microbiology quiz 4-7-15 Flashcards
what is the name of the enzyme that unwinds and unzips the DNA
helicase
what is the name of the substance that holds the two strands of DNA apart after the helicase has unzipped it
SSB protein ( single strand binding)
what is the name of the enzyme that builds RNA on the sense strand
RNA polymerase
what is the name of the strand that is in the 3’ to 5’ position
the sense strand
what prime is the sense strand
3’ to 5’ prime
what happens to the 5’ to 3’ prime strand during transcription
nothing it isn’t used
what is the process of copying the code of DNA called
transcription
after transcription has taken place what happens to the DNA
the hydrogen bonds will reattach and wind the DNA back up to its original shape
true or false
DNA is permanently changed after transcription has occured
false it is unchanged
what is the name of the mRNA sense strand also called
the complimentary copy
when is transcription complete?
when the mRNA is made
how is mRNA read?
in 3 nucleotides at a time
what is a codon?
3 nucleotides on the mRNA
what does a codon code for
an Amino Acid
what is the product of transcription
mRNA
is DNA required for translation
no
what is the name of the two binding sites on the ribosome
p-site and a-site
what part of translation carries the codon
the mRNA
what part of translation carries the anticodon
the tRNA
what is the purpose of the tRNA
to carry the amino acids to the ribosome
what is the name of the amino acid binding site on every tRNA
ACC
what is the purpose of the amino acid binding site?
it tell what AA it carries
what is the name of the site located at the bottom loop of the tRNA
the anticodon
what is the purpose of the anticodon
it tells what AA the tRNA is carrying
how many AA does bacteria make?
all 20
how many AA does every cell need to carry
all 20
how do humans get their AA
they consume it in their diet
what are the 2 sections of the ribosome called
the large subunit and the small subunit
where is the area that signals the start of translation and what is the codon called
the start codon is AUG and it signals the start of translation when it enters the P site
when does the A site become available
when the P site is full
if the start codon is AUG than what must the anticodon be
UAC
what is the name of the 3 codons that will not have tRNA to attach to them
the stop codon
what happens to the ribosome at the end of transcription
it breaks away into the 2 subunits
what must be positioned at the P site to start transcription
AUG
what is the amino acid that codes AUG
methionine
can there be more than 1 codon to code for a certain AA
yes
how many AA are found in nature
20
what differentiates 1 tRNA from another
its anticodon
how many different tRNA can exist in every cell in every organism
64 - the 3 stop codons= 61
what is it called when multiple ribosomes are attached to 1 mRNA molecule in both prokaryotes and eukaryotes
polyribosomal complex
name a difference between prokaryotes and eukaryotes during transcription
- eukaryotes must do translation than transcription
prokaryotes can do it simultaneously - 1 mRNA codes for 1 protein in eukaryotes and multiple in prokaryotes
- eukaryotes must get rid of the introns and prokaryotes don’t have introns
why cant a eukaryote do transcription and translation simultaneously like prokaryotes
because in eukaryotes the mRNA has to leave the nucleus and in bacteria both happens in the nucleoid region
what is meant by the word expressed when talking about genes
it means that the gene is turned on to make the product
what is meant by the word non-expressed when talking about genes
it means that the gene is turned off and no products are made
what is the name of genes ( 60-80%) that are turned on all of the time
constitutive genes
what is the name of genes ( 20-40%) that are turned on and off as needed
regulated genes
what part of the gene codes for the repressor proteins
the regulator
what part of the gene binds RNA polymerase 1
the promotor
what part of the gene binds active repressor proteins
the operator
what part of the gene codes for the protein
the structural gene
what part of the gene signals the stop for transcription
the terminator
what is the operon sequence
the unit consists of the a regulatory gene, repressor site, and structural site
how many different codons code for methionine in the genetic code
only 1
a particular AA can be coded for more than 1 AA is a back up system known as
redundancy
what part of transcription codes for the AA
the mRNA
what does the operon code for
protein and whether or not its made
where do the repressor proteins attach when turned on
the operator site
what does the active repressor proteins block from getting to the structural gene
RNA polymerase
name the pathway that tells the operon what to do
promotor, structural gene than the terminator
what happens when the active repressor protein binds to the operator site, preventing the RNA polymerase from getting to the structural gene
the gene is turned off and no mRNA is made
name the type of operon that is normally off but must be turned on
induction
are the active proteins, active or inactive in an induction operon
normally active
name the type of operon that is normally on until its turned off
repression
are the active proteins, active or inactive in a repression operon
normally inactive
what type of reaction do induction genes produce
catabolic reactions
what type of reaction do repression genes produce
anabolic reactions
