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Questions and Answers
What is the primary function of cilia in microorganisms?
What is the primary function of cilia in microorganisms?
What major constituent is commonly found in the cell walls of many algae?
What major constituent is commonly found in the cell walls of many algae?
Which structure in bacterial cells is primarily involved in adherence to surfaces?
Which structure in bacterial cells is primarily involved in adherence to surfaces?
What is the composition of a bacterial capsule primarily made of?
What is the composition of a bacterial capsule primarily made of?
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How do flagella and cilia differ in length?
How do flagella and cilia differ in length?
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Which protein primarily composes the flagella's structure?
Which protein primarily composes the flagella's structure?
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What role do pili play in bacterial cells?
What role do pili play in bacterial cells?
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What is one of the main protective functions of the bacterial capsule?
What is one of the main protective functions of the bacterial capsule?
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What is the primary role of the Golgi apparatus in the cell?
What is the primary role of the Golgi apparatus in the cell?
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What function do microfilaments and microtubules serve in the cell?
What function do microfilaments and microtubules serve in the cell?
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Which structure is primarily involved in the energy production of the cell?
Which structure is primarily involved in the energy production of the cell?
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What is the main purpose of the plasma membrane in a cell?
What is the main purpose of the plasma membrane in a cell?
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What role does the nucleoid play in prokaryotic cells?
What role does the nucleoid play in prokaryotic cells?
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What is the primary function of Rubisco in photosynthetic organisms?
What is the primary function of Rubisco in photosynthetic organisms?
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Which structures serve as storage reservoirs for phosphate in bacteria?
Which structures serve as storage reservoirs for phosphate in bacteria?
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What is a major constituent of the cell walls of many algae and oomycetes?
What is a major constituent of the cell walls of many algae and oomycetes?
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Through which mechanism do transmissible plasmids operate in gram-positive or gram-negative bacteria?
Through which mechanism do transmissible plasmids operate in gram-positive or gram-negative bacteria?
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What distinguishes flagella from cilia in terms of size?
What distinguishes flagella from cilia in terms of size?
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Which type of endoplasmic reticulum (ER) is abundant in cells that synthesize large amounts of protein?
Which type of endoplasmic reticulum (ER) is abundant in cells that synthesize large amounts of protein?
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In which area of the cell is the nucleoid located?
In which area of the cell is the nucleoid located?
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What is the primary function of the Golgi apparatus?
What is the primary function of the Golgi apparatus?
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What type of plasmids are often found in greater numbers within a cell?
What type of plasmids are often found in greater numbers within a cell?
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Which component is NOT typically found in yeast cell walls?
Which component is NOT typically found in yeast cell walls?
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What do gas vacuoles primarily provide to aquatic prokaryotes?
What do gas vacuoles primarily provide to aquatic prokaryotes?
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What makes the cytoplasmic membrane selectively permeable?
What makes the cytoplasmic membrane selectively permeable?
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What are sulfur granules in photosynthetic bacteria used for?
What are sulfur granules in photosynthetic bacteria used for?
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Which statement accurately describes the cytoplasmic matrix?
Which statement accurately describes the cytoplasmic matrix?
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What percentage of yeast cell walls is made up of protein?
What percentage of yeast cell walls is made up of protein?
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What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER)?
What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER)?
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What is the primary function of the Golgi apparatus?
What is the primary function of the Golgi apparatus?
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Which of the following structures is characterized by having two membranes and being involved in energy production?
Which of the following structures is characterized by having two membranes and being involved in energy production?
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What is the role of lysosomes within a cell?
What is the role of lysosomes within a cell?
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What is the primary role of ribosomes in eukaryotic cells?
What is the primary role of ribosomes in eukaryotic cells?
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Which structure is considered the control center of the cell?
Which structure is considered the control center of the cell?
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What distinguishes eukaryotic ribosomes from prokaryotic ribosomes?
What distinguishes eukaryotic ribosomes from prokaryotic ribosomes?
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What structure primarily increases the surface area for energy production in mitochondria?
What structure primarily increases the surface area for energy production in mitochondria?
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What is the function of nuclear pores in the nucleus?
What is the function of nuclear pores in the nucleus?
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Study Notes
Prokaryotic Cell Surfaces
- Flagella are long, filamentous structures made of flagellin protein, enabling motility and swarming.
- Fimbriae are shorter than flagella and made of fimbrilin, aiding adhesion to surfaces.
- Pili are abundant in negative bacteria, made of pilin, and facilitate bacteriophage attachment, hemagglutination reactions, and bacterial conjugation.
- Capsule is a sticky gelatinous layer composed mostly of complex polysaccharide, sometimes including amino acids, protecting bacteria from environmental factors, particularly drought, and providing resistance to phagocytosis.
- Slime layer is similar to the capsule but less organized and loosely attached, providing protection and aiding adhesion.
Internal Structures of Prokaryotes
- Ribosomes are sites of protein synthesis and are smaller in prokaryotes than in eukaryotes.
- Cytoplasm is the gel-like substance within the cell membrane containing ribosomes, DNA, and other cellular components.
- Nucleoid is the region containing the bacterial chromosome (DNA), which is not enclosed by a membrane, giving prokaryotes a simple structure.
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Plasmids are extrachromosomal genetic material (DNA) that can replicate independently of the bacterial chromosome, often containing genes for functions such as:
- Antibiotic resistance, using enzymes
- Heavy metal resistance, using reductase enzymes.
- Ultraviolet light resistance, through DNA repair mechanisms.
- Production of enterotoxins (exogenous toxins).
- Carboxysomes are polyhedral, protein compartments containing Rubisco, a key enzyme for carbon dioxide fixation.
- Gas vacuoles, present in some aquatic prokaryotes, provide buoyancy and allow for regulation of depth in the water column.
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Inorganic storage granules:
- Polyphosphate granules (volutin granules): store phosphate, an essential component of cell constituents like nucleic acids.
- Sulfur granules: store sulfur produced by photosynthetic bacteria from hydrogen sulfide.
Eukaryotic Cell Surfaces
- Cilia and flagella are involved in motility, but differ in length (cilia are shorter) and movement patterns.
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Cell wall is a rigid outer layer that encloses both eukaryotic and prokaryotic cells.
- In algae and oomycetes, it primarily contains cellulose.
- In fungi, it contains chitin, a polymer of N-acetyl glucosamine.
- In yeast, the cell wall has a composition of β-glycans, mannan, and protein.
Eukaryotic Internal Structures
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Cytoplasmic Membrane (Plasma Membrane) is a lipid bilayer containing phospholipids and cholesterol, with embedded:
- Integral proteins acting as membrane transporters.
- Peripheral proteins acting as enzymes for interactions with the cell's environment.
- Glycolipids in the outer layer serve as recognition sites.
- Cytoplasmic Matrix is the environment where organelles reside and where many important biochemical processes take place.
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Endoplasmic Reticulum (ER):
- Rough ER (RER): has ribosomes attached and is involved in protein synthesis and transport.
- Smooth ER (SER): lacks ribosomes and plays roles in lipid synthesis and detoxification.
- The Golgi Apparatus is a stack of flattened sacs (cisternae) involved in packaging and secretion of various materials, including lysosome formation.
- Lysosomes are membrane-bound organelles containing enzymes for the intracellular digestion of macromolecules.
- Eucaryotic ribosomes are larger than prokaryotic ribosomes and can be either free in the cytoplasm or attached to the ER, with both types involved in protein synthesis.
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Mitochondria are double-membrane bound organelles with cristae (folds of the inner membrane) that increase surface area. They are the sites of:
- Electron transport and oxidative phosphorylation, generating ATP.
- Tricarboxylic acid cycle and fatty acid catabolism.
- Nucleus is the largest organelle in eukaryotic cells, enclosed by a double membrane (nuclear envelope) containing pores for transport. It stores the genetic information (DNA) and acts as the control center of the cell.
- Nucleolus is responsible for ribosomal RNA synthesis and ribosome construction.
Function Summary of Eukaryotic Organelles
- Cilia and flagella: Cell movement
- Cell wall: Provides strength and shape to the cell
- Plasma membrane: Mechanical cell boundary, semi-permeable barrier for transport, mediates cell-cell interactions and adhesion
- Cytoplasmic matrix: Environment for organelles; location of metabolic processes
- Microfilaments and microtubules: Cell structure and movement; form cytoskeleton
- Endoplasmic reticulum: Transport of materials; protein and lipid synthesis
- Ribosomes: Protein synthesis
- Golgi apparatus: Packaging and secretion of materials; lysosome formation
- Lysosomes: Intracellular digestion
- Mitochondria: Energy production through the tricarboxylic acid cycle, electron transport, and oxidative phosphorylation
- Vacuole: Temporary storage and transport, digestion (food vacuoles), water balance (contractile vacuole)
- Nucleoid: Repository for genetic information; control center for the cell
- Nucleolus: Ribosomal RNA synthesis; ribosome construction
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Description
This quiz explores the key components of prokaryotic cell surfaces and internal structures. Topics include flagella, fimbriae, pili, capsules, slime layers, and ribosomes. Test your knowledge on how these features contribute to bacterial motility, adhesion, and protection.
