Microbiology Chapter 2
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Questions and Answers

What shape do bacillus bacteria exhibit?

  • Spherical
  • Twisted
  • Rod-shaped (correct)
  • Irregular

What function does the glycocalyx serve for bacteria?

  • Facilitating movement
  • Protection from antibiotics
  • Adherence to surfaces (correct)
  • Energy production

Which statement correctly describes the composition of the bacterial cell wall?

  • Includes only lipopolysaccharide
  • Composed solely of proteins
  • Consists of phospholipids only
  • Made of peptidoglycan, which includes NAG and NAM (correct)

What is the role of flagella in prokaryotic cells?

<p>Assist in movement (D)</p> Signup and view all the answers

What distinguishes Gram-negative bacteria from Gram-positive bacteria?

<p>An outer membrane with lipopolysaccharide (B)</p> Signup and view all the answers

What type of movement does positive taxis describe?

<p>Movement toward an attractant (C)</p> Signup and view all the answers

Which bacterial structure primarily assists in DNA transfer between cells?

<p>Pili (C)</p> Signup and view all the answers

What characteristic is true regarding spirochetes?

<p>They possess axial filaments for movement (C)</p> Signup and view all the answers

What is the primary role of the rough endoplasmic reticulum in eukaryotic cells?

<p>Protein synthesis (D)</p> Signup and view all the answers

Which structure in eukaryotic cells contains DNA in the form of chromosomes?

<p>Nucleus (B)</p> Signup and view all the answers

Which of the following statements about mitochondria is true?

<p>They multiply by binary fission. (D)</p> Signup and view all the answers

What function do vacuoles primarily serve in plant cells?

<p>Substance storage and rigidity (D)</p> Signup and view all the answers

What type of ribosomes are found in eukaryotic cells?

<p>80S (C)</p> Signup and view all the answers

Which organelle is responsible for modifying and packaging proteins?

<p>Golgi complex (C)</p> Signup and view all the answers

Which component of the outer membrane of gram-negative bacteria acts as an endotoxin?

<p>Lipid A (A)</p> Signup and view all the answers

Which of the following is NOT a function of lysosomes?

<p>Photosynthesis (D)</p> Signup and view all the answers

What is the result of bacterial exposure to lysozyme in gram-positive bacteria?

<p>Formation of a protoplast (B)</p> Signup and view all the answers

What is a characteristic feature of peroxisomes in eukaryotic cells?

<p>Catalase that destroys H2O2 (C)</p> Signup and view all the answers

What type of membrane transport involves proteins for movement from high to low concentration without energy expenditure?

<p>Facilitated diffusion (B)</p> Signup and view all the answers

What distinguishes the cell walls of Archaea from those of bacteria?

<p>Presence of pseudomurein (A)</p> Signup and view all the answers

What describes the plasma membrane's structure?

<p>A lipid bilayer with integral and peripheral proteins (B)</p> Signup and view all the answers

Which statement about mycoplasma is accurate?

<p>They naturally lack cell walls. (B)</p> Signup and view all the answers

What is the effect of alcohols on the plasma membrane?

<p>Destroys the plasma membrane (B)</p> Signup and view all the answers

What is the primary function of the O polysaccharides in the outer membrane?

<p>Function as antigens (C)</p> Signup and view all the answers

Which statement accurately describes a significant difference between prokaryotic and eukaryotic cells?

<p>Eukaryotic cells have a membrane-bound nucleus, while prokaryotic cells do not. (A)</p> Signup and view all the answers

What is the primary component found in the cell walls of prokaryotic cells?

<p>Peptidoglycan (A)</p> Signup and view all the answers

Which of the following organelles is associated with the Golgi complex?

<p>Lysosomes (A)</p> Signup and view all the answers

Which of the following statements is true regarding the structure and function of the ribosomes?

<p>Eukaryotic ribosomes are typically more complex than prokaryotic ribosomes. (A)</p> Signup and view all the answers

How do rough and smooth endoplasmic reticulum differ structurally?

<p>Rough ER has ribosomes attached, whereas smooth ER does not. (A)</p> Signup and view all the answers

Which of the following statements correctly explains the endosymbiotic theory related to eukaryotic organelles?

<p>Chloroplasts and mitochondria evolved from free-living prokaryotes. (C)</p> Signup and view all the answers

Which feature distinguishes eukaryotic cells from prokaryotic cells regarding cellular organization?

<p>Membrane-bound organelles (B)</p> Signup and view all the answers

What primary function does the Golgi complex serve in the cell?

<p>Modification and packaging of proteins (C)</p> Signup and view all the answers

What structural component do centrioles consist of?

<p>9 triplet microtubules (D)</p> Signup and view all the answers

According to the endosymbiotic theory, what is the basis for the evolution of eukaryotic cells?

<p>They originated from symbiotic prokaryotes living within other prokaryotes. (C)</p> Signup and view all the answers

What characteristic of endospores allows bacteria to withstand adverse conditions?

<p>Protective endospore wall (B)</p> Signup and view all the answers

What distinguishes facilitated diffusion from active transport?

<p>Facilitated diffusion does not require energy; active transport requires energy. (B)</p> Signup and view all the answers

Which statement accurately describes gram-positive bacteria?

<p>They retain the violet stain after decolorization. (A)</p> Signup and view all the answers

What is a primary function of porins in gram-negative bacteria?

<p>Facilitate diffusion of small water-soluble molecules (A)</p> Signup and view all the answers

What happens to the violet stain in gram-negative bacteria when treated with a decolorizing agent?

<p>It is released due to the dissolution of the outer membrane. (B)</p> Signup and view all the answers

What is group translocation's unique characteristic regarding material movement across the plasma membrane?

<p>The substrate is changed after crossing the membrane. (C)</p> Signup and view all the answers

What is the main function of the extracellular enzyme amylase?

<p>To hydrolyze starch into sugars (C)</p> Signup and view all the answers

Which type of cell is characterized by the presence of membrane-enclosed organelles?

<p>Eukaryotic cells (D)</p> Signup and view all the answers

What structural component do archaea lack when compared to bacteria?

<p>Peptidoglycan cell walls (A)</p> Signup and view all the answers

What do bacterial endospores allow bacteria to do?

<p>Survive in harsh conditions (D)</p> Signup and view all the answers

What is the significance of lipid A in gram-negative bacteria?

<p>It acts as an endotoxin (D)</p> Signup and view all the answers

In a hypertonic environment, what happens to water in the cell?

<p>Water passively leaves the cell (D)</p> Signup and view all the answers

Which component allows bacteria to adhere to surfaces in a biofilm?

<p>Fimbriae and glycocalyx (A)</p> Signup and view all the answers

What was a key observation in the life cycle of Coxiella burnetii?

<p>It has distinct coccoid and bacillary forms. (B)</p> Signup and view all the answers

Flashcards

Compare prokaryotic and eukaryotic flagella

Prokaryotic flagella are simpler in structure, composed of a single protein called flagellin, and rotate like a propeller. Eukaryotic flagella are more complex, made of microtubules arranged in a 9+2 pattern, and undulate whip-like.

Compare prokaryotic and eukaryotic cell walls

Prokaryotic cell walls contain peptidoglycan, a unique polymer of sugars and amino acids. Eukaryotic cell walls, if present, are made of cellulose, chitin, or other complex polysaccharides.

Compare prokaryotic and eukaryotic plasma membranes

Prokaryotic plasma membranes are structurally similar to eukaryotic membranes but lack sterols (like cholesterol) that provide greater rigidity.

Compare prokaryotic and eukaryotic cytoplasm

Prokaryotic cytoplasm lacks the extensive network of membrane-bound organelles found in eukaryotes.

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Size difference between prokaryotic and eukaryotic ribosomes

Prokaryotic ribosomes are smaller (70S) than eukaryotic ribosomes (80S).

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Define organelle

An organelle is a membrane-bound compartment within a eukaryotic cell that performs a specific function.

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Compare the nucleus of a eukaryote and the nucleoid of a prokaryote

The eukaryotic nucleus is a membrane-bound organelle that contains the cell's DNA, while the prokaryotic nucleoid is a region within the cytoplasm where the DNA is localized but not enclosed by a membrane.

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Effect of erythromycin on prokaryotic and eukaryotic cells

Erythromycin inhibits protein synthesis in prokaryotes by binding to the 50S ribosomal subunit, effectively stopping bacterial growth. It has little effect on eukaryotes as their ribosomes are different (80S).

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Glycocalyx

A gelatinous layer surrounding some bacteria that can protect them from phagocytosis, enable them to adhere to surfaces, prevent desiccation, and even provide nutrients.

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Flagella

Long, filamentous appendages that rotate to propel prokaryotic cells. They consist of a filament, hook, and basal body.

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Taxis

A type of movement in bacteria where they respond to stimuli in their environment; positive taxis is moving towards an attractant, negative taxis is moving away from a repellent.

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Spirochetes

Spiral-shaped bacteria that use axial filaments for movement.

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Fimbriae

Short, bristle-like appendages that help bacteria adhere to surfaces.

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Pili

Longer, thicker, hair-like appendages that play a role in twitching motility and DNA transfer.

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Cell Wall

The rigid outer layer that surrounds the bacterial plasma membrane, protecting it from changes in water pressure. It is composed of peptidoglycan.

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Peptidoglycan

A polymer found in bacterial cell walls that is made up of NAG and NAM (sugar molecules) linked by chains of amino acids. It is targeted by antibiotics like penicillin.

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What is lipopolysaccharide?

A complex molecule composed of sugars (O polysaccharides) and lipid A, found in the outer membrane of gram-negative bacteria.

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What characterizes a gram-positive cell wall?

A type of bacterial cell wall that is thicker and more rigid than gram-negative cell walls, containing a large amount of peptidoglycan.

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What characterizes a gram-negative cell wall?

A type of bacterial cell wall that is thinner and less rigid than gram-positive cell walls, containing a smaller amount of peptidoglycan and an outer membrane.

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What is pseudomurein?

A type of bacterial cell wall that is not composed of peptidoglycan, but instead uses a different molecule called pseudomurein. This is found in Archaea.

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What is an acid-fast cell wall?

A type of cell wall found in some bacteria, like Mycobacterium, that contains a thick layer of mycolic acid outside a thin peptidoglycan layer.

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What is lysozyme?

An enzyme that can break down peptidoglycan, causing cell wall damage in gram-positive bacteria.

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What is passive transport?

The process of the movement of molecules across a membrane from an area of high concentration to an area of low concentration, without requiring cellular energy.

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What is osmosis?

The movement of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration.

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What is the cytoplasm?

The fluid inside the eukaryotic cell, excluding the nucleus.

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What are organelles?

They are membrane-bound structures within the eukaryotic cell that perform specialized functions.

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What's the function of the nucleus?

It is the control center of the eukaryotic cell, containing DNA in the form of chromosomes.

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What is the endoplasmic reticulum (ER)?

It's a network of interconnected membranes that serve as a transport system, provide a surface for chemical reactions, and store synthesized molecules.

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What is the Golgi complex?

It consists of flattened sacs called cisterns. It functions in membrane formation and protein secretion.

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What are lysosomes?

They are small, membrane-bound sacs containing digestive enzymes. They are the recycling centers of the cell.

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What are mitochondria?

They are the powerhouses of the cell, generating ATP for energy. They have their own DNA and ribosomes.

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What are chloroplasts?

They are the sites of photosynthesis in plants. They contain chlorophyll and have their own DNA and ribosomes.

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What are centrioles and what do they do?

Centrioles are cylindrical structures found in animal cells and some eukaryotic protists. They are composed of nine triplets of microtubules arranged in a ring. Centrioles play a crucial role in cell division, helping to organize the spindle fibers needed for chromosome separation.

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What is the endosymbiotic theory?

The endosymbiotic theory proposes that eukaryotic cells evolved from a symbiotic relationship between different prokaryotic organisms. This relationship involved one prokaryotic cell engulfing another, leading to a symbiotic association where the engulfed cell became an organelle within the larger cell. Over time, this symbiotic relationship led to the evolution of complex eukaryotic cells with specialized organelles.

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What is sporogenesis in bacteria?

Sporogenesis in bacteria refers to the process of forming a dormant, highly resistant structure called an endospore.

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What are endospores?

Endospores are highly resistant structures formed by certain bacteria to survive harsh environmental conditions. They can withstand extreme temperatures, radiation, and desiccation.

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What happens to an endospore when conditions improve?

When conditions become favorable, the endospore germinates, giving rise to a new, metabolically active bacterial cell.

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What is facilitated diffusion?

Facilitated diffusion is a type of passive transport where molecules move across the cell membrane with the assistance of carrier proteins. This process does not require energy expenditure because it moves molecules down their concentration gradient.

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What is active transport?

Active transport is a process where cells use energy to move molecules across the cell membrane against their concentration gradient. This means moving molecules from an area of low concentration to an area of high concentration.

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What is group translocation?

Group translocation is a type of active transport where the molecule being transported is chemically modified as it crosses the cell membrane. This modification often involves the addition of a phosphate group.

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Study Notes

Functional Anatomy of Prokaryotic and Eukaryotic Cells

  • Prokaryotes differ from eukaryotes by lacking membrane-bound organelles.
  • Bacteria are typically coccus (spherical), bacillus (rod-shaped), or spiral (twisted).
  • The glycocalyx is a gelatinous layer outside the cell wall, offering protection against phagocytosis.
  • Flagella and axial filaments are involved in motility, fimbriae help adhere, and pili transfer DNA.
  • Gram-positive cells have a thick peptidoglycan layer, while gram-negative ones are surrounded by an outer membrane.
  • Archaea have distinctive cell walls (pseudomurein) unlike bacteria. Mycoplasms lack walls.
  • Prokaryotic cells have plasma membranes controlling substance entry/exit, including simple & facilitated diffusion, osmosis, and active transport. Group translocation is an energy-expensive transport method.
  • Nucleoid contains DNA; ribosomes synthesize proteins.
  • Inclusions are storage granules.
  • Endospores are resistant structures allowing survival in adverse conditions.
  • Eukaryotic flagella and cilia differ from prokaryotic. These structures are significantly different.
  • Eukaryotic cells contain organelles beyond basic machinery (nucleus, ER, Golgi, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisome, centrosomes).
  • Endosymbiotic theory proposes the origin of some organelles from engulfed prokaryotes.
  • Prokaryotic and eukaryotic cells vary in chemical composition and chemical reactions but share basic metabolic processes.

Bacterial Cell Structures

  • Cell wall composition differs between Gram-positive and Gram-negative bacteria based on peptidoglycan layer thickness and presence of an outer membrane.
  • The outer membrane of Gram-negative species contributes to antibiotic resistance by blocking penetration.
  • Atypical cells like Mycoplasma lack cell walls due to different chemical composition and protective mechanisms.
  • Damage to cell walls causes protoplasts or spheroplasts formation, and L-form formation, both related to bacteria lacking full cell wall structures.
  • Structures internal to the cell wall (plasma membrane, cytoplasm) differ in substance composition.

Eukaryotic Cell Structures

  • Eukaryotic flagella and cilia are distinct compared to prokaryotic ones.
  • Eukaryotic cells are characterized by a cell wall composition that differs among different eukaryotic types.
  • Cytoplasm is the internal environment within the plasma membrane.
  • Eukaryotic cells utilize ribosomes for protein synthesis in the cytoplasm or on the rough endoplasmic reticulum.
  • Organelles include endoplasmic reticulum, Golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes, and centrosomes each with specific functions related to cellular activities.

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Ch 4 Study Guide: Functional Anatomy of Prokaryotic & Eukaryotic Cells PDF

Description

Test your knowledge on bacterial structures and functions with this quiz. Explore key concepts like the shape of bacillus bacteria, the role of glycocalyx, and the differences between Gram-negative and Gram-positive bacteria. Assess your understanding of prokaryotic cell movement and DNA transfer mechanisms.

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