the section of dna being used to make the strand of rna is known as a gene.
the section of dna being used to make the strand of rna is known as a gene.
the section of dna being used to make the strand of rna is known as?
a gene
toehold mediated strand displacement (tmsd) is an enzyme-free molecular tool to exchange one strand of dna or rna (output) with another strand (input). it is based on the hybridization of two complementary strands of dna or rna via watson-crick base pairing (a-t/u and c-g) and makes use of a process called branch migration . although branch migration has been known to the scientific community since the 1970s, tmsd has not been introduced to the field of dna nanotechnology until 2000 when yurke et al. was the first who took advantage of tmsd . he used the technique to open and close a set of dna tweezers made of two dna helices using an auxiliary strand of dna as fuel . since its first use, the technique has been modified for the construction of autonomous molecular motors, catalytic amplifiers, reprogrammable dna nanostructures and molecular logic gates . it has also been used in conjunction with rna for the production of kinetically-controlled ribosensors . tmsd starts with a double-stranded dna complex composed of the original strand and the protector strand . the original strand has an overhanging region the so-called “toehold” which is complementary to a third strand of dna referred to as the “invading strand”. the invading strand is a sequence of single-stranded dna (ssdna) which is complementary to the original strand . the toehold regions initiate the process of tmsd by allowing the complementary invading strand to hybridize with the original strand, creating a dna complex composed of three strands of dna . this initial endothermic step is rate limiting and can be tuned by varying the strength (length and sequence composition e.g. g-c or a-t rich strands) of the toehold region . the ability to tune the rate of strand displacement over a range of 6 orders of magnitude generates the backbone of this technique and allows the kinetic control of dna or rna devices .
toehold mediated strand displacement
on the leading strand, dna polymerase can make a complementary dna strand without any difficulty because it reads the template strand from 3' to 5'. however, there is a problem going in the other direction on the lagging strand. to counter this, short sequences of rna acting as primers attach to the lagging strand a short distance ahead of where the initiation site was. the dna polymerase can start replication at that point and go to the end of the initiation site. this causes the formation of okazaki fragments. more rna primers attach further on the dna strand and dna polymerase comes along and continues to make a new dna strand.eventually, the last rna primer attaches, and dna polymerase, rna nuclease, and dna ligase come along to convert the rna (of the primers) to dna and to seal the gaps in between the okazaki fragments. but, in order to change rna to dna, there must be another dna strand in front of the rna primer. this happens at all the sites of the lagging strand, but it does not happen at the end where the last rna primer is attached. ultimately, that rna is destroyed by enzymes that degrade any rna left on the dna. thus, a section of the telomere is lost during each cycle of replication at the 5' end of the lagging strand's daughter.
telomere