View
2
Download
0
Category
Preview:
Citation preview
BiochemistryMacromolecules and Enzymes
Unit 02
Organic Compounds
● Compounds that contain CARBON are called organic.
What is Carbon?● Carbon has 4 electrons in outer shell.
● Carbon can form covalent bonds with as many as 4 other atoms (elements).
● Usually with C, H, O or N.
● Example: CH4(methane)
Macromolecules
● Macromolecules are large organic molecules.
Macromolecules, con’t. ● Large organic molecules.
● Also called POLYMERS.
● Made up of smaller “building blocks” called MONOMERS.
● Examples:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids (DNA and RNA)
How are macromolecules
formed?
Answer: Dehydration Synthesis● Also called
“condensation reaction”
● Forms polymers by combining monomers by “removing water”
How are macromolecules
separated or digested?
Answer: Hydrolysis● Separates
monomers by “adding water”
Carbohydrates
Carbohydrates● Carbohydrates include small sugar
molecules to large sugar molecules.
● Examples:
A. monosaccharide
B. disaccharide
C. polysaccharide
Carbohydrates: MonosaccharidesMonosaccharide:
one sugar unit1C: 2H: 1H ratio
Examples:Glucose (C6H12O6)
Deoxyribose
Ribose
Fructose
Galactose
Carbohydrates: DisaccharidesDisaccharide: ● two sugar unit
Examples:
● Sucrose (glucose+fructose)
● Lactose (glucose+galactose)
● Maltose (glucose+glucose)
Carbohydrates: PolysaccharidesPolysaccharide: - many sugar units
Examples:- starch (bread, potatoes)
● glycogen (stored in liver)
● cellulose (lettuce, corn)
Function of CarbohydratesCarbohydrates● Quick source of energy
● Energy storage
● Structure (cellulose)
Carbohydrates: Energy SourceEnergy Source● Main source of energy for most organisms
● Cells utilize glucose for energy● Breaking of C-C bonds releases a lot of
energy ● Sugars have 5 C-C bonds per glucose
molecule
Carbohydrates: Energy SourceEnergy Source● Plants produce glucose through photosynthesis
● Animals obtain glucose from plants ● Human digestive system breaks down carbohydrates to
simple sugars● Small intestine absorbs simple sugars and blood transports
them to cells● Cells use glucose to form ATP (Cellular Respiration)
Carbohydrates: Energy StorageEnergy Storage● Animals
● Extra glucose is stored as glycogen
● Liver and muscle cells
● Plants● Stored as starch
Carbohydrates: StructureStructural Unit
● Cellulose is made up of glucose molecules
● Makes up cell walls of plants
● Uses
● Support plants
● Important in animal diets by helping digestive tract work smoothly
● Fun Fact
● Animals lack the enzyme to digest cellulose
● Some animals have a symbiotic relationship with a microorganism that can digest cellulose
Lipids
Lipids● Lipids
● Compounds which are not soluble in water.● “Stores the most energy”
● Examples:
● Fats/Oils
● Phospholipids
● Steroids
Lipids: Fats/OilsStructure of Fat/Oil
● Composed of 1 glyceroland 3 fatty acids.
Fatty acids are insoluble.
Lipids: Fats/OilsSaturated Fats
● All single bonds
● Solids
● Animal Fat
Unsaturated Fats
● 1+ double bond(s)
● Liquids
● Fish and Plant Oils
Lipid: Phospholipid● Phosphate Head:
● Polar
● Hydrophilic (attracted to
water)
● Two Fatty Acid Tails:
● Nonpolar
● Hydrophobic (avoids water)
● Two Layers
● Outsides: Polar Heads
● Inside: Nonpolar Tails
Cell Membrane Structure●Lipid Bilayer: a
double layer of
phospholipids that
make up the cell
membrane
Other lipids● Lipids
● Fatty acids
● Fats and waxes
● Steroids
● Cholesterol
● Testosterone
● Phospholipids
Lipids: FunctionsFunctions of lipids
● Long term energy storage
● Protection against heat loss (insulation)
● Protection against water loss
● Cutin (waxy coating on leaf) prevents water loss
● Chemical messengers (hormones)
● Major component of membranes (phospholipids)
Nucleic Acids
Nucleic AcidsNucleic acids are composed of long chains of nucleotideslinked by dehydration synthesis.
31
Nucleic acids• Nucleotides include
Phosphate groupPentose sugar (5-carbon)Nitrogenous bases
Adenine (A)Cytosine (C)Guanine (G)Thymine (T) DNA onlyUracil (U) RNA only
Nucleic Acids● Two types
● Deoxyribonucleic acid● DNA● Sugar: Deoxyribose● Double helix
● Ribonucleic acid ● RNA● Sugar: Ribose● Single strand
33
DNA - double helix
P
P
P
O
O
O
1
23
4
5
5
3
3
5
P
P
PO
O
O
1
2 3
4
5
5
3
5
3
G C
T A
Function of Nucleic AcidsNucleic Acids● Stores and transmit information in the form of
a code
● Passes this information from one generation to the next
Proteins
ProteinsFour levels of protein structure:
A.Primary Structure
B.Secondary Structure
C.Tertiary Structure
D.Quaternary Structure
Proteins● Primary Structure● Amino acids
(20 different kinds)● Bound together by
peptide bonds● Straight chains
Proteins● Secondary Structure● 3-dimensional folding
arrangement of a primary structure held together by hydrogen bonds.● Alpha Helix: Coils
● Beta Pleated Sheets: Folds
Proteins● Tertiary Structure● Structures bent and
folded into a more complex 3-D arrangement of linked polypeptides
● Bonds: H-bonds, ionic, disulfide bridges (S-S)
● Call a “subunit”
Proteins● Quaternary Structure● Composed of 2 or more
“subunits”
● Globular in shape
● Form in aqueous environments
● Example: enzymes (hemoglobin)
Proteins: FunctionsShape of protein determines its functionFunctions of Proteins● Storage: albumin (egg white)
● Transport: hemoglobin
● Regulatory: hormones
● Movement: muscles
● Structural:membranes, hair, nails
● Enzymes: cellular reactions
Proteins: Fun Facts●Essential Amino Acids: 8 of the 20 AA must be
obtained from diet because humans cannot make
them
●Different organisms need different amino acids● Domestic cats must eat taurine, however humans
can produce it.
ENZYMES
◼Most enzymes are proteins
◼Act as a catalyst to speed up a chemical reaction
by helping molecules react with each other faster
WHAT IS AN ENZYME?
◼Reusable!
◼Specific for what they catalyze (speed up)
▪ End in “-ase”
▪ Named for the reaction they help. For example…
▪ Sucrase breaks down sucrose
▪ Proteases break down proteins
▪ Lipases break down lipids
▪ DNA polymerase builds DNA
ENZYMES ARE…
◼Lactase breaks down lactose, a common component of dairy products (like milk)
◼People lacking the enzyme lactase are considered “lactose intolerant”-they can’t digest large amounts of milk!!
CASE STUDY: LACTOSE INTOLERANCE
◼Re-used again for the same reaction with other
molecules
◼Very little enzyme is needed to help in many
reactions!
ENZYMES ARE NOT USED UP!
Product
s
Substrat
e
Active
Site
Enzym
e
◼Remember, enzymes are specific!
◼Lock and Key Model: Shape of
enzyme allows substrate to fit
▪ Specific enzyme for each
specific reaction
LOCK AND KEY MODEL
Chemical
ReactionEnzyme + Substrate → Enzyme +
Product
REACTANTS
◼Enzymes work by weakening bonds, which lowers
ACTIVATION ENERGY
▪ Activation Energy=energy needed for the chemical
reaction to occur (energy needed to activate!)
▪ By lowering the activation energy, the reaction can occur
faster!
SO…HOW DO ENZYMES WORK?
Reactions can occur without
the help…but not at the
speed our bodies need!
◼Temperature
▪ High temperatures can cause enzymes to denature (unfold and lose shape), while low temperatures slow molecules down
◼pH
▪ Changes in pH changes protein shape (most human proteins sit at a pH of 6-8)
◼Denaturing=extreme temperature and pH can change enzyme shape, rendering it useless!
WHAT EFFECTS ENZYME ACTIVITY?
◼Every reaction in your body is helped by an
enzyme. They are necessary for all biological
reactions!
◼Video
WHY ARE ENZYMES IMPORTANT?
Recommended