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