
Semi-conservative replication of DNA was first demonstrated by Matthew Meselson and Franklin Stahl in 1958 using the bacterium Escherichia coli.
