High School Biology
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50 free High School Biology trivia questions with answers — science & nature quiz, new questions added Oct 2026.
High school biology is where the big ideas of life science first click into place: how a handful of elements build every living thing, how a cell copies its DNA, and why children resemble their parents without being copies of them. This quiz follows the course from start to finish. It opens with atoms, bonds and the molecules of life, moves through cell structure, DNA and meiosis, and carries on into inheritance, evolution, ecology and the human body. Every question comes with its answer and a short explanation, so a wrong guess still teaches something. Use it as a sample test before an exam, a review game for a class, or a quick check of how much of the course has stuck since graduation.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which farm animal was Dolly, the first mammal cloned from an adult body cell, born in Scotland in 1996?
Sheep
Dolly was a Finn-Dorset sheep, cloned at the Roslin Institute from a single mammary gland cell. Her preserved body is on display at the National Museum of Scotland in Edinburgh.
Q 02Which organelle, normally inherited only from the mother, supplies most of a cell's chemical energy?
Mitochondrion
The mitochondrion carries its own small genome, similar to a bacterium's. In mammals the father's copies, delivered by the sperm, are usually destroyed by the egg cell after fertilization.
Q 03Which chemist led the X-ray diffraction work at King's College London that produced Photo 51 of DNA?
Rosalind Franklin
Rosalind Franklin's team produced Photo 51 in 1952, an image taken by her student Raymond Gosling. Its diffraction pattern revealed the helical shape of DNA.
Q 04Which DNA base pairs with adenine in the double helix but is normally missing from RNA?
Thymine
Thymine binds to adenine in DNA, while RNA uses uracil in its place. Chemically the two are close cousins: thymine is uracil with one extra methyl group attached.
Q 05Which Augustinian friar established the basic rules of heredity by cross-breeding pea plants in the 1850s and 1860s?
Gregor Mendel
Gregor Mendel tracked seven traits of his pea plants, among them seed shape and flower color. Recognition as the founder of genetics came only after his death.
Q 06Which naturalist's five-year voyage on HMS Beagle led to the book On the Origin of Species?
Charles Darwin
Charles Darwin sailed on the Beagle from 1831 to 1836. A keen taster of exotic animals, he ate puma, iguana and armadillo along the way, and by mistake a rhea he had meant to study.
Q 07Which English scientist coined the biological term cell in Micrographia, a 1665 book of microscope observations?
Robert Hooke
Robert Hooke coined the term for the tiny walled pores he saw in a thin slice of cork, which he compared to a honeycomb.
Q 08Which enzyme in human saliva starts digestion by splitting starch into simpler sugars?
Amylase
Amylase is why starchy foods such as rice and potatoes can turn sweet as they are chewed. It is already converting some of their starch into sugar before they are swallowed.
Q 09Which inherited blood disorder did Queen Victoria pass to the royal families of Spain, Germany and Russia?
Hemophilia
Hemophilia reached three royal houses through two of Victoria's daughters, Alice and Beatrice. Tests on the remains of Russia's Romanovs suggest it was the rarer form, type B.
Q 10Which genetic condition is caused by the presence of all or part of a third copy of chromosome 21?
Down syndrome
Down syndrome is named after John Langdon Down, the English physician who described it in the 1860s. Its genetic cause was not discovered until 1959.
Q 11Which subatomic particles do two atoms share in pairs to form a covalent bond?
Electrons
Electrons shared in pairs hold atoms together, an idea the chemist Gilbert Lewis proposed in 1916. Carbon can form four such bonds at once, enough to build the skeleton of every organic molecule.
Q 12Which term describes atoms of one element with different numbers of neutrons, the basis of radiometric dating?
Isotopes
Isotopes of an element share a proton count but differ in mass. Radiometric dating compares a radioactive one with the decay products it turns into at a known, constant rate.
Q 13Which weak attraction between neighboring water molecules gives water its high surface tension and boiling point?
Hydrogen bond
Q 21Which event in prophase I of meiosis swaps DNA segments between paired chromosomes, shuffling a parent's genes?
Crossing over
Crossing over is why siblings differ: each chromosome a parent passes on is a fresh patchwork of the two that parent inherited. Thomas Hunt Morgan built the theory on what Frans Janssens saw in 1909.
Q 22Which term describes a cell, such as a human sperm or egg, that carries only one set of chromosomes?
Haploid
Haploid cells are made when meiosis splits the 46-chromosome human set in half. Two of them then fuse at fertilization, restoring the full count.
Q 23Which single cell forms when a sperm fertilizes an egg, combining two sets of chromosomes?
Zygote
Hydrogen bonds make water molecules cling together so tightly that trees can pull it more than 100 m up their trunks.
Q 14Which class of biological molecules includes fats, waxes and sterols and does not dissolve readily in water?
Lipids
Lipids are hydrophobic, and that is what makes them useful. Those with one water-loving end line up in sheets, forming the thin membranes around cells.
Q 15Which branched carbohydrate do humans store in the liver and skeletal muscles as an energy reserve?
Glycogen
Glycogen is the animal counterpart of plant starch. Liver stores keep blood sugar steady between meals, while muscle stores are mostly burned on the spot by the muscle that holds them.
Q 16Which element do bacteria living in the root nodules of legumes capture from the air and turn into ammonia?
Nitrogen
Nitrogen gas from the air becomes ammonia inside the nodules, and the plant builds it into amino acids. It is why legumes such as clover, soybeans and peanuts need less fertilizer.
Q 17Which particle, found in every living cell, builds proteins by reading the code in messenger RNA?
Ribosome
A ribosome is two subunits locked around a strand of messenger RNA. Bacterial ones differ enough from ours that some antibiotics can jam them while leaving human cells unharmed.
Q 18Which process moves water through a selectively permeable membrane toward the side with more dissolved solute?
Osmosis
Osmosis is the main agent of support in many plants. Water flowing into their cells presses against the cell walls, and when that pressure is lost the plant wilts.
Q 19Which group of organisms, made up of bacteria and archaea, has cells with no membrane-bound nucleus?
Prokaryotes
Prokaryotes take their name from Greek words for 'before' and 'kernel', a nod to cells that came before the nucleus. They reproduce asexually, usually by splitting in two.
Q 20Which molecule, often called the energy currency of the cell, drives muscle contraction and nerve impulses?
ATP
ATP is spent and rebuilt so quickly that a typical adult gets through roughly their own body weight of it over the course of a day.
Zygote comes from a Greek word meaning 'joined' or 'yoked'. In humans it makes its first division, into two cells, about 30 hours after fertilization.
Q 24Which meiosis error, a failure of chromosomes to separate, leaves cells with an abnormal chromosome number?
Nondisjunction
Nondisjunction in humans most often traces to the egg rather than the sperm, and the risk climbs with the mother's age. The cells that result carry a chromosome too many or too few.
Q 25Which stage of mitosis lines the chromosomes up along the cell's equator before they are pulled apart?
Metaphase
Metaphase holds every chromosome in a tug-of-war between fibers pulling from opposite poles. A checkpoint lets division continue only once each one is attached and evenly balanced.
Q 26In which part of the cell cycle, before mitosis begins, does a cell grow and copy its DNA?
Interphase
Interphase is where a cell spends most of its life. Typical cells of adult mammals stay in it for about 24 hours, at least 90% of the time a full round of division takes.
Q 27Which constricted region of a chromosome links the two sister chromatids together during cell division?
Centromere
The centromere divides each chromosome into a short arm, labeled p, and a long arm, labeled q. The p is said to stand for the French word petit, meaning small.
Q 28Which pair of scientists published the double helix model of DNA in the journal Nature in 1953?
Watson and Crick
Watson and Crick fitted the model into a paper barely a page long, printed on pages 737 and 738 of the journal. The two shared a Nobel Prize for it with Maurice Wilkins in 1962.
Q 29Which enzyme separates the two strands of DNA at the replication fork so that each can be copied?
Helicase
Helicase works like a motor, burning cellular fuel to push the two strands apart. Some versions do the job as ring-shaped clusters of six units.
Q 30Which three-base unit of messenger RNA specifies a single amino acid in a growing protein?
Codon
A codon is one of 64 possible three-letter combinations, though cells use only 20 standard amino acids. Three of the 64 mean stop, and carry the names amber, ochre and opal.