Macromolecules
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50 free Macromolecules trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Almost everything a living thing is made of, once the water is taken away, belongs to one of four families of giant molecules. Carbohydrates fuel cells and hold plants upright. Lipids store energy and wall off every cell. Proteins do most of the work, from moving muscles to fighting infection. Nucleic acids carry the instructions for building all the rest. This quiz covers the ground a high school or first-year biology unit does. There are questions on what each class is built from, how small units are joined into long chains and split apart again, the lab tests that reveal what is in a food sample, and where these molecules turn up in bread, hair, wood and blood. The scientists who worked it all out are here too. The first questions are for anyone curious about what food and bodies are made of. The later ones are closer to what a biology student meets before a test. Every answer comes with a short explanation, so even a miss leaves you knowing something new.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which carbohydrate, the most abundant organic polymer on Earth, makes up 90% of cotton fibre?
Cellulose
Cellulose passes through the human gut undigested as dietary fibre. Cows and termites can live on it only because microbes in their guts break it down for them.
Q 02Which protein, the most abundant in the bodies of mammals, takes its name from the Greek word for glue?
Collagen
Collagen turns into gelatin when skin, bones and sinews are boiled, which is how animal glue was made for centuries. It accounts for 25% to 35% of a mammal's protein.
Q 03Which tough protein builds human hair and fingernails as well as rhino horns and bird feathers?
Keratin
Keratin gets its strength from sulfur cross-links between its chains, which is why burning hair smells so sharp. The same protein makes hooves, claws and wool.
Q 04Which protein network in wheat flour traps gas bubbles and gives bread dough its stretch and chew?
Gluten
Gluten forms when two wheat proteins, gliadin and glutenin, are wetted and kneaded. It is also the base of seitan, the mock meat sold as vegetarian duck and chicken.
Q 05Which shape did James Watson and Francis Crick propose for the DNA molecule in their Nobel Prize-winning model?
Double helix
Double helix became a household phrase after Watson used it as the title of his 1968 memoir. The two strands wind around each other like a twisted ladder.
Q 06Which hormone, made by beta cells in the pancreas, became the first protein ever to be fully sequenced?
Insulin
Insulin takes its name from the Latin for island, after the clusters of pancreas cells that make it. It tells the body's cells to take up sugar from the blood.
Q 07Which natural fibre, made mostly of the protein fibroin, turned up in 8,500-year-old tombs in China?
Silk
Silk is about 75–80% fibroin, wrapped in a gummy protein called sericin that is boiled off before reeling. A whole cocoon can be unwound as one continuous thread.
Q 08Which synthetic polymer from DuPont was sold as toothbrush bristles before it caused a rush for stockings?
Nylon
Nylon stockings sold 64 million pairs in their first year on the market. The first 4,000 pairs offered in Wilmington, Delaware, were gone within three hours.
Q 09Which iron-containing protein fills red blood cells and carries oxygen from the lungs to the body's tissues?
Hemoglobin
Hemoglobin makes up about 96% of a red blood cell's dry weight. Each molecule is built from four protein chains and can carry up to four oxygen molecules at once.
Q 10Which tough carbohydrate forms both the outer shells of insects and crabs and the cell walls of mushrooms?
Chitin
Chitin is the second most abundant polysaccharide in nature, with about a billion tons made each year. Squid beaks are built from it too.
Q 11Which simple sugar, made by plants during photosynthesis, circulates in human blood as blood sugar?
Glucose
Glucose is the most abundant simple sugar in nature, and every living organism can use it for energy. Its name comes from the Greek for sweet.
Q 12Which carbohydrate do green plants make to store energy, filling staples such as potatoes and rice?
Starch
Starch is the most common carbohydrate in the human diet. Wheat, maize and cassava are packed with it too, which is why it feeds most of the world.
Q 13Which branched carbohydrate do humans store in the liver and muscles as a quick reserve of energy?
Glycogen
Glycogen makes up 5–6% of the liver's fresh weight, roughly 100–120 grams in an adult. The skeletal muscles hold about 400 grams more.
Q 21Which Y-shaped proteins does the immune system release to recognise and neutralise bacteria and viruses?
Antibodies
Antibodies each bind to one particular target, and the body can make a variety to match almost any shape. The word antigen is usually explained as short for antibody generator.
Q 22Which type of RNA, used in the Pfizer and Moderna COVID-19 vaccines, carries a gene's instructions for a protein?
Messenger RNA
Messenger RNA was given its name by François Jacob and Jacques Monod, and its existence was shown in 1961. In a vaccine it has a person's own cells make a harmless piece of a virus.
Q 23Which chemist oversaw the DNA X-ray image Photo 51 yet died four years before its structure won a Nobel Prize?
Rosalind Franklin
Q 14Which sugar, refined from sugarcane and sugar beet, is the chemical name for ordinary white table sugar?
Sucrose
Sucrose makes up about a fifth of a sugar beet root by weight. Each molecule is two simple sugars joined together, which the gut has to split apart.
Q 15Which sugar in milk causes bloating in adults who no longer make the enzyme needed to digest it?
Lactose
Lactose makes up around 2–8% of milk by mass. Most mammals stop making the enzyme that splits it after weaning, so digesting milk as an adult is the unusual trait.
Q 16Which fatty substance, first found in gallstones, is the raw material for vitamin D and the sex hormones?
Cholesterol
Cholesterol got its name from the Greek for solid bile, because it was first identified in gallstones in 1769. Every animal cell also builds it into its outer membrane.
Q 17Which kind of fat, solid at room temperature in butter and lard, has chains with no double bonds?
Saturated fats
Saturated fats also turn up in a few plant foods, notably coconut oil and palm kernel oil. Their straight chains pack closely, while a double bond bends a chain and keeps oils liquid.
Q 18Which lipids do plants secrete onto the surface of their leaves to control evaporation and shed rain?
Waxes
Waxes are also what bees secrete to build honeycomb. They shed water so well that people use them in polishes, candles and waterproof coatings.
Q 19Which building blocks of proteins include nine essential kinds that the human body cannot make?
Amino acids
Amino acids come in more than 500 kinds in nature, yet only 22 are ever built into proteins. The last of the 20 common ones, threonine, was not discovered until 1935.
Q 20Which natural polymer of isoprene is collected as milky latex by cutting the bark of a tropical tree?
Rubber
Rubber was first used by the Olmec of ancient Mexico, who made balls from it for the Mesoamerican ballgame. Each of its chain molecules can weigh up to a million daltons.
Rosalind Franklin died of ovarian cancer in 1958, aged 37. The photograph was taken by her PhD student Raymond Gosling, and it was the 51st diffraction image he had made.
Q 24Which element, dripped onto bread or potato in a classic school food test, turns the food blue-black?
Iodine
Iodine slips inside the coiled amylose chains in such foods, and the trapped molecules look blue-black. Counterfeit-detector pens use the same reaction on wood-pulp paper.
Q 25Which process, triggered by heat or acid, unfolds a protein and turns a raw egg white solid and opaque?
Denaturation
Denaturation scrambles a protein's folded shape but leaves the chain itself unbroken. It is why cooked meat turns firm and why a boiled egg stays solid after it cools.
Q 26Which infectious agents, misfolded proteins carrying no genes at all, cause mad cow disease in cattle?
Prions
Prions spread by making normal copies of the same protein misfold in turn. Stanley Prusiner built the name from protein and infection, and won a 1997 Nobel Prize.
Q 27Which particle, itself built of RNA and protein, assembles every protein that a living cell makes?
Ribosome
Ribosomes were first seen in 1955 by George Palade and were at first called Palade granules. The part that actually joins the chain together is RNA, not protein.
Q 28Which element do food labs measure to gauge protein content, since fat and carbohydrate contain none?
Nitrogen
Nitrogen stands in for protein so reliably that fraudsters exploit it. In China's 2008 milk scandal, melamine was added to watered-down milk to fool the test.
Q 29What are the small molecules called that join end to end by the thousand to form a polymer?
Monomers
Monomers get their name from the Greek for one part. A chain may repeat a single kind, as most plastics do, or mix several kinds, as proteins and DNA do.
Q 30Which molecule, the energy currency of cells, do people recycle at a rate of their own body weight each day?
ATP
ATP is built like a single link of an RNA chain with two extra phosphate groups attached. An average adult turns over around 50 kilograms of it every day.