amino acids: Simple molecules that occur naturally in plant and animal tissues and that are the basic building blocks of proteins.
atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
average: (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.
bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.
blood sugar: The body circulates glucose, a type of simple sugar, in blood to tissues of the body where it will be used as a fuel. The body extracts this simple sugar from breakdown of sugars and starches. However, some diseases, most notably diabetes, can allow an unhealthy concentration of this sugar to build up in blood.
blood vessel: A tubular structure that carries blood through the tissues and organs.
carbohydrates: Any of a large group of compounds occurring in foods and living tissues, including sugars, starch and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down in an animal’s body to release energy.
carbon: A chemical element that is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules. (in climate studies) The term carbon sometimes will be used almost interchangeably with carbon dioxide to connote the potential impacts that some action, product, policy or process may have on long-term atmospheric warming.
cardiologist: A doctor that specializes in the branch of medicine dealing with functions and diseases of the heart.
carnivore: An animal that either exclusively or primarily eats other animals.
cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell. (in telecommunications) A technology that relies on a large number of base stations to relay signals. Each base station covers only a small area, which is known as a cell. Phones that rely on this system are typically referred to as cell phones.
cellulose: A type of fiber found in plant cell walls. It is formed by chains of glucose molecules.
cereals: A group of plants in the grass family that provides an edible seed, which serves as a food staple (such as wheat, barley, corn, oats and rice).
chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.
chemical reaction: A process that involves the rearrangement of the molecules or structure of a substance, as opposed to a change in physical form (as from a solid to a gas).
cholesterol: A fatty material in animals that forms a part of cell walls. In vertebrate animals, it travels through the blood in little vessels known as lipoproteins. Excessive levels in the blood can signal risks to blood vessels and heart.
chyme: A term for the partially digested mass of food leaving the stomach.
citrus: A genus of flowering trees that tend to produce fruits with a juicy edible flesh. There are several main categories: the oranges, mandarins, pummelos, grapefruits, lemons, citrons and limes.
compound: (often used as a synonym for chemical) A compound is a substance formed when two or more chemical elements unite (bond) in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O.
concentration: (in chemistry) A measurement of how much of one substance has been dissolved into another.
constant: Continuous or uninterrupted. (in mathematics) A number that is known and unchanging, usually based on some mathematical definition. For example, π (pi) is a constant equal to 3.14. . . and defined as the circumference of a circle divided by its diameter.
constipation: Difficulty defecating because the stool is too dense or because the intestinal tract does not contract sufficiently to efficiently move wastes through it.
diabetes: A disease where the body either makes too little of the hormone insulin (known as type 1 disease) or ignores the presence of too much insulin when it is present (known as type 2 diabetes).
diet: (n.) The foods and liquids ingested by an animal to provide the nutrition it needs to grow and maintain health. Sometimes this is a specific food-intake plan. (v.) To adopt a specific food-intake plan. People may adopt one for religious or ethical reasons, to address food allergies or to control a disease such as high blood pressure or diabetes. They may also adopt one in an effort to lose weight, although this can be unhealthy if not done under the guidance of a health professional, such as a physician or registered dietician.
disaccharide: A water-soluble carbohydrate made from the linking of two simple sugars (each a saccharide molecule). The most well-known disaccharide is sucrose (also known as table sugar). It’s a molecular mashup of the simple sugars glucose and fructose.
dissolve: To turn a solid into a liquid and disperse it into that starting liquid. (For instance, sugar or salt crystals, which are solids, will dissolve into water. Now the crystals are gone and the solution is a fully dispersed mix of the liquid form of the sugar or salt in water.)
enzymes: Molecules made by living things to speed up chemical reactions.
fat: A natural oily or greasy substance occurring in plants and in animal bodies, especially when deposited as a layer under the skin or around certain organs. Fat’s primary role is as an energy reserve. Fat also is a vital nutrient, though it can be harmful if consumed in excessive amounts.
fatty acid: A large molecule made of up chains of carbon and hydrogen atoms linked together. Fatty acids are chemical building blocks of fats in foods and the body.
fiber: Something whose shape resembles a thread or filament. (in nutrition) Components of many fibrous plant-based foods. These so-called non-digestible fibers tend to come from cellulose, lignin, and pectin — all plant constituents that resist breakdown by the body’s digestive enzymes.
fructose: A simple sugar. Along with glucose, fructose makes up half of each molecule of sucrose (also known as table sugar).
fruit: A seed-containing reproductive organ in a plant.
fuel: Any material that will release energy during a controlled chemical or nuclear reaction. Fossil fuels (coal, natural gas and petroleum) are a common type that liberate their energy through chemical reactions that take place when heated (usually to the point of burning).
gastrointestinal tract: The organs — basically the stomach and intestines — that break down foo and absorb the nutrients needed by the body.
glucose: A simple sugar that is an important energy source in living organisms. As an energy source moving through the bloodstream, it is known as “blood sugar.” It is half of the molecule that makes up table sugar (also known as sucrose).
glycogen: A form of stored energy. This highly branched polymer of glucose (a type of sugar) is the body’s main source of energy. It’s derived from carbohydrates in the diet. When we consume more glucose than the body can immediately use, the excess is converted to glycogen, mostly in muscle and the liver.
gut: An informal term for the gastrointestinal tract, basically the stomach and intestines. These organs digest — break down — foods and absorb their nutrients for use by the body.
heart attack: Permanent damage to the heart muscle that occurs when one or more regions of it become starved of oxygen, usually due to a temporary blockage in blood flow.
honey: A viscous (gooey) material that honeybees store in their honeycombs. The bees make it from nectar. Foraging bees visit flowers in search of that sugary liquid. Back at the hive, honeybees will add some enzymes to the nectar, then deposit the amber colored liquid into the hive’s combs. As worker bees use their wings to fan the cells containing this liquid, the goo heats up and some of its water will evaporate to form honey.
hormone: (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.
hydrogen: The lightest element in the universe. As a gas, it is colorless, odorless and highly flammable. It’s an integral part of many fuels, fats and chemicals that make up living tissues. It’s made of a single proton (which serves as its nucleus) orbited by a single electron.
immune system: The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.
insoluble: Incapable of being dissolved into a fluid or gas. Salt and sugar can dissolve in water, for example, but some other substances, including some of those with large molecules such as proteins, do not.
insulin: A hormone produced in the pancreas (an organ that is part of the digestive system) that helps the body use glucose as fuel.
insulin resistance: A condition where the body begins to ignore the presence of insulin, a hormone needed to help move energy (sugar) from the blood and into cells where it can fuel their activities. Insulin resistance is an early symptom of people at risk of developing type 2 diabetes.
kidney: Each in a pair of organs in mammals that filters blood and produces urine.
lignin: A natural substance that helps strengthen the cell walls of plants. Although lignin is made from a large number of sugar molecules, which should provide energy, livestock can’t digest this material because of the way its sugars are chemically bonded together.
link: A connection between two people or things.
literally: An adjective indicating that the phrase it modifies is precisely true. For instance, to say: “It’s so cold that I’m literally dying,” means that this person actually expects to soon be dead, the result of getting too cold.
liver: An organ of the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, break down harmful substances for excretion by the body, and secrete bile, a greenish fluid released into the gut, where it helps digest fats and neutralize acids.
molecule: A group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in air is made of two bound oxygen atoms (O2). Water is made of two hydrogen atoms and one oxygen atom (H2O).
monosaccharide: A simple sugar, such as glucose or fructose, comprising a single saccharide unit. These are the simplest types of carbohydrates.
muscle: A type of tissue used to produce movement by contracting its cells, known as muscle fibers. Muscle is rich in protein, which is why predatory species seek prey containing lots of this tissue.
nutrient: A vitamin, mineral, fat, carbohydrate or protein that a plant, animal or other organism requires as part of its food in order to survive.
nutrition: (adj. nutritious) The healthful components (nutrients) in the diet — such as proteins, fats, vitamins and minerals — that the body uses to grow and to fuel its processes. A scientist who works in this field is known as a nutritionist.
oligosaccharide: A type of small-ish carbohydrate that contains between three and 10-monosaccharide units (simple sugars).
online: (n.) On the internet. (adj.) A term for what can be found or accessed on the internet.
organ: (in biology) Various parts of an organism that perform one or more particular functions. For instance, an ovary is an organ that makes eggs, the brain is an organ that makes sense of nerve signals and a plant’s roots are organs that take in nutrients and moisture.
oxygen: A gas that makes up about 21 percent of Earth’s atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).
pancreas: This abdominal organ makes digestive juices (containing enzymes that aid in the breakdown of food) and several hormones, including insulin.
podcast: A digital audio or video series that can be downloaded from the Internet to your computer or smartphone. Some podcasts also are shows that are broadcast on radio, television or other media.
polysaccharide: A carbohydrate made from many monosaccharide units (simple sugars). In theory, a polysaccharide could have as few as two monosaccharide building blocks. In fact, many complex types contain hundreds to thousands of sugar units — or more.
population: (in biology) A group of individuals (belonging to the same species) that lives in a given area.
processed foods: Foods purchased from a grocery story that are substantially different from the raw materials that went into them. Examples include most foods that come in cans, bottles, boxes or bags. Examples include breakfast cereals, frozen pizzas, canned tuna, jars of spaghetti sauce and dill pickles.
protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Antibodies, hemoglobin and enzymes are all examples of proteins. Medicines frequently work by latching onto proteins.
pyramid: A monumental structure with a square or triangular base and sloping sides that meet in a point at the top. The best known are those made from stone as royal tombs in ancient Egypt.
risk: The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
saccharide: The basic building block of carbohydrates, saccharides can be simple or complex, ring shaped or a short chain molecule. They are a structural feature of all living cells and serve as a major energy source in animals.
secrete: (noun: secretion) The natural release of some liquid substance — such as hormones, an oil or saliva — often by an organ of the body.
social media: Digital media that allow people to connect with each other (often anonymously) and to share information. Examples include Twitter, Facebook, Instagram, TikTok and WhatsApp.
soluble: Some chemical that is able to dissolve some liquid. The resulting combo becomes a solution.
sprint: To run at top speed over a fairly short distance. In competitive running, the 100-meter race is a sprint. A person who is doing this kind of running is called a sprinter.
starch: A soft white chemical made by all green plants. It’s a relatively long molecule made from linking together a lot of smaller, identical building blocks — all of them glucose, a simple sugar. Plants and animals use glucose as an energy source. Plants store that glucose, in the form of starch, as a reserve supply of energy. Animals that consume starch can break down the starch into glucose molecules to extract the useful energy.
stool: (in medicine) Another name for feces.
stroke: (in biology and medicine) A condition where blood stops flowing to part of the brain or leaks in the brain.
system: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body’s circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation’s railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.
taste: One of the basic properties the body uses to sense its environment, especially foods, using receptors (taste buds) on the tongue (and some other organs).
tissue: Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.
vitamin: Any of a group of chemicals that are essential for normal growth and nutrition and are required in small quantities in the diet because either they cannot be made by the body or the body cannot easily make them in sufficient amounts to support health.
wood: A porous and fibrous structural tissue found in the stems and roots of trees, shrubs and other woody plants.
