Answer: Option A
Explanation:
Before the mRNA which has been processed from DNA is taken and transported to the ribosomes in the cytoplasm for the translation process, some modifications are made to the mRNA before transport. This includes
1. Capping: addition of 5'-5' phosphate bonds to the 5' terminus of the mRNA. Forms the cap structure that is essentials for binding to ribosomes via special proteins attached to the cap structure
2. Addition of poly(A) tail: a poly(A) addition signal (AAUAAA) is attached to the 3' terminus of the mRNA. They are important in translation initiation and degradation prevention
3. Splicing: this is likely the most remarkable processing in eukaryotes. It involves the removal of intron regions by excision from the present-mRNA and then ligating the exon regions together giving rise to the mRNA.
a notochord is definitely the backbone. it appears as a tiny flexible rod made from mesoderm cells. which is one third of the layer of embryos.
To activate the kinases, cyclins connect to them. The activity of cyclin-dependent kinases changes with cyclin concentration. At the G2 phase, Cyclin and a Cdk unite to start mitosis (M phase). This mixture produces MPF (maturation-promoting factor), which encourages the cell to continue mitosis through the M phase. The cyclin is broken down at the G1 phase, and the Cdk is recycled.
<h3>What about cyclins?</h3>
- A family of regulatory proteins known as cyclins manages how the cell cycle develops.
- Cyclins cause the phosphorylation of cyclin dependent kinases (CDKs), which regulate the cell cycle.
- A target protein will attach to a complex made up of a cyclin and a CDK, and the complex will phosphorylate the protein.
- Cyclins collaborate with an enzyme family known as the cyclin-dependent kinases to control the cell cycle's activities (Cdks).
- A Cdk that is not bound to a cyclin is inactive, but when it is, it becomes a functioning enzyme that can alter target proteins.
- By phosphorylating and inactivating target substrates, cyclins are the regulatory subunits of holoenzyme CDK complexes that control progression through cell-cycle checkpoints.
- Cyclin-dependent kinases (CDKs) are protein kinases that require a distinct subunit - a cyclin - that provides domains necessary for enzymatic action.
- The cyclins associate with various CDKs to offer specificity of function at various stages during the cell cycle.
- In response to various extracellular and intracellular signals, CDKs modify transcription and play significant roles in the regulation of cell division.
Learn more about cyclins here:
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Answer:
The cell divides into two cells
Explanation:
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