BIO 212 Module 4 Homework

Check the answers that apply to catabolite repression and the lac operon.

- CAP is active when bound to cAMP - Adenyl cyclase synthesizes cAMP when glucose levels are low - The lac operon contains a CAP recognition site

Check all of the choices that apply to BOTH eukaryotic and archaeal replisome components.

- FEN-1 - RFC-L - MCM^2 - PCNA

Evaluate the statements below and choose those that correctly apply to mobile genetic elements.

- The att site in MGIs is compatible with the attC site often found in E. coli tRNA genes - MGIs are transposons that transfer large segments of a donor chromsome compared to ICEs - ICEs contain genes for a type IV secretion systen that allow integration into a host chromosome

Molecular chaperones function to _________.

- recognize unfolded or partially denatured proteins- prevent incorrect folding of proteins- fold newly formed proteins to their proper shape Choose the protein secretion systems only found in Gram-negative bacteria.

Which of the following are typically used when preparing a DNA profile?

- restriction endonucleases - gel electrophoresis

Under normal environmental conditions, Rhizobium synthesizes the σ70 sigma factor. When the only nitrogen available is nitrogen gas, Rhizobium synthesizes the σ60 sigma factor. From this information you can deduce _________. (Check all that apply.)

- σ60 is used for expression of genes involved in nitrogen fixation - σ60 allows for expression of a specific subset of genes - σ60 binds to a different promoter than σ70

During transcription elongation, how many pyrophosphate molecules are produced from the incorporation of 20 ribonucleoside monophosphates?

20

Pair the ribosomal structure with the correct organism.

80s ribosome- Eukaryote 70s ribosome- Bacteria 70s ribosome- Archaea

If a region of DNA contained numerous mismatches due to a modifying agent that caused methylation of guanine, which of the following mutagens is most likely the cause?

A DNA modifier such as an alkylating agent

Site-specific recombination systems _________.

All of the choices are correct.

Which statement best describes the mechanism(s) of posttranslational regulation of gene expression?

Allosteric regulation following transcription of mRNA occurs in many biosynthetic pathways.

You and a classmate are discussing early experiments in genetics, and you state that Avery, MacLeod, and McCarty provided the first evidence that DNA carries genetic information. Your classmate argues that Griffith was the first to demonstrate this. Which statement best defends your argument?

Although Griffith first demonstrated transformation, Avery, MacLeod, and McCarty provided evidence that DNA rather than protein or RNA was the transforming agent.

Aminoacyl-tRNA synthetases catalyze covalent addition of __________ __________ to tRNAs.

Amino acids

If you were to design a novel hydrophobic protein, which type of monomers would be most essential to incorporate in the molecule in order to achieve the desired result?

Amino acids with nonpolar side chains

Which of the following are newly acquired characteristics of E. coli cells successfully transformed with pGLO?

Ampicillin resistance

he Polymerase Chain Reaction is used to ________ a specific sequence of DNA.

Amplify

The __________ is a factor-independent termination site found in the leader region of certain operons, which, under the influence of ribosome behavior, controls the continued transcription of that operon.

Attenuator

In the CRISPR/Cas system __________.

Bacteria integrate portions of the viral genome into their own so they have a molecular snapshot of their attacker to prevent future encounters

Which was common to experiments done by Avery and colleagues as well as Hershey and Chase?

Bacterial cells

Put these DNA fragments in order of their position after gel electrophoresis, starting with the one closest to the negative end of the gel and ending with the one closest to the positive end of the gel.

Biggest to smallest

It is easier to transform bacteria with plasmid DNA since plasmids _________.

Can independently replicate within the host and are not as easily degraded as are linear fragments

Bacterial chromosomes are ____________ and can have two replication forks for ____________ replication.

Circular; bidirectional

__________ activate repressor proteins, thereby decreasing the synthesis of certain enzymes.

Corepressors

If flagellar rotation of Escherichia coli cells is __________ , then CheA is __________.

Counterclockwise; unphosphorylated

Transformation with a linear DNA fragment may result in _________.

Either homologous recombination or unsuccessful transformation

Transposable elements contribute to the __________ of bacterial and archaeal chromosomes, plasmids, and other mobile genetic elements, leading to new variations, species, and strains.

Evolution

Streptococcus pneumoniae becomes competent during the ________ phase of bacterial growth.

Exponential

Acridine orange is a purine base analogue.

False

Because of its larger size, the replication rate of eukaryotic genomes is significantly faster than the replication rate of bacterial and archaeal genomes.

False

During regulation of biofilm formation in Pseudomonas, cells leave the biofilm when levels of cyclic dimeric GMP are high.

False

In the presence of both glucose and lactose, the lactose repressor is not bound to the operator and the genes of the lactose operon are expressed.

False

Riboswitches regulate transcription, rather than translation, in cells.

False

Two-component signal transduction systems are found in the Bacteria, but not in Archaea.

False

When tryptophan levels in a cell are low, a cell will stall transcription but continue translation of the tryptophan operon.

False

n an F+ × F− mating, all or part of the host chromosome usually is transferred to the recipient.

False

The initiator codon for translation of polycistronic and other mRNAs in bacteria is generally ____________ .

Formyl methionine

Which of the following is used to detect the products of PCR?

Gel electrophoresis

Please select the statement that best describes the purpose of gel electrophoresis.

Gel electrophoresis separates DNA fragments based on size.

Who first demonstrated transformation using mice and two strains of Streptococcus pneumoniae?

Griffith

Choose the term that identifies the type of bond that links the nitrogenous bases together in the DNA double helix.

Hydrogen bond

Bacterial genes residing on these chromosomes generally do not have ____________ , so there is no splicing of resultant mRNA transcripts.

Introns

The unexpressed regions of split genes are called _________.

Introns

Which of the following statements about DNA polymerase is false?

It can only add bases to the exposed 5' end of a preexisting strand

On mRNA molecules, a nontranslated sequence called the ___________ usually precedes the initiation codon.

Leader

The order of gene transfer in an Hfr × F− mating is best represented by _________.

Part of the plasmid followed by the chromosome followed by the rest of the plasmid

Repair of thymine dimers using light to split the dimers apart into separate monomers is called _________.

Photoreactivation

Furthermore, bacterial mRNAs can be ____________ with several genes on a single molecule.

Polycistronic

Such transcripts lack the ____________ commonly seen in eukaryotic mRNAs as well.

Pony A tails

The region at which the RNA polymerase binds is the __________ region.

Promoter

A(n) __________ is a latent form of a virus genome that remains within the host without destroying it.

Prophage

Which of the following describes a mechanism that eukaryotic organisms can employ to alter protein production as an alternative to regulating transcription initiation?

RNA molecules within the spliceosome can direct alternative splicing of the primary transcript so that different proteins can be made from the same coding region.

Transposons that insert at a new location while a copy remains at the original location are said to mediate ________ transposition.

Replicative

The bacterial replicative DNA polymerase is recruited to the single origin only after the initiator protein DnaA begins assembly of the bacterial replisome and the replication forks move bidirectionally from the origin until the entire _________ shaped chromosome is replicated.

Ring

Which of the following is the most error-prone of the repair mechanisms?

SOS repair

A suitable system for detecting mutant phenotypes is known as a ___________.

Screen

________ translocate proteins from the cytoplasm across or into the plasma membrane.

Sec pathways

____________ translocate proteins from the cytoplasm across or into the plasma membrane.

Sec pathways

When a DNA molecule is replicated, the daughter molecules contain one strand of parental DNA and one strand of newly synthesized DNA; this is called __________ replication.

Semiconservative

A consensus sequence in the untranslated leader sequence of a prokaryotic mRNA, which serves as a ribosome binding site is called the _____ - _____ sequence.

Shine-Dalgarno

How does the size of a DNA fragment relate to its speed of passage through the agarose gel?

Smaller fragments move through the gel faster.

When an F' plasmid acts as the donor in a mating, which of the following do(es) not happen?

Some chromosomal genes not on the plasmid are transferred.

The sensor kinase for the OmpF: OmpC two-component regulatory system is _________.

The EnvZ protein

Some mutations arise from the alteration of single pairs of nucleotides and from the addition or deletion of one nucleotide pair in the coding regions of a gene; these are known as _________ mutations.

The RNA transcribed from the operon is translated into a single polypeptide that is spliced by proteases to create individual proteins.

The terminator versus anti-terminator function of the T box-based riboswitch used by Gram-positive bacteria to regulate amino acid-related genes is determined by _________.

The binding of the appropriate uncharged tRNA

If a mutation occurred resulting in a single nucleotide addition to the below DNA sequence, what do you suspect would happen?

The mutation results in a new "stop codon" resulting in the loss of the original functional gene

If chromosomal DNA from a host and phage DNA are carried by a transducing particle, what can be concluded regarding transduction in this case?

Transduction in this case is specialized rather than generalized.

In general, riboswitches regulate __________ in Gram-negative bacteria such as Escherichia and __________ in Gram-positive bacteria such as Bacillus.

Translation; transcription

Distinguish between transcriptional riboswitches and translational riboswitches by classifying the characteristics of each group

Translational riboswitch-- -Occlusion of the Shine-Delgarno site---Thiamine biosynthesis operon---Gram-negative bacteria---Ribsome binding inhibition Transcriptional riboswitch- -Riboflavin operon---Gram-positive bacteria---Interrupted mRNA production---FMN as effector

Protein translocation differs from protein secretion in that __________.

Translocation refers to movement from the cytoplasm to or across the plasma membrane, whereas secretion refers to movement of the protein to the exterior of the cell

Bacteria with DNA described as having "hairpin ends with inverted repeats" must not have circular chromosomes.

True

Differences in eukaryotic, bacterial, and archaeal transcription are attributable to both polymerase differences and organization of protein-coding genes.

True

If 5-bromouracil was added to a culture of actively dividing bacterial cells, resulting mutations could eventually become a stable part of the cellular genome.

True

One way to regulate gene expression is through the production of different sigma factors. These cause RNA polymerase to bind to different sets of promoters, thereby altering the pattern of gene expression.

True

Photoreactivation repairs thymine dimers by splitting them back into separate thymines.

True

Regulation of translation initiation by micro RNAs and small interfering RNAs is possible since transcription and translation are spatially separated in eukaryotes. This is not the case in bacteria and archaea, where translation begins before transcription has ended.

True

Signal recognition particles (SRPs) are associated with the Sec translocation system.

True

The genes that code for tRNA often contain multiple tRNA sequences controlled by a single promoter, requiring posttranscriptional modification by ribonucleases.

True

The process of transcriptional regulation was studied by scientists ahead of translational and posttranslational regulation because the mechanism of transcription itself was better understood than that of translation and posttranslational protein modification.

True

When a chemorepellent is present in the media, the number of tumbles performed by a peritrichous bacteria would decrease, while the number of runs would increase.

True

____________ , also called ____________ , move proteins from the cytoplasm across both the plasma membrane and the outer membrane.

Type I secretion systems; ABC secretion systems

____________ are observed in a number of pathogens and transport proteins that pass from the periplasmic space across the outer membrane.

Type II secretion systems

____________ are used by pathogens to secrete virulence factors from the cytoplasm, across both the plasma membrane and outer membrane, and into host cells.

Type III secretion systems

____________ can transport DNA during conjugation in addition to proteins.

Type IV secretion systems

___________ start with Sec-dependent transport across the plasma membrane, but the proteins then form a channel in the outer membrane through which they autotransport.

Type V secretion systems

In terms of transcription regulation, the role of a helix-turn-helix is most similar to that of a(n) .

Zinc finger

Regulation of transcription by attenuation vs. riboswitches differs in that _________.

attenuation contributes to transcriptional regulation by directing alternative folding of the leader mRNA depending on levels of tryptophan in the cell, whereas riboswitches are nontranslated areas in the leader mRNA that are bound by nonprotein molecules

In terms of global gene regulation, which of the following molecules is most similar to c-di-GMP and cAMP?

ppGpp