Prokaryotic and Eukaryotic Cell Anatomy and Physiology Flashcards

Flashcards based on lecture notes covering prokaryotic and eukaryotic microbiology, cell wall structures, staining techniques, and organelle functions.

What chemical components are shared by both prokaryotic and eukaryotic cells?

Both contain nucleic acids, proteins, lipids, and carbohydrates.

How is DNA typically organized and enclosed in a prokaryotic cell?

The DNA is usually arranged as a single, circular chromosome and is not enclosed in a membrane.

Which bacterium is a noted exception to the single-chromosome rule in prokaryotes?

Vibrio cholerae, which имеет two chromosomes.

What specialized chromosomal proteins are associated with DNA in eukaryotes but typically absent in prokaryotes?

Histones and nonhistones.

What is the typical diameter and length range for a bacterial cell?

Diameter is $0.2$ to $2.0\,\mu m$ and length is $2$ to $8\,\mu m$.

What are the common arrangements of cocci based on their division planes?

Diplococci (pairs), streptococci (chains), tetrads (groups of four), sarcinae (cubes of eight), and staphylococci (grapelike clusters).

What is the difference between a capsule and a slime layer in the glycocalyx?

A capsule is organized and firmly attached to the cell wall, while a slime layer is unorganized and loosely attached.

Which bacterium uses its glycocalyx to attach to teeth, causing dental caries?

Streptococcus mutans.

What are the three basic parts of a bacterial flagellum?

The filament (made of flagellin), the hook, and the basal body.

How does the basal body of a flagellum differ between Gram-negative and Gram-positive bacteria?

Gram-negative bacteria have two pairs of rings (outer and inner), whereas Gram-positive bacteria have only the inner pair of rings.

What is the function of the H antigen?

It is a flagellar protein used to identify serovars of Gram-negative bacteria, such as E. coli $O157:H7$.

How do spirochetes like Treponema pallidum move through thick body fluids?

They use axial filaments (endoflagella) anchored at one end that wrap around the cell beneath an outer sheath, causing corkscrew movement.

What are fimbriae used for in pathogenic bacteria like Neisseria gonorrhoeae?

They are used for attachment to mucous membranes and other surfaces.

What sugar molecules make up the carbohydrate backbone of peptidoglycan?

$N$-acetylglucosamine ($NAG$) and $N$-acetylmuramic acid ($NAM$).

How does penicillin affect bacteria?

It interferes with the final linking of peptidoglycan rows by peptide cross-bridges, weakening the wall and causing lysis.

What are the primary characteristics of a Gram-positive cell wall?

It consists of many layers of peptidoglycan forming a thick, rigid structure and contains teichoic acids.

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

Lipid $A$, which is the lipid portion of the lipopolysaccharide ($LPS$).

What are the steps and colors of the Gram stain procedure?

Crystal violet (purple), Iodine (mordant), Alcohol (decolorizer), and Safranin (pink/red counterstain).

Why is carbolfuchsin used to stain Mycobacterium species?

Because they are acid-fast bacteria containing approximately $60\%$ mycolic acid (a hydrophobic waxy lipid) that resists standard staining.

What is the difference between a protoplast and a spheroplast?

A protoplast is a wall-less spherical cell derived from a Gram-positive bacterium, while a spheroplast is a spherical structure derived from a Gram-negative bacterium with some outer membrane remaining.

What is the Fluid Mosaic Model of the plasma membrane?

A model describing the membrane as a dynamic structure where phospholipids and proteins move freely, with a viscosity similar to olive oil.

Which transport process is exclusive to prokaryotes and involves the chemical alteration of a substance like glucose?

Group translocation, which uses high-energy compounds like phosphoenolpyruvic acid ($PEP$).

What are plasmids and what traits do they typically carry?

Small, circular, extrachromosomal DNA molecules that carry genes for antibiotic resistance, toxin production, or enzyme synthesis.

How do prokaryotic and eukaryotic ribosomes differ in size and sedimentation rate?

Prokaryotic ribosomes are $70S$ (composed of $30S$ and $50S$ subunits), while eukaryotic ribosomes are $80S$ (composed of $40S$ and $60S$ subunits).

What are metachromatic granules (volutin)?

Inclusions that serve as a reserve of inorganic phosphate used for $ATP$ synthesis, commonly found in Corynebacterium diphtheriae.

What is the role of dipicolinic acid ($DPA$) in bacterial endospores?

It combines with calcium ions to protect the endospore DNA against damage.

What is the structural arrangement of microtubules in eukaryotic flagella and cilia?

A $9 + 2$ array, consisting of nine pairs of doublets in a ring and two single microtubules in the center.

What are the main components of fungal and algal cell walls?

Fungi walls mostly contain chitin (polymer of $NAG$), while algae walls contain cellulose.

What are the functions of the Rough ER and the Smooth ER in eukaryotes?

Rough ER synthesizes secretory proteins and membrane molecules; Smooth ER synthesizes phospholipids, fats, steroids, and detoxifies drugs.

How do peroxisomes differ from lysosomes in their enzyme content and function?

Peroxisomes contain enzymes like catalase to break down toxic hydrogen peroxide ($H_2O_2$) produced during the oxidation of amino acids and fatty acids.