Unit 1 Notes 4: Organic Macromolecules

Macromolecules

carbohydrates, lipids, proteins, nucleic acids

The function of macromolecules is based on its...

structure

Within cells, small organic molecules are joined together to form

larger molecules

Within cells, large molecules are digested into

small molecules

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Monomers

building blocks of polymers

Three of the four classes of life's organic molecules are polymers

carbohydrates, proteins, and nucleic acids

condensation reaction (dehydration synthesis)

Joins monomers: one monomer provides a hydroxyl group while the other provides a hydrogen to form a water molecule, which is removed.

hydrolysis reaction

water is used to break down a polymer

Enzymes

Proteins that speed up chemical reactions

Carbohydrates serve as

fuel and building material

Carbohydrates

include sugars and the polymers of sugars

Carbohydrate terms

Sugars and starches, glycogen, cellulose, monosaccharide, disaccharide, polysaccharide, CH2O, "-OSE", isomers

Monosaccharides are the

building blocks of carbohydrate macromolecules

The simplest carbohydrates are

Monosaccharides or simple sugars

Carbohydrate macromolecules are

polysaccharides, polymers composed of many sugar building blocks

Monosaccharides have

molecular formulas that are usually multiples of CH2O (Ex: Glucose (C6H12O6) is the most common monosaccharide)

Sugars can take both

linear or ring forms

Rings are more formed in

aqueous solutions

Glucose can take two forms (isomers) by changing the position of the

OH on the number 1 carbon

Disaccharide are formed when

a dehydration reaction (condensation reaction) joins two or more monosaccharides together

The formation of disaccharides form a covalent bond called a

glycosidic linkage

Disaccharide are broken down by

hydrolysis

Polysaccharides (the polymers of sugars)

are created by condensation reactions (dehydration reactions) and broken down by hydrolysis

Polysaccharides have

storage and structural roles

The structure and function of a polysaccharide are determined by its

sugar monomers and the positions of glycosidic linkages

Starch

A storage polysaccharide in plants consisting entirely of glucose monomers.

Plants store surplus starch as granules within

chloroplasts and other plastids

Glycogen

is a storage polysaccharide in animals

Humans and other vertebrates store glycogen mainly in

liver and muscle cells

Cellulose

Is a structural polysaccharide, which is a major component of tough plant cell walls

Like starch, cellulose is a polymer of glucose, but

the glycosidic linkages differ

The difference of cellulose and starch is based on the

two ring forms for glucose: alpha and beta

Polymers with alpha glucose are

helical (starch)

Polymers with beta glucose are

straight (cellulose)

A cellulose molecule is an

unbranched beta glucose polymer

Parallel cellulose molecules

grouped into microfibrils, which form strong building materials for plants

Enzymes that digest starch by hydrolyzing alpha linkages

can't hydrolyze beta linkages in cellulose

Cellulose in human food

is indigestible and passes through the digestive tract as insoluble fiber

Some microbes use ___ to digest cellulose

enzymes

Many herbivores, from cows to termites, have

symbiotic relationships with these microbes

Chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

Lipids

the one class of large biological molecules that do not form true polymers

Lipids are formed by

dehydration reactions (condensation reactions) and break down by hydrolysis

Lipids are

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

The most biologically important lipids are

fats, phospholipids, steroids

Fats (lipids) are constructed from two types of smaller molecules:

glycerol and fatty acids (the building blocks of fats)

Glycerol

a three-carbon alcohol with a hydroxyl group attached to each carbonated

fatty acids

consists of a carboxyl group attached to a long carbon skeleton

In a fat, _ fatty acids are joined to glycerol by an ____, creating a ____, or triglyceride

3, ester linkage, triacylglycerol

fatty acids vary in

length (number of carbons) and in the number and locations of double bonds

Saturated fatty acids have

maximum number of hydrogen atoms possible and no double bonds

Unsaturated fatty acids have

one or more double bonds

The presence of double bonds in the hydrocarbon changes the ____ of a lipid

properties

Saturated fats are ____ at room temperature

solid (most animal fats)

unsaturated fats or oils are ____ at room temperature

liquid (plant fats, fish fats)

Diets rich in saturated fats

may contribute to cardiovascular disease by promoting atherosclerosis

The major function of fats

is energy storage

Humans and other mammals store their fat in

adipose cells; adipose tissue also cushions vital organs and insulates the body

Phospholipids

Similar to fats but have two hydrocarbon chains and a negatively charged phosphate group

The two fatty acids tails are ____, but the phosphate group and its attachments form a ____ head (Remember Unit 1 Notes 2!)

hydrophobic and hydrophilic

When phospholipids are added to water, they

self-assemble into a bilayer, with the hydrophobic tails pointing toward the interior

The structure of phospholipid results in a ____ found in ____

bilayer arrangement, cell membranes

Phospholipids are the major component of

cell membranes

Steroids

lipids characterized by a carbon skeleton consisting of four fused rings

Cholesterol

an important steroid, is a component in animal cell membranes

Although cholesterol is essential in animals,

high levels in the blood may contribute to cardiovascular disease

Many cholesterol based hormones are also

steroids

Proteins account for more than __% of the dry mass of most cells

50

Proteins are ____ molecules each with a unique 3-D shape

structurally complex

Protein functions include

Enzymatic actions, structural support, storage, transport, cellular communications, movement, and defense against foreign substances

Enzyamtic protein function

Selective acceleration of chemical reactions (Ex: Digestive enzymes)

structural protein function

support (Ex: silk fibers; collagen and elastin in animal connective tissues; keratin in hair, horns, feathers, and other skin appendages)

storage protein function

storage of amino acids (Ex: Ovalbumin in egg white; casein, the protein of milk; storage proteins in plant seeds)

transport protein function

transport of other substances (Ex: Hemoglobin, transport proteins)

hormonal protein function

coordination of an organism's activities (Ex: Insulin, a hormone secreted by the pancreas)

receptor protein function

response of cell to chemical stimuli (Ex: Receptors in nerve cell membranes)

Contractile and motor protein function

movement (Ex: Actin and myosin in muscles, proteins in cilia and flagella)

defensive protein function

protection against disease (Ex: Antibodies combat bacteria and viruses)

Enzymes are a type of

A protein that acts as a catalyst to speed up chemical reactions.

Enzymes can perform their functions

repeatedly, functioning as workhorses that carry out the processes of life

Lysozyme is an enzyme present in

sweat, tears, and saliva

amino acids

are organic molecules with carboxyl and amino groups

Amino acids differ in their properties due to

differing side chains, called R groups

Amino acids are classified by properties:

Polar, nonpolar, and charged (ionic)

Polypeptides are

polymers of amino acids joined in a specific sequence

A protein consists of one or more

polypeptides

Polypeptides are constructed by

Condensation reactions (with amino acids( and broken down by hydrolysis)

Amino acids are linked by

peptide bonds to form a polypeptide

Polypeptides range in length from

a few to more than a thousand monomers

Each polypeptide has

A unique linear sequence of amino acids

A functional protein consists of one or more

polypeptides twisted, folded, and coiled into a unique shape

The sequence of amino acids determines

a protein's three-dimensional structure

Proteins structure (shape) determines its

function

The primary structure of a protein is its

unique sequence of amino acids (the polypeptide chain)

The secondary structure found in most proteins

consists of coils and folds in the polypeptide chain. This is because of the hydrogen bonding between C=O and N-H groups

Two types of secondary structure

alpha helix and beta pleated sheet

teritary structure

is determined by interactions between side chains (R groups)

quatermary structure

results when a protein consists of multiple polypeptide chains

Collagen is a

a fibrous protein consisting of three polypeptides coiled like a rope