1.2 chemistry of life 2

lipid

biomacromolecule not soluble in water, made up of primarily of hydrocarbon chains with some oxygen and sometimes phosphorous or nitrogen

fatty acids

long non-polar hydrogen chains with a COOH on end

triglyceride

most abundant lipid in living things, act as reserve fuel storage, three carbon glycerol attached to three fatty acids

adipocytes

fat cells, where triglycerides are stored

chylomicron

triglyceride plus cholesterol, formed after absorbing broken down fatty acids in intestines

phospholipid

polar head group joined to non-polar tail group

amphipathic

“of both kinds” describes phospholipids which are polar

phospholipid head group

negatively charged phosphate group and positive, usually nitrogen containing group, hydrophilic

tail group of phospholipid

hydrocarbon chain, hydrophobic

steroid

lipid made up of four fused carbon rings with other functional groups, most commonly alcohols, unique structure from other lipids

cholesterol

a steroid that is essential structurally in animal cell membranes, but forms arterial plaque in excess, which can cause heart attacks. bile salts, estrogen, progesterone, testosterone synthesized from cholesterol

protein functions

(1) can act as enzymes and regulate metabolic functions

(2) store amino acids

(3) act as hormones

(4) form antibodies for immunological defense

(5) act as carriers for transport and also form membrane channels

(6) form cell surface receptors to receive chemical messages

(7) act as structural molecules for support and movement

amino acids

organic compounds that serve as the foundational building blocks of protein, 20 of them make up all naturally occurring proteins, made up of an amino group, a carboxyl group, and an R group

enzymes

protein catalysts that speed up reactions

hemoglobin

protein that carries oxygen in red blood cells

essential amino acids

humans must get from food

non-essential amino acids

amino acids that the body can manufacture

phenylketonuria

no phenylalanine hydroxylase makes it so the body cannot break down phenylalanine

peptide bond

holds amino acids together to form proteins

polypeptide

a long chain of amino acids

primary structure

order of amino acids in a protein

collagen

an important protein in skin, tendons and ligaments, provides elasticity and strength because of its   triple helix secondary structure

α-helix

a spring-like coil configuration that comprises the basic structural unit  of some fibrous proteins that make up wool, hair, skin, and fingernails. These fibers are elastic and can stretch to some extent

ß-sheet

formed when a polypeptide chain snakes back and forth alongside itself, making a pleated sheet that is strong and flexible, but not elastic

hydrogen bonding

in proteins, between N-H hydrogen and C=O oxygen, holds secondary structure together

secondary structure

local folded structures like a-helix, b-sheet

tertiary structure

the total 3-D shape of the polypeptide chain, determined by interactions between side-chain R-groups, by hydrogen bonding, and by hydrophobic interactions

quaternary structure

made up by interactions between polypeptide chains in a protein with multiple

hemoglobin

globular protein made up of 4 polypeptide chains

denaturing

change in protein structure due heat, causing loss of quaternary and tertiary structure (unfolding)

nucleic acids

DNA or RNA, molecules that carry genetic information within the cell

DNA (deoxyribonucleic acid)

contains a vast amount of hereditary information and is responsible for the inheritable characteristics of living organisms

RNA (ribonucleic acid)

responsible for deciphering the hereditary information in DNA and using it to synthesize proteins

nucleotides

monomers that make up the polymers of nucleic acids, made up of 1) five-carbon sugar (deoxyribose or ribose) 2) a phosphate group and 3) a nitrogen-containing ring called a nitrogenous base

DNA nitrogenous bases

adenine (A), guanine (G), cytosine (C) or thymine (T)

RNA nitrogenous bases

adenine (A), guanine (G), cytosine (C) or uracil (U)

double-helix

structure of DNA in which two chains of nucleotides are held together by hydrogen bonds on the bases

what determines the properties of an amino acid?

the R group/ side chain