Chapter 3 Flashcards
Macromolecule
A very large molecule built from smaller repeating units (monomers). the four main classes in biology are carbohydrate, lipids, nucleic acids, and proteins
Polymer
A long molecule consisting of many similar or identical monomers linked together by covalent bonds
monomer
a small molecule that serves as the building block of a polymer
Dehydration reaction
A chemical reaction in which two molecules are joined together by removal of a water molecule, often forming a covalent bond in the process (synthesis of polymers)
Hydrolysis Reaction
A chemical reaction in which a molecule is split into two smaller molecules by addition of a water molecule, breaking a covalent bond (breakdown of polymers)
Carbohydrate
A class of macromolecules that includes sugars and sugar polymers, serving as a source of energy, a source of carbon, and structural components
Monosaccharides
A simple sugar, the monomer f carbohydrates, containing one carbonyl group and multiple hydroxyl groups.
Disaccharides
A sugar molecule consisting of two monosaccharides joined by a glycosidic linkage.
Polysaccharides
A carbohydrate polymer consisting of many monosaccharides joined together by glycosidic linkages
Glycosidic bonds (linkages)
A covalent bond that join two carbohydrate mo0lecules (monosaccharides or larger units). Formed by a dehydration reaction
Starch
A storage polysaccharide found in plants, composed of glucose monomers linked by a-1,4-glycosidic bonds (and a-1,6 at branch points)
Cellulose
A structural polysaccharide found in plant cell walls, a linear, un branched polymer of glucose linked by B-1,4-glycosidic linkages
glycogen
A storage polysaccharide found in animal liver and muscle cells, a highly branched polymer of glucose by a-1,4- and a-1,6-glycosidic bonds
Lipid
A diverse group of hydrophobic macromolecules, including fats, phospholipids, and steroids. They are not true polymers and are characterized by their insolubility in water
Fat (triacylglycerol)
A lipid composed of one glycerol molecule and three fatty acid molecules joined by ester linkages. Functions in energy storage, insulation, and protection.
Glycerol
A three-carbon alcohol with a hydroxyl group attached to each carbon, a component of fats and phospholipids
Fatty acids
A long hydrocarbon chain with a carboxyl group at one end, a component of fats and phospholipids
Ester linkage
The covalent bond that connect the glycerol molecule to the fatty acids in a fat. Formed by a dehydration reaction
Phospholipid
A li[id composed of a glycerol molecule, two fatty acids, and phosphate group. The main structural component of cell membranes, exhibiting amphipathic properties
Amphipathic
Having both hydrophilic (water-loving) and hydrophobic (water-fearing) parts
Steroid (sterol)
A type of lipid characterized by a carbon skeleton consisting of four fused rings
Saturated fatty acid
A fatty acid in which carbon atoms in the hydrocarbon chain are connected by single bonds, resulting in a straight molecule
Unsaturated fatty acid
A fatty acid containing one or more carbon-carbon double bonds in its hydrocarbon chain, resulting in a bent molecule
Cis fatty acid
An unsaturated fatty acid where the hydrogen atoms adjacent to the double bond are on the same side, creating a ben in the chain. Most naturally occurring
Trans fatty acids
An unsaturated fatty acid where the hydrogen atoms adjacent to the double bonds are on opposite sides, resulting in a more linear chain similar to a saturated fatty acid. Often produced artificially through hydrogenation.
Nucleotide
The monomer unit of nucleic acids, consisting of a nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and one or more phosphate groups
Ribonucleotide
A nucleotide containing ribose as its five-carbon sugar; found in RNA
Deoxyribonucleotide
A nucleotide containing deoxyribose as its five-carbon sugar; found in DNA
Nitrogenous base
A molecule containing nitrogen and having chemical properties of a base. in nucleic acids, these include adenine (A), guanine (G), cytosine(C) thymine (T) (IN DNA), and uracil (U) (In RNA)
Phosphodiester bond
A covalent bond that links sugar of one nucleotide to the phosphate group of the next in a nucleic acid chain
Directionality (of nucleic acids)
The inherent polarity of a nucleic acid strand due to the asymmetric nature of the sugar-phosphate backbone, resulting in a distinct 5’ end (with a phosphate group) and a 3’ end (with a hydroxyl group)
DNA double helix
The three-dimensional structure of DNA, consisting of two antiparallel strands wound around each other, with the sugar-phosphate backbones on the outside and the nitrogenous bases paired in the interior viz hydrogen bonds
Base-pairing
The specific hydrogen bonding interactions between nitrogenous bases in nucleic acids: adenine (A) with thymine (T) (in DNA) or uracil (U) (in RNA), and guanine (G) with cytosine (C)
Antiparallel
The orientation of the two strands in a DNA double helix, where one strand runs in the 5’ to 3’ direction and the other runs in the 3’ to 5’ direction
RNA strand
A single-stranded nucleic acid molecule that plays various roles in the cell, including carrying genetic information and participating in protein synthesis
Protein
A functional biological molecule composed of one or more polypeptides folded into a specific three-dimensional structure
Amino acid
A monomer unit of proteins, consisting of a central alpha (a) carbon atom bonded to an amino group, a carboxyl group, a hydrogen group, and a unique side chain (R group)
peptide bond
A covalent bond that links the carboxyl group of one amino acid to the amino group of another, formed by a dehydration reaction
Directionality (of polypeptides)
The inherent polarity of a polypeptide chain due to the presence of a free amino group at one end (N-terminus) and free carboxyl group at the other end (C-terminus)
Polypeptide
linear chain of amino acids linked together by peptide bonds
Primary structure (of protein)
The linear sequence of amino acids in a polypeptide chain, determined by the genetic code
Secondary Structure (of protein)
Localized, repetitive folding patterns within a polypeptide chain, such as the alpha (a) helix and beta (B) sheet, stabilized by hydrogen bonds between backbone atoms
Tertiary structure (or protein)
The overall three-dimensional shape of a single polypeptide chain, resulting from interaction between the side chain (R groups) of amino acids. These interaction include hydrogen bonds, ionic bond, hydrophobic interactions, and disulfide bonds
Conservative Change (amino acid substitution)
The replacement if one amino acid with another that has similar chemical properties
Non-conservative change (amino acid substitution)
The replacement of one amino acid with another that has significantly different chemical properties
Denature (of protein)
The process by which a protein loses its native three dimensional structure due to the disruption of non-covalent bonds and interactions. This typically leads to a loss of function
Degradation (protein)
The breakdown of a protein into smaller peptide or individual amino acids, involving the breaking of peptide bonds (the covalent bonds of primary structure)
