Can anyone answer these 2 questions?

Question

1. Discuss or explain the role of microfilaments in cytokinesis.


2. Summarize or explain cell division in prokaryotes.

Answer 1

Actin is a globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament). These form the cytoskeleton - a three-dimensional network inside an eukaryotic cell. Actin filaments provide mechanical support for the cell, determine the cell shape, enable cell movements (through lamellipodia, filopodia, or pseudopodia); and participate in certain cell junctions, in cytoplasmic streaming and in contraction of the cell during cytokinesis. In muscle cells they play an essential role, along with myosin, in muscle contraction. In the cytosol, actin is predominantly bound to ATP, but can also bind to ADP. An ATP-actin complex polymerizes faster and dissociates slower than an ADP-actin complex. Actin is one of the most abundant proteins in many eukaryotic cells, with concentrations of over 100 μM. It is also one of the most highly conserved proteins, differing by no more than 5% in species as diverse as algae and humans.
--> http://en.wikipedia.org/wiki/Actin

Prokaryotes such as bacteria use a relatively simple form of cell division called binary fission. The diagram at 1.shows a bacterial cell. The cell wall and membrane are in red, the bacterial chromosome in blue, the cytoplasm in light green. The yellow dot represents a point of attachment of the chromosome to the cell membrane.

Typically bacterial chromosomes consist of a single loop of DNA, often called circular DNA. Eukaryotes have a linear DNA molecule.
Duplication of the DNA. During this step the bacterial chromosome replicates leading to two identical chromosomes attached to separate points of attachment. This may seem like a simple process but it is not as discussed here.
The cell begins to divide, each cell with an identical chromosome.
The result is two identical daughter cells.

Rate of multiplication in Bacteria. Bacteria can divide every twenty to thirty minutes. This gives bacteria remarkable powers of multiplication. Consider a single bacteria. After 24 hours there would be 2^48 or 2.81 x 10^14 bacteria. This is within the range of the number of eukaryotic cells in the human body.

This has obvious implications for dealing with bacterial diseases because since bacteria multiply so rapidly it is critical to treat bacterial diseases swiftly and as completely as possible.

Fortunately bacteria rarely are able to sustain this high rate of multiplication for long because of limitations in nutrient availability and various bacteria feeding organisms(bacteriovores)and bacteria infecting viruses(bacteriophages).
--> http://staff.jccc.net/pdecell/celldivision/prokaryotes.html