Chapter 5: The Structure and Function of Large Biological Molecules Flashcards
macromolecule
- a giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction
- polysaccharides, proteins, nucleic acids
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
enzyme
- 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
dehydration reaction
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
carbohydrate
a sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides)
monosaccharide
- the simplest carbohydrate, active alone of serving as a monomer for disaccharides and polysaccharides
- aka simple sugars
- have molecular formulas that are generally some multiple of CH2O
polysaccharide
a polymer of many monosaccharides, formed by dehydration reactions
glucose (C6H12O6)
the most common monosaccharide
disaccharide
a double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction
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 glycosidic linkages
amylose
an enzyme that hydrolyzes starch (a glucose polymer from plants) and glycogen (a glucose polymer from animals) into smaller polysaccharides and the disaccharide maltose
glycogen
- an extensively branched glucose storage polysaccharide found in the liver and muscle of animals
- the animal equivalent of starch
cellulose
a structural polysaccharide of plant cell walls, consisting of glucose monomers joined by B glycosidic linkages
chitin
a structural polysaccharide, consisting of amino sugar monomers, found in many fungal cells walls and in the exoskeletons of all arthropods
lipid
any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water
fat
- a lipid consisting of three fatty acids linked to one glycerol molecule
- aka a triacylglycerol or triglyceride
glycerol
a three-carbon alcohol with a hydroxyl group attached to each carbon
fatty acid
- a carboxylic acid with a long carbon chain
- vary in length and in the number and location of double bonds
- three linked to a glycerol molecule form a fat molecule, also called a triacylglycerol or triglyceride
triacylglycerol (triglyceride)
- a lipid consisting of three fatty acids linked to one glycerol molecule
- aka a fat
saturated fatty acid
a fatty acid in which all carbons in the hydrocarbon tail are connected
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
saturated fats
- fats made from saturated fatty acids that are solid at room temperature
- most animal fats
unsaturated fats
- fats made from unsaturated fatty acids that are liquid at room temperature
- plant fats and fish fats
- oils
hydrogenation
the process of converting unsaturated fats to saturated fats by adding hydrogen
energy storage
the major function of fats
adipose cells
where humans and other mammals store their long-term food reserves
adipose tissue
- a connective tissue that insulates the body and serves as a fuel reserve
- contain fat-storing cells called adipose cells
phospholipid
- 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
- form bilayers that function as biological membranes
steroid
a type of lipid characterizes by a carbon skeleton consisting of four fused rings with various chemical groups attached
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
protein
a biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure
enzymatic proteins
- function: selective acceleration of chemical reactions
defensive proteins
- function: protection against disease
storage proteins
- function: storage of amino acids
transport proteins
- function: transport of substances
hormonal proteins
- function: coordination of an organism’s activities
receptor proteins
- function: response of cell to chemical stimuli
contractile and motor proteins
- function: movement
structural proteins
- function: support
polypeptide
a polymer of many amino acid linked together by peptide bonds
peptide bond
the covalent bond between amino acids
amino acid
- an organic molecule possessing both a carboxyl and an amino group
- serve as the monomers of polypeptides
functional protein
consists of one or more polypeptides precisely twisted, folded, and coiled into a unique shape
sickle-cell disease
- an inherited blood disorder that results from a single amino acid substitution in the protein hemoglobin
- the abnormal hemoglobin molecules cause the red blood cells to aggregate into chains and to deform into a sickle shape
denaturation
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
x-ray crystallography
- a technique used to study the three-dimensional structure of molecules
- depends on the diffraction of an x-ray beam by the individual atoms of a crystallized molecule
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
- two types are DNA and RNA
gene expression
the process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs
the flow of genetic information
DNA -> RNA -> protein
polynucleotide
- a polymer consisting of many nucleotide monomers in a chain
- the nucleotides can be those of DNA or RNA
nucleotide
the building bloc of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and one to three phosphate groups
nucleoside
the portion of a nucleotide without the phosphate group
- nitrogenous base + sugar
pyrimidine
- one of two types of nitrogenous bases found in nucleotides, characterized by a six-membered ring
- cytosine (C), thymine (T), 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
- adenine (A), guanine (G)
deoxyribose
the sugar component of DNA nucleotides, having one fewer hydroxyl group than ribose, the sugar component of RNA nucleotides
ribose
the sugar in RNA
double helix
the form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape
antiparallel
an arrangement where the backbones of DNA molecules run in opposite 5’ -> 3’ directions from each other
complementary base pairing
only certain bases in DNA pair up and form hydrogen bonds:
- adenine (A) always with thymine (T)
- guanine (G) always with cytosine (C)
this feature of DNA structure makes it possible to generate two identical copies of each DNA molecule in a cell preparing to divide
uracil (U)
in RNA, thymine (T) is replaced by __________, which always pairs with adenine (A)
genomics
the systematic study of whole sets of genes (or other DNA) and their interactions within a species, as well as genome comparisons between species
proteomics
the systematic study of sets of proteins and their properties, including their abundance, chemical modifications, and interactions
