ch 5 quiz 1 Flashcards
central dogma of biology
DNA self-replicates, its information flows from DNA to RNA to proteins
where does transcription take place, what does it involve
in nucleus, starts with DNA makes RNA
where does translation take place, and what does it involve
in cytoplasm in the ribosome, it makes protein
transcription definition
process of copying DNA sequence into mRNA transcript that can carry a coded message for a protein from the nucleus to the ribosome
translation definition
process of reading the mRNA code to produce a sequence of amino acids by the ribosome to make a functional protein
why is mRNA necessary in gene expression
it takes the message from the nucleus to the ribosome
3 types of RNA
1) mRNA (messenger) takes the message to robosome
2) rRNA (ribosomal) makes up ribosome
3) tRNA (transfer) carries amino acids, holds anticodon, builds amino acids
steps in transcription
1) initiation - promoter, RNA polymerase and transcription factus bind to the promoter - starts transcription
2) Elongation - RNA polymerase seperates 2 stands of DNAa nd uses the template strand to create a complementary strand (mRNA)
3) termination - RNA polymers matches the termination system (non-coding sequence) and ends transcription
post-transcriptional modifications
-capping-moddifies guanine
-polyadenylation - adds ademine at the end
-splicing - removing non coding parts (introns), and hooking on coding parts (extrons)
steps to translation
1)initiation - rRNA hooks to mRNA and finds AUG sequence to start
2) elongation - amino acids added by tRNA are added until stop codon
3) termination - RNA detatches, protein is released
Post-translational modifications occur
why do do anticodons and codons consist of 3 bases
because 3 allows for enough combinations for 20 amino acids
is every gene in every cell expressed all the time
no, not every gene is required at every time, and if they were it could interfere wih transcription
what happens to proteins after they are synthesized, does the location of synthesis matter?
they get sent to where they need to be
yes it does matter, proteins synthesized in the ribosomes go to the cell, but proteins synthesized on the RER go outside the cell, or into the membrane
how are genes turned on and off
one gene has the power to turn others on and off in a complex network of interactions
