Microbiology Chapter 5 Quiz

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Questions and Answers

What is the primary structure of bacterial DNA?

Multiple linear chromosomes

Circular single-stranded structure

Single circular chromosome (correct)

Double stranded linear structure

Which of the following is NOT a characteristic of plasmids?

They can encode antibiotic resistance.

They are essential for bacterial growth. (correct)

They can be integrated into the chromosome.

They are circular, double-stranded DNA.

Which component is found in the eukaryotic nucleus?

Nucleolus (correct)

Ribosomes

Endospores

Plasmids

What type of cellular organization is typical of eukaryotic DNA?

Multiple linear chromosomes Signup and view all the answers

Which statement correctly describes the membranes of eukaryotic cells?

Eukaryotic cells contain membranous organelles. Signup and view all the answers

What is the role of Gram's iodine in the staining process?

It stabilizes the dye by forming large complexes. Signup and view all the answers

What effect does alcohol have on gram-negative bacteria during the staining procedure?

It removes the dye from the peptidoglycan layer. Signup and view all the answers

Which component of the cell wall allows gram-positive bacteria to retain the dye complex more effectively?

A thicker peptidoglycan layer Signup and view all the answers

What is the purpose of applying safranin in the final step of the staining procedure?

To stain the now colorless gram-negative bacteria. Signup and view all the answers

During the staining process, what happens to the outer membrane of gram-negative cells when alcohol is applied?

It fractures and releases the dye complexes. Signup and view all the answers

What is a significant characteristic of Gram-positive bacterial cell walls?

Presence of teichoic acids Signup and view all the answers

Which of the following correctly describes Gram-negative bacterial cell walls?

Have a bilayer membrane with phospholipids Signup and view all the answers

What role does mycolic acid play in acid-fast bacteria?

It helps the bacteria to survive desiccation Signup and view all the answers

During differential Gram staining, what is the first step performed?

Applying crystal violet Signup and view all the answers

What appearance do Gram-negative bacteria display after the Gram staining procedure?

Pink Signup and view all the answers

What is contained in the large periplasmic space of Gram-negative bacteria?

Outer membrane components Signup and view all the answers

What is the function of the Lipid A portion of lipopolysaccharides in Gram-negative bacteria?

Causes fever and inflammation Signup and view all the answers

Which statement about S-layers in archaea and bacteria is true?

They are composed of a monomolecular layer of proteins Signup and view all the answers

What term describes the variation in size and shape of cells of a single bacterial species due to genetic and nutritional differences?

Pleomorphism Signup and view all the answers

Which arrangement describes a pair of cocci bacteria?

Diplococci Signup and view all the answers

What is the primary function of the slime layer glycocalyx in Streptococcus mutans?

Attachment to surfaces Signup and view all the answers

What type of flagella arrangement has a single flagellum at one end of the bacterial cell?

Monotrichous Signup and view all the answers

Which of the following is NOT a function of the glycocalyx?

Photosynthesis Signup and view all the answers

Which structure is involved in adhesion to other cells and surfaces in bacteria?

Fimbriae Signup and view all the answers

What is the primary characteristic of endospores?

They are dormant and resistant cells. Signup and view all the answers

Which of the following correctly describes the life cycle of endospores?

Dormant phase and vegetative phase Signup and view all the answers

What is the term used for a highly organized, tightly attached layer outside the bacterial cell wall?

Capsule Signup and view all the answers

Which arrangement of bacilli refers to a chain of several cells?

Streptobacilli Signup and view all the answers

Which domain of life does Clostridium belong to?

Bacteria Signup and view all the answers

What type of flagella arrangement has flagella dispersed over the surface of the cell?

Peritrichous Signup and view all the answers

Which of the following cellular components assist protozoans in movement?

Pseudopodia Signup and view all the answers

Which type of bacterial arrangement consists of cells that remain partially attached by a small hinge region?

Palisades Signup and view all the answers

What type of bacteria forms endospores?

Some Gram-positive genera Signup and view all the answers

Which statement about saprophytic fungi is correct?

They decompose dead organic matter. Signup and view all the answers

Study Notes

Exam 1 Review

The exam covers bacterial cell wall structure (Gram +, Gram -, Acid fast), bacterial cellular morphology and arrangement, prokaryotic and eukaryotic cell components, bacterial chemotaxis, endospores, fungi and protozoa, and taxonomy (Domains and Kingdoms).
Bacterial DNA is circular, double-stranded, and helical, represented by one chromosome.
Eukaryotic DNA is linear (mostly), double-stranded, and helical, represented by multiple chromosomes.
Plasmids are small, circular, double-stranded DNA molecules, often free or integrated into the chromosome. They are duplicated and passed on to offspring and may encode antibiotic resistance, tolerance to toxic metals, enzymes, and toxins. They are useful in genetic engineering, as they are readily manipulated and transferred between cells.
Eukaryotic cells include a nucleus, often the largest organelle, containing most of the cell's DNA. It's surrounded by a nuclear envelope with pores and contains a semiliquid nucleoplasm and chromatin. RNA components of ribosomes are synthesized in the nucleolus within the nucleoplasm.
Mitochondria have an outer and inner membrane, cristae, and a matrix containing ribosomes.
Gram-positive bacterial cell walls have a relatively thick peptidoglycan layer, with teichoic and lipoteichoic acids. Gram-positive bacteria appear purple after Gram staining.
Gram-negative bacterial cell walls have a thin peptidoglycan layer, an outer membrane containing LPS (lipopolysaccharide) with lipid A, and a periplasmic space between the inner and outer membranes. They appear pink after Gram staining, and lipid A can cause inflammation, shock, and blood clotting.
Many bacterial and archaeal types have S-layers outside the cell wall or outer membrane. These layers are a monomolecular layer of a protein (or in some cases, two identical proteins or glycoproteins).
Differential Gram staining involves 4 steps; Crystal violet, Gram's iodine, alcohol, and safranin (red dye) to distinguish between Gram-positive and Gram-negative bacteria.
Bacterial shapes and arrangements are varied; coccus (spherical), rod, curved. Pleomorphism is variation in size and shape of cells within a bacterial species. Arrangements can include single cells, pairs (diplococci), groups of four (tetrads), irregular clusters (staphylococci and micrococci), chains (streptococci), packets of 8-64 cells (sarcina), and chains of rod-shaped cells (streptobacilli), among others..
Bacteria move using flagella (monotrichous, lophotrichous, amphitrichous, and peritrichous). Spirochetes have endoflagella, which are confined within the periplasm between the inner and outer cell membranes.
Fimbrae are hair-like bristles on the cell surface used for adhesion to other cells or surfaces and biofilm formation.
Pili are used for bacterial conjugation, a form of bacterial mating.
Glycocalyx (capsule or slime layer) is a coating of molecules external to the cell wall, made of sugars and/or proteins. Capsules are highly organized, and slime layers are loosely organized and are involved in attachment and inhibit killing by white blood cells.
Chemotaxis is the movement of bacteria in response to a chemical signal. Bacteria exhibiting chemotaxis move towards attractants and away from repellents.
Taxonomy is the science of organizing, classifying, and naming living things. It involves domains (Archaea, Bacteria, Eukarya), kingdoms, phyla, classes, orders, families, genera, and species.
Endospores are dormant resting cells produced by some genera of Bacillus and Clostridium. They are the hardiest of all life forms, withstanding extremes in heat, drying, freezing, radiation, and harsh chemicals. Sporulation is the formation of the endospore, and germination is the return to a vegetative form. Examples of bacteria that form endospores include Clostridium tetani, Clostridium perfringens, Clostridium botulinum, Clostridium difficile, and Bacillus anthracis.
Protozoa (Kingdom Protista) use pseudopodia, flagella, or cilia to move.
Fungi include molds (intertwining filaments called hyphae forming mycelium) and yeasts (unicellular, budding or fission, may form pseudo-hyphae). They are saprophytic, meaning they live on dead, decomposing matter.

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Description

Test your understanding of key concepts in microbiology regarding bacterial and eukaryotic cell structures, DNA organization, and staining techniques. This quiz covers the primary characteristics of DNA, the role of various components in cell staining, and insights into gram-positive and gram-negative bacteria.