Commission: Refined and Updated Storyboard

EXT. Bloodstream

"This bustling highway is the human bloodstream, the regular route of travel for many Cells, specifically, Red and White Blood Cells."

"Every so often, there are trespassers in the bloodstream and this is where White Blood Cells come in handy."

INT. Bone Marrow 'Police Station'

"White Blood Cells start of as Hematopoietic Cells in the Bone Marrow."

"These Hematopoietic Cells grow and mature to become White Blood Cells."

"The next step is Mitosis, where the White Blood Cell divides and increases its numbers in order to tackle bigger threats."

INT. White Blood Cell

"Mitosis takes place over several phases."

"First of all is the Prophase, where the chromosomes coil up and condense. This makes them shorter and thicker, and the nuclear envelope containing them is broken down. The separate copies of a single chromosome are known as sister chromatids. Spindle fibres are formed whilst centrioles move to either end of the Cell."

"The next step is the Metaphase. The chromosomes line up in the centre of the Cell. Microtubules formed during the Prophase attach to the sister chromatids."

"The sister chromatids begin to separate, this is the beginning of the Anaphase. The sister chromatids are held together by the centromere, which begins to divide as each sister chromatid, moves down its spindle fibre."

"The final step is the Telophase, in which the two now separate groups of chromosomes reach opposite sides of the Cell."

 "Both groups gain a new nuclear envelope and the chromosomes uncoil."

INT. Bone Marrow 'Police Station'

"The division is finalised through a process known as Cytokinesis, where the cytoplasm and organelles divide. The completed processes of Mitosis and Cytokinesis result in two separate cells that are genetically identical, known as daughter cells."

EXT. Bloodstream

"These daughter cells are free to duplicate further before they go on to fulfil their specified tasks."