W15 L1 - RNA

Flashcards about RNA structure, function, and types. These flashcards cover the key differences between RNA and DNA, the types and function of RNA.

What is the typical structure of RNA?

A single-stranded molecule, unlike DNA which is double-stranded.

In what instances can RNA be double-stranded?

In some viruses, the genome is encoded in double-stranded RNA.

What is intramolecular base pairing in RNA?

Base pairing within the same RNA strand.

What bases are found in RNA?

The bases A, G, C, and Uracil (U).

Which base replaces Thymine (T) in RNA?

Uracil.

What sugar is found in RNA?

Ribose.

What makes RNA less stable compared to DNA?

The presence of a hydroxyl (OH) group in the two prime position of ribose.

How is RNA generated in cells?

RNA is generated from DNA by RNA polymerases.

Which strand of DNA does RNA polymerase use as a template?

The bottom strand.

How can a DNA sequence be converted to an RNA sequence?

Replace every T (Thymine) in the DNA sequence with a U (Uracil).

What is RNA called before modification in eukaryotic cells?

Pre-mRNA.

What are other RNA molecules besides mRNA called before modification?

Heteronuclear RNA (hnRNA).

What is the five prime cap modification in mRNA?

A seven methyl guanosine attached to the five prime end.

What is the purpose of the five prime cap?

To make the mRNA molecule more stable.

What is added at the three prime end of mRNA in eukaryotic cells?

Lots of Adenines (A's) are added.

What is the purpose of the poly A tail?

To make the messenger RNA more stable.

What does tRNA stand for?

Transfer RNA (tRNA).

What is the function of tRNA?

To transport amino acids to the ribosome.

What type of base pairing gives tRNA its characteristic shape?

Intramolecular base pairs.

What does rRNA stand for?

Ribosomal RNA (rRNA).

What are ribosomes?

The factories where proteins are made.

What percentage of a ribosome is made up of rRNA?

About 80%.

What protects ribosomal RNA from degradation?

Proteins.

What additional RNA molecules are found in many cells?

MicroRNA (miRNA) and small interfering RNA (siRNA).

What is siRNA and what is its function?

Double-stranded RNA molecule involved in protection against viruses.

What are microRNAs and what do they do?

Single-stranded RNA molecules that can activate or inhibit gene activation.

What are microRNAs sometimes referred to as?

Master switches.

What changes can lead to cancer?

Changes in the microRNA profile.

How does the oxygen in the two prime position of RNA cause it to break down?

Attack the phosphate group and form a bond, breaking the RNA strand.

What enzymes generate RNA from the information the DNA provides?

RNA polymerases.