Why is a cap added to mrna, but not to trna or rrna? a-transfer rna and rrna exhibit complex structures with double stranded regions. the three-dimensional shapes of these molecules keep the 5\' end of the rna away from the enzymes that process the cap. b-transcription and processing of mrna occur in the nucleus, where cap binding proteins are found. these proteins, which add and modify the cap, are not found in the cytoplasm, where trna and rrna are transcribed and processed. c-each of the three types of rna are transcribed by different rna polymerases. only rna polymerase ii, involved in mrna synthesis, contains a domain capable of interacting with enzymes that form the cap. d-only mrna contains introns. capping occurs simultaneously with intron removal because the same enzymes and proteins involved in both of these processes must bind to rna at the same time.

The correct option is C ' Each of the three types of RNA are transcribed by different RNA polymerases. Only RNA polymerase II, involved in mRNA synthesis, contains a domain capable of interacting with enzymes that form the cap.'

Explanation:

All the different type of RNA's undergo the process of transcription. However, their transcription is carried on by different types of RNA polymerases.

The transcription of the mRNA is carried by RNA polymerase II. The process of capping is essential so that the mRNA is stopped from degradation.

The rRNA is transcribed by RNA polymerase I which cannot add a cap tothe RNA.

The tRNA is transcribed by the RNA polymerase II, but the domain is different which cannot undergo the process of capping.

i think the answer is g1

hope i

-lavira: )

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle