Microorganisms Lecture 1: Cells Overview
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Questions and Answers

Which of the following is NOT a branch of microbiology?

  • Bacteriology
  • Virology
  • Mycology
  • Botany (correct)

    • Edward Jenner is known as the father of bacteriology.

    False

    What is the primary advantage of small cell size in prokaryotic cells?

    Higher surface to volume ratio allows for faster nutrient and waste exchange.

    The study of fungi is known as __________.

    <p>Mycology</p> Signup and view all the answers

    Which microorganism is known to have a beneficial effect on human nutrition?

    <p>Probiotics</p> Signup and view all the answers

    Match the following morphological shapes with their descriptions:

    <p>Coccus = Spherical shape Bacillus = Rod shape Spirochete = Long, thin, wavy body Spirillum = Curved or spiral shape</p> Signup and view all the answers

    Eukaryotic cells generally have a faster growth rate compared to prokaryotic cells due to their larger size.

    <p>False</p> Signup and view all the answers

    List one function of the cytoplasmic membrane.

    <p>Selective barrier, protein anchor, or energy conservation.</p> Signup and view all the answers

    Which of the following are types of microbial cells?

    <p>Both A and B</p> Signup and view all the answers

    All microorganisms are multicellular organisms.

    <p>False</p> Signup and view all the answers

    What are the two fundamental types of cells found in microorganisms?

    <p>Prokaryotic and Eukaryotic</p> Signup and view all the answers

    Cyanobacteria can carry out __________, a process that produces oxygen.

    <p>photosynthesis</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Prokaryotic cells = Single-celled organisms without a true nucleus Eukaryotic cells = Multicellular organisms with membrane-bound organelles Cyanobacteria = Bacteria that can carry out photosynthesis Anoxic Earth = Earth's early atmosphere without oxygen</p> Signup and view all the answers

    Which of the following is NOT a characteristic shared by prokaryotic and eukaryotic cells?

    <p>Presence of a nucleus</p> Signup and view all the answers

    Microorganisms can live in complex communities.

    <p>True</p> Signup and view all the answers

    What was the state of the Earth's atmosphere when microorganisms first appeared?

    <p>Anoxic (no oxygen)</p> Signup and view all the answers

    What is the primary function of endospores?

    <p>Survival in unfavorable conditions</p> Signup and view all the answers

    Endospores can only remain dormant for a few days before they must germinate.

    <p>False</p> Signup and view all the answers

    What three steps are involved in endospore activation and germination?

    <p>Activation, germination, and outgrowth</p> Signup and view all the answers

    The structure connecting the filament to the flagellum motor is called the ______.

    <p>hook</p> Signup and view all the answers

    Match the parts of a bacterial flagellum with their functions:

    <p>Filament = Main part composed of flagellin Hook = Connects filament to motor Flagellum motor = Generates torque for rotation Stator = Surrounds the rotor</p> Signup and view all the answers

    What drives the rotation of archaeal flagella?

    <p>Hydrolysis of ATP</p> Signup and view all the answers

    The core of an endospore includes ribosomes and a nucleoid.

    <p>True</p> Signup and view all the answers

    What is the fastest known organism on Earth?

    <p>Methanocaldococcus</p> Signup and view all the answers

    What component makes up the tail of archaeal cell membranes?

    <p>Isoprene</p> Signup and view all the answers

    All bacteria have peptidoglycan in their cell walls.

    <p>True</p> Signup and view all the answers

    What type of cell wall structure is primarily found in Gram positive bacteria?

    <p>Multiple layers of peptidoglycan</p> Signup and view all the answers

    The toxic component of the Gram negative cell wall is called ______.

    <p>lipid A</p> Signup and view all the answers

    Match the following cell wall structures with their characteristics:

    <p>Gram positive = Thick peptidoglycan layer with teichoic acids Gram negative = Thin peptidoglycan layer with outer membrane Archaea = Variety of cell wall types including polysaccharides and proteins Peptidoglycan = Glycan tetrapeptide structure providing rigidity</p> Signup and view all the answers

    Which of the following describes the function of porins in Gram negative bacteria?

    <p>Act as channels for solute transport</p> Signup and view all the answers

    The cell walls of archaea are typically composed solely of peptidoglycan.

    <p>False</p> Signup and view all the answers

    What is the basic unit of peptidoglycan?

    <p>Glycan tetrapeptide</p> Signup and view all the answers

    What is the primary function of the mitochondria in eukaryotic cells?

    <p>Respiration</p> Signup and view all the answers

    Mitosis is unique only to prokaryotic cells.

    <p>False</p> Signup and view all the answers

    What is the primary role of histones in eukaryotic cells?

    <p>To tightly pack DNA into chromosomes</p> Signup and view all the answers

    The process of converting a diploid cell into haploid cells is called ______.

    <p>meiosis</p> Signup and view all the answers

    Match the following cellular structures with their functions:

    <p>Chloroplasts = Photosynthesis Hydrogenosomes = Fermentative metabolism Nucleus = Contains chromosomes Mitochondria = Aerobic respiration</p> Signup and view all the answers

    Which component of taxonomy refers to the process of characterizing organisms?

    <p>Identification</p> Signup and view all the answers

    Binomial nomenclature consists of three names for classifying organisms.

    <p>False</p> Signup and view all the answers

    Who is credited with founding the science of taxonomy?

    <p>Carolus Linnaeus</p> Signup and view all the answers

    Which of the following statements correctly describes Chargaff’s Rule?

    <p>A pairs with T and G pairs with C</p> Signup and view all the answers

    In prokaryotes, DNA replication is unidirectional.

    <p>False</p> Signup and view all the answers

    What enzyme is primarily responsible for replicating chromosomal DNA in prokaryotes?

    <p>DNA polymerase III</p> Signup and view all the answers

    In RNA transcription, the chain grows in the ______ direction.

    <p>5' to 3'</p> Signup and view all the answers

    Match the following DNA replication terms with their definitions:

    <p>Leading Strand = Synthesis occurs continuously toward the replication fork Lagging Strand = Synthesis occurs discontinuously away from the replication fork Topoisomerase = Enzyme that prevents over-winding of the DNA Proofreading = Mechanism to detect and correct mismatches in DNA</p> Signup and view all the answers

    What is the function of primase in DNA replication?

    <p>To provide a primer for DNA polymerase</p> Signup and view all the answers

    Intrinsic terminators require additional factors for transcription termination.

    <p>False</p> Signup and view all the answers

    The nucleic acid backbone consists of alternating ______ and ______ molecules.

    <p>sugar, phosphate</p> Signup and view all the answers

    Study Notes

    Lecture 1: Microorganisms

    • Microorganisms, also called microbes or germs, are too small to be seen with the naked eye, requiring a microscope. They exhibit diverse forms and functions, including single-celled organisms like bacteria and protozoans and multicellular eukaryotes.
    • Microbial cells interact dynamically with their environment and other cells. Two fundamental types are prokaryotic and eukaryotic cells.
    • Prokaryotic cells, including bacteria and archaea, are simpler than eukaryotic cells, which possess membrane-bound organelles.
    • Prokaryotic cells lack a true nucleus, with genetic material located in a nucleoid region. Eukaryotic cells have a true nucleus.
    • Both prokaryotic and eukaryotic cells share common structures such as cell membranes, cytoplasm, ribosomes, and genetic material (DNA).

    Microbial Cells: Prokaryotic vs Eukaryotic

    • Prokaryotic: Single-celled organisms (bacteria, archaea). Simpler structure; lack membrane-bound organelles like a nucleus.
    • Eukaryotic: Multicellular or single-celled organisms. More complex structure; possess membrane-bound organelles.

    Differences between Prokaryotic and Eukaryotic Cells

    • Prokaryotes are simpler, lacking membrane-bound organelles.
    • Eukaryotic cells have true nuclei and membrane-bound organelles.
    • Shape and structure differ: prokaryotes have simpler forms, while eukaryotes can be diverse.

    Microbial Origins and Microscopy

    • Life on Earth first appeared between 3.8 and 4.8 billion years ago.
    • Early life lacked oxygen.
    • Later evolution of photosynthesizing organisms resulted in the Great Oxygenation Event.
    • Robert Hooke was an early observer and described "cells."
    • Antoni van Leeuwenhoek observed and documented bacteria.
    • Microscopy now uses light or electrons, improving resolution and magnification.

    Lecture 2: Cells of Bacteria and Archaea

    • Cell Structure: Prokaryotic (bacteria and archaea) cells contain a cell membrane, often a rigid cell wall, and cytoplasm. External structures like capsules, fimbriae, and pili can also be present.
    • Surface-to-Volume Ratio: Small cells have a higher surface-to-volume ratio, allowing for quicker nutrient uptake and waste removal.
    • Cell Membrane Function: The Cytoplasmic membrane separates the inside of the cell from the environment.
    • It acts as a selective barrier regulating what enters and exits the cell
    • Anchors proteins for various functions, including energy production
    • Microbial Cell Morphology: The cell's shape differs between bacterial and archical cells
    • Bacteria is spherical, rods, spiral or curved.

    Bacterial Cell Walls

    • Peptidoglycan: A rigid polymer, component of bacterial cell walls, providing structural support and resistance to osmotic lysis.
    • Differences in Gram-positive and Gram-negative bacteria: The structure of the cell wall, including the presence/absence of an outer membrane and peptidoglycan layers, determines how the cell interacts with dyes (distinguish gram reaction).
    • Gram-positive: Thicker peptidoglycan layer, retaining crystal violet stain in a gram stain.
    • Gram-negative: Thinner peptidoglycan layer, losing the stain and taking up counterstain. The presence of an outer membrane further contributes to their differences in cell wall structure.

    Lecture 3: Microbial Taxonomy

    • Taxonomy is the science of classifying organisms.
    • Methods and criteria, including morphology (shape and arrangement), staining, growth characteristics, nutritional requirements, and physiological properties, are used to classify organisms.
    • Binomial nomenclature is the formal system of naming species (genus species).

    Lecture 4: Flow of Genetic Information

    • DNA Replication: DNA replicates in a semiconservative manner, producing two identical copies of the original DNA molecule.
    • Transcription: DNA is transcribed to mRNA, a process that results in a molecule complementary to a specific DNA sequence.
    • Translation: mRNA is translated into proteins through the process of assembling amino acids.

    Lecture 11: RNA Transcription

    • DNA synthesis involves leading and lagging strands with replication forks in both directions.
    • RNA polymerase plays a key role in transcription, using DNA as a template to synthesize RNA.
    • Transcription termination regions are critical sequences that signal the end of transcription, a crucial step for preventing indefinite RNA chains.

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    Description

    This quiz covers the fundamental concepts of microorganisms, focusing on the differences between prokaryotic and eukaryotic cells. It explores their structures, functions, and interactions with their environment. Perfect for beginners looking to understand basic microbiology principles.

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