GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
RNA polymerase uses DNA as a template.
|
|
|
DNA polymerase III does not require localized unwinding of the DNA.
|
|
|
DNA polymerase III uses primer, usually made of RNA.
|
|
|
RNA polymerase makes a single-stranded molecule.
|
Detailed explanation-1: -Evidence that RNA arose before DNA in evolution can be found in the chemical differences between them.
Detailed explanation-2: -Primers are required because DNA polymerases, the enzymes responsible for the actual addition of nucleotides to the new DNA strand, can only add deoxyribonucleotides to the 3’-OH group of an existing chain and cannot begin synthesis de novo.
Detailed explanation-3: -Primers are necessary because DNA polymerase can only extend a nucleotide chain, not start one. DNA polymerase begins to synthesize a new DNA strand by extending an RNA primer in the 5’ to 3’ direction. Each parental DNA strand is copied by one DNA polymerase.
Detailed explanation-4: -RNA can direct the creation of proteins and perform other essential functions of life that DNA can’t do. RNA’s versatility is one reason that scientists think this polymer came first, with DNA evolving later as a better way to store genetic information for the long haul.