Biochemistry: Macromolecules and Their Functions

Carbohydrates

Provide short and long term energy storage for organisms. They provide energy for the body's metabolism.

Lipids

One of the four major classes of large, complex organic macromolecules.

Proteins

One of the four major classes of large, complex organic macromolecules.

Nucleic acids

One of the four major classes of large, complex organic macromolecules.

CHNOPS

The six important elements that most biological molecules are made from: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.

Covalent Bonds

Bonds that can either be non-polar (ie. lipids) or polar (ie. water).

Ionic Bonds

Bonds that are always polar (ie. charged).

Polymers

Long molecules formed by covalently linking many subunits.

Monomers

Each repeating subunit of a polymer.

Dehydration Synthesis

A reaction through which macromolecules are assembled.

Hydrolysis

A reaction through which macromolecules are broken down into their individual subunits.

Carbohydrate Composition

Almost always have two atoms of hydrogen and one atom of oxygen for every atom of carbon. The general formula is (CH2O)n.

Monosaccharides

Carbohydrates with three to seven carbon atoms, known as simple or energy sugars.

Disaccharides

Also known as double or transport sugars, made up of two monosaccharides through dehydration synthesis.

Polysaccharides

Carbohydrates that consist of many linked simple sugars, also known as complex, storage or structural sugars.

Trioses

Monosaccharides with 3 carbon atoms.

Tetroses

Monosaccharides with 4 carbon atoms.

Pentoses

Monosaccharides with 5 carbon atoms.

Hexoses

Monosaccharides with 6 carbon atoms.

Heptoses

Monosaccharides with 7 carbon atoms.

Isomers

Compounds that have the same chemical formula but different molecular shapes.

Sucrose

A disaccharide formed from glucose and fructose.

Maltose

A disaccharide formed from glucose and glucose.

Lactose

A disaccharide formed from glucose and galactose.

C12H22O11

The formula for disaccharides like sucrose, maltose, and lactose.

Starch/Amylose

Stores energy in plants.

Glycogen

Stores energy in animals.

Cellulose

Makes up cell walls in plants.

Chitin

Found in arthropod exoskeletons and cell walls in fungi.

Polysaccharide Structure

Determines function.

Glycogen Molecules

More branched than amylose or cellulose, packing more glucose units into a single cell.

Energy Storage in Animals

Glycogen is the main storage form of glucose in the body, particularly in the liver and muscles.

Cellulose Molecules

More linear, storing less glucose but providing more structural support for plants.

Cellulose-Digesting Bacteria

Herbivores need these in their digestive tract to obtain more nourishment from their diets.

Monosaccharides

Simple or energy sugars.

Disaccharides

Double or transport sugars.

Polysaccharides

Complex or storage sugars.

Glucose

Example of a monosaccharide.

Fructose

Example of a monosaccharide.

Galactose

Example of a monosaccharide.

Maltose

Example of a disaccharide.

Sucrose

Example of a disaccharide.

Lactose

Example of a disaccharide.

Triglycerides

Fats/Oils that store 2.25 times more energy per gram than any other biological molecule.

Saturated Fatty Acids

Contain the maximum number of hydrogen atoms, solid at room temperature, and harder to digest.

Unsaturated Fatty Acids

Have double bonds between some carbon atoms, liquid at room temperature, and easier to digest.

Dietary Perspective on Unsaturated Fats

Healthier as they increase HDL (good cholesterol) and decrease LDL (bad cholesterol).

Dietary Perspective on Saturated Fats

Increase LDL in the body, leading to a greater risk of heart disease.

Phospholipids

Structural lipids found in most animal membranes, including cell membranes.

Phospholipid Bilayer

Formed by phospholipids butting up tail to tail.

Steroids

Lipids consisting of four interconnected carbon rings, serving as components of membranes or as vitamins and hormones.

Cholesterol

One of the most abundant steroids, serving as a major component of membranes that wrap around & insulate many nerve fibers and a chemical precursor of several important animal hormones.

Insolubility of Cholesterol

Like other lipids, it is insoluble in water and may settle out of solution when present in high concentrations, which can cause gallstones and atherosclerosis.

Triglycerides

Stores energy.

Phospholipids

Major component of cell membrane structure.

Steroids

Function as hormones.

Glycerol

A component of triglycerides, connected to two fatty acids.

Fatty Acids

Can be unsaturated (oils) or saturated (fats).

Cholesterol Structure

Composed of interconnected carbon rings.

Protein Functions

Proteins serve essential functions including structural support, enzymatic catalysis, transport & storage, movement, immune protection, hormonal regulation, and sensory perception.

Structural Support

Major component of bone, cartilage, feathers, fur, hair, biological membranes, and chromosomes.

Enzymatic Catalysis

All enzymes are proteins that play unique roles in growth and function.

Transport & Storage

Proteins serve as carriers of important small molecules and ions, such as iron atoms carried in mammalian blood by transferrin.

Movement

Muscle fibers are composed primarily of protein filaments.

Immune Protection

Immunoglobulins are a group of highly specific protein molecules.

Hormonal Regulation

Several hormones are proteins and others are transported throughout the body by proteins.

Sensory Perception

Responses of nerve cells to specific stimuli are often mediated by specific receptor proteins.

Amino Acids

The subunits of proteins, consisting of a central carbon atom bonded to a hydrogen atom, an amino group, a carboxyl group, and an R group.

Essential Amino Acids

Nine amino acids that cannot be synthesized and must come from diet: threonine, tryptophan, valine, lysine, methionine, phenylalanine, histidine, isoleucine, and leucine.

Peptide Bonds

Amino acids bond together in strands to form proteins, connected by peptide bonds via dehydration synthesis.

Dipeptide

Formed when two amino acids are connected together.

Tripeptide

Formed when three amino acids are connected together.

Polypeptide

A chain of many amino acids.

Protein Structure

Different amino acids along the strand attract and repel each other, causing the strands to coil and twist, resulting in a complex 3D structure.

Denaturation

The loss of tertiary and secondary structures of proteins due to external stress or compounds, such as cooking.

Deamination

The loss of tertiary and secondary structures by the removal of amine group(s), usually facilitated by enzymes called deaminases.

Hemoglobin

Oxygen-transport protein in red blood cells.

Cell Membrane Proteins

Relay signals between the cell's internal and external environments; move molecules and ions across the membrane; allow cells to identify each other and interact.

Catalase

Catalyzes the decomposition of hydrogen peroxide to water and oxygen, preventing the build-up of carbon dioxide within the blood.

Keratin

Key component of skin, hair, and nails.

DNA (deoxyribonucleic acid)

A double-stranded nucleic acid molecule that governs the processes of heredity in the cells of organisms.

RNA (ribonucleic acid)

Plays a role in gene expression and protein synthesis.

Nucleotides

Subunits that make up nucleic acids, including adenine, guanine, cytosine, thymine, and uracil.

Enzymes

Specialized protein molecules that function as biological catalysts.

Carbonic Anhydrase

An enzyme produced by red blood cells that enables carbon dioxide and water to react to form about 600,000 molecules of carbonic acid each second.

Lock and Key Approach

A model for how enzymes work, where the enzyme's active site is specifically shaped to fit the substrate.

Optimal Temperature

The temperature range at which specific enzymes function best.

Inhibitors

Molecules that attach to the enzyme and reduce its ability to bind substrate.

Competitive Inhibitors

Inhibitors that compete with the substrate to occupy the active site of the enzyme.

Non-Competitive Inhibitors

Inhibitors that attach elsewhere on the enzyme, changing its shape and reducing its ability to bind substrate.

Chemical Reactions

Processes that occur in the body, such as the oxidation of glucose, which releases energy.

Catalysts

Substances that speed up chemical reactions and lower the energy required for the reaction without being consumed.

Macromolecules

Large molecules discussed earlier that can be used for chemical reactions in the body.

Temperature Effects on Enzymes

Enzymes are affected by temperature and pH, with specific enzymes having an optimal functioning range.

Denaturation

The process by which proteins lose their structure and function due to high temperatures.

Substrate

The reactant molecule that an enzyme acts upon.

Chemical Energy

Energy released from chemical reactions, such as the oxidation of glucose.

Biological Catalysts

Substances that increase the rate of biological reactions, primarily enzymes.

Phosphate Group

A component of nucleic acids, along with a nitrogenous base and a five-carbon sugar.

Five-Carbon Sugar

A component of nucleic acids, which can be either deoxyribose or ribose.