Lesson Overview
2.3 Carbon Compounds
Organic and inorganic compounds
Organic
• Carbon-carbon bonds
• With Hydrogen
• LARGE, COMPLEX
– Ex. Nutrients
• Made in living things
4 Main life molecules
•
•
•
•
Carbohydrates
Lipids (fats)
Nucleic acids (DNA)
proteins
Inorganic
• Might have carbon, but NO
– Hydrogen
– Carbon-carbon bonds
– Ex. CO2 CaCO3
• Small, few atoms
• Some are in living things
Inorganics needed for life:
• Water
• Minerals, salts
Vitamins are organic,
need in small amounts
The Carbon Atom
What makes carbon so special?
Atomic number _____ valence electrons ____
How many bonds form?
Carbon-carbon bonds  big, complex structures
Carbon can make large molecules
Organic – compounds with at least one carbon atom,
and always with hydrogen
Carbon can form large, complex structures
• Carbon-carbon bonds
• chains, branches, rings
Macromolecules
Are large molecules (macro)
made of smaller units
• Form by linking smaller molecules
(monomers) together in chains
• polymer – long chain of monomers
• Chemical process is polymerization
• Chemical reaction is dehydration
synthesis (or condensation)
• All organisms use the SAME
MONOMERS!!!
How do monomers link together?
DEHYDRATION SYNTHESIS (Condensation) reaction
“Put together” by “removing water”
Cells synthesize large molecules by linking small
molecules together
• Each link removes one water molecule
** need enzymes, special molecules that help in all
chemical reactions in a cell**
LE 3-3a
How do monomers link together?
Short polymer
Unlinked monomer
Dehydration
reaction
Longer polymer
New bond formed
How do large molecules break apart?
Hydrolysis reaction
(Hydro – water; lysis = break)
1. ADD a water molecule – breaks a linking bond
2. Water separates into H atom and OH group
3. These atoms bond to the smaller molecules that form
where the link breaks
4. Result  two separate smaller molecules
**Enzymes needed**
• Ex. Lactose intolerance -- lactase enzyme does not break down
lactose sugar
• Many enzyme names end in -ase
LE 3-3b
How do large molecules break apart?
Water molecule
is added
Hydrolysis
reaction
Breaks linking bond
Carbohydrates
SUGARS, STARCHES, FIBER
• Elements: CARBON, HYDROGEN, OXYGEN (2H : 1O)
• Functions: mostly for ENERGY ; some for STRUCTURE
Monomer: SIMPLE SUGAR or MONOSACCHARIDE
•
Carbon chain with –OH groups
• Can be chain or ring shape
- more stable as a ring
• Ex. Glucose is a simple sugar
Monosaccharides
• Some function alone
• Some combine to make larger molecules
• most common size: 5-6 carbons in chain
CARBS – MAIN SOURCE OF ENERGY FOR
ALL ORGANISMS
GLUCOSE C6 H12 O6
• energy molecule for ALL organisms
• Molecule used in cell respiration to make energy
• Monomer for all complex carbs
STARCH is a large polymer made of glucose
Some shortcuts for drawing organic
molecules
Isomers of glucose
C6H12O6 is also the formula for two other sugars,
FRUCTOSE and GALACTOSE
same atoms, but different sugar  different structure
ISOMERS: molecules with the same formula but different shape
– Different shape  have different properties
–
**DON’T confuse
isomer and isotope.
They are two
different things!!
Important Monosaccharides
ISOMERS: All have the same molecular formula C6H12O6
but different structural formula
1. glucose – #1 energy for all organisms
• Broken down for energy in cellular respiration
• Building unit for all complex carbs, ex. starch
2. fructose – found in fruits, honey, syrup
• Has the sweetest taste
3. galactose – part of lactose, the sugar in milk
Disaccharides – double sugars
Cells link two single sugars to form disaccharides
• dehydration synthesis
• For short-term stored energy
Glucose
Maltose
Animation:
Disaccharides
Many carb names
end
in -ose
Glucose
Important disaccharides
• Sucrose:
glucose + fructose
– “table sugar”
– in plant sap
– We get it from sugar beets and sugar cane
• Lactose:
in milk
• Maltose :
• In seeds, stored food for embryonic plant
• Animals make it when they digest
complex carbs like starch
LE 3-7
Polysaccharides = complex carbs
Starch granules in
potato tuber cells
Glycogen
granules in
muscle
tissues
Cellulose fibrils in
a plant cell wall
Cellulose
molecules
• Polymers of glucose
• Link by dehydration synthesis
• Long-term stored energy, or structure
STARCH
Glucose
monomer
GLYCOGEN
CELLULOSE
Storage polysaccharides
Starch – storage form of carbs in plants
•
•
Stored in seeds, roots, special cell parts
Foods: vegetables, fruits, grains
Glycogen – storage form of carbs
in animals
• In liver and muscle cells
• If glucose levels in blood drop, glycogen
is changed into glucose
Starch
granules
Structure polysaccharide- Cellulose
• structure and support in plants
• in cell walls, wood, paper, cotton, fabrics
• Strong and flexible: linked parallel chains
Cellulose
makes plant
cell walls
Lipids – fats, oils, and waxes
Elements: carbon, hydrogen, oxygen
(less O than in carbs)
Functions: stores concentrated energy
– Long-term storage
– 9 cal/g
• more than 2X calories of carbs (4 cal/g)
Nonpolar (no +/- areas) do NOT dissolve in water
hydrophobic – “stay away from water”
Other Lipids Functions
1. Cell parts, especially membranes
2. Waterproof coverings (ex. fruits, leaves,
feathers)
3. Some hormones (chemical messengers)
4. Transport fat-soluble vitamins (needed in
chemical reactions)
5. Insulates (stores heat); padding,
6. Protection – padding, especially around vital
organs
7. Lubricates smooth movement in joints
Two lipid monomers
1) Glycerol
- 3 carbon chain
- each carbon has OH (hydroxyl group)
2) Fatty Acid
- Hydrocarbon chain
- has carboxyl group on one end - COOH
* C-H nonpolar covalent bonds
Lipid monomers join by
dehydration synthesis
-OH group on each molecule
is site for linking bond
- Each link makes one water
molecule
Triglyceride – common FAT molecule
One glycerol +
three fatty acids
(3 dehydration reactions)
- makes 3 water molecules
Notice the double bond 
Molecule bends at this point
Make a triglyceride – dehydration synthesis
To Break Down a Fat
3 hydrolysis reactions
• Uses 3 water molecules
Saturated and Unsaturated Fats
Saturated fatty acids
– “saturated” with hydrogen atoms
– All carbon-carbon bonds are single
– Solid at room temp, mostly animal fats
• Except: coconut and palm oils
– Health hazard  increases cholesterol in blood
Unsaturated Fats
Have one or more Unsaturated fatty acids
• One or more double bonds between carbons
• Liquid at room temp, most plant oils, fish (omega- 3)
• Healthier for humans – less cholesterol forms
Monounsaturated
Polyunsaturated
Saturated fats pack tightly
 solid at room temperature
Unsaturated fats pack loosely
 liquid at room temperature
What are “trans fats”?
1. Hydrogen is added to unsaturated fats
a. “hydrogenated vegetable oil”
b. Makes them more saturated
2. In processed foods, baked goods
3. For texture and taste, longer shelf life
4. Can’t digest  raises cholesterol
- higher risk of heart disease, diabetes
Food labels list types of carbs and fats
Cholesterol and steroids A different type of lipid
Carbon backbone is four joined carbon rings
• various chemical groups attached to carbon rings
--> Causes different properties
cholesterol
Cholesterol – an important steroid
• Makes up part of animal cell membranes
• Raw material for other molecules
– steroid hormones
– cortisone and other anti-inflammatories
Other Steroid molecules
All have backbone of 4 joined carbon rings
Estrogen
Testosterone
Why is Cholesterol bad?
WHERE DOES IT COME FROM?
 we make it in our liver
 we eat it in animal products
WHY IS TOO MUCH OF IT UNHEALTHY?
 If we eat more than we use, excess circulates in the blood
 Forms a soft, waxy substance called plaque
 ATHEROSCLEROSIS – fatty deposits inside blood vessels
Clogs blood vessels – blocks flow of blood
Inside a blood vessel
-fatty plaque reduces space
Heart Disease
Coronary arteries supply
blood to heart muscle
Fatty plaques build up inside artery – decreases space for blood to flow
Tissues don’t get enough blood ” heart attack”
Angioplasty – a treatment for clogged
blood vessels
Catheter inside
artery, guided to
site of blockage
Balloon inflated
then removed;
mesh stent
remains
Bypass surgery – detour around
clogged blood vessels
Restores blood flow to heart muscle
Phospholipids and waxes
Phospholipids
• Two fatty acids and phosphorus
• Main component of cell membranes
Waxes
• a single fatty acid linked to an alcohol
• Form waterproof coatings
Proteins
Elements: carbon, hydrogen, oxygen, nitrogen
(sometimes sulfur)
Monomer: amino acids
3 parts: 1) amino group (NH2)
2) carboxyl group (COOH)
3) side chain (R group)
20 different R groups
Parts of an amino acid
20 different R groups
- make 20 different amino acids
Making a protein polymer
Polymer = polypeptide
Polymer: - link
polypeptide
- formsacids
by linking
amino
acids
many amino
 long,
long
chains
 Uses dehydration synthesis
- Dehydration
synthesis
Each bond makes one water molecule
- Each bond makes a water molecule
 Special type of covalent bond – peptide bond
Peptide
bond = between amino acids
Peptide bond
Functions of Proteins
1. structure – many cell parts
2. control chemical reactions (enzymes)
3. transport substances (ex. Hemoglobin)
4. fight disease (antibodies)
5. chemical messengers
6. movement (muscles)
Levels of Organization in Proteins
A protein's shape determines its function
• Made of one or more polypeptide chains
folded into a unique shape
• “Form follows function”
• Must be a specific shape to act on another
molecule
Primary structure
Primary structure: the sequence of amino acids
– assembled in ribosomes
Amino acids
Sequence is coded in DNA
More Complex Structure
Coiling or folding in parts of the
polypeptide chain
• Chain folds into a 3-D shape
– Depends on side groups that
interact
• Two or more polypeptides can be
folded together
• Hydrogen bonds connect different
areas on the molecule
What is a “protein”?
• One or more polypeptides folded into a
specific, functional 3-dimensional shape
Collagen – in skin, joints
hemoglobin – carries oxygen
in the blood
How important is protein shape?
Normal hemoglobin
– in red blood cells, carries oxygen
Sickle Cell Disease
– abnormal shape of hemoglobin
- carries less oxygen  cell stress
 wrinkles  clogs tiny blood vessels
Sickled and normal red blood cell
Scanning Electron Microscope
Sickled red blood cells
Light microscope
Protein Denaturation
Denature – lose shape (and function)
Chemical or physical changes
- break bonds that hold the 3-D shape
Denaturation can be caused by changes in ion
concentration, pH, temperature, and others
Nucleic Acids
Elements: Carbon, Hydrogen, Oxygen,
Nitrogen and Phosphorus
Function: DNA – stores genetic & cell instructions
RNA – uses DNA instructions to make proteins
Monomer: nucleotide
3 parts: 5-carbon sugar
phosphate group
nitrogen base
LE 3-16a
Parts of a
nucleotide
Nitrogenous
base
Phosphate
group
5-carbon Sugar
Bases:
A – adenine
T – thymine
C – cytosine
G – guanine
U - uracil
LE 3-16b
Nucleic Acid is a nucleotide polymer
Nucleotide
DNA - Polynucleotide
sugar-phosphate backbone
nitrogen bases bond to sugars
Sugar-phosphate
backbone
DNA is two polymers of nucleotides
Structure:
- Deoxyribose sugar
- Hydrogen bonds hold two
polymer chains together at
A-T and C-G
Function:
- Base sequence on one chain
is a “gene”
- Genes direct the amino acid
sequence in a protein
- One molecule of DNA holds
thousands of genes
RNA is a single polymer chain
Structure: RNA – ribose sugar
Bases: A, C, G, and Uracil
Function: Carries a single gene
Uses the gene to make a protein
ALL ORGANISMS USE THE SAME GENETIC CODE
LE 3-16c
Base
pair
Energy in Chemical Reactions
• Life processes are chemical
• Need energy added
(ACTIVATION ENERGY) to
start reactions
• Cells cannot use or make
heat
• ENZYMES speed up reactions
– lower activation energy
Enzyme-substrate complex
• Substrate – molecule an enzyme acts upon
• Active site – region on enzyme molecule that binds to
substrate molecule - must fit together!!
Active site
substrate
How enzymes work
Enzymes are “biologic catalysts”
catalyst - speeds reaction but is not changed or used up
enzymes are specific – act on only one kind of molecule
Two models for enzyme action:
Induced fit – shape of enzyme
changes when substrate attaches
Lock-and-key model – perfect fit,
no shape change
Name – for chemical process or
substrate; often end in -ase
An anabolic reaction
Enzymes catalyze all reactions
A catabolic reaction
Factors Affecting Enzyme Action
3-dimensional protein molecule - shape is critical
Temperature - heat makes molecules move faster
 more contact between enzyme and substrate
 faster reaction rate
BUT, high temps denature proteins!
Enzymes and pH
Work best at a specific pH
- changes in pH break bonds holding molecule shape
Enzyme activity and concentration
More enzyme or more substrate  increase reaction rate
- BUT, only up to a point
• limiting reactant – all molecules being used
Enzyme Inhibitors
Competitive inhibitors
- bind to active site
- block substrate
Noncompetitive inhibitors
- change shape of active
site by binding somewhere
else on the enzyme
Feedback inhibitors
- a product made in the
reaction binds to the
enzyme, stops reaction