Chapter 3.5 - Protein synthesis ✓ Flashcards
Define protein synthesis and the two main processes.
-Protein synthesis is the process of making new proteins from the genetic information encoded in DNA.
-The two main processes that facilitate protein synthesis are transcription and translation
Define transcription
Transcription is the process of synthesizing mRNA molecule using the DNA template strand.
Define translation
Translation is the process by which ribosomes synthesize proteins using mRNA as a template.
Where are genes found within a cell?
They are found in chromosomes
What role does RNA polymerase play in transcription?
RNA polymerase binds to the promoter region of a gene, unwinds the DNA, and synthesizes the mRNA strand by joining free-floating RNA nucleotides.
Which strand of DNA is used for transcription?
The template strand (anti-sense strand) is used for transcription.
How does the coding strand compare to the mRNA?
The coding strand (sense strand) has the same sequence as the mRNA, except thymine (T) is replaced with uracil (U).
What direction does RNA polymerase synthesize the mRNA strand?
RNA polymerase synthesizes the mRNA strand in a 5’ to 3’ direction.
What are codons in the context of transcription?
Codons are triplets of RNA bases that correspond to the DNA bases, specifying the amino acids during translation.
What post-transcriptional modifications occur in eukaryotic cells?
In eukaryotes, the pre-mRNA undergoes modifications like the removal of introns and the joining of exons to form mature mRNA
Where does the mature mRNA go after processing?
The mature mRNA exits the nucleus via nuclear pores and enters the cytoplasm for translation.
What happens during the termination of transcription?
Transcription ends when RNA polymerase reaches a termination sequence, releasing the pre-mRNA.
What happens during the initiation phase of translation?
The ribosome binds to the mRNA molecule, and the start codon signals the beginning of translation.
How are codons translated during elongation?
A tRNA molecule with an anticodon complementary to the mRNA codon binds, and the ribosome facilitates peptide bond formation between amino acids.
What occurs during the termination of translation?
A stop codon enters the ribosome, attracting release factors that cause the ribosome to disassemble and release the completed polypeptide chain.
Define phosphodiester bond
A phosphodiester bond is a covalent bond that links a 3’ carbon in one sugar to a 5’ carbon in another sugar in DNA and RNA.
