Sept 1 Building Blocks and Linear Biopolymers Flashcards
what kind of polymers are DNA RNA and protein?
informational polymers
what is a polymer?
chain of monomers linked by covalent bonds
what constitutes the information in informational polymers?
the order of the different kids of monomers in the polymer chain, the “sequence”
what is the information in the case of DNA, RNA and proteins?
the DNA/RNA/protein sequence
What is the common generic structure of an informational biopolymer?
- a common element, all monomers of that class of informational biopolymer have the same
- a “characteristic” element that makes each monomer specific and different
what are the names of the different structure and what they do?
common elements: “backbone”, bind by covalent bonds with other monomers
characteristic elements: “side chains” that protrude from the backbone
how many joining sites does the common element need to have to make a linear polymer?
TWO joining sites (monomers can join on both sites)
how many joining sites on the common element to make branched polymers?
THREE joining sites (can make branching)
are informational biopolymers linear or branched? and why?
what happens in some cases?
informational biopolymers are linear
packaging and handling of linear molecules may be more efficient than that of branched molecules
sometimes the two ends can join together, making a circular but unbranched molecule (DNA molecule of bacteria and some viruses)
what type of monomers are informational biopolymers made of?
asymmetric monomers
what does asymmetric monomers mean?
there are two joining sites per monomer but the two sites are different
A and B
A can only join with B
B can only join with A
what does this create in the polymer?
it creates an asymmetric polymer
there is an A end and there is a B end and they are chemically distinct
in what direction does the polymer chain growth go?
the growth only occurs at one end, it is unidirectional
what is the convention when depicting biopolymers on paper?
the growing side is on the right
monomers are added on the right end
what are the two major types of informational biopolymer units?
nucleotides (DNA and RNA) and amino acids (proteins)
for nucleic acids, what is the monomer and the typical chain length?
DNA:
nucleotides
10^3 to 10^8
RNA:
nucleotides
20 to 10^4
for proteins, what is the monomer and the typical chain length?
amino acids
100 to 1000
what is the common element that forms the backbone of nucleotides?
pentose sugar phosphate (heterocyclic base)
5C sugar and a PO4 (phosphate) attached to the 5th carbon
what are the joining sites on the common element?
the 5’ phosphate:
the acid
negative charge
the 3’ hydroxyl (OH)
to which end are monomers added in the growth of a nucleic acid?
the 3’ hydroxyl (OH) end
what is the difference in the nucleotides between RNA and DNA?
RNA has ribose sugar, OH found on 2’ carbon
DNA has 2-deoxyribose sugar, missing OH on the 2’ carbon (only an H there)
how does the absence of a hydroxyl group on the 2’ of DNA sugar affect it?
DNA is much more resistant to chain cleavage by hydrolysis therefore it has greater stability
what is the bond between the pentose sugar and the base?
N-glycosidic bond
(nitrogen bonded to a sugar)
What are purines?
adenine and guanine
what are pyrimidines?
uracil thymine and cytosine