Microbio 4000: Exam 2 Key concepts
Test Questions with All Actual
Answers.
What is DNA replication? - Answer When DNA makes a copy of itself
Uses DNA as template
Makes 2 copies of dsDNA - 1 parent, 1 daughter strand
DNA Polymerase synthesizes from 5' to 3'
What is gene expression? - Answer the way in which DNA, RNA, and proteins are involved in
putting genetic information into action in living cells
DNA directs protein synthesis
Involves Transcription and Translation
Prokaryotic Gene expression vs Eukaryotic - Answer Prokaryotic: both transcription and
translation happen simultaneously in the cytoplasm
Eukaryotic: transcription and translation happen independently, transcription in nucleus and
translation in cytoplasm
How do bacteria sense changes in environment? - Answer 1. Two-component systems:
sensor protein on membrane triggers response regulator in cytoplasm that changes gene
expression (tells to turn on/off gene)
2. Quorum Sensing: autoinducers dispense chemical signals
How do bacteria sense population density? - Answer Autoinducers through quorum sensing;
signaling proteins produced in response to changes in cell density
What are inducible vs repressible vs constitutive operons? - Answer -inducible operons:
usually off, turned on in response
-repressible operon: usually on, turned off in response
-constitutive operon: always on
How do bacteria use DNA-binding proteins to regulate gene-expression? - Answer control
transcription of operons, by binding to operator sites in the DNA near the promoter
-activator proteins: promote RNA polymerase binding, increasing transcription
-repressor proteins: block RNA polyermase movement, decreasing transcription
*can be used in both inducible and repressible operons
, How do bacteria use sigma factors to regulate gene expression? - Answer interchangeable
portion of RNA polyermase itself (subunit), responsible for determining the specificity of
promoter DNA binding and control how efficiently RNA synthesis (transcription) is initiated
Describe products of each:
1. DNA replication
2. Transcription
3. Translation - Answer 1. DNA Polyermase uses DNA template to make a copy of DNA strand
2. RNA polyermase uses DNA template to make RNA transcripts (mRNA, tRNA, rRNA)
3. Ribosome binds anticodon from rRNA along with amino acid to the attached codon of mRNA
to make a protein
-What are silent, missense and nonsense mutations?
-what mutations results in frameshifts?
-When is a mutation considered a knockout? - Answer -Silent: codes for same amino acid
(degenerate), Missense: codes for a different amino acid
Nonsense: codes for a STOP codon
-changes in reading frame; through insertion or deletion (transposons)
-Knockout is when a gene is inactivated/nonfunctional; could be from missense or nonsense
what are transposons? Why do they inactivate genes? insertion sequences vs complex
transposons? Why are they mobile elements? - Answer large additions (jumping genes),
insert self into gene, often inactivating gene making it a knockout
insertion sequence (simple IS): just transposase gene and inverted repeats - simple functioning
complex: contains insertion sequences plus additional genes - other functions
mobile elements because they are DNA sequences that can move around the genome, change #
of copies/location, affecting nearby genes
Spontaneous vs Induced mutations - Answer spontaneous: random change in the DNA arising
from errors in replication or ROS produced in aerobic cell
induced: results from exposure to known mutagens (happens more often)
How can bacteria repair DNA? - Answer -mismatch repair enzymes: identify incorrect base,
cut and replaced
-excision repair enzymes: distorted base identified, cut and replaced
-photolyases: T=T identified, enzymes use light to break
Test Questions with All Actual
Answers.
What is DNA replication? - Answer When DNA makes a copy of itself
Uses DNA as template
Makes 2 copies of dsDNA - 1 parent, 1 daughter strand
DNA Polymerase synthesizes from 5' to 3'
What is gene expression? - Answer the way in which DNA, RNA, and proteins are involved in
putting genetic information into action in living cells
DNA directs protein synthesis
Involves Transcription and Translation
Prokaryotic Gene expression vs Eukaryotic - Answer Prokaryotic: both transcription and
translation happen simultaneously in the cytoplasm
Eukaryotic: transcription and translation happen independently, transcription in nucleus and
translation in cytoplasm
How do bacteria sense changes in environment? - Answer 1. Two-component systems:
sensor protein on membrane triggers response regulator in cytoplasm that changes gene
expression (tells to turn on/off gene)
2. Quorum Sensing: autoinducers dispense chemical signals
How do bacteria sense population density? - Answer Autoinducers through quorum sensing;
signaling proteins produced in response to changes in cell density
What are inducible vs repressible vs constitutive operons? - Answer -inducible operons:
usually off, turned on in response
-repressible operon: usually on, turned off in response
-constitutive operon: always on
How do bacteria use DNA-binding proteins to regulate gene-expression? - Answer control
transcription of operons, by binding to operator sites in the DNA near the promoter
-activator proteins: promote RNA polymerase binding, increasing transcription
-repressor proteins: block RNA polyermase movement, decreasing transcription
*can be used in both inducible and repressible operons
, How do bacteria use sigma factors to regulate gene expression? - Answer interchangeable
portion of RNA polyermase itself (subunit), responsible for determining the specificity of
promoter DNA binding and control how efficiently RNA synthesis (transcription) is initiated
Describe products of each:
1. DNA replication
2. Transcription
3. Translation - Answer 1. DNA Polyermase uses DNA template to make a copy of DNA strand
2. RNA polyermase uses DNA template to make RNA transcripts (mRNA, tRNA, rRNA)
3. Ribosome binds anticodon from rRNA along with amino acid to the attached codon of mRNA
to make a protein
-What are silent, missense and nonsense mutations?
-what mutations results in frameshifts?
-When is a mutation considered a knockout? - Answer -Silent: codes for same amino acid
(degenerate), Missense: codes for a different amino acid
Nonsense: codes for a STOP codon
-changes in reading frame; through insertion or deletion (transposons)
-Knockout is when a gene is inactivated/nonfunctional; could be from missense or nonsense
what are transposons? Why do they inactivate genes? insertion sequences vs complex
transposons? Why are they mobile elements? - Answer large additions (jumping genes),
insert self into gene, often inactivating gene making it a knockout
insertion sequence (simple IS): just transposase gene and inverted repeats - simple functioning
complex: contains insertion sequences plus additional genes - other functions
mobile elements because they are DNA sequences that can move around the genome, change #
of copies/location, affecting nearby genes
Spontaneous vs Induced mutations - Answer spontaneous: random change in the DNA arising
from errors in replication or ROS produced in aerobic cell
induced: results from exposure to known mutagens (happens more often)
How can bacteria repair DNA? - Answer -mismatch repair enzymes: identify incorrect base,
cut and replaced
-excision repair enzymes: distorted base identified, cut and replaced
-photolyases: T=T identified, enzymes use light to break
