CARBON OXYGEN HYDROGEN

Short term energy supply

› Glucose produces ATP energy

Short term energy storage

› Glycogen is stored in the liver and muscles

Structure

› Plant cell walls, insect exoskeletons

Cell Membrane markers

› Cell “identity tags”

All carbs have the formula Cn(H2O)n

HYDROGEN + CARBON + OXYGEN =

FATS

=

Long term energy storage› Pack energy into a small space

Insulation and Padding› Protects organs

Structure› Cell membranes

Chemical Messengers› Steroids

All lipids do not dissolve in water = hydrophobic

CARBON + OXYGEN + HYDROGEN + NITROGEN

+ SULPHUR

Starch is the nutrient storage form of

carbohydrates in plants.

Glycogen is the nutrient storage form of

carbohydrates in animal.

Cellulose is a rigid, structural carbohydrate

found in the cells walls of many organisms.

Proteins are an extremely diverse group of

biological molecules composed of the small

molecules called amino acids.

Proteins are created by linking together amino

acids into protein links called polypeptide chains.

There are twenty amino acids of which 12 can be

synthesized by the human body and 8 must be

ingested in the foods we eat. These 8 are referred

to as the essential amino acids.

Sequences of amino acids are strung together to

produce polypeptide chains, which then fold up into

working proteins.

Important groups of proteins include enzymes, which

hasten chemical reactions, and structural proteins,

which make up such structures as hair.

The primary structure of a protein is its amino acid

sequence; this sequence determines a protein’s

secondary structure—the form a protein assumes

after having folded up

The activities of proteins are determined by their

final folded shapes.

Antibodies help to fight diseases.

ala

ala

gln

gln

ile

ile

. . . produces a polypeptide chain like this:

A typical protein would

consist of hundreds of

amino acids

The linkage of several

amino acids . . .

Figure 3.20

Primary structure

Secondary structure

Tertiary structure

(a)

(b)

(c)

(d) Quaternary structure

amino acid sequence

beta pleated sheet

alpha helix

random coil

folded polypeptide

chain

two or more

polypeptide chains

Four Levels of Structure In Proteins

The primary structure of any

protein is simply its sequence

of amino acids. This sequence

determines everything else

about the protein’s final shape.

Structural motifs, such as

the corkscrew-like alpha

helix, beta pleated sheets,

and the less organized

“random coils” are parts

of many polypeptide

chains, forming their

secondary structure.

These motifs may persist

through a set of larger-scale

turns that make up the

tertiary structure of the

molecule

Several polypeptide chains

may be linked together in a

given protein, in this case

hemoglobin, with their

configuration forming its

quaternary structure.

There are about 20 different amino acids, each

with a different chemical structure and

characteristics; for instance, some are polar,

others are non-polar. The final protein structure is

dependent upon the amino acids that compose it.

Protein function is directly related to the structure

of that protein. A protein's specific shape

determines its function.

antibodies and enzymes are proteins.

Defensive proteins/anti bodies

Virus

Antibodies

Bacterium

Function: Protection against disease

Example: Antibodies inactivate and help destroy

viruses and bacteria.