Organic Molecules
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Transcript Organic Molecules
ORGANIC
MOLECULES
Honors Anatomy & Physiology
4 Categories
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
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
1.
2.
polymers of hundreds to thousands of
monosaccharides joined by glycosidic
linkages
function determined by its sugar monomers
& positions of glycosidic linkages
2 types:
storage of monosaccharides to be used for
energy when needed
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
1.
2.
large molecules assembled from smaller
molecules by a dehydration reaction
2 parts:
Glycerol
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
1.
2.
3.
Plants: storage of energy
Animals:
storage of energy
protect organs
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
2.
roughly spherical
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/flashanima
t/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
1.
2.
3.
also depends on physical & chemical
environment protein is in:
pH
salt concentration
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
1.
1.
are polymers made of monomers called
nucleotides
genes code for a.a. sequences in proteins
DNA
deoxyribonucleic acid
RNA
ribonucleic acid
Nucleic Acid Roles
DNA:
1.
self-replication
2.
reproduction of organism
3.
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
1.
each has 1 or 2 rings that include N
are bases because the N atoms can take up
H+
2 families:
Pyrimidines
2.
(1) 6-sided ring made of C & N
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 Acids
added 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