Chapter 5: Macromolecules

Macromolecules

A bigger molecule formed by the joining of smaller molecules

Proteins

A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific 3D structure. All are unbranched polymers constructed from the same set of 20 amino acids (can be hundreds or thousands of amino acids connecting for different proteins). Humans contain thousands of different kinds.

Fatty Acid

A carboxylic acid with a long carbon chain (usually 16 or 18). Vary in length in the number and location of double bonds. C-H bonds make it hydrophobic. At one end is a carboxyl group

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; functions in disassembly of polymers to monomers

Gene

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA). Amino Acid sequence of a polypeptide is programmed by this.

Fat

A lipid consisting of 3 fatty acids linked to one glycerol molecule (called triglyceride or triaclyglycerol) Fatty Acids linked by dehydration reaction. Important energy source.

Phospholipid

A lipid made of glycerol joined to 2 fatty acids and a phosphate group. Hydrocarbon chains of the fatty acids act as a nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head (amphipathic). They form the bilayers that function as biological membranes.

Polymers

A long molecule consisting of many similar or identical monomers linked together by covalent bonds. Ex: Carbohydrates, proteins and nucleic acids

Enzymes

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

Amino Acid

A molecule containing both a carboxyl and amino group. Serves as monomers for polypeptides. There are 20 kinds and they make proteins (can be hundreds or thousands of amino acids connecting for different proteins). Central carbon is the α carbon

Polypeptides

A polymer of many amino acids linked together by peptide bonds

Polysaccharides

A polymer of many monosaccharides, formed by dehydration reactions. Plants: Cellulose, Starch Animals: Glycogen and Chitin

Starch

A storage polysaccharide (for energy) in plants, consisting entirely of glucose monomers joined by glycosidic linkages. Can later be withdrawn from carb "bank" for later use by hydrolysis.

Cellulose

A structural polysaccharide (building material) of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages. Few organisms can digest cellulose but can digest starch because of the different structure.

Carbohydrates

A sugar (monosaccharide) one of its dimers (disaccharides) polymers (polysaccharides)

Cholesterol

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

Glycogen

An extensively branched glucose storage polysaccharide (for energy) found in the liver and muscle of animals, the equivalent of starch.

trans-fats

An unsaturated fat formed artificially during hydrogenation of oils, containing one or more trans double bonds

Lipids

Any of a group of large molecules, including fats, phospholipids and steroids that mix poorly, if at all, with water. Consist mostly of hydrocarbons

Nucleotides

Building block of a nucleic acid, consisting of: 1) A 5 carbon sugar 2) Sugar covalently bonded to a nitrogenous base 3) One or more phosphate groups

Peptide Bond

Covalent bond between carboxyl group on one amino acid and the amino group on another. Formed by dehydration reaction

deoxyribonucleic acid

DNA. A nucleic acid molecule, usually double stranded-helix, in which each polynucleotide consist of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases: adenine (A), cytosine (C), guanine (G), and Thymine (T); capable of being replicated and and determining the inherited structure of a cell's proteins. Not DIRECTLY involved in cell function (the commander of sorts)

Maltose

Maltose is the disaccharide formed when two glucose molecules are linked by dehydration synthesis.

mRNA

Messenger RNA. Each gene along a DNA molecule directs synthesis of a type of mRNA to send to ribosomes

Polynucleotides

Polymer consisting of many nucleotide monomers in a chain. Nucleotides can be those of DNA or RNA

Nucleic Acids

Polymer consisting of many nucleotide monomers. Blueprint for proteins and uses them for cellular activities

Storage Polysaccharide

Polysaccharides that allow surplus sugars to be stored. Starch is one kind. Can later be withdrawn from carb "bank" for later use by hydrolysis. Starch and Glycogen

Ribosomes

Protein synthesizing structure of a cell. Produces polypeptides which folds into or is part of a protein

ribonucleic acid

RNA. A nucleic acid molecule consisting of a polynucleotide made up of nucleotide monomers with a ribose sugar and the nitrogenous bases: adenine (A), cytosine (C), guanine (G), and Thymine (T). Usually single-stranded; functions in protein synthesis, gene regulation, and as the genome of some viruses.

Saturated fats are solid. Unsaturated fats are liquid. why?

Saturated fats: The molecules are packed closely together. Unsaturated Fats: The molecules can't pack together close enough to solidify because of the kinks in some of their fatty acid hydrocarbon chains

Structural Polysaccharide

Strong materials are built from these. Cellulose in plants to form the tough cells walls. Chitin in arthropods for exoskeletons

Chitin

Structural polysaccharide, carbohydrate used by arthropods to build exoskeletons.

deoxyribose

Sugar component of DNA nucleotides, having one or fewer hydroxyl groups than ribose

ribose

Sugar component of RNA nucleotides

Monomers

The subunit that serves as a building block of a polymer. They form larger molecules by dehydration reactions.

Diversity of Polymers

40-50 common monomers and some rare ones can create many different kinds of polymers (can be hundreds of monomers in a chain)

Disaccharide

-A double sugar, consisting of two monosaccharides joined by a glycosidic linkage (a covalent bond formed between two monosaccharides by a dehydration reaction) -Carbon sources that can be converted to other molecules or combined into polymers

Monosaccharides

-The simplest carbohydrate, active alone or serving as a monomer for disaccharide and polysaccharides. Also known as SUGARS. -Monosaccharides molecular formulas that are generally some multiple of CH₂O. Can vary in length and geometry. -Carbon sources that can be converted to other molecules or combined into polymers

The Four Levels of Protein Structure

1) Amino Acid Sequence 2) Local Folding (α helix and β pleated sheet are the 2 main types) 3) Tertiary Structure: Overall shape of a polypeptide resulting from interactions between the side chains 4) Quaternary Structure: Overall protein structure that results from the aggregation of polypeptide subunits (some proteins form from +2 polypeptide chains aggregated)

Nitrogenous bases

1) Pyrimidine: Contains a six-membered ring of carbon and nitrogen atoms. 2) Purines: Larger with a six-membered ring fused to a five membered ring All bases have a polar edge for hydrogen bonding

Difference between α and β glycosidic linkages

Differ in placement of hydroxyl group

How Fats are formed

Fatty Acids linked by dehydration reaction to a glycerol molecule

Saturated Fatty Acid

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

Unsaturated Fatty Acid

Fatty acid with one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces number of hydrogen atoms attached to the carbon skeleton. Usually in plants and fishes

Amphipathic

Having both a hydrophilic and hydrophobic region.

Difference between hexose, pentose, and dissaccharides

Hexose and pentose circularize while disaccharides form long chains

How are phospholipid lipid bilayers arranged?

Hydrophilic heads face water while hydrophobic tails touch each other. Main fabric of membranes

How do polypeptides differ?

In length, number of amino acids, order of amino acids

Steroids

Lipids characterized by a carbon skeleton consisting of 4 fused rings with various chemical groups attached. Component of cell membranes, and also signals molecules that travel through the body

How do amino acids differ?

Their "R" Groups. Can be nonpolar, polar, or charged. The side chains physical and chemical properties determine unique characteristics of an amino acid

Shape of 5 and 6 carbon sugars

They circularize (hexose and pentose)