Biological molecules

Biological Molecules

Chemical elements that make up carbohydrates

CARBON OXYGEN HYDROGEN

  

FUNCTIONS 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

Chemical elements that make up fats

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

FUNCTIONS

Chemical elements that make up PROTEINS

CARBON + OXYGEN + HYDROGEN + NITROGEN

+ SULPHUR

Large molecules from smaller ones

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.

Proteins from amino acid

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 wouldconsist of hundreds ofamino acids

The linkage of several amino acids . . .

Levels of Protein Structure

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 polypeptidechain

two or morepolypeptide 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.

Shape and structure f protein molecules to their function

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 diseaseExample: Antibodies inactivate and help destroyviruses and bacteria.