What’s the Matter?
Matter is anything that has mass and takes up space. All living things consist of
matter.
All known matter can be divided into a little more than 100 different substances called
elements.
Elements and Compounds
An element is pure substance that cannot be broken down into other substances.
Each element has a particular set of properties
the major elements in the human body are: oxygen, carbon, and hydrogen
In your body, most elements are combined with other elements to form chemical
compounds.
A compound is a unique type of matter in which two or more elements are combined
chemically in a certain ratio.
Atoms and Molecules
The smallest particle of an element that still has the properties of that element
is an atom.
An atom has a central nucleus that is positive in charge.
The nucleus is surrounded by negatively charged particles called electrons.
he smallest particle of a compound that still has the properties of that compound is a
molecule.
A molecule consists of two or more atoms.
For example, a molecule of water consists of two atoms of hydrogen and one atom
of oxygen. H2O.
Biochemical Compounds
most of the compounds in living things are biochemical compounds.
A biochemical compound is a carbon-based compound that is found in living
organisms.
A chemical bond is the sharing of electrons between atoms.
Classes of Biochemical Compounds
Biochemical compounds make up the cells and tissues of living things.
They are also involved in all life processes.
all biochemical compounds can be grouped into just four main classes:
carbohydrates, proteins, lipids, and nucleic acids.
Characteristics of Biochemical Compounds
all biochemical compounds contain hydrogen and oxygen as well as carbon.
Almost all biochemical compounds are polymers.
Polymers are large molecules that consist of many smaller, repeating molecules,
called monomers.
Most biochemical molecules are macromolecules. The prefix macro- means “large,”
and many biochemical molecules are very large indeed.
They may contain thousands of monomer molecules.