organic compounds why is carbon so special? copyright © 2009 pearson education, inc
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Organic compounds Why is Carbon so special?
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macromolecules composed of combinations of amino acids bound together with peptide bonds * provide structure to cells (10-30% cell
mass)
Figure 2.17Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Building blocks of protein
20 types of amino acids
Joined by peptide bonds
All are insoluble in water Provide energy, protection, insulationExamples:
Neutral fats or triglycerides Phospholipids Steroids Eicosanoids
Composed of three fatty acids three fatty acids bonded to a glycerol moleculeglycerol molecule
Figure 2.15a
Main functions:• Energy storage• Insulation• Protection
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Functions Major source of cellular fuel (Ex: glucose) Structural molecules (Ex: ribose sugar in
RNA) Three classes:
Monosaccharides Disaccharides Polysaccharides
Figure 2.15a
ExampleHexose sugars (the hexoses shown here are isomers)
ExamplePentose sugars
Glucose Fructose Galactose Deoxyribose Ribose
(a) MonosaccharidesMonomers of carbohydrates
*Isomers have the same molecular formula but the atoms are arranged differently.
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Figure 2.15b
ExampleSucrose, maltose, and lactose(these disaccharides are isomers)
Glucose Fructose Glucose Glucose Glucose
Sucrose Maltose Lactose
Galactose
(b) DisaccharidesConsist of two linked monosaccharides
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Figure 2.15c
ExampleThis polysaccharide is a simplified representation of glycogen, a polysaccharide formed from glucose units.
(c) PolysaccharidesLong branching chains (polymers) of linked monosaccharides
Glycogen
Glycogen – animal storageStarch – plant storage
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The Biomolecules There are four types of biological molecules
– Carbohydrates– Lipids– Proteins– Nucleic acids
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The biomolecules are ginormous
– AKA macromolecules – Polymers – Monomers– Can you think of another
analogy?
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CARBOHYDRATES
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Function
Carbohydrates basically have two functions. Energy storage Structural support
Carbohydrates – ”sugars”– Simple sugars (monosaccharides)
– Glucose– Fructose– Galactose
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Food Sources of Simple Carbs Fruit Chips Candy Soda (not diet) foods that sometimes make us crash…
Structuralformula
Abbreviatedstructure
Simplifiedstructure
Polysaccharides are polymers Storage molecule Structural compound Also called “complex carbs”
Food Sources = Wheat Pasta, Whole grain products, Oatmeal
Energy lasts longer because it takes longer to breakdown the polymer into its monomers.
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Common Polysaccharides Starch is a storage polysaccharide composed
of glucose monomers and found in plants Glycogen is a storage polysaccharide
composed of glucose, which is hydrolyzed by animals when glucose is needed
Cellulose is a polymer of glucose that forms plant cell walls
Chitin is a polysaccharide used by insects and crustaceans to build an exoskeleton
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Lipids are grouped together because…
They contain ________ as much energy as a polysaccharide.
3 kinds:
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The structure of a fat…another name is…
Fats are mostly energy-storage molecules
Some fatty acids contain double bonds This causes kinks in the hydrocarbon chain These are called unsaturated fats because…
saturated fats…
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Saturated or Unsaturated?
What else do you know about saturated and unsaturated fat?
Phospholipids are similar to fats but … VERY COOL because … they are a major part of …
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Phospholipids in a Lipid Bilayer
hydrophilic head
two hydrophobic tails
Phospholipids in a Lipid Bilayer
one layer of lipids
one layer of lipids
Water
Water
Hydrophobictails
Hydrophilicheads
Water
Myelin Sheath
Steroids are lipids composed of 4 fused rings Cholesterol is an example of a steroid that is also part
of cell membranes Sex hormones Steroids also regulate how our bodies deal with stress
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A protein is a polymer built from combinations of 20 amino acid monomers
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Polypeptide Formation
glutaminemethionine serine arginine
methionine
serine
methionine serine
Stepped Art
THEME?
Only 20 amino acids exist…
What does a protein do?
Just some common examples…
Structural (hair and nails) Contractile (muscles) Defensive (antibodies of the immune system) Signal (hormones) Receptor (on membrane to receive signals) Transport (hemoglobin, carry molecules)
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It’s important to have protein in our diet EVERY DAY…
(explain why)
Food Sources for Protein
Groove
A protein’s shape determines its function. If something messes up
the shape, it will no longer function…THEME?
Groove
primary structure –the order of amino acids determined by DNA slightest change affects the protein’s function
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One wrong amino acid in the 574 amino acid chain = sickle cell anemia
secondary structure is… alpha helix (slinky) pleated sheet (fold) held in place with…
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Spider silk is as strong as steel due to the H-bonds in the secondary structure
Uses include:•Surgical thread•Bulletproof vests•Fishing wire
If for some reason a protein’s shape is altered, it can no longer function Denaturation Caused by…
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5 Many proteins aggregate by the thousands into much larger structures, such as the keratin filaments that make up hair.
A protein’s primary structure consists of a linear sequence of amino acids (a polypeptide chain). Each type of protein has a unique primary structure.
1
glycinelysine glycine arginine
Stepped Art
2 Secondary structure arises as a polypeptide chain twists into a coil (helix) or sheet held in place by hydrogen bonds between different parts of the molecule. The same patterns of secondary structure occur in many different proteins.
3 Tertiary structure occurs when a chain’s coils and sheets fold up into a functional domain such as a barrel or pocket. In this example, the coils of a globin chain form a pocket.
4 Some proteins have quaternary structure, in which two or more polypeptide chains associate as one molecule. Hemoglobin, shown here, consists of four globin chains (green and blue). Each globin pocket now holds a heme group (red).
Figure 3-16 p47
Protein monomers are called _________.
The difference between primary and secondary structure is:
Some common functions of proteins are:
If a protein structure is altered, it can no longer _______.
Variant Creutzfeldt–Jakob Disease (vCJD)
Nucleotides
Nucleotide A small organic molecule consisting of a sugar with a five-
carbon ring, a nitrogen-containing base, and one or more phosphate groups
ATP A nucleotide with three phosphate groups Important in phosphate-group (energy) transfer
Figure 3-18a p49
A ATP, a nucleotide monomer of RNA, and also an essential participant in many metabolic reactions.
sugar: ribose
3 phosphate groups
base: adenine (A)
A Chain of Nucleotides
B A chain of nucleotides is a nucleic acid. The sugar of one nucleotide is covalently bonded to the phosphate group of the next, forming a sugar–phosphate backbone.
The DNA Molecule
The cell uses the order of nucleotide bases in DNA (the DNA sequence) guide production of RNA and proteins