4. Why are transcription and translation two separate but necessary steps for protein

synthesis? In other words, why can't the DNA code be read and translated directly?

Not all of the DNA codes for proteins. Infact, majority of the DNA is non - coding. Hence, it is more reliable to convert the DNA into only the coding form i. e mRNA for translation or making of proteins.

The DNA itself cannot travel through the nuclear pores. Hence, converting it into mRNA is necessary.

The process of protein synthesis occurs in the ribosomes. Hence, it is necessary that an mRNA might be present to transfer information of the DNA into the ribosomes for protein synthesis.