organic compounds why is carbon so special? copyright © 2009 pearson education, inc

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