DNA
0Loading crowd target
0Loading crowd target
7correct to beat the crowd
146 free DNA trivia questions with answers — science & nature quiz, new questions added Oct 2026.
50 free DNA trivia questions with answers. Are you a DNA expert or just curious about genetics? Our DNA trivia quiz features 50 challenging questions covering everything from the structure of DNA to modern genetic engineering. Whether you're a student, scientist, or science enthusiast, this quiz will test your understanding of one of biology's most fundamental molecules.
30 of 146 questions with answers and explanations. Play the quiz
Q 01What does DNA stand for?
Deoxyribonucleic acid
DNA stands for deoxyribonucleic acid; the 'deoxy' refers to its sugar, 2-deoxyribose, which is ribose missing one oxygen atom.
Q 02Which living ape, along with the bonobo, is humanity's closest relative by DNA?
Chimpanzee
Chimpanzee DNA is almost 99% identical to ours where the two can be lined up, yet that small gap still adds up to tens of millions of single-letter differences built up over about six million years.
Q 03Which three components make up a single DNA nucleotide?
Base, sugar, and phosphate group
Base, sugar, and phosphate group: the sugars and phosphates link into each strand's backbone, so only the order of the bases is left to carry the genetic message.
Q 04Which base takes thymine's place in RNA?
Uracil
Uracil takes thymine's place in RNA; a likely reason DNA uses thymine instead is that cytosine can decay into uracil, so a distinct base lets repair enzymes spot the damage.
Q 05In a DNA molecule, Adenine (A) always pairs with which other base?
Thymine (T)
Adenine always pairs with thymine; Erwin Chargaff found in the late 1940s that DNA's amounts of A and T, and of G and C, are always equal, a clue Watson and Crick used.
Q 06What is the primary function of DNA in living organisms?
To store and pass on genetic information
To store and pass on genetic information; some viruses break the rule and use RNA as their genetic material instead.
Q 07Which physicist's 1944 book What Is Life? inspired both Watson and Crick to study the gene?
Erwin Schrödinger
Erwin Schrödinger, of the famous cat, argued that heredity must be written into an 'aperiodic' solid, a molecule whose structure holds a code; Watson and Crick each named the book as an inspiration.
Q 08Which journal published Watson and Crick's 1953 paper on DNA's structure?
Nature
Nature ran the paper on 25 April 1953, little more than a page long, alongside two others carrying the supporting X-ray data, one of them co-written by Rosalind Franklin.
Q 09Which organelle of plant cells carries its own small genome, a relic of once free-living bacteria?
Chloroplast
Chloroplasts descend from a photosynthetic bacterium that was engulfed by an early cell; they still carry DNA of their own, separate from the rest of the plant's.
Q 10Unlike DNA, RNA is typically found in what form?
Single-stranded
Single-stranded RNA can still fold back on itself into short double-stranded hairpins, which is how transfer RNA gets its cloverleaf shape.
Q 11According to the central dogma of molecular biology, what is the general flow of genetic information?
DNA → RNA → Protein
Information flows DNA → RNA → protein; Francis Crick first stated the idea in 1957, and retroviruses later showed it can also flow from RNA back into DNA.
Q 12What term describes DNA copying, in which each new molecule keeps one of the original strands?
Semi-conservative
Semi-conservative copying was confirmed in 1958 by Meselson and Stahl, whose experiment ruled out the rival ideas that the old strands stay together or are scattered in pieces.
Q 13What is the process of building a protein from an RNA template called?
Translation
Q 21What does a 'silent' point mutation refer to?
It leaves the encoded amino acid unchanged
A silent mutation leaves the encoded amino acid unchanged; because most amino acids are specified by several codons, many third-position (wobble) changes have no effect on the protein.
Q 22Which type of RNA carries a gene's instructions to the ribosomes for protein synthesis?
Messenger RNA (mRNA)
Messenger RNA (mRNA) is what the Pfizer and Moderna COVID-19 vaccines deliver: a synthetic strand that tells cells to make the virus's spike protein and is broken down within days.
Q 23What is the primary role of DNA polymerase during DNA replication?
Translation takes place on ribosomes, and antibiotics such as tetracycline work by jamming the ribosomes of bacteria.
Q 14What is the unit of DNA wound around a core of eight histone proteins called?
Nucleosome
A nucleosome wraps about 147 base pairs, nearly two turns of double helix, around eight histones; the beads-on-a-string chain they form is how two metres of DNA fit in each cell.
Q 15What is the name for an agent, such as certain chemicals in tobacco smoke, that causes changes in DNA?
Mutagen
Mutagens range from chemicals to radiation such as X-rays; because the DNA changes they cause can lead to cancer, many of them are also carcinogens.
Q 16What are small, circular DNA molecules in bacteria that replicate independently called?
Plasmids
Plasmids often carry antibiotic-resistance genes and can pass from one bacterium to another, even across species, which helps drug resistance spread so fast.
Q 17Which fruit is a classroom favourite for extracting DNA because each cell carries eight copies of its genome?
Strawberry
Strawberry cells are octoploid, with eight sets of chromosomes where ours have two, so a mashed berry mixed with detergent and alcohol yields a clump of DNA big enough to see.
Q 18Which of these can tell identical twins apart?
Fingerprints
Fingerprints are shaped by conditions in the womb as well as by genes, so identical twins, whose DNA profiles match, end up with different ridge patterns.
Q 19Who first isolated 'nuclein', now known as DNA, in 1869?
Friedrich Miescher
Friedrich Miescher was studying the proteins of cells when he found a substance rich in phosphorus that behaved like no protein he knew.
Q 20What is the name for the enzyme that separates DNA's two strands during replication?
Helicase
Helicase unzips the two strands using energy from ATP; a faulty human helicase causes Werner syndrome, a disorder of premature ageing.
Building new strands from nucleotides
Building new strands from nucleotides works only by extending an existing strand, which is why each new strand has to begin with a short stretch of RNA.
Q 24What is folding DNA into nanoscale shapes using complementary base pairing called?
DNA origami
DNA origami was unveiled in 2006 by Caltech's Paul Rothemund, who folded a long viral DNA strand into shapes such as smiley faces using more than 200 short 'staple' strands.
Q 25What dismissive nickname was long given to the stretches of DNA that don't code for proteins?
Junk DNA
Junk DNA is not all junk: some of these non-coding stretches turned out to be switches that control when and where genes are turned on.
Q 26In the film Jurassic Park, gaps in the dinosaurs' DNA are patched with DNA from which animals?
Frogs
Frogs: the borrowed amphibian DNA is the story's explanation for how the park's all-female dinosaurs manage to change sex and start breeding.
Q 27What is the process called when RNA is used as a template to synthesize DNA, as retroviruses do?
Reverse transcription
Reverse transcription is the step HIV depends on, which is why many antiretroviral drugs are reverse transcriptase inhibitors.
Q 28Which of these organisms carries roughly five times as much DNA in each cell as a human?
An onion
An onion is the star of the 'onion test', biologists' reminder that the amount of DNA an organism carries says little about how complex it is.
Q 29Angelina Jolie's 2013 essay about her preventive surgery put which cancer-risk gene in the headlines?
BRCA1
BRCA1 normally helps repair damaged DNA, so a faulty copy sharply raises the risk of breast and ovarian cancer; Jolie's doctors put her own breast-cancer risk at 87%.
Q 30What do you call the DNA-and-histone complex that condenses into chromosomes?
Chromatin
Chromatin packs tightly where genes are switched off and loosens where they are active, which helps the same DNA behave differently in different cell types.