General Overview Flashcards
What are the components of bright-field microscopy?
Parts include: light source, condenser, objective lenses, eyepiece, and stage.
Bright-field microscopy uses visible light to illuminate samples and is suitable for observing stained specimens.
What type of microscopy is best for observing live cells without staining?
Phase contrast microscopy.
Phase contrast microscopy enhances contrast in transparent samples, allowing for the visualization of live cells.
What is the function of fluorescence microscopy?
To visualize fluorescently labeled structures within cells.
Fluorescence microscopy uses specific wavelengths of light to excite fluorescent dyes, making it possible to study specific proteins or structures.
What are the two types of electron microscopy?
Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).
TEM provides detailed images of internal structures, while SEM gives 3D images of surface topography.
How do you calculate magnification in microscopy?
Magnification = (Objective lens power) x (Eyepiece lens power).
This formula helps determine how much larger the specimen appears compared to its actual size.
What is the basic structure of bacterial cells?
Components include: cell membrane, cell wall, nucleoid, cytoplasm, and ribosomes.
Bacterial cells lack membrane-bound organelles and have a simpler structure compared to eukaryotic cells.
What distinguishes Gram-positive cells from Gram-negative cells?
Gram-positive cells have a thick peptidoglycan layer; Gram-negative cells have a thin peptidoglycan layer and an outer membrane.
The Gram stain procedure differentiates these cell types based on their cell wall composition.
What are the major classes of antibiotics?
Penicillins, tetracyclines, beta-lactams, cephalosporins, and fluoroquinolones.
Each class targets different aspects of bacterial growth and function.
What is binary fission?
A method of bacterial cell division where one cell divides into two identical cells.
This process involves replication of the genome and separation of the cytoplasm.
What is the role of plasmids in bacteria?
Plasmids are small, circular DNA molecules that can carry genes for antibiotic resistance or other functions.
They can be transferred between bacteria, contributing to genetic diversity.
Fill in the blank: The primary inputs of fermentation are _______.
glucose.
Fermentation converts glucose into energy, producing byproducts like ethanol or lactic acid.
What is chemotaxis?
Movement of an organism in response to a chemical stimulus.
Bacteria can move toward nutrients or away from harmful substances through chemotaxis.
True or False: The lytic cycle is a viral replication process that results in the destruction of the host cell.
True.
In the lytic cycle, new viral particles are produced, leading to lysis of the host cell.
What are the mechanisms of horizontal gene transfer?
Transduction, conjugation, and transformation.
These processes allow bacteria to acquire genetic material from other organisms, contributing to evolution.
What is the significance of 16S amplicon sequencing?
It is used to analyze bacterial community composition and diversity.
This technique targets the 16S rRNA gene, which is highly conserved among bacteria.
