lecture 3 Flashcards
element
can’t be broken down
-single atom
atom
smallest particle of an element that still retains its properties
molecule
two or more atoms join together chemically
compound
molecule that contains at least two different elements
covalent bond
strong bonds formed by the sharing of electrons between adjacent atoms
bond strength/dissociation energy
amount of energy required to break a bond
-covalent= more energy needed to break
polar covalent bond
unequal sharing of electrons due to a difference in EN
non covalent interactions
bond that does not involve the sharing of electrons
-ex. the components of DNA (A and T, G and C)
-very weak, but cumulatively very stong!!!
Ionic bonds
results from the loss or gain of electrons
hydrogen bonds
very important in biochemistry!!!!
-covalently bonded H atom on a donor group interacts w a pair of non-bonded electrons on an acceptor group
Hydrogen acceptors are
electronegative atoms (generally N or O)
polar molecules surrounded by water can dissociate into
acid= releases protons
base= accepts a proton
macromolecule: nucleic acid
subunit: nucleotide
Macromolecule: triacylglycerol and membrane lipid
subunit: fatty acid
macromolecule: polysaccharide
subunit: sugar
macromolecule: protein
subunit: amino acid
the simplest sugars are
monosaccharides
monosaccharides can be joined through glycosidic bonds to form
disaccharides (two monomers together), oligosaccharides (2-10 monomers) or polysaccharides (more than 10 monomers)
function of sugars (5)
- energy source
ex. glucose can be stored as glycogen - can be used for structure
ex. cellulose forms cell walls
ex. chitin found in the insect cytoskeletons - slime, mucus
ex. Phlegm is sweet due to the oligosaccharide chains (glycans ) covalently attached to amino acid side-chains of the glycoproteins in phlegm - modification of proteins and lipids
- information storage (ribose and deoxyribose in DNA)
Fatty acids (FA) –> triacylglycerols (TAG) and membrane lipids
FAs for TAG which serve as an energy source
FAs form membrane lipids which contribute to membrane structure and function
amino acids have the same basic structure with a
variable side chain
polypeptides
long chains of amino acids
how is the final 3D structure of a protein formed?
amino acids fold by using covalent and noncovalent interactions
Nucleoside components
base+ sugar (e.g. adenosine)
Nucleotide components
base+ sugar+ phosphate [e.g. adenosine monophosphate (AMP)]
RNA
ribonucleic acid
DNA
deoxyribonucleic acid
Functions of nucleotides
- short-term energy carriers (ATP)
- storage and retrieval of biological information (DNA, RNA)
Macromolecules are the most
abundant of the organic molecules in a living cell
Examples of macromolecules
DNA, RNA, protein, polysaccharides
native state of a molecule (concept)
generally, all molecules of a given protein or RNA species adopt the same 3D conformation despite the countless folding possibilities!!!
which type of interactions specify the precise shape of the molecule (native state)
noncovalent interactions
(electrostatic interactions, hydrogen bonds, van der waals attractions, hydrophobic interactions)
strong binding of macromolecules requires
-good specificity between macromolecules
(the cumulative effect of many covalent bonds can be very strong but require multiple points of contact)
what interactions act as building blocks to form much larger structures?
noncovalent interactions
metabolic intermediates
the compounds formed along the pathways leading to the end product but have no real function
weak attractions between adjacent water molecules are
hydrogen bonds
