Exam 2 T/F AGR3303

The tumor inducing (Ti) plasmid in soil bacteria can be moved and replaced by your gene of interest for plant transformation

true

Ti plasmid can be modified or engineered as a vector for plant transformation

true

The Illumina sequencing has a much higher throughput than Sanger sequencing method

True Throughput - number of sequencing reactions to be done simultaneously in one run in sequences

insertion or removal of one or more nucleotide base pairs in a gene usually results in a frame shift mutation

true

siRNA in RITS binds to DNA and causes methylation, restricting transcription

True

GAL4 is a transcription repressor for the galactose-digesting enzyme gene

False GAL4 is an activator

The lengths of reads from Illumina sequencing method is much longer than the reads from Sanger method

False Length of reads from Sanger are much longer, Illumina is normally 50-150bp and up to 300bp while Sanger is 500-800bp

RITS consists of miRNA

False RITS consist of siRNAs and proteins the siRNA in RITS binds to DNA and causes methylation -> restricts transcription

Restriction enzymes randomly cut dsDNA and produce either cohesive or blunt ends

False Restriction enzymes recognize specific nucleotide sequences (4-8 base pairs long) to cut dsDNA (double stranded DNA)

Illlumina sequencing is more advanced than Sanger sequencing method, which makes Sanger sequencing method lost its value

False Sanger is still gold standard

A missense mutation changes a codon that specifies an amino acid into one that terminates translation

False a missense mutation is a base substitution that results in a different aa a nonsense mutation is a substitution that changes a sense codon into a stop codon

Addition of acetyl groups to the tails of histone proteins usually results in repression of transcription, FLD deacetylates histones that bind to regions of FLC gene and stimulates its transcription

False addition of acetyl groups (acetylation) of histone proteins weakens their interaction w/ DNA and allows transcription factors to bind to DNA, increasing transcription

Nonsense mutations do not alter the amino acid sequence chain

False change sense codon (for an aa) into a stop codon

During gene cloning, the vector DNA sequence with foreign DNA will integrate into the host DNA. When the host cell divides, copies of the recombinant DNA molecules are passed to the progeny

False cloning vector carries the foreign DNA piece (recombinant DNA) independent of the bacterial host DNA

In the absence of allolactose, the lac operon is constitutively transcribed

False constitutively transcribed - always being transcribed when allolactose or lactose is present, genes are expressed to metabolize lactose (negative inductable)

A repressible gene should be under control by a repressor

False regulator protein can be repressors (negative control, inhibits transcription) or activators (positive control, stimulates transcription) these can be inducible operons (transcription normally off) or repressible operons(transcription normally on)

Taq polymerase enzyme, used for PCR, denatures at 94C

False the Taq polymerase can tolerate this temp while DNA denatures into single strands

In the absence of tryptophan, the genes of the trp operon for tryptophan synthesis are not expressed

False they are expressed, then tryptophan is present it binds to the repressor and makes it active which binds to the operator which shuts off transcription (negative repressible)

A mutation that changes G/C base pair to A/T is a transversion mutation

False A=T G=_C Transition (common) - like to like (purine->purine) Transversion -like to unlike (purine -> pyrimidine)

Agarose-gel electrophoresis can be used to separate DNA or RNA molecules only on the basis of their electrical charge

False Agarose gel electrophoresis uses both electrical change and size to separate DNA/RNA molecules

In eukaryotes, most structural genes are found within operons

False In most prokaryotes, structural genes are found within operons

PCR has three recurring steps: denature, primer annealing, and hybridization

False PCR (polymerase chain reaction) 3 steps are denaturing, primer annealing, and primer extension

Plasmid is a small circular DNA and thousands of of base pairs with functional genes but does not have its own origin of replication

False Plasmids have an ori (origin of replication)

Somatic mutation are not transmitted to new daughter cells

False Somatic mutations are passed to daughter cells

When siRNAs are present, the rate of its target mRNA degradation decreases and the rate of protein production increases

False Targeted mRNA degradation increases and protein production decreases How it works: siRNA pairs with protein to form RISC (RNA-induced silencing complex) -> siRNA in RISCs pair w/ mRNA and cleaves it -> mRNA is degraded, broken down, and amount of protein is decreased

Illumina sequencing is a method of sequencing by synthesis, which relies on incorporation of nucleotides with an irreversible terminating group by a DNA polymerase

False The nucleotides in Illumina sequencing have reversible terminating groups

Base analogs are mutagenic because they distort the structure of DNA

False base analogs cause the base to change (base substitution)

During RNA interference, miRNA in RISCs match the mRNA imperfectly and stimulate the translation of targeted mRNA

False miRNA matching up imperfectly inhibits translation of targeted mRNA

in a bacterial operon, promoter is bound by regulator protein to regulate its transcription

False the promoter is bound by RNA polymerase the regulator protein is encoded within the promoter (can be active/inactive)

After gene cloning, bacteria with 'empty' or no insert plasmids are blue because they have a functional lacZ. so we are not selecting the blue colony for the cloned gene

True bacteria with the inserted gene have nonfunction lacZ and are white

An expression vector is needed for GMO

True ensures transcription and translation cloning vectors - carry recombinant DNA

Lac operon has both negative and postive controls

True regulatory proteins negative control - repressor, represses transcription positive control - activator, stimulates transcription

During DNA replication, incorporation of 5-Bromouracil can lead to transition mutation

True 5-BU is a base analog (has BR atom) for thymine

DNA fragment clusters are generated for optical detector in the Illumina sequencer to be able to detect string enough signal during sequencing

True

During RNA interference for cleavage of mRNA, siRNA in RISC pairs with mRNA and RISC cleaves the mRNA

True

For a gene under negative control, the regulator protein is a repressor

True

For a gene under positive inducible control, regulator protein is an activator and normally the gene is inactive in transcription

True

RNA interference is also known as RNA silencing and posttranscriptional gene silencing

True

The rate of degradation of mRNAs is important in gene regulation in eukaryotes

True

During Sanger sequencing, the incorporation of a deoxynucleotide terminates DNA synthesis because it lack 3'OH

false dideoxynucleotide terminates DNA synthesis because it has an H at 3'C (lack OH to create phosphodiester bond w/ next nucleotide)

A cloning vector has three important characteristics: 1. origin of replication 2. selectable marker 3. unique restriction enzyme sites

true

DNA replication errors cause spontaneous mutations

true

In a general sense, highly condensed DNA bound with histone proteins represses gene expression

true

Regulatory genes are genes whose products control the transcription or translation of other genes

true

Alternative splicing is known to be important in the regulation of the sexual development in Drosophila

true determines male/female

UV light can be absorbed by pyrimidine in DNA resulting in pyrimidine dimers

true pyrimidine dimers are a chemically bonded adjacent pyrimidines on a DNA strand, often block DNA replication which inhibits cell division

transposition can cause gene mutation

true transposition - the movement of TE (transposable elements /transposons- DNA sequences capable of moving positions in the genome) from one location to another in the genome facilitated by transposase