Potassium channels remain open for another few tenths of a second, with resultant excess negativity inside the fiber; this process is called hyperpolarization.

TLS Online TPP Program

#Id: 2973

#Unit 3. Fundamental Processes

in mammalian cells, Cdt1 is targeted for degradation by the action of a protein complex that is recruited to the origin of replication by PCNA, the eukaryotic counterpart of the bacterial beta-clamp.

TLS Online TPP Program

#Id: 2974

#Unit 3. Fundamental Processes

In Xenopus extracts, replication can be initiated if ORC is removed after it has loaded Cdc6 and MCM proteins.

TLS Online TPP Program

#Id: 2975

#Unit 3. Fundamental Processes

The MCM proteins, once activated, are required for elongation as well as for initiation.

TLS Online TPP Program

#Id: 2976

#Unit 3. Fundamental Processes

The MCM proteins continue to function at the two bidirectional replication forks as the replication helicase.

TLS Online TPP Program

#Id: 2977

#Unit 3. Fundamental Processes

In yeast, the combined action of Cdc6, Cdtl, and the MCM proteins provides the licensing function.

TLS Online TPP Program

#Id: 2978

#Unit 3. Fundamental Processes

This alteration to the structure of the chromosome is accomplished by the enzyme topoisomerase. Replication cannot occur on supercoiled DNA, only the relaxed form.