Exam Four Flashcards
bronsted and lowry definitions of acids and bases
ACIDS: release a H+
BASES: accept H+
keq/ the equilibrium constant
aA + bB = cC + dD
Keq = [C]c[D]d/ [A]a[B]b
products/reactants
- solids and solvents are omitted
keq > 1 (reactants are favored)
keq < 1 (products are favored)
keq = 1 (reactants = products)
le chatelier’s principle
when a reversible reaction is pushed out of equilbrium, the reaction responds to reach a new equilibrium
- any changes in conc. pressure or temp can be a disruption
- RATE OF FORWARD REACTION INCREASES (addition to the reaction)
- RATE OF REVERSE REACTION INCREASES (removal from reaction)
the equilibrium constant of water
Kw = 1.0 x 10^-14
a solution with a higher H3O+ than OH- will be:
have a pH lower than 7, and be acidic
pH scale
acidic pH < 7
neutral pH = 7
basic pH > 7
acid and base strength
STRONGER THE ACID - more H3O+ PRODUCTION - LOWER PH
STRONGER THE BASE - more OH- - HIGHER PH
LARGER KA - STRONGER ACID
LOWER PKA - STRONGER ACID
neutralization
- occurs when an acid and a base react to form a salt and water
- reaction seen when proper amounts of acid and base are added
titration
- lab technique used to determine conc. of an acid and base solution
- acid solution (unknown), base of known conc. is ADDED to consume acid
- specific indicator added to find titration end point
buffers
- solution that is resistant to a pH change when a small amount of acid or base is added
- created from weak acid and conjugate base; are within a 50:50 ratio
- most resistant to pH changes when the pH is equal to pKa of the acid
carbohydrates
- can be seen through sugars and starches
- help provide energy
- used to store energy
- plants produce them through photosynthesis
- stored carbs can be broken down to produce energy
monosaccharides
classified by their functional group
- aldoses - contains aldehyde
- ketoses - contains ketone
chiral C atom
one that is attached to 4 different atoms or groups of atoms
D or L sugars
D sugars: -OH attached to the chiral carbon FURTHEST FROM CARBONYL GROUP to the RIGHT
L sugars: -OH attached to the LEFT
amino sugars
an -OH group of a monosaccharide has been replaced by an amino (-NH2) group
benedict’s reagent
- used in the lab to oxidize aldehydes
- sugars that give a POSITIVE RESULT - looks for reducing sugars (in urine)
- sugar is being oxidized while Cu2+ is reduced
- helps monitor diabetes
alpha and beta anomers
alpha anomer - has the C#1 -OH pointing down
beta anomer - has the C#1 -OH pointing up
*always gonna be the first carbon - anomeric carbon (typically on the right side of ether group)
- creates a GLYSODIC BOND with other saccharides
cellulose
- example of a polysaccharide
- important to maintain the structure of plants
- humans lack the enzyme that hydrolyzes cellulose
- has many intra and inter chain H bonds
- composed of glucose
starch
- example of a polysaccharide
- energy storage molecule for plants
- composed of glucose
- has alpha (1 to 4) glycosidic bond that makes starch coil
amino acids
- contains 1 carboxyl group and 1 amino group
- there’s around 20 different AA’s found in proteins
- named as alpha-amino acids
glycogen
- another polysaccharide
- composed of glucose
- energy storage compound
- animal starch
nonpolar amino acids
only contain ALKYL GROUPS
polar neutral amino acids
- has sulfur or oxygen atoms, sometimes alcohol
acidic amino acids
have a CARBOXYLIC ACID ATTACHED and is negatively charged
basic amino acids
have a couple of NITROGEN ATOMS attached and are POSITIVELY CHARGED
pH charges
- peptide will change if the pH is changed
pH 1 - net charge 2+
pH 7 - net change 0
pH 14 - net charge 2-
fibrous proteins
- exist in long fibers or strings
- often seen in hair and skin
- typically tough and water insoluble
globular proteins
- spherical in shape
- highly folded
- water-soluble
- also are known as enzymes
- has nonpolar amino acids in interior, has polar amino acids on surface
primary structure
- order of amino acid residues/amino acid sequence
- listed from N-terminus to C-terminus
the loss of the native conformation of a protein caused by heat
- denaturation
quaternary structure in proteins occurs only in proteins composed of:
- more than one polypeptide chain
- maintained by non-covalent interactions
- regulates protein activity
secondary structure
- how protein chain is folded, twisted, or bent
- has alpha-helix and beta-sheets
(both stabilized by hydrogen bonds)
tertiary structure
the overall 3D shape of a protein
b sheets
- form when different segments of a polypeptide chain align side by side
- parallel sheets - same direction
- antiparallel sheets - opposite directions
examples of non-amino acids compounds called prosthetic groups:
the heme group and several metal ions
