The human zona pellucida has four major glycoproteins— ZP1, ZP2, ZP3, and ZP4

TLS Online TPP Program

#Id: 3963

#Unit 2. Cellular Organization

The capsid is assembled around the genome for single-stranded RNA viruses in TMV.

TLS Online TPP Program

#Id: 3965

#Unit 2. Cellular Organization

Inserting DNA into a phage head involves two types of reaction:

translocation and condensation. Both are energetically unfavorable.

The genome is packaged into the empty capsid by the terminase enzyme.

TLS Online TPP Program

#Id: 3966

#Unit 2. Cellular Organization

In E.coli, Protein HU is a dimer that condenses DNA, possibly wrapping it into a beadlike structure.

TLS Online TPP Program

#Id: 3967

#Unit 2. Cellular Organization

The bacterial genome consists of a large number of loops of duplex DNA (in the form of a fiber), each of which is secured at the base to form an independent structural domain.

TLS Online TPP Program

#Id: 3968

#Unit 2. Cellular Organization

Each domain consists of -40 kilobases of DNA, or may be smaller, 10 kb each. About -400 domains in the E. coli genome. The ends of the domains appear to be randomly distributed instead of located at predetermined sites on the chromosome.

TLS Online TPP Program

#Id: 3969

#Unit 2. Cellular Organization

An unrestrained supercoil in the DNA path creates tension, but no tension is transmitted along DNA when a supercoil is restrained by protein binding.