Chem Exam 4

lipids

organic molecules that are not water soluble.

• no specific functional group

4 basic categories of lipids

fats and waxes, complex lipids, steroids; prostaglandins, leukotrienes, thromboxanes

fats and waxes

fatty acids, 12-20 carbon monocarboxylic acids

unsaturated fatty acids

have double bonds, can undergo chemistry to metabolize easier.

• melting points are lower than saturated fat melting points.

all natural unsaturated fatty acids are

cis unsaturated fatty acids

• have a lower melting point

polyunsaturated fats

more desirable because lower melting point and more reactive

• means its easier to metabolize

triglycerides

glycerol backbone with 3 fatty acids

soap

glycerol and the sodium salts of fatty acids.

created when a triglyceride reacts with a base such as NaOH

linoleic and linolenic fats

essential fats

• alpha and omega fatty acids

• need from outside sources

complex lipids

phospholipids and glycolipids

phospholipids

have a glycerol or sphyngocine backbone

• both include a phosphate group

Phosphate group adds dual solubility

glycolipids

have a sphingocine backbone and a sugar group

also possesses dual solubility

steroids

4 rings: 3 six membered rings, 1 five membered ring

ex. cholesterol

Cholesterol

liver breaks down HDL into bile salts.

building block of steroids and sex hormones

bile salts

amphipathic molecules that act as detergents

prostaglandins

mediate fever and pain

leukotrienes

trigger inflammation, bronchioconstrictors (athsma)

thromboxanes

promote blood clotting, vasoconstrictor

proteins

polyamides, come from a carboxylic acid reacting with an amine (dehydration rxn)

Amino acids

20 common

all are water soluble and have a high melting point

react with itself due to zwitteronic forces

amino acid structure

alpha carbon, amine group, carboxyl group, and R group

primary structure of protein

amino acid sequence, amide bonding through dehydration

2º structure

folding patterns: alpha helix or beta pleated sheet

• occur through hydrogen bonding between two amino acids in the backbone

3º structure of proteins

interactions with the R group

• ionic bond

• hydrophobic interactions

• hydrogen bonding

• disulfide linkage

• metal ion coordination

4º structure of protein

consists of more than one amino acid chain

ex. hemoglobin

protein function

1. enzymes

2. immunoglobulins

3. transport proteins

4. regulatory proteins (insulin)

5. structural proteins

6. movement

7. receptor proteins

denaturing proteins

ruining a proteins shape, done by denaturing bonds in the 2º or 3º structures.

denaturing methods

1. adding an acid or base

2. [O] or [H]

3. adding salts or metals

4. physically mixing it

5. heat

6. adding organic compounds or solvents

enzymes

proteins found in the cell that are responsible for catalyzing chemical reactions

• super specific, usually 1 enzyme for a given chemical reaction.

• make reactions faster by 10⁸ - 10²⁰

• remain unchanged

• each cell contains > 3000 enzymes

lock and key method

reactant is the substrate and the active site on the enzyme is what it’s interacting with

induced fit model

the enzyme is always moving but it accommodates the substrate as the substrate approaches.

What can alter the active site

pH and temp.

most enzymes optimal pH is 5-8.

• if not at optimum, the enzymes will denature and no longer work

cofactors

inorganic enzyme helpers that make for proper enzyme activity.

• minerals

coenzymes

organic helpers for proper enzymatic activity

ex. vitamins

competitive enzyme inhibition

the inhibitor blocks the active site, not allowing the substrate access to it, thus no reaction.

adding more substrate can override and increase the rate of reaction

non-competitive inhibition

interact at a different spot on the enzyme, changes the shape of the active site.

• substrate cannot interact and no reaction occurs

• adding more substrate does not increase the rate of reaction.

allosteric/non-competitive regulation

inhibitor

proenzyme/zymogen

group on/group off inactive group preventing enzyme from working

feedback control

one of the products acts as an inhibitor.