Biochemistry

Ch.2-3 & 3

(2-3) Water Structure

• O is -, while the H’s are +– Uneven distribution of charge

O

H H

Polar vs. Nonpolar

• Polar: 1 end is + & other is –– “Like dissolves like”– Charges help break apart other cmpds

• Nonpolar: even distribution of charge

Hydrogen Bond

• Weak force of attraction b/w a H atom in 1 molecule & a negatively charged atom in a 2nd molecule

Properties of Water

• Cohesion: attractive force b/w like particles– Ex: water attracts to itself & forms “skin”

• Adhesion: attractive force b/w unlike substances– Ex: water clinging to edges of a glass

Capillarity

• Rxn of a liquid surface w/ a solid– Combine adhesion & cohesion

• Allows water to creep up the interior of a narrow vessel– Ex: water flows up a flower’s

stem

Temp. Moderation

• Water must gain or lose a large amt. of E for its temp. to change

• Helps cells maintain homeostasis

(3-1) Carbon Compounds

• Organic cmpds: contain C atoms bonded to other elements such as H, O, & N

• Functional groups: influence properties of a molecule– Ex: -NH2 for amino acids

Building Blocks

• Molecules are made up of smaller parts called monomers

• 2 = dimer

• 3 or more = polymer

Making a Macromolecule

• Condensation rxn: formation of larger molecules by removing a H+ from 1 monomer & a OH- from the other monomer

• H+ & OH- combine to form H2O

Breaking a Macromolecule

• Hydrolysis rxn: the use of water to break polymers back into monomers– Reverse of condensation rxn

E Currency

• Life requires a constant supply of E

• ATP (adenosine triphosphate)– Releases E when broken down

(3-2) Molecules of Life

• Carbohydrates - monosaccharides

• Proteins – amino acids

• Lipids – fatty acids

• Nucleic Acids - nucleotides

Nutrition Facts

• Lipids

• Sugars

• Amino acids

1. Carbohydrates

• Monosaccharide = monomer– Glucose

• Disaccharide = 2 monomers– Table sugar

• Polysaccharide = 3+ monomers– Starch, cellulose, glycogen

2. Protein

• Amino Acid = monomer– 20 different types

• Peptide bond holds amino acids together

• Dipeptide & Polypeptide = chains of amino acids

Most Diverse Group of Molecules

Enzymes

• Most are proteins– ase ending

• Protease (digests proteins)

• Catalysts– Speed up rxns by reducing activation E

(essential for cell function)

• Reduce efficiency if change in T or pH– Active site changes shape (lock & key)

pH

• Acids: inc. the H+ conc. • Bases: inc. the OH- conc. • pH = -log[H+]

– As [H+] inc., pH dec. (10 fold)

• pH scale: 1-14– Acidic = <7– Neutral = 7– Basic = >7

3. Lipids

• Fatty acids = monomer– Hydrophilic (water loving): polar head– Hydrophobic (water fearing): nonpolar tail

• Store the most E

Complex Lipids

• Fats: triglycerides– Saturated – bad– Unsaturated – good

• Phospholipids: cell barrier– Waxes: protective covering

• Steroids: cholesterol, hormones

4. Nucleic Acids

• Nucleotide = monomer

• Store impt. info in the cell & make proteins– DNA & RNA