Basic Chemistry & Biochemistry:
The Chemical Basis of Life
Biology I
Part I: Basic Chemistry:
Key Words and Concepts
• Element
• Atom
• Compounds
• Molecule
• Ions
• Acid and Base
• pH
• Diffusion and Osmosis
Review: Basic Chemistry
• Matter
• anything that has a mass and takes up a space
• all matter is composed of elements
• Element
• is a substance that can not be broken down into
simpler substances. Example: oxygen (O), hydrogen
(H), carbon (C)
• Each element has a set of properties that distinguish
it from from other elements. Example: copper is a
bronze colored solid that conducts heat; oxygen is
odorless/colorless at room temperature.
Review: Basic Chemistry
• Atom
• is the smallest particle of an element that retains the
characteristics of that element
• Example: all atoms of copper have the properties
of copper
• The center of each atom contains a nucleus
composed of 2 different particles: protons (+ charge)
and neutrons (with no charge)
• Moving in regions outside the nucleus is a particle
called the electron (- charge)
Structure of an Atom
Review: Basic Chemistry
• Atom
• Every atom in an element has an equal
number of protons and electrons, and is
electrically balanced, or neutral
• Every atom has energy, or the ability to do
work
• This energy (called chemical energy), comes
from electrons in the atom
Review: Basic Chemistry
• Compounds
• Substances made from elements are compounds. A
chemical formula shows the kinds and proportions
of atoms in a compound. Ex: NaCl stands for sodium
chloride (salt) from sodium (Na) and chlorine (Cl)
• Molecules
• Are the smallest units of a compound that still have
the properties of that compound. (in H2O, the ratio of
H and O is 2:1, so the formula is H2O)
• Ions
• Electrically charged (+/-) molecules are called IONS
Review: Basic Chemistry
• Acids and Bases
• Two common groups of compounds that
react in water are ACIDS and BASES
• Acid is a substance that releases
hydrogen ions (protons) when mixed
with water (proton donor)
• Example: CH3COOH --–H20–
H+ + CH3COO–
• Base is a substance that separates in
water, forming ions that react with
hydrogen ions (proton acceptor)
• Example: NaOH + CH3COOH --– H20 + CH3COONa
Review: Basic Chemistry
• pH
• The strength of an acid or base is measured by the
pH scale (0-14, 7 being neutral: water)
• pH of acid solution: 0-7; of basic solution 7-14
• The pH scale is based on powers of 10. Thus Cola
with a pH of 3 is 10 times more acidic than Tomato
juice with a pH of 4
• Living cells are very sensitive to pH of their
environment. Our cells are in a pH of 7.2. If the pH
changes by only 2/10th of a point, cells die
Review: Basic Chemistry
• Diffusion & Osmosis
• Diffusion : movement of
a molecule/substance
from a higher to a lower
concentration
• Osmosis : movement of
water molecules through
a semi-permeable
membrane from a higher
to a lower water
concentration
Biochemistry
What is Biochemistry?
• Biochemistry is the study of the
chemical interactions of living things.
• Biochemists study the structures and
physical properties of biological
molecules.
• Often are involved in the manufacture of
new drugs and medical treatments
Elements in Living Organisms
• The most common elements found in
living organisms include:
•Carbon (C)
•Oxygen (O)
•Nitrogen (N)
•Hydrogen (H)
•Phosphorus (P)
•Sulfur (S)
Periodic Table of the Elements (excerpt)
Biochemistry:
Where Chemistry & Biology Meet
• Living things require millions of
chemical reactions just to survive.
• Metabolism = all the chemical
reactions occurring in the body.
• Organic molecules:
•
•
•
•
usually associated with living things.
always contain CARBON.
are “large” molecules, with many atoms
always have covalent bonds (share electrons)
Macromolecules of Cells
• Macro = large
• 4 types of macromolecules
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids
Macromolecule #1: Carbohydrates
• Sugars and groups of sugars
• Purposes: energy and structure
• Includes three types:
• Monosaccharide (1 sugar – quick energy)
• Disaccharide (2 sugars – short storage)
• Polysaccharide (many sugars – energy
long storage & form structures)
Macromolecule #1: Carbohydrates
• Polysaccharide Examples:
•Glycogen— stored for future energy
needs. Found in liver, muscle & sperm.
•Cellulose— used to form fibers for
plant structures. Humans can’t digest
(fiber). Most abundant organic
molecule.
•Chitin— exoskeletons of some
crustaceans & insects.
Polysaccharides
Polysaccharides
Macromolecule #2: Lipids
• Insoluble in water (think oil & water)
4 types:
• 1-triglycerides (fats & oils)
• (long-term energy storage, insulation)
• 2-phospholipids (cell membranes)
• 3-steroids (cell signaling)
• cholesterol molecules modified to form sex
hormones. (e.g. testosterone, estrogen, etc.)
• 4-waxes (protection, prevents water loss)
• Used mainly by plants, but also bees, some furry
animals and humans.
Triglycerides
Phospholipids
Steroids
Waxes
Macromolecule #3: Proteins
• Most complicated of all biological molecules.
• Serve the most varied purposes, including:
Support
structural proteins (e.g., keratin, collagen)
Enzymes
speed up chemical reactions
Transport
cell membranes channels, transporters in blood
(e.g., Hemoglobin)
Defense
antibodies of the immune system
Hormones
cell signaling (e.g., insulin)
Motion
contractile proteins (e.g., actin, myosin)
Collage
n
Antibodies
Cellular Transport
Motion
actin & myosin
fibers in muscles
Macromolecule #3: Proteins
• The building blocks of proteins are
AMINO ACIDS. There are only 20
types of Amino Acids.
• There are millions of different proteins,
and they are all built from different
combinations of the 20 amino acids.
• Amino acids join together to form
peptides, polypeptides, and
polypeptide chains.
Macromolecule #4: Nucleic Acids
• Nucleotides: building blocks of nucleic acids.
• Each nucleotide contains
• (a) phosphate molecule,
• (b) nitrogenous base, and
• (c) 5-carbon sugar
• Several types of nucleic acids, including:
• DNA: deoxyribonucleic acid
• Genetic material, double stranded helix
• RNA: ribonucleic acid
• Genetic material, single stranded
• ATP: adenosine triphosphate
• High energy compound
DNA
Nucleotide Structure
CHEMISTRY IS LIFE…