Protein Synthesis Flashcards
What is transcription?
the copying of DNA into mRNA
Where does transcription occur and why?
in the nucleus….because DNA can’t leave the nucleus
The central dogma theory of molecular biology states that genetic information flows in which direction?
from DNA to RNA to proteins
Where does protein synthesis take place?
ribosome
What is translation?
the decoding of mRNA instructions into a protein
Where does translation take place?
ribosome
How does RNA differ from DNA?,
single stranded v. double stranded, sugar ribose v. sugar deoxyribose, base uracil v. base thymine, mobile v. immobile, 1 type v. 3 types
How are RNA and DNA similar?
both nucleic acids, both needed for production of proteins
Where do the instructions to make proteins come from?
the DNA molecule?
Which DNA strand is used as a template to produce the mRNA strand?
the coding strand
Where on the DNA does transcription begin?
the promotor region
Where on the DNA does transcription end?
the terminator region
What are the 3 steps of transcription? What happens in each?
initiation (RNA polymerase binds to DNA at promoter region on coding strand), elongation (mRNA gets longer as RNA polymerase adds complementary RNA nucleotides), termination (RNA polymerase reaches the terminator region and everything detaches including newly made mRNA strand)
How do you prevent an attack by viruses/bacteria on the newly formed mRNA strand? (modifications)
By RNA processing: adding an mG cap to the 5’ end and a poly A tail to the 3’ end
What is RNA splicing?
the removing of introns and joining together of exons
What are introns?
non-coding regions on the mRNA
What are exons?
coding regions on the mRNA
What are the monomers of proteins?
amino acids
What type of bond holds amino acids together?
peptide bond
How many A.A. are there in life?
20
The two binding sites on the tRNA are?
the anticodon site and the amino acid site
What is the function of the tRNA molecule?
to transfer the A.A. to its complementary codon at the ribosome
What are the three binding sites on the ribosome?
E (exit), P, A
What are the 3 steps of translation?
initiation, elongation, termination
What happens during initiation of translation?
small ribosome binds to mRNA, first tRNA carrying MET binds to the start codon on mRNA AUG, large ribosome then attaches
What are the 3 steps of elongation in translation?
codon recognition, peptide bond forms, translocation
What happens during codon recognition?
the codon in the A site is recognized and the tRNA with the complementary anticodon binds to it, bringing the appropriate A.A.
What happens during peptide bond formation?
A peptide bond forms between the A.A. in the P site and the A.A. in the A site.
What happens during translocation?
The mRNA slides moving the tRNA that was in the P site to the E site (to exit), and the tRNA that was in the A site to the P site. This opens up the A site for a new codon to be recognized.
What happens during termination of translation?
A stop codon is recognized and a release factor docks in the A site, causing everything to disassemble. A.A. chain is now complete.
What is the first site on the ribosome to be occupied?
P site
What is the start codon? Start A.A.?
AUG and Met
What do genes on your DNA code for?
proteins
What codes for the A.A.?
the codon on the mRNA
If the anticodon is AUU, what is the codon?
UAA
If the DNA code is ATT what is the codon?
UAA
If the codon is CGU, what DNA did it come from?
GCA
If the anticodon is GCA, what DNA did it come from?
GCA
What is happening in the P site?
the growing A.A. chain is being held
What is the function of the mRNA?
to carry the instructions on how to make proteins out to the ribosome
