LECTURE 4: eukaryotic microbes

What is mycology?

The study of fungi, including yeasts and molds.

What is parasitology?

The study of parasites, including protozoa and helminths.

What is an ectoparasite?

A parasite that lives on the outside surface of a host, such as lice or ticks.

What is a hypha?

A multicellular tubular structure through which fungi grow. 

What are conidia?

Fungal spores that function as reproductive units. 

What is a mycosis?

A disease caused by a fungus. (Plural = mycoses.)

What is a trophozoite?

The active, feeding, growing, and multiplying stage of a protozoan.

What is a cyst?

A protected growth stage with a thick wall that is resistant to environmental stress and is often the infectious form. 

What is a helminth?

A parasitic worm.

What are ova?

Helminth eggs, which are often the infectious and diagnostic form. 

What are the major differences between eukaryotic and prokaryotic cells?

Eukaryotic cells- larger, membrane-bound organelles, multiple linear chromosomes, more complex transport systems

prokaryotes- lack membrane-bound organelles and a nucleus

Which evolved first, prokaryotes or eukaryotes?

Prokaryotes evolved first; eukaryotic cells evolved from prokaryotic ancestors. 

Why are eukaryotic cells generally more complex?

They contain specialized organelles that divide cellular functions among different compartments. 

What is the function of the nucleus?

It houses and protects the cell's DNA. 

What is the function of mitochondria?

Energy production (ATP generation) for the cell.

What features make mitochondria similar to bacteria?

They have their own DNA, their own ribosomes, and reproduce independently, supporting the endosymbiotic theory.

What is the function of ribosomes?

Protein synthesis. 

Where are eukaryotic ribosomes located?

Free in the cytoplasm or attached to the rough endoplasmic reticulum.

What type of ribosomes do eukaryotes have?

80S ribosomes.

What is the function of lysosomes?

They contain digestive enzymes that break down macromolecules and cellular debris. 

What is the cytoskeleton?

A network of protein filaments and tubules throughout the cytoplasm. 

What are the three major components of the cytoskeleton?

Microtubules, intermediate filaments, and microfilaments. 

What are the major functions of the cytoskeleton?

Cell shape, motility, and intracellular transport.

Which organelle organizes microtubules?

The centrosome (containing centrioles).

What is the function of the rough ER?

Protein synthesis and transport.

What is the function of the smooth ER?

Lipid synthesis, detoxification, and calcium storage.

What is the function of the Golgi apparatus?

Modifies, packages, and distributes proteins and lipids.

What is endocytosis?

Importing material into a cell by membrane invagination to form a vesicle.

What is phagocytosis?

Endocytosis of large particles.

What is receptor-mediated endocytosis?

A highly specific form of endocytosis that uses membrane receptors.

What is exocytosis?

Exporting material from a cell through vesicles that fuse with the plasma membrane.

Why is cell transport important in infectious disease?

Many pathogens use host cell transport mechanisms to enter and move within cells.

What are yeasts?

Unicellular fungi

What are molds?

Multicellular fungi composed of hyphae.

How do yeast colonies typically appear?

Smooth and creamy. 

How do mold colonies typically appear?

Fluffy or fuzzy.

What are dimorphic fungi?

Fungi that grow as molds in the environment and as yeasts in the human body. 

What is the function of fungal spores (conidia)?

Reproduction and spread of fungi. 

What is the function of bacterial endospores?

Survival during unfavorable environmental conditions.

Are fungal spores and bacterial endospores the same?

No. Fungal spores are reproductive structures, while bacterial endospores are survival structures.

What are protozoa?

Microscopic, unicellular eukaryotes in Kingdom Protista. 

Why is Protista called a "catchall kingdom"?

Because it contains many diverse organisms that do not fit neatly into other kingdoms.

How are protozoa classified?

Primarily by how they move (motility). 

What are amoebae?

Protozoa that move using pseudopods.

What are flagellates?

Protozoa that move using flagella.

What are ciliates?

Protozoa that move using cilia. 

What are Apicomplexa?

Protozoa lacking obvious motility structures that move by gliding. 

What are nematodes?

Roundworms that are non-segmented. 

What are cestodes?

Segmented flatworms (tapeworms).

What are trematodes?

Non-segmented flatworms (flukes). 

How do eukaryotic flagella differ from prokaryotic flagella?

Eukaryotic flagella contain microtubules and move with a whip-like motion, while prokaryotic flagella are made of flagellin and rotate like a propeller.

What are cilia?

 Short, hair-like structures that move fluids or propel cells.

What is the major structural component of cilia and eukaryotic flagella?

Microtubules arranged in a 9+2 pattern.

How are fungi identified in the laboratory?

Microscopy with fungal stains (KOH), culture, colony appearance, and microscopic structures

How are protozoa identified in the laboratory?

Microscopy using special stains such as trichrome. Traditional culture is generally not used.

How are helminths identified in the laboratory?

Microscopy, examination of ova, and gross examination of adult worms. 

How are bacteria identified in the laboratory?

Microscopy, Gram staining, culture, biochemical tests, immunologic tests, and molecular methods.

How are bacteria commonly classified?

By shape, arrangement, Gram reaction, metabolism, and genetic characteristics.

How are fungi commonly classified?

By spore (conidia) type and arrangement. 

How are protozoa commonly classified?

By mode of motility.

How are helminths commonly classified?

By body shape and whether they are segmented or non-segmented.