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Questions and Answers
What are the two general types of cells?
What are the two general types of cells?
Prokaryotic cells are typically larger than eukaryotic cells.
Prokaryotic cells are typically larger than eukaryotic cells.
False
What is the primary component of the cell wall in prokaryotic cells?
What is the primary component of the cell wall in prokaryotic cells?
Peptidoglycan
Which of these is NOT a characteristic of bacteria?
Which of these is NOT a characteristic of bacteria?
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The nucleus of bacteria consists of a single ______ which is circular double stranded DNA (helix).
The nucleus of bacteria consists of a single ______ which is circular double stranded DNA (helix).
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What is the name given to the extra-circular chromosomal DNA found in the cytoplasm of bacteria?
What is the name given to the extra-circular chromosomal DNA found in the cytoplasm of bacteria?
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All bacteria have a cell wall.
All bacteria have a cell wall.
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What is the primary function of the cell wall in bacteria?
What is the primary function of the cell wall in bacteria?
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Which of the following is NOT a common bacterial arrangement?
Which of the following is NOT a common bacterial arrangement?
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Match the bacterial shape with its corresponding example.
Match the bacterial shape with its corresponding example.
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Which of the following is considered an external structure of the bacterial cell?
Which of the following is considered an external structure of the bacterial cell?
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What is the primary function of fimbriae in bacteria?
What is the primary function of fimbriae in bacteria?
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What is the structural composition of the bacterial flagellum?
What is the structural composition of the bacterial flagellum?
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Which of the following is NOT a function of the glycocalyx?
Which of the following is NOT a function of the glycocalyx?
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Gram-positive bacteria have a thicker peptidoglycan layer than Gram-negative bacteria.
Gram-positive bacteria have a thicker peptidoglycan layer than Gram-negative bacteria.
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Which of the following is a characteristic of the outer membrane in Gram-negative bacteria?
Which of the following is a characteristic of the outer membrane in Gram-negative bacteria?
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The Gram stain is a technique used to identify fungi.
The Gram stain is a technique used to identify fungi.
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Which of the following bacterial groups lack a typical cell wall structure?
Which of the following bacterial groups lack a typical cell wall structure?
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The cell membrane is referred to as the 'fluid mosaic model' due to its rigid and unchanging structure.
The cell membrane is referred to as the 'fluid mosaic model' due to its rigid and unchanging structure.
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What are the primary components of the bacterial cell membrane?
What are the primary components of the bacterial cell membrane?
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What is the primary function of mesosomes in bacteria?
What is the primary function of mesosomes in bacteria?
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The bacterial cytoplasm is primarily composed of water.
The bacterial cytoplasm is primarily composed of water.
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Which of the following is NOT a type of cytoplasmic inclusion found in bacteria?
Which of the following is NOT a type of cytoplasmic inclusion found in bacteria?
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Endospores are highly resistant to environmental stressors like heat, radiation, and chemicals.
Endospores are highly resistant to environmental stressors like heat, radiation, and chemicals.
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Which of the following is a group of bacteria that are beneficial for the conversion of milk into curd?
Which of the following is a group of bacteria that are beneficial for the conversion of milk into curd?
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Which of the following bacterial groups is responsible for nitrogen fixation in soil?
Which of the following bacterial groups is responsible for nitrogen fixation in soil?
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Harmful bacteria are responsible for infectious diseases like pneumonia, tuberculosis, and viridans.
Harmful bacteria are responsible for infectious diseases like pneumonia, tuberculosis, and viridans.
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Microbial growth refers to an increase in the size of an individual cell.
Microbial growth refers to an increase in the size of an individual cell.
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Which of the following is NOT a phase of bacterial growth?
Which of the following is NOT a phase of bacterial growth?
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Bacteria can grow at any temperature.
Bacteria can grow at any temperature.
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Which of the following environmental factors does NOT influence bacterial growth?
Which of the following environmental factors does NOT influence bacterial growth?
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What is the optimal pH range for most bacteria that cause human diseases?
What is the optimal pH range for most bacteria that cause human diseases?
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Halophiles are bacteria that can only survive in the presence of high salt concentrations.
Halophiles are bacteria that can only survive in the presence of high salt concentrations.
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Which of the following is a primary requirement for bacterial growth, serving as a source of energy and building blocks?
Which of the following is a primary requirement for bacterial growth, serving as a source of energy and building blocks?
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Bacteria can synthesize all 20 amino acids.
Bacteria can synthesize all 20 amino acids.
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Which of the following is NOT a trace element often required by bacteria?
Which of the following is NOT a trace element often required by bacteria?
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Study Notes
Microbiology: Prokaryotic & Eukaryotic Cells
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Prokaryotic cells lack membrane-bound organelles and a nucleus, are smaller than eukaryotic cells (about 10 times smaller), have a cell wall primarily made of peptidoglycan, reproduce faster and thus multiply more rapidly, and have a higher surface-area-to-volume ratio compared to larger cells
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Eukaryotic cells have a membrane-bound nucleus and membrane-bound organelles, evolved about 2 million years after prokaryotes, and have cell walls composed of cellulose or chitin. Examples of organisms with eukaryotic cells include fungi, algae, protozoa, plants, and animals.
Microbial Growth
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Microbial growth refers to the increase in a population's number of cells, rather than an individual cell's size. Cell division leads to population growth.
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Asexual reproduction in microbes can occur via binary fission (simple cell division) or budding (bubble-like growth).
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Bacteria growth cycles can be divided into four phases:
- Lag phase: minimal cell increase. Cells are preparing for rapid growth.
- Log phase: exponential growth and multiplication.
- Stationary phase: growth rate slows as resources become scarce.
- Death phase: cell death begins to exceed growth rate.
Bacterial Classification
- Bacteria are characterized based on several factors.
- Shape (coccus, bacilli, vibrio, spirilla, spirochete).
- Cell wall composition (Gram-positive or Gram-negative).
- Arrangement (single cells, chains, clusters).
- Mode of respiration (aerobic, anaerobic, facultative).
Bacterial Cells: External Structures
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Glycocalyx: a surface coating that protects bacteria from desiccation and aids in attachment. Includes a slime layer (loosely attached) and a capsule (tightly attached).
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Flagella: specialized structures that facilitate movement (lophotrichous, amphitrichous, peritrichous)
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Fimbriae: hairlike structures that help bacteria attach to surfaces.
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Pili: tubular structures that permit conjugation (exchange of genetic material) between cells.
Bacterial Cells: Internal Structures
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Cytoplasm: A jelly-like substance that fills the cell and contains ribosomes responsible for protein synthesis, as well as inclusion bodies.
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Nucleic region (chromosome located in the nucleoid region): Contains a single circular chromosome of double-stranded DNA, as well as plasmids which are additional circles of DNA (used for genetic engineering).
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Ribosomes: responsible for protein synthesis (prokaryotic ribosomes are distinguished from eukaryotic ribosomes, used in medical treatments.
Bacterial Growth Factors
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Factors that influence bacterial growth include physical factors like pH, temperature, hydrostatic pressure, tonicity, and radiation, as well as nutritional factors like oxygen requirements, carbon sources, nitrogen sources, sulfur sources, and phosphorus sources.
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Specific vitamins and essential minerals are also important nutritional factors.
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Description
This quiz covers the fundamental differences between prokaryotic and eukaryotic cells, including their structures, functions, and reproduction methods. It also explores the concepts surrounding microbial growth, including population dynamics and growth phases. Test your knowledge on these essential microbiological principles!
