Explanation:
Differentiation in cells occurs due to the silencing of some genes in the DNA of the cell while leaving others open to RNA polymerase enzymes.
Silencing occurs through the mediation of histones that tightly coil up DNA into heterochromatin in some regions. This way the genes in these regions are inaccessible to transcription enzymes and proteins and cannot be expressed. This means that proteins associated with these genes are not produced.
The open genes, on the other hand, in the euchromatin region, produce the necessary proteins that are associated with the determined function of the cell.
An example is that while the hepatocytes cells and brain cells of the same person have the same DNA, the genes for producing bile are silenced in the brain cells (and are open in hepatocytes) while genes responsible for producing neurotransmitters are silenced in hepatocytes but open in brain cells.
Learn More:
For more on gene silencing check out;
brainly.com/question/12777212
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brainly.com/question/10225586
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Answer:
Water slips between cracks in rocks on earth this is called weathering but on the moon there is no water so this cannot happen.
The first answer is A and the second answer is B
Answer:
The correct answer is A it transport the food generated by photosynthesis.
Explanation:
Both xylem and phloem are the examples of vascular tissue present in plants.xylem helps in the transport of water from root to different parts of the plants.
Whereas phloem helps in the transport of photo synthate from mesophyll tissue to sieve element companion cell complex.The transport of photosynthate to different non photo sythetic parts of a plant involves both symplastic and appoplastic pathway.
Symplastic pathway is a passive process depending on the pressure gradient for the transport of solutes through the plasmodesmata which connect 2 adjacent plant cells.
Appoplastic pathway is an active transport process occuring against the concentration gradient which does not involve plasmodesmata.
