Biological Molecules II

Polymer

long molecule consisting of many buildings' blocks; composed of monomers  

Monomer

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

Dehydration Synthesis

occurs when 2 monomers bond together through the loss of a water molecule 

Hydrolysis

polymers that are disassembled to monomers through the process of adding water   

Enzyme Section

speed up chemical reactions without being consumed in the reaction 

Polypeptide

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

Amino Acid

are organic molecules with carboxyl and amino groups 

Protein

biologically functional molecule that consists of one or more polypeptides 

Peptide Bond

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

Catalyst

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

Protein Structure

A protein’s structure determines its function 

• Have 4 levels of structure: 

• Primary: protein’s unique sequence of amino acids 

• Secondary: consists of coils and folds in the polypeptide chain  

• The result of hydrogen bonds between constituents' of the polypeptide backbone 

• Include the α helix and the β pleated sheet 

• Tertiary: the overall shape of a polypeptide 

• Determined by interactions among various side chains (R groups)  

• Quaternary Structure: arises when a protein consists of two or more polypeptide chains 

• Results from interactions between multiple polypeptide chains 

Denaturation

the loss of a protein’s native structure 

• Is biologically inactive 

Nucleic Acids

• 2 Types  

• DNA (Deoxyribonucleic Acid) 

• Provides directions for its own replication  

• Directs synthesis of messenger RNA (mRNA) ad, through mRNA, controls protein synthesis, a process called gene expression  

• Contains thymine  

• RNA (Ribonucleic Acid) 

• Contains uracil 

Polypeptide

molecules made up of nucleotides that are linked together by covalent bonds to form a chain 

Ribose

the sugar in RNA

Deoxyribose

the sugar in the DNA

Double Helix

formed by DNA molecules have two polynucleotides spiraling around an imaginary axis 

Carbohydrate

macromolecules are polysaccharides, polymers composed of many sugar building blocks 

Monosaccharide

The simplest carbohydrates; AKA simple sugars serve as major nutriets for cells and as raw materials for building molecules

Disaccharide

formed when a dehydration reaction occurs joins two monosaccharides 

Glycosidic Linkage

Positions determine the structure and function of a polysaccharide are determined by its sugar monomers and the positions of its glycosidic linkages 

Polysaccharide

the polymers of sugars, have storage and structural roles 

• The structure and function of a ____ are determined by its sugar monomers and the positions of its glycosidic linkages 

Starch

a storage polysaccharide of plants, consists entirely of glucose monomers 

• Plants store surplus as granules 

• Most animals have enzymes that can hydrolyze this, making glucose available as a nutrient 

Glycogen

is a storage polysaccharide in animals 

Lipid

• do not form true polymers 

• Has little to no affinity for water 

• Are hydrophobic because they mostly consist of hydrocarbons, which form nonpolar covalent bonds 

• Most biologically important forms are fats, phospholipids, and steroids 

Fat

type of lipid; constructed from two types of smaller molecules: glycerol and fatty acids 

• separate from water because water molecules hydrogen bond to each other and exclude the fats 

• Primary function is energy storage 

Fatty Acid

consists of a carboxyl group attached to a long carbon skeleton 

• Two tails tails are hydrophobic; the phosphate group and its attachments form a hydrophilic head 

Saturated fatty acid

have the maximum number of hydrogen atoms possible and no double bonds 

Unsaturated fatty acid

have one or more double bonds 

Phospholipid

two fatty acids and a phosphate group are attached to glycerol  

• are major constituents of cell membranes 

• When are added to water, they self- assemble into a bilayer, with the hydrophobic tails pointing toward the interior  

• This feature results in the bilayer arrangement found in cell membranes 

• bilayer forms a boundary between a cell and its external environment 

Steroid

• are lipids characterized by a carbon skeleton consisting of four fused rings 

• Cholesterol, is a component in animal cell membranes 

Cholesterol

an important steroid, is a component in animal cell membranes 

• Although ___ is essential in animals, high levels in the blood may contribute to atherosclerosis