MB 351 Test 3

Which of the following is involved in translation?

Sigma factors are involved in the regulation of bacterial _______.

This term describes a bacterium that has the capacity to take up DNA via transformation.

During the process of _________ transduction, the phage will carry both bacterial chromosomal DNA and phage DNA.

How does the amount of available glucose impact the transcription of the lac operon?

Retroviruses require the activity of __________ to complete their infection cycle.

Viral genomes can consist of...

Which of the following is primarily responsible for the shape of a virion?

Bacillus thuringiensis produces a toxin that can be used...

Prokaryotic genes are typically organized into operons.

Promoters are specific sequences of ________ that are recognized by ____________.

The horizontal gene transfer process known as transduction...

Bacteria can acquire new DNA from the immediate environment in the process of...

In negative control of the tryptophan operon, what molecule acts as the corepressor?

Nearly all viruses are constructed of:

Virus replication results in the death of the cell in __________ infection(s).

Protein molecules are made from RNA template sequences via the transcription process.

You have identified a eukaryotic gene that you want to express in bacteria. You will need to isolate __________.

What do you predict in regard to the functionality of this altered PmoC1 protein compared to wild type PmoC1?

is the gene sequence found at the 5' end of DNA, which RNA polymerase recognizes as a binding site to initiate transcription.

base pairs upstream (toward the 5′ end) from the start of the gene. These are consensus sequences that are responsible for recruiting the sigma subunit of RNA polymerase to initiate transcription.

is the point at which synthesis of the mRNA molecule strand complementary to the DNA sequence begins to be produced.

exists downstream from the initiation sequence. This sequence signals the end transcription of the DNA sequence. Upon reaching this point, the RNA polymerase detached from the DNA.

is a sequence of the mRNA to which a ribosome binds to initiate translation, or protein synthesis. It is located 6-7 nucleotides upstream of the start codon.

is the first triplet of genes to be translated by the bound ribosome into a protein. Typically, this start codon is AUG.

indicates the end of translation of the mRNA sequence by the ribosome, and the ribosome disassociates from the mRNA. The stop codon does not code for an amino acid.

Indicate whether each has a role in transcription, translation, both, or neither. mRNA DNA polymerase -10/-35 consensus sequences start codon initiation site (also called +1) ribosome binding site (RBS) stop codon

How many promoters would be necessary to allow transcription of the pmoCAB operon?

How many mRNA molecules will be produced when this operon is transcribed?

How many ribosome binding sites will be present on the RNA produced when the pmo operon is transcribed?

How many start codons and stop codons will be present on the RNA produced when the pmo operon is transcribed?

Arrange the statements in the correct order to describe the process of replication of the leading strand.

(written 5' to 3'): TAA GCG TAG AAC TTG Which of the following sequences represents the mRNA (written 5' to 3') that will be generated from this template DNA sequence?

For each of the following phrases, indicate whether it occurs during transformation, conjugation, generalized transduction, or specialized transduction. Donor and recipient cels must be of an opposite mating type. A phage infects the bacterial cell, thereby transferring bacterial, plasmid, and/or viral DNA to the recipient. Requires direct contact between bacterial cells, which is typically mediated by a sex pills. Naked DNA is transferred from donor to recipient. During phage infection, particular bacterial genes are transferred to the recipient. Requires the recipient cell to be competent.

Transcription begins when RNA polymerase binds to the promoter sequence, assisted by σ factor that recognizes the promoter.

As RNA pol moves along template strand, it opens up a transcription bubble and ribonucleotides are added to the 3'OH of the ribose of the preceding ribonucleotide. Chain growth is from 5' to 3' end, thus newly synthesized strand is antiparallel to template strand.

Transcription stops when it reaches the terminator sequence. This can be self determining/intrinsic/Rho independent, where a stem loop structure forms from the transcribed RNA sequence, pulling apart the RNA pol. OR termination can be enzyme/Rho dependent, where a terminator protein binds to terminator sequence and pushes RNA pol off.

30S subunit binds to Shine-Dalgarno sequence just upstream of start codon on mRNA, followed by arrival of formylmethionine aminoacyl tRNA binding to start codon. Next, 50S subunit binds onto this complex.

Elongation of the polypeptide chain begins by a new charged aminoacyl-tRNA binding to the codon in the A site of the ribosome. The 50S subunit catalyzes formation of a peptide bond between the 2 amino acids.

Ribosome must advance 3 nucleuotides down mRNA during translocation. After translocation, an empty tRNA sits in the E site and the peptidyl-tRNA is in the P site. tRNA in E site is ejected, a new aminoacyl tRNA enters A site.

The ribosome reaches a non-sense (stop) codon, a release factor binds in the vacant A site. The polypeptide is released from the tRNAs. The ribosome falls apart.

Insertion or deletion of one or more nucleotide pairs. Changes codon reading and multiple amino acids. Effect on phenotype very likely.

transfer of genes from an organism to its offspring

transfer of genes between cells of the same generation

in which free DNA released from one cell is taken up by another.

in which DNA transfer involves cell-to-cell contact and a conjugative plasmid in the donor cell.

in which DNA transfer is mediated by a virus/phage.

encode enzymes for catabolism of unusual compounds

encode antibiotic resistance

Toxin production

carries genes for sex pili and transfer of plasmid

DNA is transferred from a donor cell to a recipient via a

Random bacterial DNA is packaged inside a phage and transferred to a recipient cell

Specific bacterial genes are packaged inside a phage and transferred to a recipient cell

has both • a catalytic ( also called an active) site • a regulatory (allosteric/effector) site

• Proteins that bind to operator • Stop RNA polymerase binding and turn off transcription

• Proteins that bind to activator site • Increase RNA polymerase binding and turn on transcription

• Inducers: molecules that bind to repressors and result in transcription being turned on. • Corepressor: molecules that bind to repressors and result in transcription being turned off.

a regulatory mechanism that stops transcripHon, through a repressor protein that brings about inhibiHon of mRNA synthesis. Two simple forms of negative regulation: • Repression • Induction

a regulatory mechanism that starts transcription through an activator protein that activates the binding of RNA polymerase to DNA.

Cells often need to coordinate the expression of multiple genes and operons in response to changing environmental conditions. Global control systems coordinate this type of regulatory mechanism.

Transcription occurs continuously and the repressor protein must be activated to stop transcription. (Example: trp operon)

Transcription does not occur unless an inducer inactivates a repressor protein. (Example: lac operon, structural genes are only transcribed when lactose is present and repressor protein is made inactive)

small molecules derived from the metabolic breakdown of larger molecules

mechanism for ensuring that the best carbon and energy source available is used first

A latent bacterial virus (phage)

A viral (phage) genome integrated in a host chromosome

A host cell carrying a prophage

The spontaneous mutations that lead to antigenic variability

If two different flu viruses infect the same cell, the progeny viruses package a random selection of the 8 RNA chromosomes.

The use of living organisms, cells, or cell components to make a product.

the insertion or modification of genes to produce desired proteins

an organism whose genetic material has been altered using genetic engineering techniques.

type of GMO that contains a genetic material from another species.

Self-replicating DNA (plasmid) used to carry the desired gene to a new cell (example: expression vectors- allows you to control expression of cloned genes)

Population of cells arising from one cell, each carries the new gene.

enzyme that recognizes a specific DNA sequence and then cuts the DNA at that site.