AP Biology Unit 1 vocab ch. 3

Macromolecule

A giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction. Ex: Polysaccharides, proteins, and nucleic acids.

Valence

The bonding capacity of a given atom; form usually equals the number of unpaired electrons in its outermost (valence) shell.

Functional groups

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and involved in chemical reactions.

ATP (adenosine triphosphate)

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed, This energy is used to drive endergonic reactions in cells.

Polymer

A long molecule consisting of many similar or identical monomers linked together by covalent bonds.

Monomer

THe subunit that serves as the building block of a polymer.

Dehydration Reaction (synthesis)

A chemical reaction in which two molecules become covalently bonded to each other with the removal of a water molecule.

Hydrolysis

A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.

Monosaccharides

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, they have molecular formulas that are generally some multiple of CH2O

Disaccharides

A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction.

Polysaccharides

A polymer of many monosaccharides, formed by dehydration reactions.

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Glycosidic linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Starch

A storage polysaccharide in plants, consisting entirely of glucose monomers joined by alpha glycosidic linkages.

Phospholipids

A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes.

Cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as many hormones.

Saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms attached to the carbon skeleton.

Unsaturated fatty acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Steroids

A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.

Enzymes

A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction. Most are proteins.

Hydrocarbon

An organic molecule consisting of only carbon and hydrogen.

Alpha Helix

A coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone (not the side chains).

Beta-pleated sheet

ONe form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds between atoms of the polypeptide backbone (not side chains).

Hydrophobic Interaction

A type of weak chemical interaction caused when molecules that do not mix with water coalesce to exclude water.

Disulfide bridges

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

Peptide bond

The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.

Polypeptide

A polymer of many amino acids linked together by peptide bonds.

Primary Structure

The level of protein structure referring to the specific linear sequence of amino acids.

Secondary structure

Regions of repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bonding between constituents of the backbone (not the side chains).

Tertiary structure

The overall shape of a protein molecule due to interactions of amino acid side chains, including hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.

Amino acid

An organic molecule possessing both a carboxyl and an amino group. They serve as the monomers of polypeptides.

Nucleic acid

A polymer (polynucleotide)) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.

Denature

In proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix. This occurs under extreme (noncellular) conditions of pH, salt concentrations, or temperature.

Pyrimidine

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring. Ex: Cytosing (C), thymine (T), and uracil (U) .

Purine

One of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring fused to a five-membered ring. Ex: Adenine (A) and guanine (G)

DNA (deoxyribonucleic acid)

A nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous base adenine (A), cytosine (C), guanine (G), and thymine (T); capable of being replicated and determining the inherited structure of a cell’s proteins.

RNA (ribosomal RNA) (rRNA)

A type of nucleic acid consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single stranded; functions in protein synthesis, gene regulations, and as the genome of some viruses.

Catalyst

A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction.

Quaternary Structure

The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide. (between two or more polypeptides)

Which nucleotides have double bond

Adenine and Thymine

Which nucleotide acid has triple bonds?

Cytosine and Guanine