I had a moment of clarity about the pervasive and indispensable functions of microtubules in the formation of living organisms.
Example: the activation of human cell division which eventually builds an entire 3 dimensional pattern of a living person.
a) a human egg contains DNA, the latent genetic blueprint of a potential 3 dimensional pattern of an entire homo sapiens (sans bacteria).
Microtubules, Cell Division and the Mitotic Spindle
Cell division is not only important to reproduce life, but to make new cells out of old. Microtubules play an important role in cell division by contributing to the formation of the mitotic spindle, which plays a part in the migration of duplicated chromosomes during anaphase. As a “macromolecular machine,” the mitotic spindle separates replicated chromosomes to opposite sides when creating two daughter cells.
The polarity of microtubules, with the attached end being a minus and the floating end being a positive, makes it a critical and dynamic element for bipolar spindle grouping and purpose. The two poles of the spindle, made from microtubule structures, help to segregate and separate duplicated chromosomes reliably.
Two Major Groups of Microtubule Motors
The bead-like construction of microtubules serves as a conveyor belt, track or highway to transport vesicles, organelles and other elements within the cell to the places they need to go. Microtubule motors in eukaryotic cells include kinesins, which move to the plus end of the microtubule – the end that grows – and dyneins that move to the opposite or minus end where the microtubule attaches to the plasma membrane.
As “motor” proteins, kinesins move organelles, mitochondria and vesicles along the microtubule filaments through the power of hydrolysis of the energy currency of the cell, adenosine triphosphate or ATP. The other motor protein, dynein, walks these structures in the opposite direction along microtubule filaments toward the minus end of the cell by converting the chemical energy stored in ATP. Both kinesins and dyneins are the protein motors used during cell division.
Recent studies show that when dynein proteins walk to the end of the minus side of the microtubule, they congregate there instead of falling off. They hop across the span to connect to another microtubule to form what some scientists call “asters,” thought by scientists to be an important process in the formation of the mitotic spindle by morphing the multiple microtubules into a single configuration.
b) a human sperm contains Mitochondria, the processors of DNA instructions which activate the cell duplication process.
Sperm swim by means of a prominent flagellum, composed of a core of microtubules, whose sliding is powered by flagellar dynein. This array of microtubules and associated motor and linker proteins is known as an axoneme. The midpiece of the sperm contains a prominent array of mitochondria, which are required to produce huge amounts of ATP, whose hydrolysis powers the conformational changes in flagellar dynein that mediate microtubule sliding.
http://worms.zoology.wisc.edu/dd2/echino/fert/sperm/sperm.html
So what we have here is a single celled dormand egg and a single celled dynamic processor of chromosomal (DNA) instructions…
This simple interactive combination of a fundamental building block and a little machine that makes copies of the building blocks and placement in accordance to the inherent blueprint contained in the DNA.
These two single celled organelles produce an entire living organism and continue to build new and and refresh old cells in the organisms.
We speak of “hard problems” in the questions of life and consciousness, but rather than ask the hard problem , we can begin to address some “hard answers” which apparently are all that is neessary for organizing a living thing.
All that is required to build an entire fully formed organism is an egg and a sperm. That’s it folks, nothing else required except a little love.