Organic Compounds Essential to Human Functioning

_______ possess carbon, bind with hydrogen, and are formed using covalent bonds into biological macromolecules.

organic molecules

_______ are organic molecules consisting entirely of carbon and hydrogen, such as methane (CH₄).

hydrocarbons

_______ are groups of atoms found along the “carbon backbone” that confer specific chemical properties to those molecules.

functional groups

Five functional groups are important in human physiology:

hydroxyl, carboxyl, amino, methyl and phosphate groups

There are four types of biological macromolecules:

carbohydrates, lipids, proteins and nucleic acids

Organic compounds are _____ made from covalently bonded monomers.

polymers

Organic compounds are made by the removal of water molecules from between two monomers:

dehydration synthesis

Organic compounds are broken by the addition of water between the monomers of a polymer:

hydrolysis

Carbohydrates

the most abundant compounds of life; monosaccharides, disaccharides, polysaccharides

Monosaccharides

one sugar unit—is the simplest carbohydrates

Disaccharides

two sugar units—are the simplest short-chain carbohydrates

There are three common disaccharides that you should be familiar with:

Lactose, Sucrose, Maltose

_____ (glucose + galactose) is present in milk.

lactose

_____ (glucose + fructose) is a transport form of sugar used by plants and harvested by humans for use in food.

sucrose

_____ (two glucose units) is present in germinating seeds.

maltose

Polysaccharides

are straight or branched chains of hundreds or thousands of sugar monomers they’re also called complex carbohydrates.

Polysaccharides

starch, glycogen, cellulose

Starch

is a plant storage form of energy, arranged as unbranched coiled chains, easily hydrolyzed to glucose units

Glycogen

is a highly-branched chain used by animals to store energy in muscles and liver.

Cellulose

a polysaccharide that is the primary component of the cell wall of green plants, is the component of plant food referred to as “fiber”.

Lipids

are greasy or oily compounds with little tendency to dissolve in water because they tend to be nonpolar (hydrophobic).

Glycerides

one or more fatty acid chains attached to a glycerol.

Different types of glycerides:

Monoglycerides (one fatty acid attached to a glycerol), Diglycerides (two fatty acids attached to a glycerol), and Triglycerides (three fatty acids attached to a glycerol).

Fatty acids

long carbon chains with hydrogen atoms attached.

_________ have only single carbon-carbon bonds in their tail and tend to be solid at room temperature.

saturated fatty acids

________ are liquids at room temperature because one or more double bonds between the carbons in the fatty acids permit “kinks” in the tails.

unsaturated fatty acids

Phospholipids and Glycolipids

formed by the attachment of two fatty acids plus a phosphate group to a glycerol.

Steroids

possess a backbone of four carbon rings but no fatty acid tails.

Steroids

possess a backbone of four carbon rings but no fatty acid tails.

Eicosanoids

are lipids derived from arachidonic acid, a fatty acid that must be absorbed in the diet because it cannot be synthesized in the body.

Leukotrienes

are produced by cells involved with coordinating the responses to injury or disease, and they will be considered in later chapters.

Prostaglandins

short chain unsaturated fatty acids in which five of the carbon atoms are joined in a ring.

_____ is important in building, repairing, and maintaining muscle tissue, but the truth is that proteins contribute to all body tissues, from the skin to the brain cells.

protein

______ act as hormones, chemical messengers that help regulate body functions.

proteins

The monomer unit of a protein is an ______.

amino acid

A polymer of amino acids is often called a _____ to reflect the special _______ that form between the amino acids during dehydration synthesis.

polypeptide; peptide bonds

_______ is defined as ordered sequences of amino acids each linked together by peptide bonds to form linear polypeptide chains.

primary structure

________ refers to the helical coil (as in hemoglobin) or sheet-like array (as in silk) that results from hydrogen or disulfide bonding of side groups on the amino acid chains.

secondary structure

_______ is the result of folding due to interactions among R groups along the polypeptide chain and is sometimes called “supercoiling”.

tertiary structure

_______ describes the twisting of two of more polypeptide chains.

quaternary structure

______ - changing the shape of a protein alters its function; it is important to maintain homeostasis in the body in order to prevent ______ of proteins.

Denaturation; denaturation

Enzymes

almost everything that happens in the body does so because an enzyme makes it possible.

Enzymes are biological important proteins that act as ______ which accelerate the rate of biochemical reaction by lowering the amount of energy required to start the reaction (activation energy).

catalysts

Nucleic Acids

large organic compounds made of carbon, hydrogen, oxygen, nitrogen, and phosphorous.

The monomer unit of a nucleic acid is a _____.

nucleotide

Each nucleotide consists of three components:

five-carbon sugar, nitrogen-containing base, phosphate group

There are two types of nitrogen bases:

purines and pyrimidines

There are _____ - either Adenine (A) and Guanine (G)

two purines

There are ______ - either Cytosine (C), Thymine (T) found only in DNA, or Uracil (U) found only in RNA

three pyrimidines

________ occurs between one purine and one pyrimidine.

complimentary base pairing

______ always binds to _____ (or uracil in the formation of RNA) with two hydrogen bonds

adenine; thymine

_____ always binds to _____ with three hydrogen bonds.

cytosine; guanine

The three most important nucleic acids:

DNA, RNA, ATP

DNA

is a double-stranded helix carrying encoded hereditary instructions.

RNA

is single-stranded and functions in translating the code to build proteins.

Sugar group

DNA contains deoxyribose sugar while RNA contains ribose sugar.

Nitrogen bases

DNA contains a combination of A, C, G, and T while RNA contains a combination of A, C, G, and U.

Number of nucleotides

DNA contains more than 45 million nucleotides while RNA contains no more than 50,000 nucleotides.

Shape

DNA is a double-stranded helix while RNA is a single-stranded straight chain.  DNA strands are arranged anti-parallel.

Function

DNA stores genetic information that controls protein synthesis while RNA performs protein synthesis as directed by DNA.

Adenosine Triphosphate (ATP)

is single nucleotide that contains three phosphate groups and can readily release the phosphates to release energy for the cell to perform work.

Phosphorylation

the addition of a phosphate group to an organic compound.