Unit 2.1 Biochemistry

1. Unit 2.1 Biochemistry

2. Vocabulary: Monomer: “mono-” = one; a single unit Polymer: “poly-” = many; chain of many linked monomers Dehydration Synthesis: a reaction by which monomers combine to form polymers by losing a molecule of water; also called condensation reaction. Hydrolysis: ‘hydro-’ = water, ‘lysis’ = to split; a reaction by which polymers are split into monomers by adding water. Nucleotide: a monomer of nucleic acids, consists of a sugar, a phosphate group, and any of five nitrogenous bases; adenine, guanine, cytosine, thymine, uracil Peptide bond: a bond that forms between two amino acid monomers to make a protein chain

3. Organic Compounds Contain Carbon • All living things are based on carbon (C): • Carbon is ‘versatile’ – can form up to four bonds with itself and/or other elements • Can form single, double, triple, ring bonds • In living systems, carbon bonds to hydrogen (H), oxygen (O), and nitrogen (N)

4. These carbon-hydrogen-oxygen (CHO) units join together to form long chains, like adding boxcars to a train, or words to make a sentence • Monomer: a single unit that can join to other units to become a long chain called a polymer • Like the individual boxcars, or the single words • Polymer: many single units (monomers) that are joined together to form a long chain • Like the whole train, or the whole sentence

5. Dehydration Synthesis (adds boxcars to the train, makes a longer sentence) • monomer + monomer + energy polymer + water • dehydration = removes water; synthesis = to put together, so to put together by removing water • As they join, one monomer releases OH-, other releases H+ to make a molecule of H2O • Also called a “condensation reaction” • Endergonic: requires energy b/c it forms a bond!

6. Hydrolysis: (takes boxcars off the train; makes the sentence shorter) • polymer + water  monomer + monomer + energy • ‘hydro’=water; ‘lysis’=break apart; uses water to break apart a molecule • Add water to break bonds between polymer units. • Exergonic – releases energy b/c it breaks a bond!

7. Four Classes of Organic Molecules • Carbohydrates: • Main function: store energyin C-O bonds • Animals use carbs to store energy as glycogen • Plants use carbs to store energy as starch • Plants also use carbs for structure in form of cellulose

8. Forms of carbohydrates: • Monomers are called “monosaccharides” • “mono-” = one; “sacchar-” = sugar • Ex: glucose, fructose, and galactose are all monomers • Polymers are called “polysaccharides” • “poly-” = many • Ex: sucrose, lactose, ribose, glycogen, starch, cellulose • If it ends in “-ose”, it’s probably a carbohydrate • glucose, fructose, galactose, sucrose, lactose, ribose, maltose

9. Lipids: “lipo-” = fat (like liposuction) • Three types of lipids (fats), three different functions: • Triglycerides: function is to store energy • “tri-” = three; “glyc-” = sweet (sugar) • Glycerol head with 3 fatty acid (lipid) tails • The many C-H bonds in the lipid tails are more efficient at storing energy than C-O bonds of glucose

10. Animal vs. Plant triglycerides: • Animals: mostly saturated tails b/c many animals have constant (warm) temperature that keeps fats fluid • Ex: butter, made from milk fat, liquid when warm, solid when cold • Plants: 2 or 3 fatty acid tails have C=C bonds that “kink” the tails, prevents tails from packing together when temperature drops, keeps plant fats “fluid” • Ex: corn oil, safflower oil, olive oil, etc…; most often liquid

11. Phospholipids: function is structure, especially cell membrane • Same as a triglyceride but a phosphate group replaces one fatty acid • Is amphipathic: both polar and nonpolar • Phosphate head is hydrophilic • Polar, so can mix with water • Lipid tail is hydrophobic • Nonpolar, so cannot mix with water

12. Steroids: main function is chemical signals • Steroids are lipids that form a ring structure • Cholesterol: decreases movement of phospholipids in the cell membrane; is also the precursor for most other hormones in the body • Testosterone, progesterone, estrogen all have similar structure but very different actions • Forms of lipids: • Monomers of lipids: triglycerides, phospholipids • Polymers of lipids: wax, oils, fats, (butter)

13. Nucleic Acids: • Function: store informationfor cell • Forms of Nucleic acids: • Monomer: a nucleotide with 3 parts: • Phosphate group • 5-carbon sugar (ribose) • Nitrogen-containing base • Polymers: DNA & RNA • DNA: Deoxyribonucleic acid • RNA: Ribonucleic acid

14. Structure of DNA is a double helix, a twisted ‘ladder’ • Sides of ladder: sugar and phosphate groups • Rungs of ladder: nitrogenous bases held together by hydrogen bonds • Thymine (T): 1 ring, pyrimidine • Cytosine (C): 1 ring, pyrimidine • Adenine (A): 2 rings, purine • Guanine (G): 2 rings, purine • Base-pairing rules: • A with T, G with C, always! • Keeps rungs even b/c always one pyrimidine with one purine

15. RNA differs from DNA in 3 ways: • Single-stranded: one-half of a ladder • Ribose sugar, not deoxyribose • Uracil in place of thymine • A with U; G with C

16. Proteins: • Function: provide structure • The protein monomer is an amino acid • 20 different amino acids but they share common structure, kinda’ like Mr. Potato-Head • Central carbon (potato body), an amine group (right hand), a carboxylic acid group (left hand), a hydrogen (hat), and an “R” group (shoes) • “R” group (shoes) determines shape of protein, influences role of protein

17. Polymers are called polypeptides, or proteins. • Peptide bond forms between H of NH2 and OH of COOH • NH2 = amine group (amino, like ammonia is NH3) • COOH = carboxylic acid group (acid) • Left hand of one potato-head holds the right hand of the next potato-head – forms a peptide bond

19. ATP = Energy! • Living organisms use energy in the form of Adenosine Tri-Phosphate (ATP) • Formed from Adenine nucleotide with 3 phosphate groups • Energy is stored in the bonds of the phosphate groups • When the bond that holds a phosphate group is broken, energy in that bond is released • But now only has two phosphate groups = ADP • Like a rechargeable battery

21. Warm-up answers for this unit:

22. Warm-up answers for this unit: