Chapter 6
The organism lives in an environment rich in organic material, particularly amino acids and proteins
Functional analysis of the genome of a prokaryote shows that 20% of the genome is for metabolism, 1 % biosynthesis of amino acids, 8% peptide ABC transporters, and 2% replication. What can you determine about the environment this organism lives in?
conjugation, transduction, and transformation
Horizontal gene flow can be accomplished in prokaryotes by __________
In horizontal gene transfer, genes are transferred from one mature adult organism to another. In vertical gene transfer, genes are transferred from adults to offspring
Horizontal gene transfer refers to the transfer of genes from one organism to another, as occurs during conjugation between bacteria. How does this differ from vertical gene transfer?
Each base is identified with a different fluorescent color
Newer sequencing techniques require only one lane on an electrophoresis gel rather than four. How is this possible?
Proteins and RNA molecules that are needed in the cell at about the same level under all growth conditions, require
constitutive expression
A common structure for proteins that bind DNA
helix-turn-helix
Regulatory proteins
regulate transcription, bind specific DNA sites, and can be influenced by small molecules
When more than one operon is under the control of a single regulatory protein, the operons are collectively called a(n)
regulon
Which type of regulator(s) specifically binds to operator regions of DNA?
repressors
Which of the following do NOT bind to the promoter sequence during regulation?
repressors, inducers, and activators
transfer of DNA between organisms of the same generation
What is the hallmark of all horizontal gene transfers?
Eukaryotes have more introns in their chromosomes
Determine why some prokaryotes have less DNA but more genes than eukaryotes
RNA has a relatively short half life compared with DNA and does not need to be as stable to perform its functions in the cell
In DNA replication in vivo, RNA primers are used. However, researchers use DNA primers instead in the lab because DNA primers are more stable. Why might this be the case?
An organism grown in nutrient rich broth to high turbidity always produces a blue pigment. When a large inoculum is transferred to a nutrient rich agar plate, it also appears blue. A researcher noticed that this never happens when very small colonies are grown on low nutrient agar plates, however. What is the most plausible conclusion?
Production of the blue pigment production is linked to quorum sensing.
The bacteria should be classified by using genomic analyses to construct phylogenies
Researchers discover a new species of bacterium that has an unusual metabolism. However, it has biochemical and morphological similarities to other species. What is the most comprehensive and effective approach to determine how to classify these bacteria?
comparative genomics
The field of study that can reveal how genes function, reveal how organisms interact with the environment, and show evolutionary relationships is __________
genes, function, and evolutionary history
The genome sequence of an organism can provide information about the organism's __________
In negative control of transcription by the lac operon, how does the presence of an inducer affect transcription?
The inducer prevents the repressor from binding to the operator.
a start codon and a ribosomal binding site (RBS)
To determine if you have identified a functional open reading frame (ORF), you should have found within the sequence _________
Transduction, conjugation, and transformation
What is an example of horizontal gene transfer in bacteria?
recombinant cell
a cell that receives DNA from an outside source and incorporates it into its own
A two-component regulatory system usually involves
both the sensor and response proteins being subject to phosphorylation.
Mechanisms for controlling enzyme activity include...
covalent modification of the enzyme. degradation of the enzyme. feedback inhibition.
Transcriptional regulators bind most frequently at the ________ site of DNA.
major groove
The function of a kinase is
phosphorylation
Regulation of enzyme activity occurs
posttranslationally
The promoters of positively controlled operons require activator proteins because
the promoters bind RNA polymerase weakly and utilize activator proteins to help RNA polymerase recognize the promoter.
because both elements contain nonessential genes
Chromosomal islands are similar to plasmids __________
duplicate genes are free to evolve into new genes
Gene duplication is essential to organisms because __________
When arginine is added to a culture already growing exponentially in a medium without arginine, what occurs?
Growth continues, but the production of enzymes required for the synthesis of arginine ceases
The stringent response is a mechanism used by bacteria that provides
an increased ability to survive in environments lacking nutrients.
In order for the helix-turn-helix motif to bind to DNA, the ________ must fit into the major groove of the DNA.
recognition helix
Possibly; it would depend on whether the gene was essential for survival and on whether you could create a diploid bacteria as well
You are interested in trying to determine the function of a particular gene in a common bacterium (meaning that it has a haploid genome). To do this, could you use a knockout mutation?
The preferential use of glucose over other available carbon substrates for growth is mechanistically explained by
catabolite repression
The lac operon is an example of ________ control in which the presence of an ________ is required for transcription to occur.
negative / inducer
Proteins required at approximately the same level throughout a cells growth cycle are often not...
subject to regulatory mechanisms and are constitutively synthesized.
