Structures and Functions of Biological Molecules

Biological Macromolecules

Biological Macromolecules

These are traditionally grouped into carbohydrates, nucleic acids, proteins, and lipids.

Polymer

A long molecule built by linking together a large number of small, similar chemical subunits called monomers.

Carbohydrates

• They are loosely defined group of molecules that all contain carbon, hydrogen, and oxygen in the molar ratio 1:2:1.

• Sugars are among the most important energy storage molecules, and they exist in several different forms.

Monosaccharides

These are simple sugars containing as few as three carbon atoms, but those that play the central role in energy storage.

glucose

The most important of the 6-carbon monosaccharides for energy storage is _____.

Polysaccharides

These are long polymers made of monosaccharides that have been joined through dehydration reactions.

Starch

A storage polysaccharide, consists entirely of a-glucose molecules linked in long chains. It is also for energy storage that enables us to do our daily activities.

Cellulose

a structural polysaccharide, also consists of glucose molecules linked in chains. It is for the structural Support of plant cell walls.

Chitin

the structural material found in arthropods and many fungi, is a polymer of N-acetylglucosamine, a substituted version of glucose. When cross-linked by proteins, it forms a tough, resistant surface material that serves as the hard exoskeleton of insects and crustaceans (crab).

Nucleic acids

These carry information inside cells. They are able to serve as templates for producing precise copies of themselves. This characteristic allows genetic information to be preserved.

Deoxyribonucleic Acid

→ Genetic information is stored in here.

→ Organisms use sequences of nucleotides in this to encode the information specifying the amino acid sequences of their proteins.

double helix

The shape of DNA.

Ribonucleic Acid

Messengers, Short lived copies of DNA are stored in this.

→ It carries information and is also responsible for protein synthesis. Also it is involved in control of gene expression.

Messenger RNA

Consists of transcribed single-stranded copies of portions of the DNA. These transcripts serve as blueprints specifying the amino acid sequences of proteins

Proteins

Polymers of Amino Acids.

Enzymes

These are biological catalysts that facilitate specific chemical reactions. They are three-dimensional globular proteins that fit snugly around the molecules they act on. This fit facilitates chemical reactions by stressing particular chemical bonds.

Defense

Other globular proteins use their shapes to "recognize" foreign microbes and cancer cells. These cell-surface receptors form the core of the body's endocrine and immune systems.

Transport

A variety of globular proteins _____ small molecules and ions. Membrane ____ proteins help move ions and molecules across the membrane.

Support

Protein fibers play structural roles. These fibers include keratin in hair, fibrin in blood clots, and collagen. The last one, collagen, forms the matrix of skin, ligaments, tendons, and bones and is the most abundant protein in a vertebrate body.

Motion

Muscles contract through the sliding motion of two kinds of protein filaments: actin and myosin. Contractile proteins also play key roles in the cell's cytoskeleton and in moving materials within cells.

Regulation

Small proteins called hormones serve as intracellular messengers in animals. Proteins also play many regulatory roles within the cell-turning on and shutting off genes during development, for example. In addition, proteins receive information, acting as cell-surface receptors.

Storage

Calcium and iron are stored in the body by binding as ions to ____ proteins.

Lipids

Hydrophobic Molecules. Also known as fats, they consist of complex polymers of fatty acids attached to glycerol and are excellent energy-storage molecules.

Triglycerides

Lipids for energy storage

Phospholipids

lipids that encloses the cell membrane.

Prostaglandin

lipids that are chemical messengers for pain.

Steroid

lipids for membrane and hormones.