Post on 17-Jan-2016
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A little intro to each of the different
Macromolecules
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Biological Molecules
• The framework of biological molecules consists of carbon bonded to other carbon molecules, or other types of atoms.
– Hydrocarbons consist of carbon and hydrogen.
Covalent bonds store considerable energy.
Make good fuels
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Biological Molecules
• Functional groups– specific groups of atoms attached to
carbon backbones retain definite chemical properties
• Macromolecules.– proteins– nucleic acids– lipids– carbohydrates
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Hydroxyl
Carbonyl
Carboxyl
Amino
Sulfhydryl
Phosphate
Methyl
Acetic acid
Functional Group
StructuralFormula
Example
Acetaldehyde
Alanine
-mercaptoethanol
Glycerol phosphate
Pyruvate
HS
P
O–
O
O
HC
H
H
OH
O
OHC
H
HN
CO
Ethanol
C
H
H
CH
H
H
OH
CH
H
HC
O
OH
H
CH3
OH
CCHO NH
CH
H
HHC
O
CHOH
H HS HC
H
CH
OH
HC
OH
H HOC
H
P
O
C
O
C
O
HHC
H
O–
O–
O–
O–
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Macromolecules
• Macromolecules are often polymers.– long molecule built by linking together
small, similar subunits Dehydration synthesis removes OH and
H during synthesis of a new molecule. Hydrolysis breaks a covalent bond by
adding OH and H.
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MACROMOLECULES
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Carbohydrates• Carbohydrates are loosely
defined as molecules that contain carbon, hydrogen, and oxygen in a 1:2:1 ratio.
– monosaccharides - simple sugars
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– disaccharides - two monosaccharides joined by a covalent bond
DisaccharideMaltose
Monosaccharide2 X Glucose
C
C
C
O
C
C
H
H
C
H
OHH
OH
OH
H
HOH
HC
C
C
O
C
C
OH
H
H
C
H
OHH
OH
OH
H
H
H
O
C
C
C
O
C
C
OH
H
H
C
H
OHH
OH
OH
H
HOH
HC
C
C
O
C
C
OH
H
H
C
H
OHH
OH
OH
H
HOH
H
H2OH2O
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– polysaccharides - macromolecules made of monosaccharide subunits
isomers - alternative forms of the same substance – Many C6H1206
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Carbohydrate Transport and Storage
• Transport disaccharides– Humans transport glucose as a simple
monosaccharide.– Plants transform glucose into a
disaccharide transport form.• Storage polysaccharides
– plant polysaccharides formed from glucose – starches
most is amylopectin– Animal starch is glycogen
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Structural Carbohydrates
• Cellulose - plants– alpha form or beta
form of ring
Chitin - arthropods and fungi
modified form of cellulose
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Lipids• Lipids are loosely defined as groups of
molecules that are insoluble in water.– fats and oils
• Phospholipids form the core of all biological membranes.
– composed of three subunits Glycerol - backbone fatty acid – long tail phosphate group – head
Polar head - hydrophilicNonpolar tail - hydrophobic
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Phospholipids form membranes
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Fats and Other Lipids• Fats consist a of glycerol
molecule with three attached fatty acids (triglyceride / triglycerol).
– Saturated fats - all internal carbon atoms are bonded to at least two hydrogen atoms – maximum # of H
– Unsaturated fats - at least one double bond between successive carbon atoms
Polyunsaturated - contains more than one double bond
usually liquid at room temperature
Double bonds in the tail
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Fats as Energy Storage Molecules
• Fats, on average, yield about 9 kcal per gram versus 4 kcal per gram for carbohydrates.
– Animal fats are saturated while most plant fats are unsaturated.
Consumption of excess carbohydrates leads to conversion into starch, glycogen, or fats for future use.
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Proteins
A. Amino acids
B. Peptide bonds
C. Polypeptide chains
H - N - C - C - OH
OH
H
Amine Group
Acid Group
R
H
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Protein Function
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Amino Acids
• contain an amino group (-NH2), a carboxyl group (-COOH) and a hydrogen atom, all bonded to a central carbon atom
– twenty common amino acids grouped into five classes based on side groups
nonpolar amino acids polar uncharged amino acids charged amino acids aromatic amino acids special-function amino acids
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Amino Acids
• Peptide bond links two amino acids.– A protein is composed of one or more long
chains of amino acids linked by peptide bonds (polypeptides).
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Alanine(Ala)
Leucine(Leu)
Isoleucine(Ile)
Phenylalanine(Phe)
Tryptophan(Trp)
Tyrosine(Tyr)
Glutamine(Gln)
Asparagine(Asn)
Threonine(Thr)
Serine(Ser)
Glycine(Gly)
Glutamicacid (Glu)
Asparticacid (Asp
Histidine(His)
Lysine(Lys)
Arginine(Arg)
Charged
Polar uncharged
Nonpolar
NONAROMATIC AROMATIC
Valine(Val)
CH3
C C
H O
CH
C C
H O
C C
H O
CH
C C
H O
H C
C C C C
H O
NH
C
C C
H O
OH
H C OH
C C
H O
C C
H O
C
NH2
O
CH2
C C O–
H O
OH
C
C C
H O
O
H
C C
H O
C C
H O
CO
C C
H O
NH
C
C C
H O
C C
H O
C N
HC NH+
CH
H
C C
H O
CO
CH3 CH3
CH3 CH3CH3
CH3 CH2
CH2
CH2
CH2
CH2
CH2CH2
NH2
CH3
CH2
NH2
H3N+ H3N+ H3N+ H3N+ H3N+ H3N+O–O–O–O–O–
H3N+H3N+H3N+H3N+H3N+
O–
O–
O– O– O– O– O–
CH2
CH2CH2 CH2 CH2
CH2
CH2
CH2
CH2
CH2
CH2
NH2+
NH3+
O–
H O
H3N+ H3N+ H3N+ H3N+ H3N+ H3N+O–O–O–O–O–
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Protein Structure The shape of proteins is extremely important and
can determine the function Water’s tendency to hydrophobically exclude
nonpolar molecules literally shoves the nonpolar portions of the protein to the interior
Many shapes Primary – the specific amino acid sequences Secondary – formed by hydrogen bonding
Alpha helix – coils Beta pleated sheet - foldbacks
motifs - folds or creases supersecondary structure
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N N N
H
H
H
H
H H
HC C C C C C N C C N CCC
O
OO
O H H
OH H
R
R
R R
R R
Motifs
Primary structure1
2
3
helix
turn motif motif
pleated sheet
Secondarystructure
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Protein Structure
Tertiary - final folded shape of globular protein (3-dimensional shape) based on bonding of side groups
Domains – independent functional units of the protein 100–200 amino acids long - encoded by a specific DNA sequence (exon)
Quaternary - forms when two or more polypeptide chains associate to form a functional protein
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Tertiarystructure
Domains
Quaternary structure
Domain 3
Domain 2
Domain 1
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Chaperone Proteins
• Chaperone proteins are special proteins which help new proteins fold correctly.
– Chaperone deficiencies may play a role in facilitating certain diseases.
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Unfolding Proteins• Denaturation refers to the
process of changing a protein’s shape.
– usually rendered biologically inactive
pH temperature Ionic concentration -
salt-curing and pickling used to preserve food
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Nucleic Acids
• Deoxyribonucleic Acid (DNA)– Encodes information used to assemble
proteins.• Ribonucleic Acid (RNA)
– Reads DNA-encoded information to direct protein synthesis.
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Nucleic Acid Structure
• Nucleic acids are composed of long polymers of repeating subunits, nucleotides.
– five-carbon sugar– Phosphate group– nitrogenous base
Purines double ringed adenine and
guanine Pyrimidines – single
ringed cytosine, thymine,
and uracil
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P
P
P
P
OH
5-carbonsugar
Nitrogenous base
Phosphate group
Phosphodiesterbonds
Adenine
O
O
O
O
Guanine
CCNN
N
C
H N
CCH
O
H
Cytosine(both DNAand RNA)
Thymine(DNA only)
Uracil(RNA only)
HCCNC
HN
CNH2
N
NCH
OCCNC
HN
CHH
OCCNC
HN
CO
HH3CH
OCCNC
HN
CO
HHH
PURINES
PYRIMIDINES
NH2
NH2
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Nucleic Acid Structure
• DNA exists as double-stranded molecules.
– double helix– complementary base pairing
Chargaff’s rule hydrogen bonding
• RNA exists as a single stand.– contains ribose instead of
deoxyribose– contains uracil in place of thymine
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Structure of DNA