Unit of energy or heat. Various precise definitions are used for different purposes (physical chemistry measurements, engineering steam tables, and thermochemistry), but in all cases the calorie is about 4.2 joules, the amount of heat needed to raise the temperature of 1 g of water by 1 °C (1.8 °F) at normal atmospheric pressure. The calorie used by dietitians and food scientists and found on food labels is actually the kilocalorie (also called Calorie and abbreviated kcal or Cal), or 1,000 calories. It is a measure of the amount of heat energy or metabolic energy contained in the chemical bonds (see bonding) of a food.
Learn more about calorie with a free trial on Britannica.com.
Unit of mass or weight used especially in the centimetre-gram-second (CGS) system of measurement. One gram is equal to 0.001 kg, about 0.035 oz, or 15.43 grains. The gram is very nearly equal to the mass of 1 cc of pure water at its maximum density. The gram of force is equal to the weight of a gram of mass under standard gravity. For greater precision, the mass may be weighed at a point at which the acceleration due to gravity is 980.655 cm/sec2. Seealso gravitation; metric system.
Learn more about gram with a free trial on Britannica.com.
Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain (safranin) and appearing red or pink. Gram-positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall. Gram-positive cell walls typically lack the outer membrane found in Gram-negative bacteria.
The following characteristics are generally present in a Gram-positive bacterium:
Both Gram-positive and Gram-negative bacteria may have a membrane called an S-layer. In Gram-negative bacteria, the S-layer is directly attached to the outer membrane. In Gram-positive bacteria, the S-layer is attached to the peptidoglycan layer. Unique to Gram-positive bacteria is the presence of teichoic acids in the cell wall. Some particular teichoic acids, lipoteichoic acids, have a lipid component and can assist in anchoring peptidoglycan, as the lipid component is embedded in the membrane.
Grams is relieved at report; Investigators looked into the traffic stop of the senator's son, but the report isn't out yet and Grams responded to a news account.(NEWS)
Dec 09, 1999; 1/3 In the wake of the disclosure of a second instance in which U.S. Sen. Rod grams asked a sheriff's office to look for...
Grams' bankroll low for a GOP incumbent; He raised nearly $4 million in 5 years but has spent about two-thirds of it.(NEWS)
Mar 03, 2000; Sen. Rod grams' campaign committee raised $3.85 million during the first five years of his term, but political experts are...
Grams' relationship brings office turmoil; Sen. Rod Grams' connections with aide Christine Gunhus are being blamed for trouble in his office and his campaign.(NEWS)
Oct 17, 1999; 1/3 On a Friday the 13th during Congress' August recess, Sam Dawson abruptly packed and left the office of Sen. Rod grams....