Glucose
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40 free Glucose trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Glucose is the sugar that life runs on. Green leaves make it from thin air and sunlight, animals carry it in their blood, and almost every living cell knows how to take it apart for energy. It is also stranger than its plain reputation suggests: it works as antifreeze for one hardy animal, betrays illness to insects, and decides whether a jar in your cupboard stays runny. This quiz turns the best glucose fun facts into questions. They cover where the sugar comes from, how the body stores, senses and spends it, the foods and drinks it hides in, and the chemists and doctors who worked out its secrets, with a short explanation after every answer. It suits biology and chemistry students revising the basics, people who keep an eye on their blood sugar, and anyone who likes a surprising science fact. No lab coat needed.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Glucose was first isolated in 1747 by German chemist Andreas Marggraf from which dried fruit?
Raisins
Raisins were Marggraf's source, and in the same year he announced finding sugar in beets, the discovery that launched Europe's sugar industry.
Q 02Which North American amphibian survives being frozen in winter by flooding its cells with glucose?
Wood frog
Wood frog hearts stop and breathing ceases while the animal is frozen, with the glucose limiting how much ice forms until the spring thaw.
Q 03Which human organ makes up about 2% of body weight but uses roughly a quarter of the body's glucose?
Brain
Brain tissue gets almost all its energy from glucose yet stores very little, so it depends on a constant supply from the blood.
Q 04Which pantry food slowly turns grainy and solid in the jar because its glucose separates out as crystals?
Honey
Honey holds more sugar than its water can keep dissolved, so the glucose drops out as solid granules; gentle warming makes it runny again.
Q 05Early Indian physicians recognized diabetes after noticing that patients' sugary urine attracted which insects?
Ants
Ants drawn to the urine were the telltale sign; in the 1670s the English physician Thomas Willis described the same symptom by its sugary taste.
Q 06Marathon runners 'hit the wall' when their muscles run out of which stored form of glucose?
Glycogen
Glycogen stores usually run low around mile 20 of a marathon, which is why athletes load up on carbohydrates before a race.
Q 07Most animals make which essential nutrient from glucose, an ability humans and guinea pigs have lost?
Vitamin C
Vitamin C is out of reach for humans because the gene for the final enzyme in the pathway is broken, so it has to come from fruit and vegetables.
Q 08Cotton fiber is about 90% which chain of glucose units, the most abundant organic polymer on Earth?
Cellulose
Cellulose passes through humans undigested, but cows and termites break it down with help from microbes living in their guts.
Q 09Roughly how much glucose is dissolved in the entire bloodstream of a healthy adult at any moment?
About 4 grams
About 4 grams, close to a single teaspoon of sugar, is all the blood carries, so the body tops it up constantly from its reserves.
Q 10When yeast ferments glucose to make beer and wine, it releases carbon dioxide and which type of alcohol?
Ethanol
Ethanol and carbon dioxide come out in equal measure, two molecules of each per glucose, and the same gas is what makes bread dough rise.
Q 11Which hormone signals the body's cells to absorb glucose from the blood?
Insulin
Insulin takes its name from the Latin word for island, and it was the first protein to have its full sequence decoded, by Frederick Sanger.
Q 12Plants build glucose out of water and carbon dioxide, powered by sunlight, in which process?
Photosynthesis
Photosynthesis was discovered in 1779 by Jan Ingenhousz, who showed that plants need light, not just soil and water.
Q 13Table sugar is glucose bonded to which other simple sugar, the sweetest of all natural carbohydrates?
Fructose
Fructose, also known as fruit sugar, is released alongside glucose when digestion splits table sugar back into its two halves.
Q 21Which other name for glucose reflects the direction its solutions rotate a beam of polarized light?
Dextrose
Dextrose comes from the Latin dexter, meaning right, because glucose solutions turn the light clockwise; August Kekulé proposed the name.
Q 22Which hormone, released by alpha cells when blood sugar falls, signals the body to release its stored sugar?
Glucagon
Glucagon was first noticed in the early 1920s, when experimental gland extracts made blood sugar briefly rise before it fell.
Q 23Which fight-or-flight hormone makes the body release extra glucose into the blood for a burst of energy?
Adrenaline
Adrenaline, also known as epinephrine, widens the pupils and sends extra blood to the muscles at the same moment.
Q 14Which organ tucked behind the stomach holds the islets of Langerhans, cell clusters that control blood glucose?
Pancreas
Pancreas tissue is mostly devoted to making digestive juices; the hormone-producing islets make up only 1 to 2 percent of the organ.
Q 15Which large organ acts as the body's glucose bank, releasing sugar into the blood between meals?
Liver
Liver cells go a step further when reserves run low, building brand-new glucose from amino acids and other leftovers.
Q 16In the United States, the glucose syrup used in candy and other sweets is most commonly made from which crop?
Corn
Corn is the American choice, while producers elsewhere make the same syrup from potatoes, wheat or cassava.
Q 17Potatoes, rice and wheat are packed with which glucose-based molecule that plants use as an energy store?
Starch
Starch is the most common carbohydrate in the human diet, and commercial glucose is made by breaking it down completely.
Q 18Which component of the human bloodstream has no mitochondria and so must run entirely on glucose for energy?
Red blood cells
Red blood cells use none of the oxygen they carry, breaking glucose down without it and leaving their whole cargo for the rest of the body.
Q 19The sugar in milk is one glucose unit joined to one unit of which other simple sugar?
Galactose
Galactose and glucose are separated by the enzyme lactase, which most mammals make less of after weaning, the root of lactose intolerance.
Q 20Which molecular formula does glucose share with several other simple sugars that differ only in structure?
C6H12O6
C6H12O6 means six carbons, twelve hydrogens and six oxygens, and the six carbons make glucose a hexose.
Q 24Which ten-step pathway, shared by almost all living things, splits one glucose molecule into two of pyruvate?
Glycolysis
Glycolysis needs no oxygen and is thought to be very ancient: its reactions could have run in the oxygen-free oceans of the early Earth.
Q 25Cells break down glucose mainly to make which molecule, often called the energy currency of life?
ATP
ATP comes out at roughly 30 molecules per glucose, short of the 38 that textbooks often quote, because some energy is lost along the way.
Q 26Hard-working muscle cells can ferment glucose into which compound, also made by the bacteria in yogurt and sauerkraut?
Lactic acid
Lactic acid fermentation releases far less energy than burning glucose with oxygen, just two units per molecule, but it needs no air supply.
Q 27Which German chemist won the 1902 Nobel Prize in Chemistry for his work on glucose and other sugars?
Emil Fischer
Emil Fischer mapped the shapes of all the known sugars in the 1890s, and the Fischer projection chemists still draw is named after him.
Q 28Whose work on how muscles store and reuse glucose made her the first woman to win a Nobel Prize in Medicine?
Gerty Cori
Gerty Cori shared the 1947 prize with her husband Carl, which made them only the third married couple to win a Nobel.
Q 29Which food-ranking scale, introduced in 1981, gives pure glucose the top reference score of 100?
Glycemic index
Glycemic index scores show how much a food raises blood sugar in the two hours after eating, measured against glucose itself.
Q 30Which medical imaging technique spots tumors by tracking a radioactive glucose lookalike that cancer cells soak up?
PET scan
PET scan tracers get trapped inside whichever cells pull in the most fuel, because the altered glucose can be absorbed but not released again.