D1.2 Protein synthesis Flashcards
What is transcription?
making RNA strand from DNA (serving as a template) only for the segment with a gene
What is the function of RNA polymerase?
-it separates the strands
-adds RNA nucleotides, complementary with the bases from DNA strand
-creates a sugar-phosphate bonds
Which strand is used as a template for transcription and why?
antisense strand, because the RNA polymerase will create a RNA strand that will be the opposite to the antisense strand but the same as the sense strand
What is sense strand?
it contains the genetic information (the ATCG sequence)
What is antisense strand?
the strand used for transcription
it is a non-coding strand of DNA that contains an opposite complementary
Which factor contributes to the increased frequency of mutations during transcription?
breaking the hydrogen bonds by an enzyme and separation of the strands
What is gene expression?
it’s a process by which an information (sequence of bases) from the gene is used to produce a protein
Describe the process of translation?
-the small subunit of the ribosome attaches to the mRNA strand
-it attracts the tRNA molecules with anticodons and aminoacids
-the ribosomal enzyme creates the peptide bond between the aminoacids creating a polypeptide
Ribosome in translation consists of …
large and small subunits
What degenerate means?
that different codons can code for the same amino acid
What happens at A site in the ribosome?
tRNA binds and the peptide bond is formed between amino acids
What is the movement of ribose sites?
A site to P site to E site
What happens at P site?
the empty tRNA moves further and the peptide chain is passed for the next tRNA
What happens at the E site?
the empty tRNA exits the site
What is a mutation?
change in base sequence (nitrogenous bases) of a gene
What is a base substitution?
it is a change to one base in a gene
What might be a result of base substitution?
might change the amino acid and overall protein structure
What is a promoter in transcription?
beginning of a gene, it’s where the RNA polymerase bind
What are transcription factors?
It’s molecules that regulate gene expression by starting or stopping transcription
What is a non-coding region?
there are base sequences that do not code for polypeptides
What is a benefit of post-transcriptional modification?
it allows for many different versions of a protein from one gene
What is post-transcriptional modification?
it means that translation happen in cytoplasm and transcription happen in nucleus
What are introns and exons?
those are base sequences of the DNA
What happens to the mRNA as it matures? (post-transcriptional modification)?
- introns are removed
- exons are sliced together
-added 5’ cap
-added poly-A-tail
