40 Fun Facts About Glucose

Glucose was first isolated in 1747 by German chemist Andreas Marggraf from which dried fruit?

Raisins were Marggraf's source, and in the same year he announced finding sugar in beets, the discovery that launched Europe's sugar industry.

Which North American amphibian survives being frozen in winter by flooding its cells with glucose?

Wood frog hearts stop and breathing ceases while the animal is frozen, with the glucose limiting how much ice forms until the spring thaw.

Which human organ makes up about 2% of body weight but uses roughly a quarter of the body's glucose?

Brain tissue gets almost all its energy from glucose yet stores very little, so it depends on a constant supply from the blood.

Which pantry food slowly turns grainy and solid in the jar because its glucose separates out as crystals?

Honey holds more sugar than its water can keep dissolved, so the glucose drops out as solid granules; gentle warming makes it runny again.

Early Indian physicians recognized diabetes after noticing that patients' sugary urine attracted which insects?

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.

Marathon runners 'hit the wall' when their muscles run out of which stored form of glucose?

Glycogen stores usually run low around mile 20 of a marathon, which is why athletes load up on carbohydrates before a race.

Most animals make which essential nutrient from glucose, an ability humans and guinea pigs have lost?

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.

Cotton fiber is about 90% which chain of glucose units, the most abundant organic polymer on Earth?

Cellulose passes through humans undigested, but cows and termites break it down with help from microbes living in their guts.

Roughly how much glucose is dissolved in the entire bloodstream of a healthy adult at any moment?

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.

When yeast ferments glucose to make beer and wine, it releases carbon dioxide and which type of alcohol?

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.

Which hormone signals the body's cells to absorb glucose from the blood?

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.

Plants build glucose out of water and carbon dioxide, powered by sunlight, in which process?

Photosynthesis was discovered in 1779 by Jan Ingenhousz, who showed that plants need light, not just soil and water.

Table sugar is glucose bonded to which other simple sugar, the sweetest of all natural carbohydrates?

Fructose, also known as fruit sugar, is released alongside glucose when digestion splits table sugar back into its two halves.

Which organ tucked behind the stomach holds the islets of Langerhans, cell clusters that control blood glucose?

Pancreas tissue is mostly devoted to making digestive juices; the hormone-producing islets make up only 1 to 2 percent of the organ.

Which large organ acts as the body's glucose bank, releasing sugar into the blood between meals?

Liver cells go a step further when reserves run low, building brand-new glucose from amino acids and other leftovers.

In the United States, the glucose syrup used in candy and other sweets is most commonly made from which crop?

Corn is the American choice, while producers elsewhere make the same syrup from potatoes, wheat or cassava.

Potatoes, rice and wheat are packed with which glucose-based molecule that plants use as an energy store?

Starch is the most common carbohydrate in the human diet, and commercial glucose is made by breaking it down completely.

Which component of the human bloodstream has no mitochondria and so must run entirely on glucose for energy?

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.

The sugar in milk is one glucose unit joined to one unit of which other simple sugar?

Galactose and glucose are separated by the enzyme lactase, which most mammals make less of after weaning, the root of lactose intolerance.

Which molecular formula does glucose share with several other simple sugars that differ only in structure?

C6H12O6 means six carbons, twelve hydrogens and six oxygens, and the six carbons make glucose a hexose.

Which other name for glucose reflects the direction its solutions rotate a beam of polarized light?

Dextrose comes from the Latin dexter, meaning right, because glucose solutions turn the light clockwise; August Kekulé proposed the name.

Which hormone, released by alpha cells when blood sugar falls, signals the body to release its stored sugar?

Glucagon was first noticed in the early 1920s, when experimental gland extracts made blood sugar briefly rise before it fell.

Which fight-or-flight hormone makes the body release extra glucose into the blood for a burst of energy?

Adrenaline, also known as epinephrine, widens the pupils and sends extra blood to the muscles at the same moment.

Which ten-step pathway, shared by almost all living things, splits one glucose molecule into two of pyruvate?

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.

Cells break down glucose mainly to make which molecule, often called the energy currency of life?

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.

Hard-working muscle cells can ferment glucose into which compound, also made by the bacteria in yogurt and sauerkraut?

Lactic acid fermentation releases far less energy than burning glucose with oxygen, just two units per molecule, but it needs no air supply.

Which German chemist won the 1902 Nobel Prize in Chemistry for his work on glucose and other sugars?

Emil Fischer mapped the shapes of all the known sugars in the 1890s, and the Fischer projection chemists still draw is named after him.

Whose work on how muscles store and reuse glucose made her the first woman to win a Nobel Prize in Medicine?

Gerty Cori shared the 1947 prize with her husband Carl, which made them only the third married couple to win a Nobel.

Which food-ranking scale, introduced in 1981, gives pure glucose the top reference score of 100?

Glycemic index scores show how much a food raises blood sugar in the two hours after eating, measured against glucose itself.

Which medical imaging technique spots tumors by tracking a radioactive glucose lookalike that cancer cells soak up?

PET scan tracers get trapped inside whichever cells pull in the most fuel, because the altered glucose can be absorbed but not released again.

Oral rehydration drinks work because the glucose in them helps the gut absorb water along with which mineral?

Sodium crosses the gut wall hand in hand with glucose and water follows, a 1960s discovery made during cholera outbreaks.

The A1c test estimates three months of average blood glucose by measuring sugar stuck to which blood protein?

Hemoglobin keeps the sugar for as long as its cell survives, three to four months, so the test works like a long-term diary.

Which sugar, made of two glucose units joined together, takes its name from the sprouted grain used in brewing?

Maltose appears when enzymes clip two glucose units at a time off long plant chains, as happens inside germinating seeds.

When glucose runs short during a long fast, the body turns fatty acids into which backup fuel?

Ketone bodies have a fruity smell, often compared to nail polish remover, that can be detected on the breath of someone running on them.

Which process between amino acids and sugars such as glucose gives seared steak and baked bread a brown crust?

Maillard reaction browning is a separate process from caramelization, which needs no amino acids at all, just sugar and heat.

Which sugar, built from two glucose units, serves as the blood sugar of insects such as locusts and butterflies?

Trehalose releases two glucose molecules in a single cut, giving insects the rapid burst of energy that flight demands.

Which tough material in insect shells and mushroom cell walls is a long chain built from a modified form of glucose?

Chitin is among the most plentiful natural materials on Earth, with living things producing an estimated billion tons of it every year.

Which German Nobel laureate first reported that most cancers ferment glucose for energy instead of burning it fully?

Otto Warburg won the 1931 Nobel Prize for separate work on a respiratory enzyme, yet the cancer finding is what carries his name: the Warburg effect.

Which sugar alcohol, made by chemically reducing glucose, sweetens many sugar-free chewing gums and mints?

Sorbitol also turns up in toothpaste and cough syrup, and pharmacies sell it as a laxative.

Benedict's solution, a school-lab test for glucose, turns from blue to brick red thanks to ions of which metal?

Copper ions in the blue solution are converted by the sugar into red copper oxide, which drops out of the liquid as a solid.