Complete question: "RNA plays important roles in many cellular processes, particularly those associated with protein synthesis: transcription, RNA processing, and translation. Drag the labels to the appropriate bins to identify the step in protein synthesis where each type of RNA first plays a role. If an RNA does not play a role in protein synthesis, drag it to the "not used in protein synthesis" bin.
1. transcription/RNA processing
2. translation
3. not used in protein synthesis
a) snRNA
b) tRNA
c) mRNA
d) RNA primers
e) pre-mRNA
f) rRNA
Answer
1. transcription/RNA processing:
a) snRNA
c) mRNA
e) pre-mRNA
2. translation
b) tRNA
f) rRNA
3. not used in protein synthesis
d) RNA primers
Explanation:
There are many RNAs, each in charge of performing a different function.
- preRNA is the precursor of the mature mRNA. These molecules possess long intermediate sequences called introns that do not codify for proteins. It occurs a posttranscriptional modification that eliminates introns and makes the RNA to get mature as mRNA.
- snRNA means "small nuclear RNA". These are small RNA molecules located in the nucleus and are implicated in the mRNA maturation process. They associate with proteins composing the small nuclear ribonucleoproteins, and their function is to contribute to the initial mARN processing that transcribes from DNA and that must maturate to be exported from the nucleus. These molecules eliminate the introns.
- mRNA means "messenger RNA". These molecules are carriers of the genetic information and are in charge of transporting it from the genome to the ribosomes. They are the mold for the new protein synthesis. Their nucleotide sequence is complementary with the nucleotide sequence of a particular DNA segment.
- rRNA means "ribosomal RNA". They are the principal ribosomal component. Ribosomes are constituted by two subunits. One of them is a big RNA molecule associated with about 20 proteins. The other subunit is composed of three RNA molecules associated with about 50 proteins.
- tRNA means "transference RNA". These molecules are in charge of transferring activated amino acids from the cytosol to the ribosomes where the new protein is being synthesized.
Protein synthesis is initiated when mRNA meets a free ribosome, the primary structure for protein synthesis. Ribosomes can be found in the rough endoplasmic reticulum or floating in the cytosol. They read the mRNA code and add the correct amino acid using transference RNA to build the protein.
