Download Chapter 6.4 The Building Blocks of Life

CHAPTER 6.4
The Building Blocks of Life
ORGANIC CHEMISTRY

Life on Earth is carbonbased
Carbon is a component of
almost all biological
molecules
 Lead to the diversity of life
on Earth


Organic chemistry:
Student of organic
compounds (compounds
containing carbon)
ORGANIC CHEMISTRY

Carbon has four electrons in its outermost energy
level so carbon can form four covalent bonds with
other atoms

Compounds can be in the shape of straight chains,
branched chains, and rings
MACROMOLECULES
Large molecules that are formed by joining
smaller organic molecules together
 Large molecules are called polymers

Molecules made from repeating units of identical or
nearly identical compounds called monomers that are
linked together by covalent bonds
 Poly=many
 Mono=one


Four types:
Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

CARBOHYDRATES
Compounds composed to carbon, hydrogen, and
oxygen in a ratio of one oxygen and two hydrogen
atoms for each carbon atom
 General formula: (CH2O)n
 n=the number of CH2O unites in a chain


3-7 are called simple sugars or monosaccharides


Two monosaccharides join together to form a
disaccharide


Ex: Glucose
Ex: Sucrose
Larger molecules are called polysaccharides

Ex: Glycogen
CARBOHYDRATES
In plants, a carbohydrate called cellulose
provides structural support in cell walls
 Chitin, a polysaccharide, is the main component
in the hard outer shell of shrimp, lobsters, and
insects

LIPIDS
Molecules made mostly of carbon and hydrogen
that make up fats, oils, and waxes
 Composed of fatty acids, glycerol, and other
components
 Main function is to store energy
 Ex: Triglyceride

Fat if solid at room temperature and oil if liquid at
room temperature
 Stored in fat cells in the body

SATURATED AND UNSATURATED FATS

Basic structure of a lipid:

Fatty acid tail
Chain of carbon atoms bonded to hydrogen and other
carbon atoms by single or double bonds
 Single bonds: Saturated fats
 Double bonds: Unsaturated fats

Saturated fats: No more hydrogens can bond to
the tail
 Unsaturated fats: t least one more hydrogen can
be accommodated in the tail
 Polyunsaturated fats: Fats with more than one
double bond in the tail

PHOSPHOLIPIDS
Responsible for the structure and function of the
cell membrane
 Lipids are hydrophobic

They do not dissolved in water
 Allows lipids to serve as barriers in biological
membranes

STEROIDS
Substances such as
cholesterol and
hormones
 Cholesterol provides
the starting point for
other necessary lipids
such as vitamin C or
hormones such as
estrogen and
testosterone

PROTEINS
Compound made of small carbon compounds
called amino acids
 Amino acids are small compounds that are made
of carbon, nitrogen, oxygen, hydrogen, and
sometimes sulfur

AMINO ACID STRUCTURE

Central carbon atom
Can form four bonds
 One bonds with hydrogen
 Other three bond with an amino group (-NH2),
carboxyl group (-COOH), and a variable group (-R)


Variable group makes each amino acid different
20 of them
 Proteins are made of different combinations of all 20
different amino acids
 Several covalent bonds called peptide bonds join
amino acids together to form proteins

THREE-DIMENSIONAL PROTEIN STRUCTURE
Proteins can have up to four levels of structures
due to the variable groups
 Number of amino acids in a chain and the order
in which they are joined, define the primary
structure
 Secondary structure: Helix and pleat



Tertiary structure: Globular


Can contain many
Ex: Hemoglobin
Quaternary structure: Long fibers
PROTEIN FUNCTION
Make up 15% of total body mass
 Involved in nearly every function of your body







Structural support
Transport substances inside the cell and between
cells
Communicate signals within the cell and between
cells
Speed up chemical reactions
Control cell growth
Ex: Skin and hair made of proteins
NUCLEIC ACIDS
Complex macromolecules that store and transmit
genetic information
 Made of smaller repeating units called
nucleotides

Composed of carbon, nitrogen, oxygen, phosphorous,
and hydrogen atoms
 Six nucleotides


Three units: nitrogenous base, phosphate, ribose sugar
Two nucleic acids in living organisms: DNA and
RNA
 Nucleotide with three phosphate groups:
Adenosine Triphosphate (ATP)


Chemical storehouse of chemical energy
DNA AND RNA
Deoxyribonucleic acid (DNA)
 Ribonucleic acid (RNA)
 Sugar of one nucleotide bonds to the phosphate of
another nucleotide
 The nitrogenous base that sticks out from the
chain is available for hydrogen bonding with
other bases
