Biology Chapter 4 (Biological Molecules)

carbohydrate

substances that include sugars, starch and cellulose; they contain carbon, hydrogen and oxygen

sugars

carbohydrates that have relatively small molecules; they are soluble in water and they taste sweet

glucose

a sugar that is used in respiration to release energy

glycogen

a carbohydrate that is used as an energy store in plant cells

iodine solution

a solutions of iodine in potassium iodine; it is orange-brown, and turns blue-black when mixed with starch

benedict’s solution

a blue liquid that turns orange-red when heated with reducing sugars

reducing sugars

sugars such as glucose, which turn benedict’s solution orange-red when heated together

fats

lipids that are solid at room temperature

oils

lipids that are liquid at room temperature

lipids

substances containing carbon, hydrogen and oxygen; they are insoluble in water and are used as energy stores in organisms

emulsion

a liquid containing two substances that do not fully mix; one of them forms tiny droplets dispersed throughout the other

protein

a substance whose molecules are made of many amino acids linked together; each different protein has a different sequence of amino acids

amino acids

substances with molecules containing carbon, hydrogen, oxygen and nitrogen; there are 20 different amino acids found in organisms

antibodies

molecules secreted by white blood cells, which bind to pathogens and help to destroy them

pathogens

microorganisms that cause disease, such as bacteria

keratin

the protein that forms hair

biuret reagent

a blue solution that turns lilac when mixed with proteins

DCPIP

a purple liquid that becomes colorless when mixed with vitamin C

nucleotides

molecules that are linked together into long chains, to make up a DNA molecule

base

one of the components of DNA; there are four bases, A, C, G, and T, and their sequence determines the proteins that are made in a cell

complementary base pairing

the way in which the bases of the two strands of DNA pair up; A always pairs with T, and C with G