Genetics, DNA & Principles of Heredity GK Questions & Answers
Genetics is the biological study of heredity, gene variation, and the molecular mechanisms governing phenotypic transmission across generations. The discipline was founded by Gregor Johann Mendel through systematic hybridization experiments on the garden pea (Pisum sativum) between 1856 and 1863, establishing three foundational principles: the Law of Dominance, the Law of Segregation, and the Law of Independent Assortment. Molecular genetics advanced following James Watson and Francis Crick's 1953 B-DNA double-helix model, constructed using Rosalind Franklin and Maurice Wilkins' X-ray diffraction data. Deoxyribonucleic acid (DNA) consists of anti-parallel polynucleotide chains of deoxyribose sugar, phosphate backbones, and nitrogenous bases obeying Erwin Chargaff's stoichiometric rules: Adenine pairs with Thymine via two hydrogen bonds (A=T), and Guanine pairs with Cytosine via three hydrogen bonds (G≡C). The Central Dogma of molecular biology defines genetic information flow: DNA replication, transcription to messenger RNA (mRNA), and ribosomal translation into functional proteins. Human somatic cells contain 46 chromosomes organized into 23 homologous pairs (22 pairs of autosomes and 1 pair of allosomes: XX female, XY male). Clinical genetics categorizes hereditary conditions into Mendelian single-gene disorders (such as Haemophilia, Thalassemia, and Sickle Cell Anaemia) and chromosomal aneuploidies (such as Down syndrome via Trisomy 21 and Turner syndrome via 45,X monosomy).
High-yield conceptual summaries for competitive exams and rapid revision.
Gregor Mendel formulated three laws of inheritance—Dominance, Segregation, and Independent Assortment—based on statistical analysis of 7 contrasting traits in Pisum sativum.
Watson and Crick (1953) elucidated the right-handed B-DNA double helix model, governed by Chargaff's rules where Purines equal Pyrimidines ([A]+[G] = [T]+[C]) with A=T (2 hydrogen bonds) and G≡C (3 hydrogen bonds).
The Central Dogma of molecular biology describes unidirectional flow of genetic information: DNA replication -> Transcription into mRNA -> Translation into polypeptide proteins.
The human genome comprises 23 pairs of chromosomes (46 total): 22 pairs of autosomes and 1 pair of sex chromosomes (XX in females, XY in males), with the SRY gene on the Y chromosome determining male sex differentiation.
In eukaryotic genetics, what specialized ribonucleoprotein complex extends telomeric tandem repeat sequences (TTAGGG in humans) at chromosome ends?
Verified Explanation
Telomerase is a specialized reverse transcriptase enzyme carrying its own RNA template that synthesizes repetitive telomeric DNA sequences at eukaryotic chromosome terminal ends, overcoming the end-replication problem.
2ID: GK-GSCI-00558
mediumBiological Principles & Living Systems
In classical Mendelian genetics, what phenotypic ratio is expected in the F2 generation of a monohybrid cross with complete dominance?
Verified Explanation
In a monohybrid cross with complete dominance (e.g., Tt × Tt), the phenotypic ratio in the F2 generation is 3 dominant : 1 recessive.
3ID: GK-SCIT-00059
easyBiotechnology Genetics
The "CRISPR-Cas9" genetic technology, for which Emmanuelle Charpentier and Jennifer Doudna won the 2020 Nobel Prize in Chemistry, is used for what?
Verified Explanation
CRISPR-Cas9 acts as programmable molecular scissors, using a guide RNA (gRNA) sequence to cut specific genomic DNA locations in living organisms.
4ID: GK-SCIT-00060
easyBiotechnology Genetics
What was the name of the first mammal successfully cloned from an adult somatic cell by Ian Wilmut and Keith Campbell in 1996 in Scotland?
Verified Explanation
Dolly was cloned using somatic cell nuclear transfer (SCNT) from an adult mammary gland cell, living until February 2003.
5ID: GK-SCIT-00071
easyBiotechnology Genetics
What is the process called where microorganisms like yeast or bacteria convert sugars into alcohol, acids, or gases in the absence of oxygen?
Verified Explanation
Fermentation has been used for millennia to brew beer, make bread, and ferment yogurt, and is now used in industrial biotech to produce bio-ethanol.
6ID: GK-SCIT-00072
easyBiotechnology Genetics
What was the massive international scientific research project completed in 2003 that successfully mapped and sequenced the entire 3 billion base pairs of human DNA?
Verified Explanation
Coordinated by the NIH and US Department of Energy alongside international partners, the HGP completed the first reference human genome.
7ID: GK-SCIT-00083
easyBiotechnology Genetics
What does the acronym "GMO" stand for in agricultural and food biotechnology?
Verified Explanation
GMOs are organisms whose genetic material (DNA) has been altered using recombinant DNA technology (e.g. Bt Cotton engineered for pest resistance).
8ID: GK-SCIT-00084
easyBiotechnology Genetics
What is "Golden Rice" genetically engineered to produce in its edible endosperm to combat childhood blindness and Vitamin A deficiency in developing nations?
Verified Explanation
Developed by Ingo Potrykus and Peter Beyer, Golden Rice contains daffodil and bacterial genes to biosynthesize beta-carotene, turning grains yellow-gold.
9ID: GK-SCIT-00090
easyBiotechnology Genetics
What are "Monoclonal Antibodies" (mAbs) in biotechnology and medical immunology?
Verified Explanation
Pioneered by Georges Köhler and César Milstein (1984 Nobel Prize), mAbs are widely used to treat cancers, autoimmune disorders, and viral infections.
10ID: GK-SCIT-00099
mediumBiotechnology Genetics
The "mRNA Vaccines" developed by BioNTech/Pfizer and Moderna for COVID-19 protect against viral infection by delivering what instructions into host muscle cells?
Verified Explanation
Katalin Karikó and Drew Weissman won the 2023 Nobel Prize in Physiology or Medicine for nucleoside base modifications enabling effective mRNA vaccine platforms.
11ID: GK-SCIT-00100
mediumBiotechnology Genetics
The "iPSCs" (Induced Pluripotent Stem Cells), for which Shinya Yamanaka won the 2012 Nobel Prize, are created by doing what to mature adult somatic cells?
Verified Explanation
The four "Yamanaka Factors" reverse cellular differentiation, creating patient-specific pluripotent stem cells capable of forming any body tissue without destroying embryos.
12ID: GK-SCIT-00111
mediumBiotechnology Genetics
The "Sanger Sequencing" method (chain-termination method), developed in 1977 by Frederick Sanger (1980 Nobel Prize), relies on which modified nucleotides to stop DNA strand synthesis?
Verified Explanation
Incorporation of fluorescently labeled ddNTPs terminates DNA polymerase elongation, generating fragments whose sizes reveal the nucleotide sequence via capillary electrophoresis.
13ID: GK-SCIT-00112
mediumBiotechnology Genetics
The "Next-Generation Sequencing" (NGS / Massive Parallel Sequencing) platforms (such as Illumina sequencing-by-synthesis) achieved which breakthrough in genomics?
Verified Explanation
NGS revolutionized clinical medicine and oncology by enabling high-throughput whole-genome, exome, and RNA sequencing in hours.
14ID: GK-SCIT-00123
mediumBiotechnology Genetics
The "Gel Electrophoresis" laboratory technique separates charged biological macromolecules (DNA, RNA, and proteins) based on what physical property?
Verified Explanation
Because the DNA phosphate backbone carries a uniform negative charge, smaller DNA fragments migrate faster through gel pores than larger fragments.
15ID: GK-SCIT-00124
mediumBiotechnology Genetics
The "Western Blot" (protein immunoblot) analytical laboratory technique is specifically used to detect and quantify what biological molecules in a tissue homogenate?
Verified Explanation
Proteins separated by SDS-PAGE are transferred onto a nitrocellulose membrane and probed with primary and enzyme-linked secondary antibodies.
16ID: GK-SCIT-00129
mediumBiotechnology Genetics
The "ELISA" (Enzyme-Linked Immunosorbent Assay) is a plate-based diagnostic laboratory technique widely used in medical testing to detect what?
Verified Explanation
ELISA uses enzyme-conjugated antibodies (such as horseradish peroxidase) that react with chromogenic substrates to produce measurable optical colorimetric signals.
17ID: GK-SCIT-00139
hardBiotechnology Genetics
The "Prime Editing" technique in genetic engineering, developed by David Liu's laboratory in 2019, improves upon standard CRISPR-Cas9 by doing what?
Verified Explanation
Prime editing uses an engineered catalytically impaired Cas9 nickase fused to an engineered reverse transcriptase with a prime editing guide RNA (pegRNA).
18ID: GK-SCIT-00140
hardBiotechnology Genetics
The "Base Editing" system, also pioneered by David Liu (2016), enables direct, irreversible chemical conversion of one target DNA base pair into another without double-strand breaks using which enzymes?
Verified Explanation
Base editors (CBEs and ABEs) provide single-nucleotide precision to correct point mutations responsible for thousands of human genetic diseases.
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hardBiotechnology Genetics
The "CAR-T Cell Therapy" (Chimeric Antigen Receptor T-Cell Therapy) is a personalized immunotherapy that genetically engineers a patient's own T cells to express what?
Verified Explanation
Autologous CAR-T therapies (such as Kymriah and Yescarta) have achieved dramatic clinical remissions in refractory leukemias and lymphomas by directing cytotoxic T cells to destroy cancer cells.
20ID: GK-INVN-00485
easyMedical Discoveries & Vaccines
Who is known as the 'Father of Genetics' for discovering the fundamental laws of inheritance through his hybridization experiments on garden pea plants (Pisum sativum)?
Verified Explanation
Augustinian friar Gregor Mendel presented his pea plant breeding experiments in 1865, formulating the Law of Segregation and the Law of Independent Assortment.
21ID: GK-INVN-00595
easyMedical Discoveries & Vaccines
Who is celebrated as the 'Father of Modern Genetics' for discovering the fundamental principles of inheritance through his hybridization experiments on garden pea plants (Pisum sativum)?
Verified Explanation
Austrian monk Gregor Johann Mendel discovered the fundamental laws of inheritance (Law of Segregation and Law of Independent Assortment) through breeding experiments conducted between 1856 and 1863.
22ID: GK-GSCI-00095
mediumBiological Principles
In cellular molecular genetics, what is the "Central Dogma" of biology formulated by Francis Crick in 1958?
Verified Explanation
Genetic information flows sequentially from DNA storage through transcription into messenger RNA and translation at ribosomes into polypeptide chains.
23ID: GK-GSCI-00115
mediumBiological Principles
What are "Plasmids" in bacterial genetics and molecular biotechnology?
Verified Explanation
Plasmids are widely used as cloning vectors in recombinant DNA technology to insert and replicate foreign genes in host bacteria.
24ID: GK-GSCI-00116
mediumBiological Principles
In genetics, what is the term for an organism having two identical alleles for a particular genetic trait (e.g. TT or tt)?
Verified Explanation
Homozygous individuals carry identical alleles at a given gene locus, whereas heterozygous individuals possess two different alleles.
25ID: GK-GSCI-00126
mediumBiological Principles
In molecular genetics, which four nitrogenous bases make up the double-helix nucleotide sequence of Deoxyribonucleic Acid (DNA)?
Verified Explanation
Watson-Crick base pairing pairs Adenine with Thymine (2 hydrogen bonds) and Guanine with Cytosine (3 hydrogen bonds); RNA contains Uracil instead of Thymine.