These four elements make up about 96% of living matter.
Oxygen, carbon, hydrogen, and nitrogen
Starch, glycogen, and cellulose are all polymers of this monosaccharide.
Glucose
A fat molecule is made of glycerol joined to three of these.
Fatty acids
Amino acids in a polypeptide are joined by this covalent bond.
Peptide bond
DNA and RNA are polymers of these monomers.
Nucleotides
Water's cohesion, high specific heat, and surface tension all come from this attraction between neighboring water molecules.
Hydrogen bonds
Table sugar is this disaccharide, made of glucose joined to fructose.
Sucrose
Fats with no double bonds between carbons in their tails, like butter, are solid at room temperature and called this.
Saturated fats
This level of protein structure is simply the sequence of amino acids.
Primary structure
RNA contains this nitrogenous base in place of thymine.
Uracil
A solution at pH 3 has this many times more H+ than a solution at pH 6.
1,000 (each pH unit is a tenfold difference)
Animals store glucose as this highly branched polysaccharide, mostly in liver and muscle cells.
Glycogen
Phospholipids have a hydrophilic head and hydrophobic tails, which makes them this.
Amphipathic
Extreme heat, pH changes, or certain chemicals can make a protein unravel and lose its shape. This is called this.
Denaturation
Adenine and guanine, which have a six-membered ring fused to a five-membered ring, belong to this family of bases.
Purines
Ibuprofen and the asthma drug albuterol each come in two mirror-image forms, and only one form works well. These forms are called this.
Enantiomers
Insects, spiders, and crustaceans build their exoskeletons from this structural polysaccharide.
Chitin
These harmful fats can form during food processing, when unsaturated fats are partially hydrogenated.
Trans fats
In sickle-cell disease, valine takes the place of this amino acid at the sixth position of hemoglobin's chain.
Glutamic acid
The two strands of the DNA double helix run in opposite 5' to 3' directions, an arrangement called this.
Antiparallel
As CO2 dissolves in seawater it forms carbonic acid. The drop in this ion makes it harder for corals to build their calcium carbonate skeletons.
Carbonate ions (CO32-)
Amylose is unbranched. Amylopectin is branched, with this type of glycosidic linkage at its branch points.
1–6 linkages
Each fatty acid in a fat is joined to glycerol by this bond, formed between a hydroxyl group and a carboxyl group.
An ester linkage
Scientists determine a protein's 3D structure with this method, which aims X-rays at a crystal of the protein.
X-ray crystallography
These bonds link the sugar of one nucleotide to the phosphate of the next, forming the DNA backbone.
Phosphodiester linkages