Download ch-3-bio-molecules

CH 3
Biological Molecules
Biochemistry Review


Elements are substances that cannot be
broken down or converted into another
substance
They are composed of atoms which are
the smallest units of matter (recall the
levels of organization)
Biochemistry Review

An atom is composed of a nucleus, an electron
cloud, and 3 subatomic particles:
Electron




Protons (p+)
Neutrons (n0)
Electrons (e-)
cloud
Nucleus
Protons and neutrons are
located in the nucleus of an
atom and electrons in the
electron cloud
p+
n0
e-
Section 3.1
Carbon in Biomolecules
Carbon & Biomolecules

Molecules are particles composed of
atoms (from elements) held together by
chemical bonds


Classified as organic and inorganic
Organic molecules are important because
they are general types of molecules that
all living organisms synthesize and use;
they are essential for life
Carbon & Biomolecules
 The
term “organic” describes
molecules that contains the element
carbon (C) and some hydrogen atoms

“Inorganic” molecules are all
molecules that do not contain carbon,
with the exception of carbon dioxide
(CO2)
Carbon & Biomolecules


Although they have a common structure
and function, the tremendous variety of
organic molecules contributes to the
diversity of structures within an individual
organism and even individual cells
The reason for this?

Carbon’s structure is very versatile when it
comes to forming bonds with other atoms
Carbon & Biomolecules


Macromolecules – large molecules
composed of similar repeating units
There are 4 main groups of
macromolecules that compose living
things:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
Section 3.2
Synthesizing Organic Molecules
Modular Approach

The modular approach involves building
organic molecules piece by piece (like a
train with individual cars):
Monomer: individual subunits (car)
 Polymer: long chains of monomers (train)

 Mono-
means “one”
 Poly- means “many”
Biomolecules & Water
 Biomolecules
are joined together or
broken apart by removing or adding
water:
 Water
can break apart polymers
(biomolecule), freeing up the monomers
OR…
 When polymers (biomolecules) are
formed, water is often produced as a
by-product
Biomolecules & Water

Dehydration synthesis reactions: when
monomers are joined together by removing
water to make biomolecules (polymers)
A
H+ is removed from one monomer and an OHfrom the other…they will form water
 The spaces left open allow the monomers to bond
together, creating a biomolecule (polymer)
Dehydration Synthesis
Biomolecules & Water

Hydrolysis reactions: when molecules are
broken apart by water

Water is added to a molecule (polymer),
causing it split back into the original
monomers
CH 3.3
What are Carbohydrates?
Carbohydrates
CH2OH
H
O
H
OH
H
H
OH
HO
H
OH
Carbohydrates
energy
molecules
Carbohydrates-Sugars


Composed of carbon, hydrogen, and
oxygen (1:2:1)
Overall function: used by organisms for
short term energy and structural support
Monosaccharides
1 sugar molecule (monomer)
 Function: mainly used to form polymers or
for cell activities
 Most common: glucose C6H12O6
 Others:

Fructosefruits
 Galactoselactose
 RiboseRNA
 DeoxyriboseDNA

Disaccharides
2 sugar molecules linked together
 Function: mainly used for short-term
energy
 Examples:

Sucroseglucose + fructose
 Lactoseglucose + galactose
 Maltoseglucose + glucose

Polysaccharides



Many sugar molecules linked together
Function: used for long-term energy storage
Examples:
 Starch: found in plant seeds & roots (FYI: 1000 to ½
million glucose)


Glycogen (animals): found in animal muscles & liver
(much smaller than starch)
Cellulose: found in plant cell walls


Animals can’t digest it, has to be broken down by microbes so
its usually just roughage/fiber for us
Chitin: found in exoskeletons and fungi cell walls
Cellulose Structure
& Location
Chitin Structure & Location
Section 3.4
What are Lipids?
Lipids: Fats & Oils
Lipids
energy storage
Lipids
Composed of mainly carbon and hydrogen
 Have nonpolar regions that make them
insoluble in water (meaning they won’t
dissolve)
 Types of lipids:

Fats
 Oils
 Waxes
 Phospholipids
 Steroids

Oils, Fats, and Waxes


Triglyceride: the chemical name of fats
and oils
Difference between fats & oils:

Fats are solid, oils are liquid
Saturated Fats


Saturated fats are made of mainly hydrogen so
the FA chains are “saturated” in hydrogen
Where we get them from: butter, bacon fat,
steak; tends to come from animals
Unsaturated
Fats


Unsaturated fats have a smaller amount of
hydrogen in their FA chains
Where we get them from: the seeds of plants
(they’re stored for the embryo) such as corn oil,
peanut oil, etc.
FYI: Unsaturated fats
Unsaturated fats can be converted to a
fat by breaking some of the double bonds
and adding some hydrogens…this is known
as a “hydrogenated oil” (allows margarine
to be solid at room temp)
 Partial hydrogenation creates trans fats
which are also solid at room temperature


Read Health Watch: Cholesterol-Friend or
Foe on pg. 45
FYI: Saturated &
Unsaturated Fats
Saturated
Unsaturated
Waxes

Function: used as a waterproof covering for:





plant leaves and stems
mammalian fur
insect exoskeletons
to construct beehives
FYI: Chemically similar to fats, but they aren’t
a food source because we and most other
animals don’t have the enzymes necessary to
break them down
Fats & Waxes
Phospholipids
Make up the plasma (cell)
membrane
 Head is hydrophilic or
“water loving”
 Tail is hydrophobic or
“water fearing”

Steroids
Structurally different from
all other lipids because it is a
ring while the others were
chains
 Common steroid: cholesterol


Component of animal cell
membranes
Section 3.5
What are Proteins?
Proteins
Amino Acids and Proteins



Monomer: amino acids (AAs); there are
20 different AAs in all
Polymer: protein (chains of AAs)
Bond between the AAs when they are
making polymers is known as a peptide
bond
Amino Acids and Proteins


Peptide: short chains of AAs (FYI: 2-49
AAs)
Polypeptide: long chains, aka a protein
(FYI: 50 or more AAs)
Protein Structure
1. Primary structure (1o)-the chain of AAs
that make up the protein
2. Secondary structure (2o)- when the
protein takes on a coiled or pleated shape
Primary/Secondary Level
Primary
Secondary
Protein Structure


Tertiary structure (3o)-the 3-D shape a
polypeptide becomes (like balling up a
piece of paper)
Quaternary structure (4o)-when
polypeptide chains link together
Tertiary/Quaternary Levels
Tertiary
Quaternary
Types of Proteins
Can be classified as functional or
structural
 Functional:

Enzymes: proteins that speed up almost all
chemical reactions that occur inside the cell
 Albumin (egg white) & Casein (milk): provides
AAs for developing young animals
 Some hormones such as insulin & growth
hormone
 Antibodies

Types of Proteins

Structural
Elastin: gives skin its
elasticity
 Keratin: main protein
found in hair, nails,
horns, scales, and
feathers
 Gossamer: the silk
protein in spiders and
silk moth cocoons

Section 3.6
What are Nucleic Acids?
Nucleic Acids
Information
storage
Nucleic Acids

Monomers: nucleotides

Polymers: nucleic acids (NAs)

2 types of nucleic acids:
DNA-deoxyribonucleic acid
 RNA-ribonucleic acid

Other Nucleotides

Not all nucleotides are part of NAs



Cyclic nucleotides: used as intracellular
messengers
Adenosine triphosphate (ATP): energy molecule
found in all organisms
Coenzymes: assist enzymes in promoting and
chemical reactions