BIOL 2604: Exam #4 || 100% Correct Answers.
Mutations correct answers spontaneous or induced; changes in base sequence of nucleic acid
Point Mutation correct answers change in single base pair and can lead to single amino acid
change in polypeptide or no change at all
Missense Mutation correct answers Substitution; change in 1 amino acid
Nonsense Mutation correct answers - premature stop codons
- results in shorter, unfinished proteins
-results in nonfunctional proteins
Silent Mutation correct answers - occur in noncoding regions or within exons
- do not cause change in phenotype
Deletions and Insertions correct answers - causes frameshift mutation
- earlier the deletion/insertion is, more mutation there will be
Frameshift Mutation correct answers - shifts reading frame which causes a very different
translation than the original
- can alter stop codon so protein can be really long or really short
SOS Regulatory System correct answers - Activated by DNA Damage
- LexA inhibits synthesis of SOS genes
- RecA causes LexA to autocleave so SOS genes can be activated
Homologous Recombination correct answers - 2 distinct genetic elements are combined in a
single element
- RecA allows for strand invasion of single strand DNA
RecA correct answers - inactivates LexA for SOS regulatory activation
- allows for strand invasion in homologous recombination
Ames Test correct answers - measures mutagenesis
- tests to see in chemical introduced can histidine negative auxotrophs to histidine positive
Transformation correct answers - uptake of "naked" DNA directly from the environment
through cell membrane
- ex: streptococcus pnemoniae
Transduciton correct answers phage mediated transfer of DNA
Generalized Transduction correct answers accidental packaging of host DNA into phage
heads
Specialized Transduction correct answers - created new viral genome that contains bacterial
genes from infected bacteria and then when it transducts another cell, it will be infected with
virus and bacterial genes
- ex: e. coli
, Conjugation correct answers - direct contact
- pilus mediated
Repression correct answers gene expression inhibited
Induction correct answers gene expressed activated
Repressors correct answers - inhibit gene regulation with bound
- stops transcription
- ex: Arginine Biosynthesis operon and lactose operon
Co-Repressors correct answers binds to repressors to allow repressors to bind to DNA to
inhibit gene expression
Inducers correct answers - either allow activators to bind to DNA or stop repressors from
binding to DNA
-activates transcription
Operon correct answers promoter along with all the genes that are controlled by it
Regulon correct answers - group of operons that are all controlled by a common regulatory
mechanism
- ex: quorum sensing
3 Steps of Transcription correct answers 1. Initiation
2. Elongation
3. Termination'
Initiation correct answers RNA polymerase binds to promoter of template strand and DNA
unwinds
Elongation correct answers - RNA polymerase moves down the template 3' to 5'
- mRNA strand
Temrination correct answers RNA polymerase reaches terminator sequence which causes the
complex to become unstable and fall off and release mRNA
Transcription in Prokaryotes correct answers - single form of polymerase
- introns rare
- little RNA processing
- few transcription initiation factors
- in cytoplasm
- polycistron messages
Transcription in Eukaryotes correct answers - multiple forms of RNA polymerase
- introns common
- extensive RNA processing
- multiple initiation factors
- in nucleus
Mutations correct answers spontaneous or induced; changes in base sequence of nucleic acid
Point Mutation correct answers change in single base pair and can lead to single amino acid
change in polypeptide or no change at all
Missense Mutation correct answers Substitution; change in 1 amino acid
Nonsense Mutation correct answers - premature stop codons
- results in shorter, unfinished proteins
-results in nonfunctional proteins
Silent Mutation correct answers - occur in noncoding regions or within exons
- do not cause change in phenotype
Deletions and Insertions correct answers - causes frameshift mutation
- earlier the deletion/insertion is, more mutation there will be
Frameshift Mutation correct answers - shifts reading frame which causes a very different
translation than the original
- can alter stop codon so protein can be really long or really short
SOS Regulatory System correct answers - Activated by DNA Damage
- LexA inhibits synthesis of SOS genes
- RecA causes LexA to autocleave so SOS genes can be activated
Homologous Recombination correct answers - 2 distinct genetic elements are combined in a
single element
- RecA allows for strand invasion of single strand DNA
RecA correct answers - inactivates LexA for SOS regulatory activation
- allows for strand invasion in homologous recombination
Ames Test correct answers - measures mutagenesis
- tests to see in chemical introduced can histidine negative auxotrophs to histidine positive
Transformation correct answers - uptake of "naked" DNA directly from the environment
through cell membrane
- ex: streptococcus pnemoniae
Transduciton correct answers phage mediated transfer of DNA
Generalized Transduction correct answers accidental packaging of host DNA into phage
heads
Specialized Transduction correct answers - created new viral genome that contains bacterial
genes from infected bacteria and then when it transducts another cell, it will be infected with
virus and bacterial genes
- ex: e. coli
, Conjugation correct answers - direct contact
- pilus mediated
Repression correct answers gene expression inhibited
Induction correct answers gene expressed activated
Repressors correct answers - inhibit gene regulation with bound
- stops transcription
- ex: Arginine Biosynthesis operon and lactose operon
Co-Repressors correct answers binds to repressors to allow repressors to bind to DNA to
inhibit gene expression
Inducers correct answers - either allow activators to bind to DNA or stop repressors from
binding to DNA
-activates transcription
Operon correct answers promoter along with all the genes that are controlled by it
Regulon correct answers - group of operons that are all controlled by a common regulatory
mechanism
- ex: quorum sensing
3 Steps of Transcription correct answers 1. Initiation
2. Elongation
3. Termination'
Initiation correct answers RNA polymerase binds to promoter of template strand and DNA
unwinds
Elongation correct answers - RNA polymerase moves down the template 3' to 5'
- mRNA strand
Temrination correct answers RNA polymerase reaches terminator sequence which causes the
complex to become unstable and fall off and release mRNA
Transcription in Prokaryotes correct answers - single form of polymerase
- introns rare
- little RNA processing
- few transcription initiation factors
- in cytoplasm
- polycistron messages
Transcription in Eukaryotes correct answers - multiple forms of RNA polymerase
- introns common
- extensive RNA processing
- multiple initiation factors
- in nucleus
