KH 01 Flashcards
What are 3 informational biopolymers?
DNA, RNA and protein
What is a polymer?
A covalent bond-linked chain of monomers
What is a sequence?
The order of the different kinds of monomer units in the polymer chain. It’s the information in an informational biopolymer. Different sequence = different information
In the case of DNA, RNA and protein, what would be the information?
The DNA sequence, the RNA sequence and the protein sequence
What are the 2 elements that form the common generic structure of informational biopolymers?
A common element (shared by all the different monomers) and a characteristic element (that makes each monomer different from the others)
What is the polymer backbone?
The common element of informational biopolymers “linked” by covalent bonding between monomers
What do the characteristic elements form that protrude form the polymer backbone?
Side-chains
If the monomer has one joining site in the common element, how many monomer units can be joined together?
Only two monomer units. It can only form a dimer (no other joining sites are exposed at the common element’s ends, there is no further chain growth)
If the monomer has two joining site in the common element, how many monomer units can be joined together?
Potentially infinite monomer units. We can make linear polymers (joining sites are exposed at the common element’s ends, further chain growth is possible)
If the monomer has three joining site in the common element, how many monomer units can be joined together?
Potentially infinite monomer units. We can make branched polymers.
Can cells make branched polymers?
Yes (ex: complex carbohydrates)
Can informational biopolymers make branched polymers?
No. Informational biopolymers are always linear and have two joining sites
Packaging and handling of (1) molecules may be more efficient than of (2) molecules
- Linear
- Branched
(this is a good thing for scientific progress because it would have been harder to determine the structures if they had been branched)
In most cases, how many ends do linear informational biopolymers have?
2 ends, but in some cases, the two ends can be joined, giving an unbranched circular molecule (ex: viruses)
Are the monomers in informational biopolymers symmetric?
No, they are asymmetric. The two joining sites are different (there is an “A” end and a “B” end. A can only join with B, B can only join with A)
Is the informational polymer symmetric?
Like the monomers, the polymer is asymmetric. The “A” end and the “B” end are also chemically distinct
Polymer growth is…?
Unidirectional. For DNA, RNA and protein, growth of the chain occurs only at one end
What is the convention when showing biopolymer representations on a sheet of paper and depicting polymer growth?
Polymer chain growth is depicted in the rightward direction. New monomers are added at the right end
What is the typical chain length of DNA?
About 1000 to 100 million nucleotides
What is the typical chain length of RNA?
About 20 to 10 000 nucleotides
What are the nucleic acids’ (DNA, RNA) monomers?
Nucleotides
What are the proteins’ monomers?
Amino acids
What is the typical chain length of protein?
About 100 to 1000 amino acids
What are the nucleotides’ polymers?
Nucleic acids
What are the amino acids’ polymers?
Protein
What is the characteristic element in nucleotides?
A heterocyclic base (ex: adenine)
What is the common element that form the polymer backbone in nucleotides?
A pentose sugar phosphate (ex: ribose)
What are the 2 joining sites on the nucleotide’s common element?
The 5’ phosphate (the acid in “nucleic acid”, has a negative charge) and the 3’ hydroxyl (OH)
Nucleic acid polymer growth is always by addition of monomers to which end?
The 3’ end
What charge do nucleic acids have?
A strong negative charge
The monomer polarity is reflected in the polymer, so we speak of the ___ end and the ___ end of a nucleic acid chain.
5’ end, 3’ end
What is the pentose sugar phosphate found in DNA?
Deoxyribose