Organic Molecules of Life Organic molecules : are compounds created by living organisms contain the elements carbon and hydrogen Carbon atoms: need four electrons to fill their outer.
Download
Report
Transcript Organic Molecules of Life Organic molecules : are compounds created by living organisms contain the elements carbon and hydrogen Carbon atoms: need four electrons to fill their outer.
Organic Molecules of Life
Organic molecules :
are
compounds created by
living organisms
contain
the elements
carbon and hydrogen
Carbon atoms:
need four electrons to fill their
outer electron shell
Must form four bonds with
other elements.
6P
6N
These are covalent bonds.
Most often bond with
Hydrogen, Oxygen, Nitrogen,
Phosphorus, Sulfur, and other
Carbon atoms
These can include:
Single bonds
(one electron shared)
Double bonds
(two electrons shared)
Or triple bonds
(three electrons shared)
Carbon Atoms:
Can bond with other atoms of carbon to form long chains
These chains can be:
Straight
Branched
Rings
Isomers
Molecules with the
same formula
Atoms are arranged
differently
Carbons are
branched in various
ways
Functional groups:
Are
special groups of atoms that
stay together and act as a single
unit
can bond with the carbon chains
determine how the entire
molecule will react.
The functional groups
you need to know are:
Hydroxyl Group
•one oxygen
and one
hydrogen
• usually
written as
-OH
Oxygen
Hydrogen
Carboxyl Group
one carbon with a
double bond to an
oxygen AND a single
bond to a hydroxyl
group
usually written as
COOH or
O=C–OH
Creates an organic
acid (carboxylic)
Oxygen
Carbon
Oxygen
Hydrogen
Amino Group
one
nitrogen
bonded to two
hydrogen
usually written
as NH2 or
H–N–H
Hydrogen
Nitrogen
Hydrogen
Phosphate Group:
One phosphorus bonded to two hydroxyl
groups, and two other oxygens (one has a
double bond)
Usually written as –P or
OH
O
P
OH
O
Phosphorus
Biological
molecules
can be
made up of
thousands
of atoms
These large molecules
are built from basic
units called
monomers
.
One monomer
The monomers are linked
together to form the large
molecules called
polymers.
Polymer – chain of
repeating monomer units
Making and Breaking Polymer
Bonds
Monomers
When two
monomers are
put together to
form larger
molecules, a
water molecule
is created.
Polymer
This process is called:
Dehydration Synthesis.
(Dehydration means to lose water
Synthesis means to build or put
things together)
When
polymers
are broken
apart, it is
done by
adding a
water
molecule.
This is called
Hydrolysis
(hydro- for water,
-lysis for breaking apart)
Types of Organic Molecules
There are four categories of organic
molecules in organisms:
Carbohydrates
Lipids
Proteins
Nucleic acids
Carbohydrates
What are Carbohydrates?
Organic compounds
Commonly called starches and
sugars
Used as:
An energy source
Energy storage
Cellular structures
Chemical Composition
Contains only three elements:
Carbon
Hydrogen
Oxygen
Ratio of hydrogen to oxygen is 2:1
(just like water)
Example: C6H12O6
Basic Unit is called a saccharide
Types of Carbohydrates
Monosaccharides
Simple,
single (mono-) sugar unit
Building block of all other
carbohydrates
Name usually ends in –ose
Used as energy source
Examples of Monosaccharides
Glucose – blood sugar
Fructose – fruit sugar
Galactose – one monomer in lactose (milk)
Isomers of C6H12O6
Examples of Monosaccharides
Ribose and Deoxyribose
5 - Carbon sugars in RNA and DNA
Types of Carbohydrates
Disaccharides
Double sugar units
synthesized from
monosaccharides
All are isomers of
C12H22O11
Formed by
dehydration
synthesis (requires
enzymes)
Examples of Disaccharides
Sucrose – table sugar
Glucose + Fructose
Maltose – seed sugar
Glucose + Glucose
Lactose – milk sugar
Glucose + Galactose
Types of Carbohydrates
Polysaccharides
Large, complex chains of many (poly-)
repeating sugar units
Polymers
Bonded together by dehydration synthesis
Used by living things as a sugar storage or for
structures
Examples of Polysaccharides
Amylose – plant starch
Glycogen – animal starch
Used as sugar storage by humans in the liver
Cellulose
Used as sugar storage in seeds, roots, stems
Very tough polymer
Used as a main component of cell walls
Indigestible by humans
Chitin
Very tough polymer
Used in exoskeletons (crab shells, insects)
Digesting Polysaccharides
Broken apart by
hydrolysis with the
help of enzymes
Lipids
What are Lipids?
Three elements: Carbon Hydrogen Oxygen
Ratio of H:O much greater than 2:1
Example: Oleic acid C18H34O3
Insoluble in water
Greasy, slippery texture
Three main groups:
Fats oils and waxes
At room temperature: Liquid – oils/Solid – fats and waxes
Phospholipids
Steroids
What are the Functions of Lipids?
Fats, Oils and Waxes:
Long term energy storage
More than twice as much energy stored than
carbohydrates
In plants: stored in and around seeds
fats- 9 Calories/gram; carbohydrates- 4 Cal/g
Peanut oil, corn oil, olive oil
In animals: stored under the skin and around
internal organs
Used as insulation and shock absorber
What are the Functions of Lipids?
Phospholipids
Structural Part of Cell membranes
Steroids
Part of cell membranes, transport of lipids,
regulate body functions (hormones)
Chemical Composition
Fats Oils, Waxes
Fatty Acid
One or more fatty acids
attached to a Glycerol
backbone
Glycerol
Fatty Acids: Long chains
of carbon with a carboxyl
group at the end
Glycerol: C3H8O3
Formed by dehydration
synthesis
NOT a polymer
Glycerol
Lipid
Formation of a Triglyceride:
Types of Fats
Saturated
All carbons of the fatty acid have single bonds
All carbons are “filled” with hydrogen
Solid at room temperature
Associated with heart disease risk
Examples: Bacon grease, butter
Types of Fats
Unsaturated
Carbons share one or more double or triple bonds
with other carbons
Monounsaturated – only one double bond
Polyunsaturated – many double or triple bonds
Liquid at room temperature
Examples: corn oil, olive oil
Phospholipids
Phosphate
group replaces
fatty acid on
one end
Used as the
main
component of
cellular
membranes
Steroids: Four Fused Rings
lipids with four fused
hydrocarbon rings
Includes:
Cholesterol - found in animal
cell membranes
Testosterone, estrogen,
progesterone - sex hormones
Vitamin D
An anabolic steroid is a
synthetic testosterone.
Proteins
Protein Functions
Structural parts
cell membrane, muscles, hair, nails, pigments
Regulators
Hormones, enzymes
Carriers
Transport materials in, out and around cells
Identification
Allow cells to recognize each other
Immune system antibodies
Composition of Proteins
Elements:
Very large, complex
carbon, hydrogen, oxygen and NITROGEN
Hemoglobin: C3032H4816O872N780S8Fe4
Monomers (building blocks) are amino
acids
20 common amino acids
9
are essential 11 are non essential
Amino Acids
The R group
is different for
each of the
twenty amino
acids
Peptide Bonds
•Chains of amino acids are
called peptides
•Amino acids are joined by
dehydration synthesis
•This occurs between the
carboxyl end of one amino
acid and the amino end of
another amino acid.
•The resulting bond is called
a Peptide bond
Primary Structure
The sequence of
amino acids in a
protein is called the
Primary Structure
The sequence is
unique for each
protein and is
determined by the
DNA
Secondary Structure
Hydrogen bonds are
formed between the
chains of amino acids
causing different
shapes.
Secondary Structure
Two shapes are common –
a helix and a sheet.
Sheet and Helix
Tertiary Structure
The 3-D
arrangement of the
molecule caused
by weak bonds
between the R
groups
The most important
structure format
Determines the
function of the
protein
Quaternary Structure
More than one protein
molecule can
combine to create a
macromolecule
This is the quaternary
structure of the
protein
This creates either
globular (hemoglobin)
or fibrous (collagen)
proteins
Nucleic Acids
Nucleic Acids are:
The largest molecules in living things
The DNA of humans has about 6 billion
monomers
Some reptiles have 20 times more units
The largest DNA known is a flower with 5
trillion units
The two most important
Nucleic Acids:
DNA (deoxyribonucleic
RNA (ribonucleic
acid)
acid)
Functions of Nucleic Acids
DNA
make up chromosomes and their genes that
carry hereditary information
found in the nucleus, mitochondria and
chloroplasts (plants)
RNA
functions in the synthesis of proteins for the cell
found in cell parts: nucleoli, ribosomes, and
throughout the cytoplasm
General Structure of
Nucleic Acids
Polymers,
with many repeating units
called nucleotides
Nucleotides have three subunits:
Phosphate
group
a five carbon sugar
a phosphate group
a nitrogenous base
(a base that contains nitrogen)
Nitrogenous
Base
Five Carbon
Sugar
Structure of DNA
The sugar backbone is
deoxyribose
Structure of DNA
The base can be one of four:
Adenine
Guanine
Thymine
Cytosine
Structure of DNA
The bases pair up –
A (adenine)
always pairs with T
(thymine)
G
(guanine) always pairs with C
(cytosine)
Structure of DNA
Structure of DNA
Two polymer
chains of
nucleotides are
connected by
weak hydrogen
bonds and are
twisted into a
double helix
Structure of DNA
Sequence
of nitrogenous bases
codes for specific amino acids
Amino acid sequence
determines the protein made in
the cell and the cellular activity
Relationship Between Proteins
and Nucleic Acids
Structure of RNA
Ribose is its sugar backbone
Structure of RNA
The base can be one of four:
Adenine
Guanine
Cytosine
Uracil
Thymine is replaced by Uracil
Structure of RNA
Only a single polymer chain is
created in RNA, but strands of
RNA have complex, folded
structures that compliment their
function.
Enzymes
What are Enzymes?
Large, Complex Proteins
Function as Organic Catalysts
Allow reactions to occur at lower
temperatures ( 37° C)
Used temporarily
Unchanged by the reaction
Can be reused
Specific to one reaction
What are Enzymes?
Bind to reactants called substrates
Enzyme names usually end in –ase and
can be named for their substrate:
Protease – proteins
Lipase – lipids
Maltase – maltose
ATPase – ATP
Acetylcholinesterase - acetylcholine
How Do Enzymes Work?
Reduces energy needed to begin reaction
(Activation energy)
Without catalyst
With catalyst
Energy
Energy
Activation Energy
Time
Time
How Do Enzymes Work?
Lock and Key Model
Products
Substrate
Active Site
Enzyme
Substrate attaches to
enzyme at active site
Enzyme
Enzyme Substrate
Complex Formed
Enzyme
Reaction takes place and
products are released
How Do Enzymes Work?
Induced Fit Model
Substrate
Enzyme
Substrate attaches
to active site
Enzyme substrate
complex formed
Enzyme
Enzyme changes shape
to match substrate –
Stressed molecule may
help to weaken bonds
Product
Enzyme
Enzyme resumes
original shape after
product formed
How Do Enzymes Work?
Coenzymes sometimes needed
Non proteins – minerals, vitamins
Smaller molecules
Part of the enzyme structure or
work along side the enzyme
Enzyme and
substrate do
not match
Coenzyme
fills in needed
shape
Coenzyme
Denaturation:
If the shape changes, the enzyme cannot function properly
Factors Affecting Enzymes
Temperature
Enzyme activity
increases with
temperature
Optimum temperature
for each enzyme
Higher temperatures
denature (change the
shape) of the enzyme’s
active site
Rate of reaction
decreases quickly after
optimum temperature
Optimum
temperature
10
20
30
40
50
Factors Affecting Enzymes
pH
Enzymes are pH dependent
Some work at low pH (acid)
Some at high pH (basic)
Surrounding solutions will
activate or deactivate enzyme by
changing the shape of the active
site
Extremely high or low pH values
generally result in complete loss
of activity for most enzymes
pH for Optimum Activity
Enzyme
pH Optimum
Lipase (pancreas)
8.0
Lipase (stomach)
4.0 - 5.0
Lipase (castor oil)
4.7
Pepsin
1.5 - 1.6
Trypsin
7.8 - 8.7
Urease
7.0
Invertase
4.5
Maltase
6.1 - 6.8
Amylase
(pancreas)
6.7 - 7.0
Amylase (malt)
4.6 - 5.2
Catalase
7.0
Factors Affecting Enzymes
Concentration:
Increasing amount of enzyme:
rate
increases then levels off
substrate levels fall and reduces efficiency
Increasing amount of substrate:
rate
increases then levels off
enzyme is saturated and no additional reactions
can occur
Presence of Inhibitors
Bind to enzyme and change shape or
compete with the substrate