Chp. 8 slides 27- 109 Flashcards
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What is the origin of replication?
Where the replication fork starts
Prokaryotes have ______ origin(s) of replication whereas eukaryotes have ______ origin(s) of replication.
One
Multiple
What is the purpose of DNA polymerase?
To proofread and see if any nucleotides were placed incorrectly
DNA –> DNA is known as _______
DNA –> RNA is known as _______
Replication
Transcription
Where does transcription take place in prokaryotes and eukaryotes?
Prokaryotes: cytoplasm
Eukaryotes: nucleus
Where does translation take place in prokaryotes and eukaryotes?
Both take place in the cytoplasm
Where does replication take place in prokaryotes and eukaryotes?
Prokaryotes: cytoplasm
Eukaryotes: nucleus
How many nucleotides does mRNA take at a time? What are those nucleotides called?
3
Codon
TRUE OR FALSE:
Transcription and translation in prokaryotes happen simultaneously
TRUE
How many sense codons are there?
How many stop codons are there?
~61 sense codons
3 stop codons
What are the 3 sections in the large subunit?
Acceptor “A” site
Peptidyl “P” site
Exit “E” site
TRUE OR FALSE:
Only non coding genes starts with methionine
FALSE
EVERY gene starts with methionine (AUG)
What makes up an operon?
A promoter, operator, and whatever genes are needed
What are the two types of operons?
- Inducible: operon is off all the time until needed
- Repressible: operon is on all the time until too much product is made
What is responsible for producing active (in inducible) and inactive (in repressible) repressor proteins?
Regulatory genes
aervbrbrnbrn tr drExplain the role of inducible operons and repressible operons in transcription
- Inducible operons regulatory genes produces an active suppressor protein which can bind to the operator
-
What regulates gene transcription?
Histones
Which chemical process allows transcription?
Which chemical process does not allow transcription?
- Acetylation allows transcription
- Methylation does NOT allow transcription
TRUE OR FALSE:
Mutations in both RNA and DNA have serious effects
FALSE
Only mutations in DNA are serious
What are the two types of mutations in DNA?
- Base substitution mutation
- Frameshift mutation
What are the 3 types of base substitution mutations?
- Silent mutation: one nucleotide changes but the amino acid does not change
- Missense mutation: one or two nucleotides change causing the amino acid to change
- Nonsense mutation: mutation causes a sense codon to become a stop codon OR causes a stop codon to become a sense codon
What is the role of the TATA box in the promoter?
To tell the RNA polymerase where to go
TRUE OR FALSE:
In eukaryotes, once the mRNA hits the termination sequence and is transcribed, it can be translated, whereas in prokaryotes, it needs to be modified first.
FALSE
Prokaryotes do not need modification, eukaryotes do
Which site does the start codon go to? Which site do the rest of the codons go to?
1st codon goes to P site and the rest go to A site first
In eukaryotes, what allows transcription and what does not allow it?
Methylation allows transcription
Acetylation does not allow transcription
What are mutagens?
Agents that cause mutations (eg. cigarettes, alcohol)
What do photolyases do?
Separate thymine dimers
What is the nucleotide excision repair?
Enzymes cut out incorrect bases and fill in correct bases
What are the following mutants:
Positive (direct) selection
Negative (indirect) selection
Auxtotroph
- Detects mutant cells because they grow/ appear different than unmutated cells
- Detects mutant cells that cannot grow or perform a certain function
- Mutant that has nutritional requirement absent in the parent
How does replica plating work in identifying mutations in colonies?
(slide 91 fill in!)
Velvet transfers bacteria from colony that includes histidine to petri plate without histidine. non growth on non histidine shows auxtotrophic mutation
What is the name of the test that exposes mutant bacteria to mutagenic substances to measure the rate of reversal of the mutation?
The Ames test (indicates degree to which a substance is mutagenic)
Explain Griffith’s experiment
- Injected mouse with living encapsulated bacteria: dead
- Injected with living non-encapsulated bacteria: alive
- Injected with heat killed encapsulated bacteria: alive
- Injected with heat killed encapsulated and living non-encapsulated bacteria: dead
DNA from dead bacteria was taken from live bacteria, showing bacteria can share genetic information and change their characteristics
