Chapter 3: The chemical basis of life II

organic molecules

molecules containing carbon are said to be ____________

organic molecules

almost all organic compounds associated with life also contain ___________

hydrogen atoms

macromolecules are

large, complex organic molecules

how many bonds can carbon make

four

how many electrons do atoms need to fill the outer shell

eight

carbon can form ______________

non polar and polar bonds

molecules with non polar bonds are ______

poorly water soluble

molecules with polar bonds are ________

more water soluble

hydrocarbons

organic molecules with high proportion of carbon-hydrogen bonds

hydrocarbons can undergo reactions that release a large amount of ______

energy

___________ can replace one or more of the hydrogens bonded to the carbon skeleton

chemical groups

functional groups are

groups of atoms with special chemical features that are functionally important

each type of functional group exhibits the _________ in all molecules in which it occurs

same properties

isomers are two molecules with an identical molecular formula but _______ and characteristics

different structures

structural isomers contain

the same atoms but in different bonding relationships

stereoisomers

identical bonding relationships, but the spatial positioning of the atoms differs in the two isomers

cis-trans isomers

carbons have covalent bonds to the same atoms, but the atoms differ in their positioning around double bond

enantiomers

isomers that are mirror images of one another

polymer

a long molecule consisting of many similar building blocks

the small building block molecules are called

monomers

the enzymes tend to

speed up chemical reactions

condensation reaction

one molecule of water removed per monomer

catalyzed by enzymes

hydrolysis reaction

one molecule of water is added per monomer released

catalyzed by enzymes

macromolecules

large molecules of life

carbohydrates serve as

fuel and building material

carbohydrates include

sugars and the polymers of sugars

carbohydrates are composed of

carbon, hydrogen, and oxygen atoms

most of the carbon atoms in a carbohydrate are linked to a

hydrogen atom and a hydroxyl group

monosaccharides

the simplest sugars

monosaccharides serve as a

major nutrient for cells and as raw material for building molecules

5 carbons

pentose

6 carbons

hexose

the most common monosaccharide

glucose

structural isomers

different arrangement of the same elements

stereoisomers

hydroxyl group of carbon 1 is above or below ring (a & b glucose)

enantiomers with mirror image structure (d & l glucose)

disaccharides are carbohydrates composed of

two monosaccharides

disaccharides are joined by _______ and separated by _______

glycosidic bond; hydrolysis

disaccharide example

sucrose, maltose, lactose

polysaccharides

many monosaccharides linked together to form long polymers

the structure and function of polysaccharides are determined by

its sugar monomers and the positions of glycosidic bonds

lipids

a diverse group of hydrophobic molecules

lipids are composed predominantly of

hydrogen and carbon atoms

a defining feature of lipids is

they are non polar and therefore vary insoluble in water

lipids comprise about _______ of the organic matter in the average human body

40%

fats are constructed from

glycerol and 3 fatty acids

a fatty acid consist of a

carboxyl group attached to a long carbon skeleton

fatty acids are joined by _______ and broken apart by _________

dehydration; hydrolysis

fatty acids vary in length and in the number and locations of _________

double bonds

Saturated fats

all carbons linked by single bonds

tend to be solid at room temp

animal fats

unsaturated fats

contain one or more double bond

tend to be liquid at room temp

plant fats

fats are important for ________

energy storage

fats can also be ___________ providing cushioning and insulation

structural

in ___________ two fatty acids and a phosphate group are attached to glycerol

phospholipids

phospholipids are

amphipathic

the heads are hydrophilic and the tails are hydrophobic

phospholipids are major constituents of

cell membranes

a ________________ can exist as a stable boundary between two aqueous compartments

phospholipid bilayer

_________ are lipids with four interconnected rings of carbon atoms

steriods

Steroids are usually __________ in water

insoluble

small differences in structure can lead to profoundly different

specific biological properities

__________ include a diversity of structures, resulting in a wide range of functions

Proteins

proteins are composed of

carbon, hydrogen, oxygen, nitrogen, and small amounts of other elements, notably sulfur

amino acids are the

monomers

amino acids are

organic molecules with carboxyl and amino groups

amino acids differ in their properties due to differing side chains called

R groups

A polypeptide is a

polymer of amino acids

amino acids are joined by

dehydration reaction

polypeptides range in length from

a few to more than a thousand monomers

________ may be formed from one or several polypeptides

proteins

Polypeptides are broken down by ______

hydrolysis

peptide bond formation is between two _________

amino acids

each polypeptide has a unique linear sequence of amino acids, with a

carboxyl end and an amino end

a protein is a

biologically functional molecules that consists of one or more polypeptides

polypeptides are

twisted, folded, and coiled into unique shape

the amino acid sequence of each polypeptide leads to a

protein’s 3D structure

a protein’s structure determines its

function

primary structure

amino acids build a simple chain held together by peptide bonds

secondary structure

amino acids that are close together, interact via hydrogen bonds between the CO and NH

tertiary structure

3D folding due to side chain interactions, created by electrostatic, hydrogen and Van Der Waals bonds

quaternary structure

built of several separate polypeptide chains that are folded together

quaternary structure are made up of

two or more polypeptides

individual polypeptide chains are

protein subunits

proteins can be formed from

serveral copies of the same polypeptide

a multimeric protein is composed from

different polypeptides

the five factors that promote protein folding and stability

hydrogen bonds

ionic bonds and other polar interactions

hydrophobic effects

van der Waals forces

disulfide bridges

many cellular processes involve steps in which two or more

different proteins interact

nucleic acids store, transmit, and help express

hereditary information

Deoxyribonucleic acid (DNA)

stores genetic information encoded in the sequence of nucleotide monomers

ribonucleic acid (RNA)

decodes DNA into instructions for linking together a specific sequence of amino acids to form a polypeptide chainnu

celiac acids are made of monomer called

nucleotides

nucleotides are made of

pentose sugar

nitrogenous base

a single or double ring of carbon and nitrogen atoms

nucleotides are joined by a phosphodiester bond, formed in a

dehydration reaction

DNA molecules have two polynucleotides spiraling around an imaginary axis forming a

double helix

RNA molecules exists in

single strands

the base pairing in DNA

adenine (A) always with thymine (T)

guanine (G) always with cytosine (C)

Base pairing in RNA

Adenine (A) always with uracil (U)

Guanine (G) always with cytosine (C)

amino is found

amino acids (proteins)

carboxyl ketone is found

steroids, waxes, proteins

aldehyde is found

linear forms of sugars and some odor molecules

carboxyl is found

amino acids, fatty acids