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?

Assist in movement Signup and view all the answers

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

An outer membrane with lipopolysaccharide Signup and view all the answers

What type of movement does positive taxis describe?

Movement toward an attractant Signup and view all the answers

Which bacterial structure primarily assists in DNA transfer between cells?

Pili Signup and view all the answers

What characteristic is true regarding spirochetes?

They possess axial filaments for movement Signup and view all the answers

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

Protein synthesis Signup and view all the answers

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

Nucleus Signup and view all the answers

Which of the following statements about mitochondria is true?

They multiply by binary fission. Signup and view all the answers

What function do vacuoles primarily serve in plant cells?

Substance storage and rigidity Signup and view all the answers

What type of ribosomes are found in eukaryotic cells?

80S Signup and view all the answers

Which organelle is responsible for modifying and packaging proteins?

Golgi complex Signup and view all the answers

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

Lipid A Signup and view all the answers

Which of the following is NOT a function of lysosomes?

Photosynthesis Signup and view all the answers

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

Formation of a protoplast Signup and view all the answers

What is a characteristic feature of peroxisomes in eukaryotic cells?

Catalase that destroys H2O2 Signup and view all the answers

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

Facilitated diffusion Signup and view all the answers

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

Presence of pseudomurein Signup and view all the answers

What describes the plasma membrane's structure?

A lipid bilayer with integral and peripheral proteins Signup and view all the answers

Which statement about mycoplasma is accurate?

They naturally lack cell walls. Signup and view all the answers

What is the effect of alcohols on the plasma membrane?

Destroys the plasma membrane Signup and view all the answers

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

Function as antigens Signup and view all the answers

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

Eukaryotic cells have a membrane-bound nucleus, while prokaryotic cells do not. Signup and view all the answers

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

Peptidoglycan Signup and view all the answers

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

Lysosomes Signup and view all the answers

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

Eukaryotic ribosomes are typically more complex than prokaryotic ribosomes. Signup and view all the answers

How do rough and smooth endoplasmic reticulum differ structurally?

Rough ER has ribosomes attached, whereas smooth ER does not. Signup and view all the answers

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

Chloroplasts and mitochondria evolved from free-living prokaryotes. Signup and view all the answers

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

Membrane-bound organelles Signup and view all the answers

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

Modification and packaging of proteins Signup and view all the answers

What structural component do centrioles consist of?

9 triplet microtubules Signup and view all the answers

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

They originated from symbiotic prokaryotes living within other prokaryotes. Signup and view all the answers

What characteristic of endospores allows bacteria to withstand adverse conditions?

Protective endospore wall Signup and view all the answers

What distinguishes facilitated diffusion from active transport?

Facilitated diffusion does not require energy; active transport requires energy. Signup and view all the answers

Which statement accurately describes gram-positive bacteria?

They retain the violet stain after decolorization. Signup and view all the answers

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

Facilitate diffusion of small water-soluble molecules Signup and view all the answers

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

It is released due to the dissolution of the outer membrane. Signup and view all the answers

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

The substrate is changed after crossing the membrane. Signup and view all the answers

What is the main function of the extracellular enzyme amylase?

To hydrolyze starch into sugars Signup and view all the answers

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

Eukaryotic cells Signup and view all the answers

What structural component do archaea lack when compared to bacteria?

Peptidoglycan cell walls Signup and view all the answers

What do bacterial endospores allow bacteria to do?

Survive in harsh conditions Signup and view all the answers

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

It acts as an endotoxin Signup and view all the answers

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

Water passively leaves the cell Signup and view all the answers

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

Fimbriae and glycocalyx Signup and view all the answers

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

It has distinct coccoid and bacillary forms. Signup and view all the answers

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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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.