Test 1 Flashcards
nucleotides
54
structural units of nucleic acids,
Five major varieties of nitrogen-containing bases
55
adenine, abbreviated A (ad’e-nen); guanine,
G (gwah’nen);
cytosine, C (si’to-sen);
Thymine ,T (thi’men);
and uracil,U(u’rah-sil).
Adenineand guanine are large, two-ring bases (called purines), whereas cytosine, thymine, and uracil are smaller, single-ring bases (called pyrimidines).
unsaturated fat
78
Of the two types of fatty acids, the unsaturated variety, olive oil for example, is said to be more “heart healthy.”
properties of proteins
48
composes I0-30o/o of cell mass and is the basic struc- tural material of the body. which include enzymes (biological catalysts), hemo- globin of the blood, and contractile proteins of muscle, have the most varied functions of any molecules in the body building blocks of proteins are molecules called amino acids, 20 common types amino acid may therefore act either as a base (proton acceptor) or an acid (proton donor). All amino acids are identical except for a single group of atoms called their r R group . Proteins are long chains of amino acids joined together by dehydration synthesis, bond pro- duces a characteristic arrangement of linked atoms called a peptide four structural levels: pri- mary, secondary, tertiary, and quaternary
Structural Levels of Proteins
48
four structural levels: pri- mary, secondary, tertiary, and quaternary. linear sequence of amino acids composing the polypeptide chain is the pri1nary structure of a protein.
Acids
39
sour taste, can react with (dissolve) many metals, and “burn” a hole in your rug. But for our purposes the most useful definition ofan acid is a substance that releases hydro- gen ions (H +) in detectable amounts. Because a hydrogen ion is just a hydrogen nucleus, which consists of a single “naked” proton, acids are also defined as proton donors.
Bases
39
Bases have a bitter taste, feel slippery, and are proton acceptors -that is, they take up hydrogen ions (H+) in detect- able amounts.
Glycogen
storage carbohydrate of animal
tissues, is stored primarily in skeletal muscle and liver cells. Like starch, it is highly branched and is a very large molecule
Triglycerides
fats when solid or oils when liquid. Triglycerides are large mol-
ecules, often consisting of hundreds of atoms. They provide the body’s most efficient and compact form of stored energy, and
when they are oxidized, they yield large amounts of energy. A triglyceride is composed of t\vo types of building blocks, fatty acids and glycerol (glis’er-ol), in a 3:I ratio of fatty acids to glycerol (Figure 2.16). Fatty acids are linear chains of carbon and hydrogen atoms (hydrocarbon chains) with an organic acid group (-COOH) at one end. Glycerol is a modified simple sugar (a sugar alcohol).
peripheral proteins
not embedded
in the lipid bilayer. Instead, they either attach loosely to integral proteins or have a hydrophobic region that anchors them
into the membrane
Hypertonic solutions
Cells lose water by osmosis and shrink
in a hypertonic solution (contains a higher concentration of nonpenetrating solutes than are present inside the cells).
Hypotonic solutions
Cells take on water by osmosis until they
become bloated and burst (lyse) in a hypotonic solution (contains a lower concentration of nonpenetrating solutes
than are present inside cells).
Phagocytosis
cell eating
cell engulfs some relatively large or solid material, such as a clump of bacteria, cell debris, or inanimate particles (asbestos fibers or glass, for example)
net diffusion
When equal volumes of aqueous solutions of different osmolarity are separated by a membrane that is penneable to all molecules in the system, net diffusion of both solute and water occurs, each moving down its own concen- tration gradient. Equilibrium is reached when the water (and solute) concentration on both sides of the rnembrane is the same
Mitochondria
typically threadlike (n1itos = thread) or lozenge-shaped membranous organelles. In living cells they squirm, elongate, and change shape al most continuously. They are tl1e power plants of a cell, providing most of its ATP supply.
enclosed by two membranes, outer me,nbrane is smooth and featureless, but the inner 111e1nbrane folds inward, forming shelflike cristae
