<span>An organism of the Kingdom Protista could be organisms that are eukaryotic. Though they are such, some organisms that belong in this kingdom can't be classified as a plant, animal or fungus. Organisms like algae and kelp which belong in this kingdom are multicellular and they are able to provide for themselves food, shelter, and oxygen in underwater environments.</span>
Cyclins
are the chemicals that regulate the cell cycle. Cyclins work by regulating the timing
of the cell cycle in eukaryotic cell. Cyclins activates cyclin dependent
kinases (CDKs) (an enzyme that works by adding <span>negatively charged phosphate groups to other
molecules in a process called phosphorylation) by binding to it to form a cyclin-Cdk
complex. This complex then functions by acting as a signal to the cell to move
to the next cell cycle phase. At the end of the event, the cyclin is degraded, Cdk
is deactivated, therefore signaling exit from a specific phase.</span>
<span>DNA replication involves unzipping the DNA molecule, followed by base pairing, which adds complementary nucleotides, to form two new identical DNA molecules that move to the new cells during cell division.</span>
generate energy by photosynthesis
Invertebrate doesn't posses "Backbone" whereas Vertebrate chordate have that. That's the only & most important difference between them.
Hope this helps!