Molecules of Life
What are organic molecules?
Compounds that contain carbon
What are biological molecules?
Carbohydrates
Lipids
Proteins
Nucleic
Acids
Organic Molecules
What is a cell made up of mostly?
Mostly water, but what else?
Carbon based molecules
Why is carbon so significant for these
molecules?
Recall that an atom’s bonding ability
• Is related to the number of electrons it
must share to complete its outer shell
Atomic number?
What does sharing electrons with other
atoms, in four covalent bonds mean?
Each carbon acts as an ‘intersection’
With 4 different branch points
Creates endless variety of (organic)
carbon molecules
Vary in length
Diversity of Carbon-Based Molecules
Different location of double bonds
Rings
Unbranched or
branched
Activity: Diversity of Carbon-Based Molecules
http://wps.aw.com/bc_campbell_essentials_3/0,11844,3107816-,00.html
Methane
Is a hydrocarbon
What is a hydrocarbon?
………..
Carbon
& Hydrogen
Methane is the simplest
Examples of larger hydrocarbons??
Octane (in gasoline)
Fatty foods
Biological Molecules
‘Carbs’
Sugar
Glucose
Glycogen
Cellulose
Oils
Fatty acids
(sat & unsat)
Butter
Food
Structural
Storage
Enzymes
Antibodies
DNA
RNA
Carbohydrates
What type of sugar is found in the following?
Small (simple) sugar molecules
Examples?
 Monosaccharides
Glucose Fructose
 Disaccharides
Lactose Sucrose
Long starch molecules in pasta, potatoes
Examples?  Polysaccharides
Starch Cellulose
These are our primary sources of dietary energy
In plants, carbs used as building material
Monosaccharides
What type of sugar is
found a sports drink?
Glucose
What type of sugar is
found in fruit?
Fructose
What about honey?
Its really sweet? Why?
It contains both glucose and fructose
Glucose and Fructose
Have the same formula… C6H12O6
Why are they ‘different’?
They are isomers
L-Dopa
Form rings in aqueous
solutions
Which sugar is this? Glucose
Why are the carbons numbered?
Disaccharides
Are ‘double sugars’
What are they
constructed from?
2 monosaccharides
Disaccharides
Disaccharides
Maltose:
glucose and glucose
Lactose:
galactose and glucose
Sucrose:
glucose and fructose
Lactose, another disaccharide
• Some people have trouble
digesting lactose
• Its a condition
called lactose
intolerance
• Missing gene for
lactase enzyme
Sucrose
The most common disaccharide is sucrose,
what do you know it as?
Common table sugar
What plants do we use to extract table
sugar?
Sugar cane
Roots of sugar beets
Polysaccharides
Are long chains of sugar units
(polymers)
(monosaccharides)
What are some polysaccharides?
Starch
Glycogen
Cellulose
Polysaccharides
Describe some characteristics of the following:
Starch
Potatoes and grains are major
sources of starch in the
human diet
Glycogen
Liver, muscle cells break down
glycogen to release glucose
when needed for energy
Cellulose
Structural component, dietary fiber
Biological
Macromolecule:
Function:
Carbohydrates
• Dietary energy
• Storage
• Plant structure
Monomer:
Examples:
• Monosaccharides (simple sugars)
(glucose, fructose)
• Disaccharides (double sugars)
(maltose, lactose, sucrose)
• Polysaccharides (long polymers)
(starch, glycogen, cellulose)
Lipids
Butter, lard, margarine, and salad oil
Do these lipids mix well with water?
Activity: Lipids
http://wps.aw.com/bc_campbell_essentials_3/0,11844,3107816-,00.html
Fats
Lipids
This diverse group of molecules includes?
Fatty acids
(energy storage, cushioning, insulation)
A biological compound consisting of three
fatty acids linked to one glycerol molecule
Steroids
(cholesterol, in membranes)
Characterized by a carbon skeleton consisting
of four rings with various functional groups
attached
Fatty Acids
Technically called?
triglycerides
A fat molecule:
Glycerol
‘saturated’
‘unsaturated’
Double bond
‘unsaturated”
3 Fatty
acids
Unsaturated fatty acids (plant oils)
Have less than the maximum
number of hydrogens bonded to the
carbons
Saturated fatty acids
(butter)
Have the maximum number of
hydrogens bonded to the
carbons
Double Bonds
What is the significance of the number of
double bonds in the hydrocarbon tails?
• Unsaturated fats tend to be liquids at room temperature
Example? vegetable oils
Impact on health? unsaturated fats are safer
• Saturated fats are solid at room temperature
Example?
butter and lard
Impact on health?
Saturated fats in the diet can lead to heart disease
Steroids
How does the structure differ from fatty acids?
Ring structure, various functional groups
How does the function differ from fatty acids?
Functional groups affect function
Example? • causes differences between
the hormones estrogen and
testosterone
(anatomical and physical development)
• cholesterol in membranes
Biological
Macromolecule:
Function:
Lipids
• Long term energy
storage
• Hormones
Monomer:
Examples:
• Fats, oils (triglycerides)
(butter, lard, margarine, salad ols)
• Steroids (lipid rings)
(cholesterol, hormones)
Proteins
What is a protein?
• A three-dimensional biological
polymer
• Constructed from a set of 20 different
monomers
• Monomers are amino acids
Activity: Protein Functions
Activity: Protein Structure
http://wps.aw.com/bc_campbell_essentials_3/0,11844,3107816-,00.html
Activity: Protein Functions
Activity: Protein Structure
http://wps.aw.com/bc_campbell_essentials_3/0,11844,3107816-,00.html
Structural Proteins
Receptor Proteins
Storage Proteins
Enzymes
Contractile Proteins
Signal Proteins
Transport Proteins
Sensory Proteins
Defensive Proteins
Gene Regulatory
Proteins
Structure, Function
Storage
Contractile
Transport
Defense
Receptor
Enzymes
Signal
Sensory
Gene regulatory
Structural
1. Hair, silk of spiders
2. Antibodies
3. Detect environmental changes
4. Change rate of a reaction
5. Control genes
6. Cell communication
7. Trigger changes inside cell
8. Carry molecules from place to place
9. Stockpile building materials
10. Can move parts of a cell or animal
The Monomers
What does each amino acid monomer
consist of?
A central carbon
atom
Bonded to four
covalent partners
Each side group is
unique
Amino
group
Carboxyl
group
Identifies each amino
acid’s characteristics
Examples of 2 different amino acids and their side groups
Structure
Proteins are complex!
To simplify, we’ll describe them in
terms of 4 levels of structure:
Primary
– a particular # and sequence of
amino acids
Secondary
– turns and folds, alpha helix,
pleated sheet
Tertiary
– irregular loops and folds, 3-D shape
Quaternary
– 2 or more polypeptides combined
What do they look like?
Quaternary structure
Tertiary
structure
Secondary
structure
Primary
structure
Biological
Macromolecule:
Proteins
Monomer:
Function:
• Many!
• Change rate of reaction
• Carry molecules
• Cell communication
Amino
group
Carboxyl
group
Examples:
• Enzyme
(lactase)
• Transport (hemoglobin)
• Defense (antibodies)
= 20 amino acids
Nucleic Acids
What are nucleic acids?
The cells information storage
molecules
• There are two types of nucleic acids
DNA, deoxyribonucleic acid
RNA, ribonucleic acid
• These ‘work together’ to synthesize protein
Activity: Nucleic Acid Functions
Synthesizing Protein
What does DNA do?
It carries instructions for building all the proteins
What does DNA do?
Information in DNA is transcribed into RNA
What does RNA do?
RNA acts as an intermediary in
the protein-making process
DNA
RNA
Protein
What else does RNA do?
RNA then translates the (transcribed) information
into the primary structure of proteins
What is the primary structure of proteins?
What does protein do?
Proteins carry out cell activities
Structure
What is the structure of nucleic acids?
They are polymers of nucleotides
What do the nucleotides contain?
Phosphate
group
Nitrogen
base
Sugar
(Deoxyribose)
What do DNA nucleotides contain?
Each DNA nucleotide has one of the
following bases:
2
1
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
4
Which one is which?
Match the numbers to the base
3
Polymers of nucleotides
Linked into long chains
Nucleotide
Called polynucleotides or
DNA strands
A sugar-phosphate backbone
joins them together
Activity: Nucleic Acid Structure
Bases
2 DNA strands
form helix
How does this happen?
Via complementary binding
(and hydrogen bonding)
A always binds with T
C always binds with G
RNA, different from DNA
It has the base uracil (U)
instead of thymine (T) in
DNA
The RNA sugar has 2 OH groups vs 1 in DNA
(Ribose vs deoxyribose)
Biological
Macromolecule:
Nucleic Acids
Monomer:
Function:
• Information
storage
Phosphate
Examples:
• DNA
• RNA
Sugar
Base
Could this be a
monomer for RNA?
Chapter 3: The Molecules of Life
Activities Quiz
http://wps.aw.com/bc_campbell_essentials_3/0,11844,3107816-,00.html
Which of these is a source of lactose?
Sugar beets milk
potatoes sugar cane
starch
If a DNA double helix is 100 nucleotide pairs long and
contains 25 adenine bases, how many guanine bases
does it contain?
25,
150,
75,
50,
200
Which of these is a polysaccharide?
Sucrose, glucose, galactose, lactose, cellulose
Defensive proteins are manufactured by the _____
system.
Immune, nervous, digestive, integumentary, cardiovascular
Which of these illustrates the secondary structure
of a protein?
A
B
C
D
E
Matching:
vocabulary definitions
RNA
Gene
Polymer
Protein
Double helix
Amino acid
Nucleotides
Polypeptide
DNA
_____
1. A double-stranded, helical nucleic acid
molecule capable of replicating and determining the
inherited structure of a cell’s proteins.
_____
2. A type of nucleic acid consisting of nucleotide
monomers with a ribose sugar and the nitrogenous
bases adenine (A), cytosine (C), guanine (G), and
uracil (U); usually single-stranded; functions in
protein synthesis and as the genome of some viruses.
_____
3. An organic molecule possessing both carboxyl and
amino groups. Amino acids serve as the monomers
of proteins
_____
4. The building block of a nucleic acid, consisting of a
five-carbon sugar covalently bonded to a
nitrogenous base and a phosphate group
_____
_____
5. A three-dimensional biological polymer constructed
from a set of 20 different monomers called amino
acids
6. A polymer (chain) of many amino acids linked
together by peptide bonds
_____
7. A long molecule consisting of many similar or
identical monomers linked together
_____
8. The form of native DNA, referring to its two adjacent
polynucleotide strands wound into a spiral shape.
_____
9. A discrete unit of hereditary information consisting of
a specific nucleotide sequence in DNA (or RNA, in
some viruses).