Transcript Carbohydrates & Begin Lipids

Unit #1
Biochemistry
The Chemistry of Life
Organic
Chemistry
Organic Compounds
• Organic compounds are
compounds that contain
carbon (with the exception
of CO2 and a few others).
Organic Compounds
• Carbon based molecules
Organic Compounds
• Make up most of living organisms
• Carbon can easily bond with up to 4
other elements
4 valence electrons =
4 covalent bonds
Can bond to 4 H
Carbon can form various bonds
• Single bond (ethane)
• C-C
• Double bond (ethene)
• C=C
• Triple bond (ethyne)
Organic Compounds
• Carbon atoms form the “backbone”
of long chains or rings
• Organic molecules can be extremely
large and complex; these are called
macromolecules (or polymers)
Ring structured
Functional Groups
• Various elements attach to the hydrocarbon
backbone to form different types of
compounds.
• These reactive clusters of atoms are called
functional groups.
• Elements include: H, O, S, N & P
Functional Groups
Hydroxyl group
• -OH
• Found in alcohols
• E.g. Ethanol
• Polar
Functional Groups
Carboxyl group
• -COOH
• Found in acids
• Polar
E.g. Vinegar
- acetic acid CH3COOH
Functional Groups
Amino group
• -NH2
• Found in bases
• E.g. Ammonia
Functional Groups
Sulfhydryl group
• -SH
• Often referred to as a thiol group
• Found in Rubber
- Thiols smell like
garlic and are often
added to natural gas
to provide a
detectable smell.
Functional Groups
Phosphate group
• -PO4
• Found in ATP
Functional Groups
Carbonyl group
• If this group is at the end, the compound is
called an aldehyde
• If it is found in the middle, it is called a
ketone
Functional Groups
Carbonyl group #1
The Aldehydes
• -COH
• E.g. Formaldehyde
Functional Groups
Carbonyl group #2
The Ketones
• -CO• E.g. acetone
Functional Groups
TEST YOUR KNOWLEDGE
• What functional groups are in this molecule?
Test Your Knowledge…
• Name the functional groups
Test Your Knowledge…
• Name the functional groups
Amino group
Carbonyl group
(Ketone)
Carboxyl group
Sulfhydryl group
Organic Compounds
The 4 main types of organic macromolecules:
Carbohydrates
Lipids
Proteins
Nucleic Acids
Making & Breaking Organic Compounds
Anabolic Reactions
Condensation Reactions (Dehydration synthesis Reaction)
• The removal of a –H from the functional group of one
unit and a –OH from another unit to form a water
molecule (H2O).
• Energy absorbed
Making & Breaking Organic Compounds
Catabolic Reactions
Hydrolysis Reactions
• A water molecule (H2O) is used to break a covalent bond
holding subunits together.
• A –H from is given to one unit and a –OH to the another
• Energy released
Enzymes
• Enzymes are biological catalysts.
• They speed up reactions without actually
being consumed in the reaction.
• They are needed for condensation &
hydrolysis reactions.
Enzyme Action Example:
Isomers
• Isomers are molecules that have the same
formula, but a different physical structure.
• Glucose (C6H12O6) and galactose
(C6H12O6) and fructose (C6H12O6) are
examples of isomers.
Isomers
• Because of their differing arrangement of
the atoms, they have different physical and
chemical properties.
• E.g. Carvone is a flavour compound that.
There are 2 isomers of carvone. One
makes things taste like spearmint the other
like caraway.
End Part I
Get ready for Carbohydrates!
Carbohydrates
• Main energy source for living things
• Breakdown of sugars supplies immediate
energy for cell activities
• Plants store extra sugar as complex
carbohydrates called starches
Carbohydrates
• The
most common organic material on Earth.
• The general formula is C : H : O
•Count the # of each atom
in the molecule shown here:
• In a ratio of 1 : 2 : 1
What are the functional groups on carbohydrates?
•
What are the functional groups on carbohydrates?
Their functional groups include:
1. Carbonyl group (an aldehyde or ketone)
2. Hydroxyl groups
Carbohydrates
•
There are 3 major classes:
- Monosaccharide,
- Oligosaccharide and
- Polysaccharide
Saccharide (means “Sugar” in Greek)
The names of carbohydrates end in “ose”.
Carbohydrates
• Single sugar molecules are called
monosaccharides
• Monosaccharides with 5 or more carbons
are linear in the dry state but form rings
when dissolved in water.
Monomer of Carbohydrates:
Monosaccharides
• Simple sugar
• It is the main source of energy in the body
• Eg. glucose – most common
galactose – milk sugar
fructose – fruit sugar
Carbohydrates
• Oligosaccharides are sugars containing 2
or 3 simple sugars attached to one another
by covalent bonds called glycosidic
linkages.
• Recognize the dehydration reaction?
Examples of Disaccharides
Examples of Disaccharides
• Sucrose = glucose + fructose
Table sugar
• Maltose = glucose + glucose
Sugar in beer
• Lactose = glucose + galactose
Sugar in milk
Carbohydrates
• Large molecules of many monosaccharide
are called polysaccharides
• Also known as complex carbohydrates.
Examples:
• glycogen – animals use it to store excess sugar
• starch – plants use to it store excess sugar
• cellulose – fibers that give plants their rigidity &
strength
• Chitin – exoskeleton & fungi
Polysaccharide: many sugars
• Some polysaccharides are straight, others
are branched.
Starch
• A storage molecule for plants.
• It is made of 2 polysaccharides:
– Amylose
– Amylopectin
The chains form
tight coils which
make them
insoluble in water.
Cellulose
• Cellulose molecules are not coiled or
branched.
• The chains form cross-linkages between
each other.
• The fibers intertwine to form microfibrils.
• Used to build cell walls.
Chitin
• Exoskeleton of insects & crabs
• The cell wall of fungi
• Chitin has uses in medicine:
– Contact lenses
– Biodegradable suture thread
Which is a monosaccharide?
A disaccharide? A polysaccharide?
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cellulose
chitin
glucose
glycogen
sucrose
starch
Which is a monosaccharide?
A disaccharide? A polysaccharide?
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Cellulose P
Chitin
P
Glucose M
Glycogen P
Sucrose D
Starch
P
End Part II
Get ready for Lipids!
Lipids:
• Store energy
• Build cell membranes (& other cell
parts)
• Act as chemical signals
Lipids:
Fall into 4 families of fats:
1. Fats
2. Phospholipids
3. Steroids
4. Waxes
Lipids:
• Contain carbon, hydrogen and oxygen
• Have fewer polar –OH bonds &
• More non-polar H-C bonds than
carbohydrates.
• Therefore, they are non-polar
• They are NOT soluble in water but they are
soluble in other non-polar substances.
Lipids:
• Fats store more energy than
carbohydrates or proteins.
• 1g fat = 38 kJ (9 Kilocalories)
• 1g carb = 17 kJ (4 Kilocalories)
• Calories are non-SI units of energy
• 1 cal = 4.18 kJ of energy
Lipids:
• Animals convert excess
carbohydrates into fats and store the
fat molecules as droplets in cells of
adipose (fat) tissue.
Lipids:
• Triacylglycerols (triglycerides) are the
most common fat in plants and
animals.
They are made
from a glycerol
backbone with 3
fatty acid chains
attached.
Lipids:
• Glycerol is a 3-carbon alcohol
containing a hydroxyl group attached
to each carbon.
Lipids:
• Fatty acids are long hydrocarbon chains containing
a single carboxyl group at one end.
• They are usually even numbered (16-18 carbons
long)
Lipids:
• Fatty acids can be saturated (meaning that all
carbons contain the maximum number of
hydrogen). These have no double bonds.
• Unsaturated fatty acids contain double or triple
bonds so they are missing hydrogen-carbon
bonds.
If they have many double/triple bonds they are called
polyunsaturated fatty acids.
Lipids:
Fatty acid shapes:
1. Saturated fatty acids have straight
chains that fit tightly together allowing
van der Waals attractions to form
along their length.
2. These cross attractions make them
solid at room temperature.
Lipids:
Fatty acid shapes:
1. Unsaturated fatty acids
have kinked chains that do
not fit tightly so van der
Waals attractions do not
form.
2. Without the van der Waal
attractions they are liquid
at room temperature.
E.g. vegetable oils, fish
oil, nut oils, etc.
Lipids:
Hydrogenation:
is a process that adds hydrogen to the double bond
areas “saturating” the fatty acid.
This converts oils, like canola and corn oil into semisolid fats known as margarine or shortening.
How to make a lipid
1. Link a glycerol unit and fatty acid chains…
2. A dehydration reaction takes place between the
hydroxyl groups on the glycerol and the carboxyl
group of the fatty acid. Three waters are removed.
3. The bond that results is called an ester linkage.
4. The process is known as esterification.
Phospholipids:
1. Form the majority of cell membranes.
2. They contains:
a)
b)
c)
d)
Glycerol molecule (backbone)
2 fatty acids (non-polar tails)
Phosphate group (highly polar head region)
Choline (nitrogen compound, part of the head)
Phospholipids:
1. Have a hydrophilic head (water-loving)
2. Have a hydrophobic tail (water-fearing)
Phospholipids:
When added to
water, the
phospholipids will
rearrange themselves
into balls called a
micelles so that the
tails all face inward
and the heads face
outward.
Phospholipids: Cell Membrane
1. The hydrophobic middle of the cell membranes do not
allow polar or charged molecules to pass through.
2. Membranes need channel pores to allow them through.
Sterols (Steroids)
1. Made from 4 fused hydrocarbon rings + numerous
functional groups.
2. Examples:
A.
B.
C.
D.
Cholesterol
Testosterone
Estrogen
Progesterone
3. Cholesterol in animal cell membranes helps to stabilize
the structure.
4. Too much cholesterol in our diets causes deposits in our
blood vessels
Sterols: Cholesterol
1. Cholesterol in animal cell membranes helps to stabilize
the bilayer structure.
2. Too much cholesterol in our diets causes deposits of fatty
acids (called plaques) to build up in in our blood vessels.
3. This condition is known as atherosclerosis.
4. When blood vessels become blocked we can suffer from:
A. Stroke (blockage in the brain)
B. Heart attack (blockage to arteries in the heart)
Cholesterol & Sex Hormones
1. Cholesterol gets converted into vitamin D (needed for
healthy bones and teeth) and bile salts (needed for the
digestion of fats)
2. Sex hormones (testosterone, estrogen and progesterone)
control the development of sex traits and sex cells (eggs
& sperm)
Waxes
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•
•
•
Waxes are long-chain fatty acids linked to alcohols or
carbon rings.
The hydrophobic molecules are firm and pliable.
Their structure makes them ideal for making waterproof
coatings on plant and animal parts.
Cutin is a wax produced by plant cells to coat the stem,
leaves and fruit.
– This helps hold water in and keep infections out!
Birds produce a waxy substance to waterproof their
feathers.
Bees produce a wax that they use to make their
honey.combs
Waxes
•
•
•
Waxes are long-chain fatty acids linked to alcohols or
carbon rings.
The hydrophobic molecules are firm and pliable.
Their structure makes them ideal for making waterproof
coatings on plant and animal parts.
Waxes
•
Cutin is a wax produced by
plant cells to coat the stem,
leaves and fruit.
– This helps hold water in and
keep infections out!
•
Birds produce a waxy substance
to waterproof their feathers.
•
Bees produce a wax that they
use to make their honeycombs.
End
Lipids!
Proteins
• Contain C, H, O, plus nitrogen
• Formed from amino acids joined
together
• More than 20 amino acids can be
joined in any order or number to
make countless proteins (think of how
many words can be made from 26 letters!)
Proteins
• Chains are folded and twisted giving
each protein a unique shape
• Van der Waals forces and hydrogen
bonds help maintain protein’s shape
• Shape of protein is important to its
function!
Proteins
• Provide structure
– Ex: Collagen- makes up your skin,
muscles & bones
• Aid chemical activities in your body
– Ex: Enzymes- work to speed up
rxns in your body
• Transport substances into or out of
cells
• Help fight diseases
Nucleic Acids
• Contain C, H, O, N plus
phosphorus
• Formed by bonding of
individual units called
nucleotides
nucleotide
Nucleic Acid
Nucleic Acids
• Store and transmit hereditary
information
–Ex: DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)