Transcript Molecules of Life Powerpoint

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?
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
Methane
Is a hydrocarbon
What is a hydrocarbon?
………..
Carbon
& Hydrogen
Methane is the simplest
Functional Groups
• Groups of atoms known as functional
groups can give special properties on
carbon-based molecules.
• Carbon is a central element to life because
most biological molecules are built on a
carbon framework.
Functional Groups
• For example, the addition of an –OH group
to a hydrocarbon molecule always results
in the formation of an alcohol.
Functional Groups
Making Polymers
Dehydration* Reaction - links
molecules together
• A covalent bond forms between
molecules and water is removed
•
Reaction by which monomers are joined to form
larger molecules
• Examples:
•
*Also called a condensation reaction
Breaking Polymers
Hydrolysis reaction – breaks down
larger molecules
• Water is added to a larger molecule to
split off a smaller molecule.
• Reaction involves breaking a covalent
bond by adding water
• Reverse of a dehydration reaction
Biological Molecules
‘Carbs’
Sugar
Glucose
Glycogen
Cellulose
Oils
Fatty acids
(sat & unsat)
Butter
Food
Structural
Storage
Enzymes
Antibodies
DNA
RNA
Carbohydrates
• Carbohydrates are formed from the
building blocks or monomers of simple
sugars, such as glucose.
• These monomers can be linked to form
larger carbohydrate polymers, which are
known as polysaccharides or complex
carbohydrates.
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
Form rings in aqueous
solutions
Which sugar is this? Glucose
Disaccharides
Are ‘double sugars’
What are they
constructed from?
2 monosaccharides
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
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
Complex Carbohydrates
• Four polysaccharides are critical in the
living world:
– starch
– glycogen
– cellulose
– chitin
Four Complex Carbohydrates
(a) Potato
(b) Liver
(c) Algae
(d) Tick
Starch
Glycogen
Cellulose
Chitin
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)
1. Starch is the nutrient storage form of
carbohydrates in plants.
2. Glycogen is the nutrient storage form of
carbohydrates in animals.
Lipids
Butter, lard, margarine, and salad oil
Do these lipids mix well with water?
Lipids do not possess the monomers-to-polymers structure
seen in other biological molecules; no one structural element
is common to all lipids.
Among the most important lipids are the triglycerides,
composed of a glyceride and three fatty acids.
Most of the fats that human beings consume are triglycerides.
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
Steroids
(a) Four-ring steroid structure
(b) Side chains make each steroid unique
testosterone
estrogen
cholesterol
Phospholipids
• A third class of lipids is the
phospholipids, each of which is
composed of two fatty acids, glycerol, and
a phosphate group.
• The material forming the outer membrane
of cells is largely composed of
phospholipids.
Waxes
• A fourth class of lipids is the waxes, each
of which is composed of a single fatty acid
linked to a long-chain alcohol.
• Waxes have an important “sealing”
function in the living world.
• Almost all plant surfaces exposed to air,
for example, have a protective covering
made largely of wax.
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?
Proteins are an extremely diverse group of
biological molecules composed of the monomers
called amino acids.
• Constructed from a set of 20 different
monomers
Proteins
• Sequences of amino acids are strung
together to produce polypeptide chains,
which then fold up into working proteins.
• Important groups of proteins include
enzymes, which hasten chemical
reactions, and structural proteins, which
make up such structures as hair.
Types of Protein
The Monomers
What does each amino acid monomer
consist of?
Amino
group
A central carbon
atom
Bonded to four
covalent partners
Each side group is
unique
Carboxyl
group
Identifies each amino
acid’s characteristics
Examples of 2 different amino acids and their side groups
Beginnings of a Protein
The linkage of several amino acids . . .
ala
gln
ala
gln
ile
ile
. . . produces a polypeptide chain like this:
A typical protein would
consist of hundreds of
amino acids
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
Levels of Protein
Structure
Four Levels of Structure In Proteins
(a) Primary structure
The primary structure of any
protein is simply its sequence
of amino acids. This sequence
determines everything else
about the protein’s final shape.
(b) Secondary structure
Structural motifs, such as
the corkscrew-like alpha
helix, beta pleated sheets,
and the less organized
“random coils” are parts
beta pleated sheet
of many polypeptide
chains, forming their
secondary structure.
(c) Tertiary structure
These motifs may persist
through a set of larger-scale
turns that make up the
tertiary structure of the
molecule
(d) Quaternary structure
Several polypeptide chains
may be linked together in a
given protein, in this case
hemoglobin, with their
configuration forming its
quaternary structure.
amino acid sequence
alpha helix
random coil
folded polypeptide
chain
two or more
polypeptide chains
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
Biological Molecules
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
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?