Transcription Process

Study Notes

Transcription

During transcription, an mRNA molecule is created in the nucleus through a process involving DNA uncoiling, nucleotide pairing, and phosphodiester bond formation.
Hydrogen bonds between complementary bases break, and one DNA strand serves as a template (antisense strand) for mRNA formation.
Free nucleotides line up through complementary base pairing and are joined by phosphodiester bonds, forming an mRNA molecule, catalyzed by RNA polymerase.
When a stop codon is reached, transcription ceases, and the RNA polymerase moves away, allowing the DNA to rejoin.

Splicing in Eukaryotic Cells

In eukaryotic cells, the pre-mRNA undergoes splicing to remove introns, leaving a strand of exons.
The mRNA then exits the nucleus through a pore and attaches to a ribosome in the cytoplasm.

Translation

In translation, amino acids join to form a polypeptide chain through a process involving mRNA, ribosomes, and transfer RNA (tRNA).
mRNA attaches to a ribosome, and tRNA collects amino acids from the cytoplasm, carrying them to the ribosome.
tRNA attaches itself to mRNA through complementary base pairing, and amino acids join by a peptide bond, releasing the tRNA.
This process repeats until a stop codon is reached, ending protein synthesis.
A ribosome can join up to 15 amino acids per second, and multiple ribosomes can move along the same mRNA strand, assembling proteins simultaneously.

Description

This quiz covers the process of transcription, where a molecule of mRNA is made in the nucleus. It describes the steps involved in unwinding DNA, using a template strand, and forming the mRNA molecule through complementary base pairing and phosphodiester bonds.