Is this a question?or an answer
Answer:
The correct answer would be "Myosin heads attach to sites on actin filaments".
The muscle cell or myofibril consists of two types of protein filaments namely; actin (thin filament) and myosin (thick filament).
The myosin heads attach to the binding sites on the actin filaments and pull it towards the M-line in order to produce contraction.
The hydrolysis of ATP provides energy for this contraction cycle.
An enzyme, which cleaves DNA after identifying a specific sequence of DNA is known as a restriction enzyme. The restriction enzymes are regarded as molecular scissors. The restriction enzymes are used by scientists to cleave a single gene from a bigger DNA piece that is, a fragment of foreign DNA and is spliced into a phage genome with the help of DNA ligase and restriction enzyme.
The packaging of recombinant phage DNA is done in vitro and is permitted to infect a bacterial cell. The infected bacteria generate novel phage particles, each comprising a foreign DNA.