3.1-3.5 - Biological Macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids

alpha-helix structure (a-helix)

type of secondary structure of proteins formed by folding of the polypeptide into a helix shape with hydrogen bonds stabilizing the structure.

amino acid

monomer of a protein: has a central carbon or alpha carbon to which an amino group, a carboxyl group, a hydrogen, and an R group or side chain is attached: the R group is different for all 20 amino acids.

beta-pleated sheet (B-pleated)

secondary structure found in proteins in which “pleats” are formed by hydrogen bonding between atoms on the backbone of the polypeptide chain.

biological macromolecule

large molecule necessary for life that is built from smaller organic molecules: include carbohydrates, lipids, proteins, and nucleic acids, each playing critical roles in cellular structure and function.

carbohydrate

biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1: carbohydrates serve as energy sources and structural support in cells and from the a cellular exoskeleton of arthropods.

cellulose

polysaccharide that makes up the cell wall of plants: provides structural support to the cell.

central dogma of life

framework explaining the flow of genetic information within a biological system, describing how DNA dictates the structure of mRNA in transcription and RNA dictates the structure of protein in translation.

chaperone (chaperonin)

protein that helps nascent protein in the folding process.

chitin

type of carbohydrate that forms the outer skeleton of all arthropods that include crustaceans and insects: it also forms the cell walls of fungi.

dehydration synthesis (condensation)

eaction that links monomer molecules together, releasing a molecule of water for each bond formed: crucial process for forming larger biomolecules like carbohydrates, proteins, and nucleic acids: formation of new bonds, requiring energy.

denaturation

loss of shape in a protein as a result of changes in temperature, pH, or exposure to chemicals.

deoxyribonucleic acid (DNA)

double-helical molecule that carries the hereditary information of the cell.

disaccharide

two sugar monomers that are linked together by a glycosidic bond.

enzyme

catalyst in a biochemical reaction that is usually a complex or conjugated protein: speed up reactions by lowering the activation energy required. catabolic break down substrates, anabolic build more complex molecules, catalytic affect the rate of reaction.

glycogen

storage carbohydrate in animals that is made up of long chains of glucose units.

glycosidic bond

bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule: links the sugar units together, forming disaccharides or polysaccharides.

hormone

chemical signaling molecule, usually protein or steroid, secreted by endocrine cells that act to control or regulate specific physiological processes.

hydrolysis

reaction causes breakdown of larger molecules into smaller molecules with the utilization of water: the reverse process of dehydration synthesis, where water is added to cleave bonds: break bonds and release energy.

lipid

macromolecule that is nonpolar and insoluble in water: include fats, oils, and steroids, and are important for energy storage, insulation, and cell membrane structure.

messenger RNA (mRNA)

RNA that carries information from DNA to ribosomes during protein synthesis: serves as a template for the sequence of amino acids in a protein, guiding the translation process.

monomer

the building blocks that combine through chemical reactions to form polymers. amino acids in proteins, nucleotides in nucleic acids, and simple sugars (monosaccharide) in carbohydrates.

monosaccharide

single unit or monomer of carbohydrates, simple sugars such as glucose or fructose. foundational components of complex sugars like disaccharides and polysaccharides.

nucleic acid

biological macromolecule that carries the genetic blueprint of a cell and carries instructions for the functioning of the cell.

nucleotide

monomer of nucleic acids: contains a pentose (5-carbon) sugar (deoxyribose or ribose), one or more phosphate groups, and a nitrogenous base (A, T or U, G, C): essential component of DNA and RNA.

omega fat

type of polyunsaturated fat that is required by the body: the numbering of the carbon omega starts from the methyl end or the end that is farthest from the carboxylic end.

peptide bond

bond formed between two amino acids by a dehydration reaction: links the carboxyl group of one amino acid to the amino group of another, resulting in a covalent connection that forms proteins.

phosphodiester

linkage covalent chemical bond that holds together the polynucleotide chains with a phosphate group linking two pentose sugars of neighboring nucleotides: bond in nucleic acids.

phospholipid

major constituent of the membranes: composed of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

polymer

chain of monomer residues that is linked by covalent bonds: polymerization is the process of polymer formation from monomers by condensation: forming essential macromolecules like proteins, nucleic acids, and carbohydrates.

polynucleotide

long chain of nucleotides: chains make up the structure of nucleic acids, such as DNA and RNA.

polysaccharide

long chain of monosaccharides (such as glucose or fructose): may be branched or unbranched: examples include starch and cellulose.

primary structure

linear sequence of amino acids in a protein: determines the protein's unique characteristics and functionality.

protein

biological macromolecule composed of one or more chains of amino acids: perform various functions including catalysis, transport, and structure.

purine

type of nitrogenous base in DNA and RNA: adenine and guanine: two carbon-nitrogen rings.

pyrimidine

type of nitrogenous base in DNA and RNA: cytosine, thymine (DNA) and uracil (RNA): single carbon-nitrogen ring.

quaternary structure

association of discrete polypeptide subunits in a protein.

ribosomal RNA (rRNA)

RNA that ensures the proper alignment of the mRNA and the ribosomes during protein synthesis and catalyzes the formation of the peptide linkage.

saturated fatty acid

long-chain of hydrocarbon with single covalent bonds in the carbon chain: the number of hydrogen atoms attached to the carbon skeleton is maximized: the fatty acids are saturated with hydrogen: these fats are typically solid at room temperature and found in animal fats.

secondary structure

regular structure formed by proteins by intramolecular hydrogen bonding between the oxygen atom of one amino acid residue and the hydrogen attached to the nitrogen atom of another amino acid residue: this includes alpha helices and beta pleated sheets.

starch

storage carbohydrate in plants: it is composed of long chains of glucose units linked by glycosidic bonds, primarily in the form of amylose and amylopectin.

steroid

type of liquid composed of four fused hydrocarbon rings forming a planar structure.

tertiary structure

three-dimensional conformation of a protein, including interactions between secondary structural elements: formed from interactions between amino acid side chains.

trans fat

fat formed artificially by hydrogenating oils, leading to a different arrangement of double bond(s) than those found in naturally occurring lipids.

transcription

process through which messenger RNA forms on a template of DNA: facilitating the transfer of genetic information.

transfer RNA (tRNA)

RNA that carries activated amino acids to the site of protein synthesis on the ribosome: translates the genetic code into a polypeptide sequence during translation.

translation

process through which RNA directs the formation of protein: involves the decoding of messenger RNA (mRNA) to assemble amino acids into a polypeptide chain, ultimately forming a protein.

triacylglycerol (triglyceride)

fat molecule: consists of three fatty acids linked to a glycerol molecule: serves as a major form of energy storage in the body.

unsaturated fatty acid

long-chain hydrocarbon that has one or more double bonds in the hydrocarbon chain: double bonds create kinks in the chain, preventing tight packing and making them liquids at room temperature.

wax

lipid made of a long-chain fatty acid that is esterified to a long-chain alcohol: serves as a protective coating on some feather, aquatic mammal fur, and leaves.