Questions and Answers
How many plasmids are likely to be found in a single bacterial cell?
0-100
How many chromosomes are likely to be found in a single bacterial cell?
1
SRNAs can regulate gene expression by:
In a two-component regulatory system, what would happen if the phosphatase is modified so it can no longer remove phosphate from the response regulator?
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What is the stringent response mediated by?
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What would best describe transcription of the lac operon if the LacI protein has been mutated so it can't bind the lac operator sequences?
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The term diauxic growth is used to describe what situation?
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Why doesn't the arginine repressor ArgR bind DNA without its corepressor?
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Since genes are arranged in operons in prokaryotes, what does it allow for?
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If you're studying a DNA-binding protein that interacts with the DNA sugar-phosphate backbone, what do you expect?
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Does RNA polymerase need all 5 subunits (alpha, beta, beta prime, omega, sigma) to create RNA?
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In which direction does DNA polymerase synthesize a new strand of DNA?
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Can SARS-CoV-2 integrate into human cells (effectively undergo lysogeny)?
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The SARS-CoV-2 viron membrane is derived from ____, while the SARS-CoV-2 viron proteins are derived from ____.
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Will a bacterium with a CRISPR system, whose ancestor was exposed to a particular virus, be able to survive another infection attempt by the same virus?
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How might a transposon or insertion element get into a microbial genome?
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What might be a beneficial outcome of horizontal gene transfer for a microbe?
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Where is a likely spot recombination might occur if a bacterium has taken up DNA from a bacterium that isn't very closely related to it?
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What kind of mutation would occur if your gene has the following codons: AGG GTC TAT TCC ATA and before the last codon, these two base pairs are inserted: TG?
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Do all mutations result in visible phenotypes?
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Study Notes
Plasmids and Chromosomes
- A single bacterial cell can contain between 0 to 100 plasmids.
- Typically, bacterial cells possess one chromosome.
Gene Regulation by sRNAs
- Small RNAs (sRNAs) regulate gene expression through various mechanisms, including:
- Direct inhibition or promotion of mRNA translation.
- Modulation of mRNA degradation and stability.
Two-Component Regulatory Systems
- If the phosphatase in a two-component system cannot remove phosphate from the response regulator, cells act as if an external signal is perpetually present.
Stringent Response
- Triggered by nutrient limitation, results in synthesis of ppGpp and pppGpp.
- Varies in its outcomes based on the organism experiencing stress.
Lac Operon Regulation
- A mutation preventing LacI protein from binding the lac operator leads to consistent low-level expression of the lac operon.
Diauxic Growth
- Describes bacterial growth in the presence of two carbon sources, where the preferred source is utilized first, followed by the secondary source.
Arginine Repressor Function
- ArgR only binds DNA with corepressor arginine due to a conformational change required for DNA interaction.
Operons in Prokaryotes
- Gene arrangement in operons allows simultaneous regulation of multiple genes for a coordinated response to stimuli.
DNA-binding Protein Interaction
- A protein interacting with the DNA sugar-phosphate backbone indicates non-specific binding to DNA.
RNA Polymerase
- RNA synthesis does not require all five subunits of RNA polymerase; it can function with fewer.
DNA Polymerase Synthesis Direction
- Synthesizes new DNA strands in the 5' to 3' direction.
SARS-CoV-2 Integration
- SARS-CoV-2 does not integrate into human cells or undergo lysogeny.
SARS-CoV-2 Viron Structure
- The viron membrane is derived from the host cell, while proteins are produced from viral sources.
CRISPR System and Viral Resistance
- Bacteria with a CRISPR system can withstand future infections from viruses previously encountered by ancestors.
Horizontal Gene Transfer Benefits
- Offers microbe advantages like new carbon source utilization, antibiotic resistance, and ecological niche survival.
Recombination in Genetic Exchange
- Recombination is likely to occur at ribosomal RNA genes when distant bacteria exchange DNA.
Mutation Types
- The insertion of base pairs can lead to a nonsense mutation in a gene's coding sequence.
Mutations and Phenotypes
- Not all mutations lead to observable changes in phenotypes.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on plasmids, chromosomes, and sRNAs with these flashcards from CMB211 Unit 2. Each card provides a key concept relevant to bacterial cell structure and gene regulation. Perfect for students looking to reinforce their understanding of molecular biology.
