The mass number is the sum of the number of protons and number of neutrons the atom has.
So, we can write the equation as:
x + 20 = 40
x = 20 neutrons.
ECM is the extracellular matrix, or the set of extracellular molecules secreted by cells with the purpose to support surrounding cells. In plants the cell wall is the ECM and in mammals ECM can be in the form of fibrils and may constitute a significant portion of the bulk of the organism and it also referred as connective tissue.
All of the following are forms of radiation except A. Stabilizing rays.
In prokaryotes the 5' UTR is 3-10 nucleotides.
In Eukaryotes the 5'UTR is 100 to many thousand nucleotides long.
Explanation:
Leader sequence or 5' UTR starts at transcription site and ends at the initiation codon just one nucleotide away from it.
It is present in mRNA.
These are GC rich and form secondary structure, helps in protein synthesis.
Shine Dalgarno sequence in prokaryotes is an example of 5'UTR.
It acts as an entry point of ribosome.