macromolecules
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Macromolecules. Organic compounds Contain both hydrogen and carbon Large molecules composed of smaller subunits Carbohydrates Proteins Lipids Nucleic Acids . Carbohydrates (Sugars). Bio-molecule consisting of carbon, oxygen, and hydrogen. - PowerPoint PPT PresentationTRANSCRIPT
Macromolecules• Organic compounds– Contain both hydrogen and carbon
• Large molecules composed of smaller subunits– Carbohydrates– Proteins– Lipids– Nucleic Acids
Carbohydrates (Sugars)• Bio-molecule consisting of
carbon, oxygen, and hydrogen.
• General molecular formula (CnH₂nOn) (C₆H₁₂O₆)
• Roles– Energy storage - plants – Structural support in cells and
tissues • Hydrophilic • Pentose/Hexose ring
structure
Monosaccharides• Simplest type of
carbohydrate• Used as primary energy
source for cellular metabolism (making ATP)
• 1 sugar unit – Glucose – grape sugar,
blood sugar– Fructose – honey, fruit
juices
Monosaccharides• Most Common– 3 carbon (linear) – triose– 5 carbon – pentose ring– 6 carbon – hexose ring
• Why?– Folding into a ring
occurs through a reaction between carbonyl group and hydroxy l group
• Link together to form disaccharides
Glucose• Linear and ring structures• Hexose ring– Two possible arrangements
• α - glucose• Β – glucose
– Isomers – same molecular formula, different structural formula• Carbon atoms have assigned numbers– Used when discussing structures of sugars
Linkages are designated α or β from the position of the –OH group on the 1 carbon
Disaccharides• Consist of two monosaccharides – Maltose – used to make beer – Sucrose – simple sugar found in
plant sap– Lactose – milk
• Used as energy sources and building blocks for larger molecules
• Joined together by a dehydration synthesis reaction
• Glycosidic bond – links monosaccharides together
• Common carbon linkages – 1 4 1 2– 1 3 1 6
Polysaccharides• Complex carbohydrate/polymer– Chain of hundreds to thousands of monosaccharides
(monomers) with many subunits– Unbranched – single chain – Branched – side chains
Polysaccharides• Assembled by dehydration reaction– Glycosidic linkage– Polymerization – linkage of identical or various monomers to
form long chains• Linear unbranched – hydrogen bonds form between molecules
• Polar • Hydrophilic• Non-soluble in water
Examples Amylose – soluble
component of starch
Glycogen – energy storage in animals
Cellulose – main component of plant cell walls
Chitin – hard exoskeleton of insect and crustaceans
Lipids• Non-polar • Made up of mostly
carbon and hydrogen • Not polymers• Do not dissolve in water• Roles – Formation of cell
membranes – Energy source – Hormones – Vitamins
• 5 main categories – Fatty acids – Fats – Phospholipids – Steroids – Waxes
Fatty Acids• Derivative of most lipids
(structural backbone)• Consists of– Single hydrocarbon
chain (14 to 22)– Carboxyl functional
group at one end (-COOH)
– Gives the fatty acid its acidic properties
• As chain length increases, insolubility in water increases
Fatty Acids• Saturated – Max number of hydrogen
atoms attached to carbons– Single bonds throughout the
carbon chain– Solid at room temp
• Unsaturated– Formation of double bonds in
carbon chain– Monounsaturated – one
double bond– Polyunsaturated – many
double bonds– Causes a bent formation in
molecule – Liquid at room temp
Fats • Consists of – 1 to 3 fatty acid
chains– Glycerol
• Dehydration synthesis– Hydroxyl group of
glycerol and carboxyl group of fatty acid
• Can have identical/different fatty acid chains
• Hydrophobic
Triglycerides • Most well known fat• Contains 3 fatty acid chains• Stored energy (food) in fat cells • Liver produces triglycerides • Yield more than twice as much energy as carbohydrates• Normal blood level – less than 150 mg/dL
Phospholipids• Consists of– 2 fatty acid chains
(hydrophobic) – Glycerol – Phosphate group • contains a polar
unit (hydrophilic)
• Amphipathic – Contains both
hydrophobic and hydrophilic regions
Phospholipids• Roles– Lipid bilayer of cell
membranes – Hydrophilic end faces
toward water– Hydrophobic end
faces inward• Unsaturated tail
makes membrane more permeable to water and small molecules
Steroids
• Consists of – Four fused carbon ring– Side group
• Sterols– Most abundant – Consists of • Single polar –OH group • Non – polar hydrocarbon chain
– Amphipathic molecule– Eg; Cholesterol , Phytosterols
Cholesterol• Formed in the liver • Structural component of
plasma membrane (nearly half)
• Amphipathic• Function– Maintains integrity of
membrane– Proper membrane
permeability/fluidity
Cholesterol • Can’t dissolve in
blood• Transported by
carriers • Types
– LDL – low density lipoprotein
– Promote cardiovascular disease
– HDL – high density lipoprotein
– Good cholesterol– removes cholesterol
from artery– Eliminated in liver
Sex Hormones• Control development of sexual traits and sex cells – Eg; testosterone, estrogen, progesterone
Waxes• Consist of – Long fatty acid chains– Alcohol molecule or Carbon
ring• Hydrophobic• Extremely non-polar• Soft Solids• Functions– Waterproof coating on various
plant and animal parts– Cutin – plants conserve water
and fights disease– Beeswax – production of
honeycomb
Proteins• Polymer with many subunits• Composed of Amino Acids
(monomers)• Folded into a 3-D structure
– Primary Secondary– Tertiary Quaternary
• Folding allows protein to function
• Structure specifies function of protein
• Formed by dehydration reaction• Peptide bonds link amino acids
together
Amino Acids• 20 different amino acids– 8 essential - supplied by
diet• Contain:– Central carbon– Amino group (-NH₂)– Carboxyl group (-COOH)– R group
• R groups give each amino acids specific characteristics– Polarity, acidity
Amino Acids
Peptide Bond• Covalent bond between
(NH₂) group of one amino acid and (COOH) group of another.
• Amino acids are only added to the C-terminal of a growing peptide
• Peptide– String of 1-49 amino acids– Contains no side branches
• Polypeptide– String of 50 or more amino
acids
Proteins• Structural – framework support
(hair, tendon, ligaments)• Defensive – infection fighters
(antibodies)• Signal – messenger (hormones)• Carrier – transport of materials
(hemoglobin)• Recognition and Receptor –
cellular markers (major histocompatability complex)
• Enzyme – catalyst (amylase)• Motile – movement (actin and
myosin)
Protein Structure• Primary Structure 1⁰– Linear sequence of amino acids in polypeptide chain– Changing one amino acid with change overall structure
of protein
Protein Structure • Secondary Structure • Polypeptides fold or coil
into patterns• Result of hydrogen bonding– β-pleated sheets
• Side-by-side alignment• (Eg; strength of silk)
– α-helix • Coil that is held together by
hydrogen bonds between every 4th amino acid
• (Eg; filamentous proteins, transmembrane proteins)
Protein Structure• Tertiary Structure 3⁰• 3-D shape of a protein• Intermolecular reactions of
amino acid R groups determines shape
• Include– Ionic bonds– Hydrogen bonds– Hydrophobic interactions
• Non-polar side groups cluster when introduced to water
– Disulfide bridges• Bond formed from two cysteine
amino acids (-SH group)• Stabilizes proteins shape
Protein Structure • Quaternary Structure 4⁰– Composed of 2 or more
polypeptides– Functional proteins– Forms subunits – Same bonds and forces
as tertiary structure
Protein Prosthetic Groups• Non-protein components– Metal ions (Fe²⁺ Mg²⁺)
• Needed for protein to function• Hemoglobin– 4 polypetide chains each with a
heme groups – Each group has a single iron ion
(Fe²⁺) – Oxygen binds to heme groups via
(Fe²⁺)– How many molecules of O₂ can
hemoglobin carry at one time?
Protein Denaturation• When a protein loses its 3-D structure• Often irreversible • Extreme temperatures• pH• Chemcials
Nucleic Acids• Polynucleotide chains
serve as assembly instructions for all proteins in living organisms
• DNA – deoxyribonucleic acid– Stores hereditary
information• RNA – Ribonucleic acid
– Hereditary molecule of some viruses
– Involved in protein synthesis
• Composed of nucleotides • Linked by a
phosphodiester bond
Nucleotides• Consists of– Nitrogenous base• Uracil (U), thymine (T), cytosine (C), adenine (A), guanine (G)
– Sugar– Phosphate groups
• Functions– Transport chemical energy– Regulate and
adjust cellular activity
Nitrogenous Bases• 2 types– Pyrimidines• Uracil (U), Thymine (T), Cytosine (C)
– Purines • Adenine (A), Guanine (G)
Phosphodiester Bond• Links nucleotides
together– Phosphate bridge forms
between the 5’ carbon of one sugar and the 3’ carbon of the next sugar.
– Forms the backbone of a nucleic acid chain
– Nitrogenous bases project from the backbone
DNA• Consists of – Deoxyribose sugar– Phosphate group– A, T, C, G
• Double stranded molecule (Double Helix)– Two strands of DNA run antiparallel to
each other (opposite direction)– 5’ to 3’ – 5’ is the end with the phosphate group– 3’ is where deoxyribose sugar is located
• Nitrogenous bases– Held together by hydrogen bonds– A pairs with T ( forms double bond)– C pairs with G (forms a triple bond)
RNA• Consists of– Ribose sugar– Phosphate group – A, U, C, G
• Single stranded molecule• Converts information stored in DNA into proteins