Bacterial Genetics and Cell Structure Quiz

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Questions and Answers

What distinguishes plasmids from episomes?

  • Episomes are self-replicating.
  • Plasmids can integrate into chromosomal DNA.
  • Plasmids lack the ability to integrate with bacterial chromosomal DNA. (correct)
  • Episomes are not essential for bacterial growth.

Which of the following statements is true regarding bacterial chromosomes?

  • They consist of a single DNA molecule. (correct)
  • They include histones in prokaryotes.
  • They contain more than 1000 genes.
  • They are composed solely of RNA.

What is the primary function of a gene within a DNA molecule?

  • To code for particular information. (correct)
  • To facilitate antibiotic resistance.
  • To assist in the formation of proteins.
  • To replicate bacterial DNA.

How many genes can typically be found in a plasmid?

<p>5 to 100 genes (A)</p> Signup and view all the answers

Which component is NOT typically associated with the genomes of prokaryotic organisms?

<p>Histones (D)</p> Signup and view all the answers

What is the Gram stain result for the rod-shaped bacteria identified in the content?

<p>Gram-negative (pink) (C)</p> Signup and view all the answers

What is the cell shape of the Gram-positive bacteria mentioned in the content?

<p>Clusters of cocci (D)</p> Signup and view all the answers

Which of the following bacteria would be classified as Enterobacteriaceae?

<p>Klebsiella (C)</p> Signup and view all the answers

What is a key factor that influences binary fission in bacterial cells?

<p>Sufficient metabolites (A)</p> Signup and view all the answers

How many different species of bacteria are mentioned in connection with different cell shapes and Gram results?

<p>Two different species (D)</p> Signup and view all the answers

What is the process by which free DNA is transferred from one bacterial cell to another?

<p>Transformation (A)</p> Signup and view all the answers

Which method of genetic transfer involves a bacteriophage?

<p>Transduction (A)</p> Signup and view all the answers

In which type of genetic transfer do mating cells physically contact each other?

<p>Conjugation (A)</p> Signup and view all the answers

Conjugation primarily occurs between which types of cells?

<p>Mating cells of the same or closely related species (A)</p> Signup and view all the answers

Which of the following statements accurately characterizes transformation?

<p>It allows for the incorporation of free DNA. (D)</p> Signup and view all the answers

What connection does conjugation have with antibiotic resistance?

<p>It allows for the sharing of plasmids carrying resistance genes. (B)</p> Signup and view all the answers

What is the role of the bacterium Yersinia pestis in the context of disease?

<p>It is associated with the Black Death. (C)</p> Signup and view all the answers

What type of organism is Yersinia pestis classified as?

<p>Gram-negative bacilli (B)</p> Signup and view all the answers

Which shape represents bacteria that are spherical or nearly spherical?

<p>Cocci (D)</p> Signup and view all the answers

What term describes paired cocci bacteria?

<p>Diplococci (B)</p> Signup and view all the answers

How do streptobacilli arrange themselves after division?

<p>In chains (A)</p> Signup and view all the answers

Which of the following best describes the phenotypic characteristics of organisms?

<p>Their appearance and metabolic traits (C)</p> Signup and view all the answers

Which of the following domains have more known species?

<p>Bacteria (C)</p> Signup and view all the answers

Which type of bacteria is described as curved or comma-shaped rods?

<p>Vibrios (B)</p> Signup and view all the answers

What are bacilli that have not separated after division called?

<p>Diplobacilli (A)</p> Signup and view all the answers

Which classification is NOT a type of Archaea?

<p>Phototrophs (D)</p> Signup and view all the answers

Which arrangement forms cocci bacteria in cubes of eight due to division in three planes?

<p>Sarcina (B)</p> Signup and view all the answers

What is the primary means of bacterial cell division?

<p>Binary fission (A)</p> Signup and view all the answers

What distinguishes spirochetes from other spiral bacteria?

<p>They are thin and flexible (A)</p> Signup and view all the answers

When do some bacteria typically produce spores?

<p>When conditions are unfavorable (C)</p> Signup and view all the answers

During the exponential growth phase, which of the following occurs?

<p>The number of dividing cells increases rapidly (A)</p> Signup and view all the answers

What is a key characteristic of staphylococci bacteria?

<p>Grapelike clusters (C)</p> Signup and view all the answers

What do chemoheterotrophs require for survival?

<p>Organic compounds alone (C)</p> Signup and view all the answers

What is a characteristic of plasmids?

<p>They are capable of self-replication (B)</p> Signup and view all the answers

What defines Archaea as extremophiles?

<p>They are known to live in very extreme environments. (C)</p> Signup and view all the answers

What characteristic is unique to Archaea compared to Bacteria?

<p>Cell membrane consisting of glycerol esters. (B)</p> Signup and view all the answers

Which of the following is true about the replication origins of Archaea?

<p>They have multiple replication origins. (B)</p> Signup and view all the answers

What type of lipid is found in the plasma membranes of Archaea?

<p>Phytanyl-glycerol ethers. (C)</p> Signup and view all the answers

Which of the following enzymes is not typically produced by Archaea?

<p>Proteins involved in aerobic respiration. (C)</p> Signup and view all the answers

How do Archaea differ in initiator tRNA compared to Bacteria?

<p>Bacteria use formyl-methionine while Archaea use methionine. (A)</p> Signup and view all the answers

Which statement about the environmental distribution of Archaea is correct?

<p>They are found alongside bacteria in various environments. (B)</p> Signup and view all the answers

What is a key characteristic of the cell wall of Bacteria?

<p>It contains peptidoglycan. (A)</p> Signup and view all the answers

What is the Gram classification of the bacteria exhibiting rod shapes in the Gram stain?

<p>Gram-negative (pink) (A)</p> Signup and view all the answers

Which type of bacterial cell division results in two equal daughter cells?

<p>Binary fission (C)</p> Signup and view all the answers

Which description accurately characterizes the Gram-positive bacteria mentioned?

<p>Cocci in clusters (D)</p> Signup and view all the answers

How many different species of bacteria are present when one is Gram-positive and the other is Gram-negative?

<p>Two species (B)</p> Signup and view all the answers

What distinguishes the Enterobacteriaceae mentioned from other bacterial families?

<p>They are primarily rod-shaped and Gram-negative. (D)</p> Signup and view all the answers

Which of the following describes diplobacilli?

<p>Paired rods that remain in pairs after division (B)</p> Signup and view all the answers

What arrangement of cocci forms grape-like clusters?

<p>Staphylococci (D)</p> Signup and view all the answers

How do spirillum bacteria differ from other spiral bacteria?

<p>They are thick and rigid (A)</p> Signup and view all the answers

Which of the following describes staphylococci arrangements?

<p>Organisms arranged randomly in clusters (B)</p> Signup and view all the answers

What describes pleomorphic bacteria?

<p>Can change between different shapes (A)</p> Signup and view all the answers

Which of the following shapes is classified as vibrios?

<p>Curved or comma-shaped (C)</p> Signup and view all the answers

What term refers to chains of cocci bacteria?

<p>Streptococci (C)</p> Signup and view all the answers

Which bacteria arrangement is known for forming cubes of eight?

<p>Sarcina (D)</p> Signup and view all the answers

What is the primary process by which free DNA is taken up by a bacterial cell from its environment?

<p>Transformation (C)</p> Signup and view all the answers

Which genetic transfer method involves the use of a bacteriophage?

<p>Transduction (C)</p> Signup and view all the answers

Conjugation in prokaryotes primarily requires what key condition?

<p>Cell-to-cell contact (A)</p> Signup and view all the answers

In what context is bacterial conjugation particularly significant?

<p>Horizontal gene transfer contributing to antibiotic resistance (D)</p> Signup and view all the answers

Which of the following statements best describes transformation?

<p>It involves the uptake of naked DNA from the environment. (C)</p> Signup and view all the answers

During which genetic transfer process can bacteria acquire traits such as antibiotic resistance?

<p>Conjugation (A)</p> Signup and view all the answers

Which component is critical for the process of transduction in bacteria?

<p>Bacteriophage (B)</p> Signup and view all the answers

Which type of bacterial genetic transfer allows for DNA exchange between closely related species?

<p>Conjugation (A)</p> Signup and view all the answers

What is a disadvantage of using dry weight measurement for estimating cell mass?

<p>It is time-consuming and involves washing and drying cells (A)</p> Signup and view all the answers

During which phase of the population growth curve do bacteria adapt to their environment?

<p>Lag phase (C)</p> Signup and view all the answers

Which method counts only viable bacterial cells?

<p>Viable counts through pour plating (B)</p> Signup and view all the answers

What happens during the stationary phase of bacterial growth?

<p>Nutrient depletion occurs and dead cells outnumber viable cells (C)</p> Signup and view all the answers

What is an advantage of measuring turbidity in bacterial growth?

<p>It is a rapid assessment method (C)</p> Signup and view all the answers

Which of the following statements correctly describes spores?

<p>Spores help microorganisms survive adverse conditions (C)</p> Signup and view all the answers

What primarily influences the rate of binary fission in bacteria?

<p>Availability of nutrients and environmental conditions (C)</p> Signup and view all the answers

What occurs at the beginning of the death phase in bacterial growth?

<p>The number of dead cells exceeds the number of viable cells (C)</p> Signup and view all the answers

What primary characteristic differentiates Archaea from bacteria?

<p>Ability to produce methane (D)</p> Signup and view all the answers

What is the classification level below Kingdom?

<p>Phylum (A)</p> Signup and view all the answers

Which metabolic condition do thermophiles thrive in?

<p>Extreme heat (C)</p> Signup and view all the answers

What describes the arrangement of bacteria that form clusters due to division in multiple planes?

<p>Staphylococci (B)</p> Signup and view all the answers

What term is used for the structural pattern formed when bacilli do not separate after division?

<p>Streptobacilli (C)</p> Signup and view all the answers

In which environment are halophiles primarily found?

<p>High salinity conditions (A)</p> Signup and view all the answers

Which process is responsible for the asexual reproduction of bacteria?

<p>Binary fission (C)</p> Signup and view all the answers

What is a primary characteristic of a plasmid?

<p>Independent self-replicating circle of DNA (D)</p> Signup and view all the answers

What distinguishes the lipid composition of Archaea from that of Bacteria?

<p>Archaea have phytanyl-glycerol ethers. (C)</p> Signup and view all the answers

How are the chromosomes of Bacteria and Archaea typically structured?

<p>Both Bacteria and Archaea have circular chromosomes. (A)</p> Signup and view all the answers

What is a characteristic of Archaea that allows them to survive in extreme environments?

<p>Unique RNA polymerase structure. (C)</p> Signup and view all the answers

Which statement correctly compares the sensitivity of Bacteria and Archaea to streptomycin?

<p>Bacteria are sensitive, Archaea are resistant. (A)</p> Signup and view all the answers

What is the primary structural difference between the cell walls of Bacteria and Archaea?

<p>Bacteria contain peptidoglycan, Archaea do not. (A)</p> Signup and view all the answers

Which characteristic is exclusive to Archaea in comparison to Bacteria?

<p>Production of bioethanol. (C)</p> Signup and view all the answers

What is a significant challenge in studying Archaea in laboratory settings?

<p>Most cannot be cultured outside their natural environments. (D)</p> Signup and view all the answers

Which of the following best defines an extremophile?

<p>Organisms that live in harsh environmental conditions. (A)</p> Signup and view all the answers

Flashcards

Cocci

Spherical or nearly spherical shaped bacteria.

Bacilli

Rod-shaped bacteria, some of which form endospores.

Vibrio

Bacteria that have a curved or comma-shaped rod structure.

Spirillum

Thick, rigid, spiral-shaped bacteria.

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Spirochetes

Thin, flexible, spiral-shaped bacteria.

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Diplococci

Pairs of cocci.

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Streptococci

Chains of cocci.

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Staphylococci

Grapelike clusters of cocci, formed by random cell division.

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What is the cell shape of bacilli?

Bacteria that have a rod-shaped appearance.

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What is the cell shape of cocci?

Bacteria that have a spherical or nearly spherical shape.

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What is binary fission?

A process of cell division where a single cell divides into two identical daughter cells.

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What is a Gram stain?

A type of bacterial staining technique that differentiates bacteria based on their cell wall composition.

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Equal/Unequal daughter cells in binary fission

The process of dividing a cell into two daughter cells, which may or may not be equal in size.

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Genome

The total genetic material of an organism, represented by its chromosomes.

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Chromosome

A single DNA molecule containing genes and associated proteins (in eukaryotes) that carries genetic information.

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Gene

A unit of DNA that codes for a specific trait or function within an organism.

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Plasmid

A small, circular DNA molecule that replicates independently of the main chromosome. Often carries genes for antibiotic resistance or other traits.

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Episome

A type of plasmid that can integrate itself into the main chromosome, and be duplicated with the chromosome during cell division.

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Transformation

The transfer of free DNA from one cell to another, occurring naturally in many bacterial species.

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Transduction

The transfer of bacterial DNA from a bacteriophage into another cell.

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Conjugation

The transfer of genetic material during cell-to-cell contact, between mating cells of the same or closely related species.

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Conjugation

A type of genetic transfer where a bacterial donor cell transfers genetic material to a recipient cell through direct contact.

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Conjugation

The transfer of genetic material from one bacterium to another via a pilus.

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Antibiotic Resistance Through Conjugation

The ability of bacteria to acquire resistance to antibiotics through genetic transfer mechanisms.

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Black Death

A deadly bacterial infection spread through flea bites, caused by the bacterium Yersinia pestis.

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Yersinia pestis

A rod-shaped, Gram-negative bacterium responsible for the Black Death, transmitted through flea bites.

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What are Archaea?

Organisms classified as prokaryotes that are often found in extreme environments such as hot springs or salty lakes.

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What are plasmids?

These are genetic elements that can move between different bacteria, contributing to genetic diversity and potential adaptation.

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What is bacterial conjugation?

The transfer of genetic material between bacteria through direct contact.

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What is bacterial transformation?

A type of horizontal gene transfer where bacteria take up free DNA from their environment.

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What is bacterial transduction?

A type of horizontal gene transfer where DNA is transferred between bacteria through bacteriophages (viruses that infect bacteria).

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What is a phylogenetic tree?

A branching diagram used to illustrate the evolutionary relationships between different organisms.

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What is biogeography?

The study of the distribution and relationships of organisms over space and time.

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What is adaptation?

The process by which organisms evolve to better suit their specific environment.

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Phenotype

Describes the observable characteristics of an organism, including its size, shape, color, and metabolic processes.

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Analytical approach

Focuses on the chemical makeup of an organism, examining its components like proteins, lipids, and carbohydrates.

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Genotypic approach

Deals with the genetic information of an organism, analyzing its DNA sequence and RNA transcripts.

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Prokaryotes

Single-celled organisms that lack a true nucleus and other membrane-bound organelles.

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Peptidoglycan

A unique, complex sugar-based molecule found in bacterial cell walls.

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Archaea

A diverse group of prokaryotes that thrive in harsh environments like deep-sea vents and hot springs.

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Binary fission

A process where one bacterial cell divides into two identical daughter cells.

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Endospores

Resistant structures formed by some bacteria under harsh conditions, providing protection and survival.

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Study Notes

Lecture 3: Bacteria and Archaea

  • Lecture presented by Dr. Claire Atkinson
  • Learning objectives included understanding bacterial structures, growth, genetics, archaea, and their differences from bacteria.

Learning Objectives

  • Identify the shapes and arrangements of bacteria (cocci, bacilli, vibrio, spirilla, pleomorphic, spirochetes, diplo, staph, strep, palisades, tetrads, and sarcina)
  • Describe bacterial growth
  • Explain bacterial genetics (genome, chromosome, gene, plasmids, episomes)
  • Define archaea
  • Contrast archaea with bacteria

Bacterial Cell Morphology

  • Bacteria exhibit diverse shapes:
    • Coccus (spherical)
    • Bacillus (rod-shaped)
    • Vibrio (curved or comma-shaped)
    • Spirilla (spiral-shaped)
    • Spirochetes (thin, flexible spirals)
    • Pleomorphic (variable shapes)
  • Arrangement after cell division affects the appearance of colonies:
    • Diplococci (pairs)
    • Streptococci (chains)
    • Tetrads (groups of four)
    • Staphylococci (clusters)
    • Sarcina (cubes of eight)

Bacterial Growth

  • Binary fission is the primary method of bacterial cell division.
  • Growth phases are characterized by the number of cells in each phase:
    • Lag phase: Cells adapt to the medium before division.
    • Log phase: Cell growth increases exponentially.
    • Stationary phase: Essential nutrients are depleted or byproducts accumulate.
    • Death phase: Number of dead cells exceeds viable cells.

Measuring Bacterial Growth

  • Methods measure cell mass or count viable cells.
    • Dry weight (most accurate but slow)
    • Turbidity (cloudiness, measured using spectrophotometer.)
    • Direct cell count (microscopic counts in counting chambers)
    • Viable counts (only live cells are counted, techniques like pour plating, spread plating)

Bacterial Genetics

  • Genome: Genetic material of an organism.
  • Chromosome: Single DNA molecule in bacteria.
  • Gene: Unit of genetic information on DNA
  • Plasmid: Small, circular DNA molecule, independent of the chromosome.
  • Plasmids can have genes that provide antibiotic resistance.
  • Episome: DNA that can integrate itself into the bacterial chromosome.

Bacterial Genetic Transfer

  • Transformation: Transfer of free DNA from one cell to another.
  • Transduction: Transfer of bacterial DNA from a bacteriophage to another bacterium.
  • Conjugation: Gene transfer between mating cells.

Archaea

  • Are prokaryotes.
  • Often live in extreme environments (extremeophiles) — such as hot springs, volcanic vents, or highly salty environments.
  • Are widely distributed in various environments alongside bacteria
  • Many archaea species are used in industrial processes such as bioremediation
  • Many bacterial enzymes are derived from archaea for many industrial processes.
  • Not much known about archaea species due to difficulty growing many types in laboratory settings.
  • Not linked to human diseases in any well-documented way.

Bacteria and Archaea Differences

  • Archaea cell walls do not contain peptidoglycan.
  • Bacteria use ester linkages and archaea use ether linkages to attach their phospholipids.
  • Bacterial ribosomes are more sensitive to streptomycin than archaea ribosomes.
  • Bacterial and archaea membranes have differences in their lipids.
  • Bacterial chromosomes and genes have different properties/composition than archaea chromosomes and genes.

Identifying Bacteria

  • Phenotypical methods like shape, color, and size
  • Analytical methods like analyzing cell components
  • Genotypic methods like genetic information (DNA, rRNA)

Taxonomy

  • The science of classifying organisms.
  • Formal system of organizing organisms by categories.
  • Can classify archaea into categories similarly to bacteria such as domains, kingdom, phyla, and so on.

Quiz Time

  • Review questions relating to cells, morphology, arrangements, arrangement after division, methods for testing, growth curves (lag, log, stationary, and death phases), antibiotics, genetic material, and bacteria vs archaea.

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