A codon Question 6 options: corresponds to a particular amino acid. consists of four nucleotides. consists of discrete amino acid regions. catalyzes RNA synthesis.

corresponds to a particular amino acid

Explanation:

All living organisms/cells consists of DNA, which encodes or stores genetic information. The DNA is made up of nucleotide bases, whose order determines the order of the nucleotides in the transcript mRNA. The mRNA is read in a group of three nucleotide sequences called CODON. Each codon specifies an amino acid i.e. codes for a specific amino acid in the genetic code.

There are about 64 possible codons made from 4 nucleotides that are read three at a time i.e. 4^3=64.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.