• Macromolecules

nucleic acids.

- larger molecules made from smaller ones.

• 4 major classes of macromolecules: carbohydrates, lipids, proteins, and • 3 of these are polymers because they are made from individual building blocks called monomers.

http://www.diabetes.org.nz/pics/carbohydrate_foods.jpg

• Monomers

- joined together through condensation or

dehydration reaction

(form macromolecules) • Requires energy; uses covalent bonds (links together monomers) • Water produced.

Water produced as by-product

• Hydrolysis

breaks polymers into monomers.

• Water added to polymer; breaks bonds, creates monomers (i.e. digestive process in animals)

• • 1

Carbohydrates Carbohydrates

- sugars (monomers) and polymers.

A

Monosaccharides

sugars.

- simple • B

Disaccharides

- double sugars (monosaccharides linked together) • C

Polysaccharides

- polymers of monosaccharides.

• Sugars named with –ose.

• Monosaccharides needed for cellular work.

• Help to synthesize other macromolecules.

• Maltose - 2 glucose molecules.

• Sucrose - 1 glucose, 1 fructose.

• Polysaccharides

walls.

- energy storage.

• Starch - energy storage polysaccharide for plants.

• Cellulose – polysaccharide; plant cell • Animals store energy as glycogen.

• Chitin - polysaccharide - makes up exoskeleton of arthropods (like crustaceans and our sowbugs!).

Chitin is used in surgery

Lipids • Lipids

• Lipids nonpolar (no affinity for water) • Fat made from glycerol and fatty acids.

- no polymers (exception)

• Saturated fatty acid -

No carbon carbon double bonds in carbohydrate chain. (hydrogen at every possible position) • Form bad fats - solid at room temperature (butter, lard)

No double-double bonds

• unsaturated fatty acid

temperature (oils) - 1+ carbon-carbon double bonds.

• Formed by removal of hydrogen atoms from carbon skeleton.

• Form good fats - liquid at room

• Purpose of fat - energy storage. • Gram of fat stores 2X as much energy as gram of polysaccharide. • Fat also cushions vital organs.

• Layer of fat can also function as insulation.

http://www.healthline.com/blogs/diet_nutrition/uploaded_images/fat-cat-712938.jpg

• MOST IMPORTANT LIPID IN BIOLOGY = Phospholipid • Phospholipids have 2 fatty acids attached to glycerol.

• Fatty acid tails are hydrophobic, phosphate group and attachments form hydrophilic head.

• When phospholipids added to water, self-assemble with hydrophobic tails pointing toward center, hydrophilic heads on outside.

• Phospholipids in cell form bilayer; major component of cell membrane.

Hydrophilic Hydrophobic

Other Lipids • Steroids

- lipids with carbon skeleton consisting of 4 fused carbon rings.

• Cholesterol - component in animal cell membranes and hormones.

Cholesterol

Proteins • Proteins

- support, storage, transport, defenses, and enzymes.

• Made in ribosomes in cell.

• Proteins - amino acids linked together to form polymer.

• 20 different amino acids that can be linked together to form thousands of different proteins.

http://images.foodnetwork.com/webfood/images/gethealthy/nutritionalallstars/LeanProteins_header.jpg

• Amino acids link -

polypeptides

combine to form proteins.

• Amino acids made of hydrogen atom, carboxyl group, amino group, variable R group (or side chain).

• R group makes amino acids different from one another.

• Shape of protein determines function.

• Shapes - 3 dimensional determined by sequence of amino acids.

• Primary structure

of protein linear sequence of amino acids determined by genetics.

• Secondary structure

shapes are usually formed: alpha coils or beta sheets.

- two

• Tertiary structure

determined by interactions among R groups.

• Quarternary structure

- joining of 2+ polypeptide subunits.

• Collagen and hemoglobin examples.

• Protein’s shape can change due to environment.

• pH, temperature, or salinity (salt concentrations) change - protein can

denature

(starts to fall apart) • Some proteins can return to functional shape after denaturation, others cannot.

Nucleic acids

• Amino acid sequence of polypeptide programmed by a gene.

• 2 types of nucleic acids:

ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).

http://www.uic.edu/classes/bios/bios100/lecturesf04am/nucleotides.jpg

• DNA gives information so RNA can create proteins.

• Flow of genetic information - DNA > RNA -> protein.

• Protein synthesis occurs in ribosomes.

• Monomers of nucleic acids -

nucleotides

.

• Nucleotides made up of 3 parts: nitrogen base, five-carbon sugar, and phosphate group.

• Nitrogen bases, rings of carbon and nitrogen, come in 2 types:

purines and pyrimidines.

• Pyrimidines

thymine (T), and uracil (U in RNA only).

- cytosine (C),

• Purines

- adenine (A) and guanine (G).

• Pyrimidines - single six-membered ring; purines - five-membered ring.

http://library.med.utah.edu/NetBiochem/pupyr/pupy3.gif

• In RNA - sugar is ribose; DNA sugar is deoxyribose.

• Difference between sugars is lack of oxygen atom in deoxyribose.

http://members.aol.com/logan20/ribose.gif

• RNA single-stranded - linear shape.

• DNA forms double helix.

• Sugar and phosphate forms backbone of double helix while nitrogen bases form connection between backbones.

• Adenine (A) always pairs with thymine (T) guanine (G) with cytosine (C).

• Due to six and five membered rings – shapes are compatible.

• Two strands are

complementary

.

http://www.emunix.emich.edu/~rwinning/genetics/pics/dna2.gif

• DNA used to show evolutionary similarities between species.

• Two species that appear to be closely-related based on fossil and molecular evidence also more similar in DNA and protein sequences than more distantly related species.