[PL 2.1] BACTERIAL CELL STRUCTURE

What is the DNA-packaging structure in prokaryotes called?

Nucleoid

Do prokaryotic nucleoids have a nuclear envelope?

No

Which group of prokaryotes is an exception by having a nuclear envelope?

Planctomycetes

What substances partially neutralize the negative charge of prokaryotic DNA?

Polyamines and magnesium ions

Do prokaryotes have a mitotic apparatus like eukaryotes?

No

What type of chromosome is found in most prokaryotic nucleoids?

Single continuous circular chromosome

What is the typical size range of prokaryotic chromosomes?

0.58 to 10 million base pairs

Which bacteria have two or more dissimilar chromosomes?

Vibrio cholerae, Brucella melitensis

Which bacteria have linear chromosomes?

Borrelia burgdorferi, Streptomyces coelicolor

What is directly associated with the number of nucleoids or chromosomes in bacteria?

Growth conditions

Is bacterial DNA haploid or diploid?

Haploid

What part of the bacterial cytoplasm contains enzymes and is the site of protein synthesis?

Cytosol

What organelle is responsible for protein synthesis in prokaryotes?

Ribosomes

What is the size of ribosomes found in prokaryotes?

70S

What are the two subunits of the 70S ribosome?

50S and 30S

What cytoplasmic structure helps bacteria survive extreme conditions?

Endospores

What chemical makes endospores heat-stable and resistant?

Calcium dipicolinate

How do endospores appear inside the cell under the microscope?

Highly refractile bodies

What stain is used to visualize endospores?

Schaeffer-Fulton stain

Which aerobic bacteria produce endospores?

Bacillus

Which anaerobic bacteria produce endospores?

Clostridium

What structures act as food reserves in bacterial cells?

Inclusion bodies

Which substance is the main food reserve in enterics?

Glycogen

Which storage substance is found in Neisseria and Clostridium?

Starch

Which storage substance is found in Bacillus and Pseudomonas?

Polybeta hydroxybutyrate

What structure consists of the membrane and surrounding layers of the cytoplasm in bacteria?

Cell envelope

Which structure serves as the primary permeability barrier in gram-negative bacteria?

Outer membrane

What are the components of the outer membrane in gram-negative bacteria?

Proteins, phospholipids, lipopolysaccharide (LPS)

Which portion of LPS is also known as endotoxin?

Lipid A

What structures in the outer membrane control the passage of nutrients and antibiotics?

Porins

Which bacterial structure is composed of NAG and NAM?

Cell wall

How are NAG and NAM units in peptidoglycan connected?

Peptide cross-linking

What bacterial structure serves as the point of flagella anchorage?

Cell wall

Which type of bacteria contains thick peptidoglycan and teichoic acids?

Gram-positive

Which teichoic acid is anchored to peptidoglycan?

Cell wall teichoic acid

Which teichoic acid is anchored to the plasma membrane?

Membrane lipoteichoic acid

What is another name for cell wall teichoic acid?

Ribitol/glycerol phosphate

What is another name for membrane lipoteichoic acid?

Glycerol teichoic acid

Which type of bacteria contains a thin peptidoglycan layer?

Gram-negative

First stain used in Gram staining

Crystal violet

Color of both gram-positive and gram-negative after crystal violet

Purple

Reagent that serves as the mordant in Gram staining

Gram’s iodine

Effect of Gram's iodine on both gram types

Remains purple

Reagent used as a decolorizer in Gram staining

Alcohol and/or acetone

Effect of decolorizer on gram-positive bacteria

Remains purple

Effect of decolorizer on gram-negative bacteria

Becomes colorless

Counterstain used in Gram staining

Safranin

Final color of gram-positive bacteria after counterstaining

Remains purple

Final color of gram-negative bacteria after counterstaining

Stains pink/red

What waxy substance is found in the cell wall of acid-fast bacteria?

Mycolic acids

How do acid-fast organisms appear in Gram staining?

Weakly gram-positive

What physical property of acid-fast bacteria makes them hard to stain?

Hydrophobic

What lipids are found in acid-fast cell walls aside from mycolic acids?

PIM and lipoarabinomannan

Which organisms lack a cell wall?

Mycoplasma and Ureaplasma

What membrane component is present in bacteria that lack cell walls?

Sterols

Which microscopy method is used to detect no-cell-wall organisms?

Fluorescence microscopy

What is the collective name for organisms that lack a cell wall?

Mollicutes

Which no-cell-wall bacterium is known for causing atypical pneumonia?

Mycoplasma pneumoniae

What is the space between the outer membrane and cytoplasmic membrane in gram-negative bacteria?

Periplasm

What is the function of the periplasm in gram-negative bacteria?

Captures nutrients and breaks down macromolecules

What is the deepest structural layer of bacterial cells?

Cell membrane

Where does energy production occur in bacterial cells?

Cell membrane

What are the primary components of the bacterial cell membrane?

Phospholipids and proteins

What structures in the cell membrane serve as enzymatic sites and nucleoid anchors?

Mesosomes

Primary stain used in Ziehl-Neelsen method

Carbolfuchsin

Primary stain used in Kinyoun method

Carbolfuchsin

Color of acid-fast organisms after primary stain

Stains red

Color of non-acid-fast organisms after primary stain

Stains red

Mordant used in Ziehl-Neelsen method

Steam

Mordant used in Kinyoun method

Tergitol

Color of acid-fast organisms after mordant application

Remains red

Color of non-acid-fast organisms after mordant application

Remains red

Decolorizer used in both acid-fast staining methods

3% HCl alcohol

Color of acid-fast organisms after decolorization

Remains red

Color of non-acid-fast organisms after decolorization

Becomes colorless

Counterstain used in both methods

Methylene blue

Final color of acid-fast organisms

Remains red

Final color of non-acid-fast organisms

Stains blue

What is the diffuse slime layer surrounding bacterial cells called?

Glycocalyx

What is the function of the glycocalyx?

Protects cells or aids in adherence

Which bacterial structure initiates biofilm formation?

Glycocalyx

Which structure helps bacteria evade phagocytosis and enhances virulence?

Capsule

How can the bacterial capsule be removed?

Boiling

What are the pili that aid in bacterial adherence called?

Ordinary pili

What is the function of ordinary pili?

Attachment to host cell surfaces

Which bacteria uses ordinary pili for attachment?

Neisseria gonorrhea

What is the structure required for bacterial conjugation?

Sex pilus

Which bacterium has a sex pilus for conjugation?

Escherichia coli

What organelle is responsible for protein synthesis in bacteria?

Ribosomes or Cytosol

What is the site of energy production in bacteria?

Cytoplasmic membrane

What structure enables bacterial motility?

Flagella

What protein composes bacterial flagella?

Flagellin

At what temperature is bacterial motility best observed?

25°C

What staining reagent is used for visualizing flagella?

Tannic acid

What do you call a bacterium with no flagella?

Atrichous

What is the term for a bacterium with one flagellum at one pole?

Monotrichous

What is the flagellar arrangement with one flagellum on each end?

Amphitrichous

What do you call a group of flagella at one pole?

Lophotrichous

What is the arrangement with a tuft of flagella on both poles?

Amphilophotrichous

What is the term for bacteria with flagella covering the entire surface?

Peritrichous