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ORGANIC MOLECULES
Honors Anatomy & Physiology
4 Categories
1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids
Carbohydrates
Simple Carbohydrates Sugars Monosaccharides Disaccharides
Complex Carbohydrates Polysaccharides
Monosaccharides
multiples of the unit CH2O glucose most common
monosaccharide
Monosaccharide Diversity 3 to 7 carbons hexose: 6 carbons long pentose: 5 carbons triose: 3 carbons
Monosaccharide Diversity most hexoses and pentoses form
rings in aqueous solutions used in cellular respiration
(especially glucose) serve as raw materials for synthesis
of amino acids and fatty acids
if not immediately used in these ways used to build disaccharides or polysaccharides
Forms of Glucose
Alpha Glucose Beta Glucose
Disaccharides
reaction: 2 monosaccharides joined in a glycosidic linkage covalent bond formed by dehydration
reaction
Disaccharides
2 glucose = maltose (malt sugar) glucose + galactose glucose + fructose = sucrose (table
sugar)
Polysaccharides
polymers of hundreds to thousands of monosaccharides joined by glycosidic linkages
function determined by its sugar monomers & positions of glycosidic linkages
2 types:1. storage of monosaccharides to be
used for energy when needed2. building material
Storage Polysaccharides
Plants store glucose (the monomers)as starch (the polymer) represents stored energy
Starch
most is made of α glucose monomers joined in 1-4 linkages simplest form of starch (amylose) is
unbranched complex starch, amylopectin, has 1-
6 linkage
Storage Polysaccharides
Animals: store glucose (the monomers) as glycogen (the polymer) in 1-4 & 1-6 linkages stored mainly in liver & muscle cells humans store about 1 days supply of
glucose this way
Cellulose
digested by very few organisms (don’t have enzymes to do it)
in humans: passes thru GI tract abrading walls & stimulating mucus secretion along the way smoother passage of food thru
not technically a nutrient but is important
“Insoluble Fiber” = Cellulose
Lipids
large group of hydrophobic molecules
do not have true monomers Includes:
Waxes Steroids Some Pigments Oils, Fats Phospholipids
Fats
large molecules assembled from smaller molecules by a dehydration reaction
2 parts:1. Glycerol2. Fatty Acid
Glycerol
Fatty Acids
long (16-18) chain of carbons (hydrophobic)
@ one end carboxyl group (hence fatty acid)
Triglyceride
3 fatty acids + glycerol
Saturated & Unsaturated
Saturated Fats
include most animal fats most are solids @ room
temperatures
Unsaturated Fats
fats of plants, fish usually liquid @ room temperature
Hydrogenated Vegetable Oil seen on some food labels means that unsaturated fats have
been synthetically converted to saturated fats to keep from separating
Plaques
deposits of saturated & trans fats (hydrogenated vegetable oils with trans double bonds) in muscularis of arteries
Trans Fats
USDA now requires nutritional labels to include amount of trans fats
some cities & Denmark ban restaurants from using trans fats
Essential Fatty Acids
cannot be synthesized in body so must be included in diet
include: omega-3 fatty acids:required for normal growth in children
probably protect against cardiovascular disease in adults
Omega-3 Fatty Acids
Functions of Fat
Plants: storage of energy Animals: 1. storage of energy2. protect organs3. insulation
Phospholipids
essential component of cell membranes
Phospholipids
when added to water self-assemble into lipid bilayers
Steroids
lipids characterized by a carbon skeleton made of 4 fused rings
cholesterol & sex hormones have functional groups attached to these fused rings
Cholesterol in Humans
part of cell membranes precursor for other steroids vertebrates make it in liver +
dietary intake saturated fats & trans fats increase
cholesterol levels which is ass’c with atherosclerotic disease
Proteins
word in Greek from “primary” account for >50% of dry mass of
most cells instrumental in almost everything
organisms do
Proteins are Worker Molecules
Proteins
humans have tens of thousands of proteins, each with specific structure & function
all made from 20 amino acids (a.a.)
Proteins are biologically functional molecules made of 1 or more polypeptides, each folded & coiled into a specific 3-D structure
Amino Acid Monomers
all a.a. share common structure:
20 Amino Acids
R Groups
its physical & chemical properties determine the unique characteristics of a.a. so affect the physical & chemical properties of the polypeptide chain
Peptide Bonds
Polypeptide Backbone
polypeptide chain will have 1 amino end (N-terminus) and 1 carboxyl end (C-terminus)
R side chains far outnumber N & C terminus so produce the chemical nature of the molecule
Protein Structure & Function
polypeptide ≠ protein
Functional Protein
is not just a polypeptide chain but 1 or more polypeptides precisely twisted, folded, & coiled into a uniquely shaped molecule
Protein Shape
determined by a.a. sequence
Protein Shape
1. Globular Protein
roughly spherical
2. Fibrous Protein
long fibers
when polypeptide released from ribosome it will automatically assume the functional shape for that protein’s (due to its primary structure)
Name that Shape
Protein Structure
determines how it functions almost all proteins work by
recognizing & binding to some other molecule
Protein Structure
http://www.stolaf.edu/people/giannini/flashanimat/proteins/protein%20structure.swf
Collagen
fibrous protein: 40% of all protein in human body
3 identical polypeptides “braided” into triple helix
gives collagen its great strength
Hemoglobin
globular protein made of 2 alpha & 2 beta subunits (polypeptides)
each has nonpolypeptide part = heme which has Fe to bind O2
Sickle Cell Disease
due to substitution of one a.a. (valine) for the normal one, glutamine
causes normal disc-shape of RBC to become sickle shaped because the abnormal hemoglobin crystallizes
Sickle Cell Disease
go thru periodic “sickle-cell crises” angular sickled cells clog small
blood vessels impedes blood flow causes pain
Protein Structure
also depends on physical & chemical environment protein is in:
1. pH2. salt concentration3. temperature
all of the above can change weak bonds & forces holding protein together
Denaturation
process in which a protein loses its native shape due to the disruption of weak chemical bonds & interactions
denatured protein becomes biologically inactive
Denaturation Agents
taking protein out of water nonpolar solvent: hydrophilic a.a that were on outer edge to core vise versa with hydrophobic a.a.
Misfolded Proteins
ass‘c with: Alzheimer’s Mad Cow disease Parkinson’s Senile Dementia
NUCLEIC ACIDS
are polymers made of monomers called nucleotides
genes code for a.a. sequences in proteins
1. DNA deoxyribonucleic acid1. RNA ribonucleic acid
Nucleic Acid Roles
DNA:1. self-replication2. reproduction of organism3. flow of genetic information: DNA
RNA synthesis protein synthesis
Nucleic Acid Roles
RNA:1. mRNA
conveys genetic instructions for building proteins from DNA ribosomes
in eukaryotic cells means from nucleus cytoplasm
prokaryotic cells also use mRNA
Nucleic Acids
polymers of nucleotides (the monomers)
Nitrogenous Bases
each has 1 or 2 rings that include N are bases because the N atoms can
take up H+ 2 families:1. Pyrimidines
(1) 6-sided ring made of C & N
2. Purines (1) 6-sided ring fused to a 5-sided
ring
Pyrimidines 1. Cytosine
2. Thymine
3. Uracil
Purines
1. Adenine
2. Guanine
Sugars in Nucleic Acidsadded to
1. Deoxyribose
2. Ribose
Phosphate Group
added to 5’ C of the sugar (base was added to 1’ C)
Nucleotide Polymers
1 nucleotide added to next in phosphodiester linkages
Nucleic Acid Backbone
Phosphodiester linkages repeating pattern of phosphate – sugar – phosphate – sugar..
notice: phosphate end
is 5’ sugar end is 3’
Linear Order of Bases
specifies start, stop of transcription/translation and codons determine primary structure of proteins (which determines the 3-D structure of a protein which in turn determines the function of the protein)
Complimentary Bases
DNA Molecules