Bio Exam 4 Chapter 12

michelleburkee2's version from 2015-11-16 09:28

Section 1

Question Answer
if a protein is made from 30 amino acids, how many nucleotides are needed to code for it production?90
for a cell to function, information from DNA must betranscribed to RNA then translated to protein
what is the analogy of DNA->RNA->protein?DNA is the blueprint that is transcribed into a message with the instructions that are then translated in a construction worker (action)
how many nucleotides code for one amino acid?three
DNA is the storage of genetic information
RNA is the carrier of genetic information
Protein isthe workhouse
who does transcription?RNA polymerase
who does translation?the ribosome
in eukaryotes, where does transcription happen?in the nucleus
in eukaryotes, where does translation happen?in the cytoplasm or the rough ER
where does transcription happen in prokaryotes?in the cytoplasm

Section 2

Question Answer
DNA is _________ then __________transcribed to RNA then translated to Protein
Transcription:the DNA is unzipped and then RNA polymerase come in and produces an mRNA with a nucleotide sequence complimentary to one of the DNA strands.
Translation:translation of the mRNA produces a protein molecule with an amino acid sequence determined by the nucleotide sequence of the mRNA
3 ways RNA is different than DNA1.) RNA is usally single stranded 2.) RNA's sugar backbone has a 2'-OH (ribose) instead of the 2'-H (deoxyibose) 3.) RNA contains the base uracil instead of thymine
does this belong to DNA or RNA: 2'-OHRNA (ribose)
does this belong to DNA or RNA: 2'-HDNA (deoxyribose)
What is required for transcription (3 groups)1. DNA (the template) 2. RNA polymerse (the enzyme) 3. adenine, guanine, cytosine, or uracil (nucleotides)

Section 3

Question Answer
T/F RNA contains the base uraciltrue
T/F RNA contains the base thyminefalse
T/F DNA contains the base uracil*false*
T/F DNA contains the base thymine*true*
makes an RNA copy of the DNA templatetranscription
what happens to the mRNA after it is transcribed?it goes through holes in the nucleus wall then gets exported to the rough ER or the cytosol where it meets with the ribosome where it will be turned into a protein
the three stages of transcription in order1.) initiation 2.)elongation 3.)termination
in RNA which nucleotides bind to eachother?Adenine to Uracil, Thymine to Adenine, Guanine to Cytosine
the RNA codes for segaments of the gene. only until the stop codon
promoter regioninitiates trasncription
elongationthe "body" of the gene
terminationa stop singnal at the end
when does transcription begin?when RNA polymerase binds to the promoter of a gene
what generates a growing strand of RNA?RNA polymerase synthesizes a sequence of RNA nucleotides along one of the DNA strands, the template strand. This is the elongation stage.
when does transcription end?when RNA polymerase reaches the termination signal, it releases the completed RNA strand and detaches from the DNA
what is the template strand?the bottom strand of DNA

Section 4

Question Answer
what happens when the RNA polymerase reaches a termination signal?transcription stops. The RNA strand detaches from the DNA and the RNA polymerase is detached from the DNA
what makes RNA?RNA polymerase
Translationmakes a protein based on the mRNA sequence
the 4 requirements of translation 1.) mRNA (template) 2.) ribosome (enzyme) 3. amino acids which are delivered by tRNAs 4. tRNAs which deliver the amino acids
where does translation happen in a eukaryotic cell?in the cytosol or rough ER
what is the anticodon of translation? and what does it do?the end of the tRNA. It has 3 nucleotides that bind to the 3 nucleotides of mRNA
where does translation happen in the prokaryotic cell?in the cytoplasm
the three types of RNA involved in protein synthesismRNA (messanger), tRNA (transfer), and rRNA (ribosomal)
function of mRNA in protein synthesiscarries the DNA gene message to the ribosome
function of tRNA in protein synthesisbrings amino acids to the ribosome
function of rRNA in protein synthesisis a part of the structure of ribosomes and catalyses the peptide bond formation

Section 5

Question Answer
translation makes a protein based off of what?the mRNA sequence
what type of RNA carries the DNA gene message to the ribosome?mRNA
what type of RNA brings amino acids to the ribosome and is the anticodon?tRNA
what type of RNA catalyses the peptide bond formation?rRNA
carries the information for the amino acid sequence of a protein. They specify the amino acids*mRNA*
combines with proteins to form ribosomes *RrNA
the large subunit of ribosome binds this to catalyze peptide bond formation between amino acids during protein synthesis *tRNA*
each ______ carries a specific amino acid to a ribosome during protein synthesis%tRNA%
how is it ensured that the correct amino acid is incorporated into the protein?the anticodon of tRNA binds with the codon of mRNA
bases in mRNA are read by the ribosome in sets of _ called ___in sets of three called codons

Section 6

Question Answer
how does it know what amino acid to use?three bases code for every amino acid
codona set of three bases
each mRNA has a _____ and a _________start and a stop codon
the start codonAUG
what does transcription produce?a mRNA strand that is complimentary to the DNA gene template strand
t/f each codon specifies one specific amino acidtrue
t/f an amino acid could be specified by as many as six different codons*true*
decoding the codons of mRNA is the job of ____ and _____tRNA and ribosomes
the product of translation isa protein
when does translation begin?when tRNA and mRNA bind to a ribosome
each DNA gene codes for how many proteins?one
what happens after transcription?mRNA leaves the nucleus and goes into the cytoplasm or rough ER to pair up with a ribosome. The ribsosome, along with tRNA are used to create an amino acid sequence for a protein that is complementary to the mRNA sequence.
how does the ribosome choose a correct tRNA?it chooses a tRNA with its exposed anticodon complimentary to the mRNA
what contains the stop codon?the mRNA contains a stop codon to say when protein synthesis ends

Section 7

Question Answer
how does MRNA syntheis differ between prokaryotes and eukaryotes?most prokaryotes genes are compact, most of the nucleotides in the prokaryote code for proteins whereas huge chunks of the eukaryote are "non coding", in prokaryotes, genes for related functions are adjacent and transcribed together
policistronicgenes for related functions are adjacent and transcribed together
in prokaryotes, what happens for coding protein?as an mRNA molecule detaches from the DNA molecule, the ribsosome immediatley begin translating the mRNA into protein
which type of cell has huge chunks of "non coding" DNA?eukaryotes
in prokaryotes, one RNA=multiple proteins
in eukaryoes, one RNA=one protein
transcription and translation can happen at the same time in*prokaryotes*
a single mRNA can have multiple start sites &prokaryotes&
how can a prokaryote code for (ex.) three different proteins in one mRNA?they must have 3 start codons and 3 stop codons

Section 8

Question Answer
if an mRNA can code for one protein only it is monosistronic. that means it is eukaroyte
if an mRNA can code for more than one protein it ispolisistronic. that means it is prokaryotic
what has to happen before the mRNA leaves the nucleus? a pre-RNA is transcribed and then processed
how is the pre-RNA processed before leaving the nucleuscaps are added on their head and tail, also the exons need to be spliced.
splicedthe gene removes introns (not used for coding)and leaves the exons (used for coding)
what happens after the exons are spliced?the finshed mRNA is moved in the cytoplasm for translation
where does splicing happen?in the nucleus
why does splicing happen?it helps in complexity; it allows for cells to use different exons to use at different times
mutations can affectprotein function

Section 9

Question Answer
mutations that usually cause no probleminversions and translocations
what happens if a gene is split in two?it will no longer code for a complete functional protein
can cause a misreading of a gene's codons during transcription (change of frame)deletions and insertions
these are almost always nonfunctional unless is of a multiple of 3 nucletidesdeletions and insertions
how can substitutions affec the codons of mRNA?may be unchanged, protein function may be destroyed by a premature stop codon, or the protein function may be changed by an amino acid sequence
substitutions are point mutations
genetic diseases are caused bysingle point mutations
are all the genes expressed at the same time?no. they are only expressed when we need them
in eukaryotes, when can gene expression be regulated?during transcription, translation, or protein activity
in prokaryotes, when is gene expression usually regulated?during transcription
operonsa cluster of genes under the control of the same promoter
operatorrepressor protein binds to this part of the operon
promoterRNA polymerase binds here
regulatory genecodes for the repressor protein
in the absence of lactose, the lactose operon would be shut off by a repressor protein
if lactose is present, it willbind to the repressor protein so that the genes can be transcribed

Section 10

Question Answer
in eukaryotes, transcriptional regulation occurs on atleast three levelsthe individtual gene, the regions of chromosomes, and the entire chromosomes
transcription factorstranscription can be regulated through these.(turn off or on transcription).
epigeneticsthe study of how cells and organisms change gene expression and function without changing the base sequence of their DNA
three ways epigenetics worksmodification of DNA, modification of chromosomal proteins, and changing transcription and translation
histoneschromosomal proteins
methylation will lead toinactivation
histone changes makeDNA more or less acessible. if it is more acessible transcription will happen
"junk RNA" (noncoding RNA) may alter transcription. can turn off entire chromosomes
microRNAs can bind to mRNA and prevent translation

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