Questions and Answers
What are the two types of cellular microorganisms?
Prokaryotic cells have a nuclear body.
False
What is the main constituent of the bacterial cell wall?
Peptidoglycan
The characteristic structure of M.tuberculosis seen in a stain is known as __________.
Signup and view all the answers
Match the following bacterial growth factors with their descriptions:
Signup and view all the answers
What type of acid composition is found in bacterial endospores?
Signup and view all the answers
Gram negative bacteria retain crystal violet stain after a Gram stain procedure.
Signup and view all the answers
Which of the following is a key function of the bacterial capsule?
Signup and view all the answers
What are pili used for in bacteria?
Signup and view all the answers
Which of these is NOT a type of bacterial flagella?
Signup and view all the answers
Endotoxins are proteins released by living bacteria.
Signup and view all the answers
What is the term for bacteria that thrive at low temperatures?
Signup and view all the answers
Which of the following nutrients is essential for bacterial growth?
Signup and view all the answers
Study Notes
Microorganisms
- Microorganisms are classified into acellular (viruses) and cellular organisms (prokaryotes and eukaryotes).
Comparison Between Eukaryotic and Prokaryotic Cells
- Prokaryotes lack a true nucleus, while eukaryotes have a defined nuclear body.
- Prokaryotic cells divide through binary fission; eukaryotic cells divide via mitosis or meiosis.
- Prokaryotes typically have peptidoglycan cell walls; eukaryotic cells may have cellulose or chitin.
- Prokaryotic cytoplasmic membranes are simpler than eukaryotic ones.
- Prokaryotes generally lack membrane-bound organelles, whereas eukaryotes contain them.
- Energy production in prokaryotes occurs in the cytoplasmic membrane; in eukaryotes, it occurs in mitochondria.
- Protein synthesis sites differ; prokaryotes use ribosomes in the cytoplasm, while eukaryotes use ribosomes attached to the endoplasmic reticulum.
Bacterial Cytology
- Cell Wall: Composed mainly of peptidoglycan, providing protection and shape to bacteria. Components like M protein and mycolic acid can enhance pathogenicity.
- Cytoplasmic Membrane: Functions as a selectively permeable barrier.
- Mesosomes: Extensions of the cytoplasmic membrane, serving as sites for chromosome attachment.
- Ribosomes: Essential for protein synthesis.
- Inclusions: Nutrient storage, with examples including metachromatic granules.
- Endospores: Highly resistant resting cells composed of calcium dipicolinate, produced by genera like Bacillus and Clostridium.
- Capsule: Enhances virulence by hindering phagocytosis; can be antigenic based on K antigens.
- Pili (Fimbriae): Include ordinary pili for attachment and sex pili for conjugation.
- Glycocalyx: Can be a capsule (organized) or slime layer (unorganized).
Bacterial Structures
- Flagella: Used for locomotion; classified by arrangements (atrichous, monotrichous, etc.).
- Periplasmic Flagella: Also known as axial filaments, contribute to cell motility.
Bacterial Virulence Factors
- Adherence and antiphagocytic factors, enzymes, and toxins (exotoxins and endotoxins) play significant roles in pathogenicity.
- Exotoxins: Secreted proteins, heat-labile, with specific pharmacological effects.
- Endotoxins: Part of the bacterial cell wall, heat-stable, less immunogenic.
Bacterial Growth Factors
-
Nutrients: Essential elements like carbon, nitrogen, and minerals are necessary for growth.
- Some organisms are halophilic, requiring high salt concentrations.
-
Oxygen and Carbon Dioxide:
- Obligate aerobe: Requires oxygen.
- Obligate anaerobe: Grows in absence of oxygen.
- Facultative anaerobe: Can switch between aerobic and anaerobic respiration.
- Microaerophilic: Requires low oxygen levels.
- Capnophilic: Prefers elevated CO2 levels.
- Temperature: Bacteria can be classified as psychrophilic, mesophilic, or thermophilic based on optimal temperature ranges.
- pH: Most bacteria thrive in neutral or slightly alkaline conditions; some extremes include acidophiles and alkaliphiles.
Growth Cycle and Culture Media
- Understanding bacterial growth cycles is essential for proper culturing and experimentation.
- Nutrient media formulation is critical for cultivating specific microorganisms.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers fundamental concepts in microbiology, focusing on the comparison between prokaryotic and eukaryotic cells. It delves into their structures, functions, and differences, providing a clear understanding of cellular biology. Perfect for students looking to review key concepts in their microbiology studies.