Chapter 13 - Diversity of Microbes, Fungi, & Protists

How are living things currently grouped?

Into 3 Domains: Archaea, Bacteria, and Eukarya.

What are prokaryotes?

Organisms that lack a nucleus and membrane-bound organelles.

What are the two groups of prokaryotes?

Bacteria and Archaea.

When did prokaryotes first appear on Earth?

About 3.5 to 3.9 billion years ago.

What type of organisms existed first on early Earth?

Anaerobic organisms that can grow without oxygen.

What role did cyanobacteria play in Earth's history?

They evolved to photosynthesize and added oxygen to the atmosphere.

What are fossilized microbial mats?

The earliest record of life on Earth, consisting of multilayered sheets of prokaryotes.

What is a stromatolite?

A sedimentary structure formed by prokaryotes in a microbial mat.

What are extremophiles?

Bacteria and Archaea that thrive in extreme environments.

What is a biofilm?

A microbial community held together in a gummy-textured material.

What are the four structures common to all cells?

Plasma membrane, cytoplasm, genetic material (DNA/RNA), and ribosomes.

What are the three basic shapes of prokaryotes?

Cocci (spherical), bacilli (rods), and spirilla (spiral).

How do prokaryotes reproduce?

Through binary fission, which is asexual.

What are the three methods of genetic recombination in prokaryotes?

Transformation, transduction, and conjugation.

What is the difference between Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have thick cell walls, while Gram-negative bacteria have thin cell walls and an outer membrane.

What is the Black Death?

A devastating pandemic caused by the bubonic plague, with mortality rates of 70-80%.

What is MRSA?

Methicillin-resistant Staphylococcus aureus, a dangerous strain of bacteria resistant to many antibiotics.

What causes foodborne diseases?

Consumption of food contaminated with pathogenic bacteria, viruses, or parasites.

What is the significance of antibiotics in relation to bacterial resistance?

Overuse and incorrect use of antibiotics lead to the natural selection of resistant bacteria.

What is a pandemic?

A widespread, usually worldwide, epidemic disease.

What is the role of hydrothermal vents in microbial life?

They provide energy for microbial mats that thrive in extreme conditions.

What adaptations do prokaryotes have for survival in harsh conditions?

They can survive high temperatures, harsh chemicals, and high radiation.

What is the impact of antibiotics on livestock?

Excessive use of antibiotics in livestock is not for disease prevention but to enhance production.

How do biofilms affect sterilization efforts?

Biofilms are resistant to common forms of sterilization.

What is the importance of the plasma membrane in cells?

It separates the cell from its environment.

What is the jellylike material inside a cell called?

Cytoplasm.

What are some potentially harmful strains of E. coli?

Certain strains can infect humans and be potentially fatal.

What is Salmonella known for?

It is a bacterium that commonly contaminates food.

What fraction of the microbial world do pathogens represent?

Pathogens represent only a small fraction of the microbial world.

What food products have humans used prokaryotes to produce?

Cheese, yogurt, sour cream, vinegar, and other fermented products.

What is microbial bioremediation?

The use of prokaryotes to remove pollutants.

What types of pollutants can bioremediation remove?

Agricultural chemicals, toxic metals, and oil spills.

What significant oil spills have involved prokaryotes in cleanup?

The Exxon Valdez spill in 1989 and the BP oil spill in 2010.

How do prokaryotes help in oil spill cleanup?

They degrade hydrocarbons in the oil when inorganic nutrients are added.

What is commensalism in the context of prokaryotes in the human body?

A relationship where the bacterium benefits and the human host is neither benefitted nor harmed.

What are gut flora?

Hundreds of species of bacteria and archaea that live in the intestine.

What functions do gut flora serve?

Assistance with metabolism, synthesis of vitamin K, immune system training, and barrier formation against pathogens.

What is the endosymbiotic theory?

It states that eukaryotes originated from one prokaryotic cell engulfing another and evolving together.

What evidence supports the endosymbiotic theory?

Fossil records and genetic evidence suggest prokaryotic cells were the first organisms on earth.

What are protists?

Eukaryotic organisms that do not fit the criteria for kingdoms Plantae, Animalia, or Fungi.

What types of environments do protists inhabit?

Aquatic environments, including freshwater, marine, damp soil, and snow.

What are some characteristics of protists?

They can be unicellular or multicellular, motile, and covered with various protective structures.

How do protists obtain energy?

Through photosynthesis, consuming organic materials, or absorbing nutrients from dead organisms.

What are the methods of reproduction in protists?

Asexual methods like binary fission and budding, and sexual reproduction involving meiosis.

What is the significance of sexual reproduction in protists?

It allows for new combinations of genes that may better suit survival in changing environments.

What are the six eukaryotic supergroups?

Groups that contain protists, animals, plants, and fungi, believed to have evolved from a common ancestor.

What is the role of genetic relationships in protist classification?

They are replacing morphological similarities in determining relationships between protist groups.

What is the function of pellicles in protists?

An outer protein covering that prevents tearing while allowing movement.

What are pseudopodia in protists?

Lobes of cytoplasm that anchor to a substrate and pull the rest of the cell towards the anchor point.

What is phagocytosis in protists?

A process where the cell membrane engulfs food particles, forming a food vacuole.

What is the significance of the first eukaryotes?

They were unicellular and evolved into more complex forms, leading to multicellularity.

What is the evolutionary significance of endosymbiotic relationships?

They led to the formation of mitochondria and chloroplasts in eukaryotic cells.

What protist causes malaria?

Plasmodium

How is malaria transmitted?

By mosquitoes

What is a major effect of Plasmodium on the body?

It can destroy up to half of the circulating red blood cells, leading to severe anemia.

Where is malaria most common?

In tropical regions, especially Africa.

What is a key method for controlling malaria?

Techniques to kill, sterilize, or avoid exposure to mosquitoes.

What protist causes downy mildew in grape plants?

A protist that parasitizes grape plants.

What disease caused by a protist led to the Irish potato famine?

Potato late blight.

What is the role of protists in aquatic ecosystems?

They serve as essential sources of nutrition for many organisms.

What are dinoflagellates and their role in coral reefs?

Photosynthetic protists that provide nutrition to coral polyps in a mutually beneficial relationship.

What happens to coral polyps without dinoflagellates?

They lose pigments and die, leading to coral bleaching.

What do fungus-like protists do?

They are saprobes that feed on dead organisms and return nutrients to the soil.

What kingdom do fungi belong to?

Kingdom Fungi.

What are some commercial applications of fungi?

Baking, brewing, wine making, and production of antibiotics.

What is the main structural component of fungal cell walls?

Chitin.

What is the vegetative body of a fungus called?

Thallus.

What are hyphae?

Thread-like structures that make up the body of a fungus.

What is mycelium?

A mass of hyphae that forms the body of a fungus.

How do fungi obtain nutrients?

By secreting enzymes onto food sources to break down nutrients before absorption.

What are the four major divisions of fungi?

Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota.

What is the role of mycorrhizae in ecosystems?

They form associations with plant roots, channeling water and minerals to plants.

What is a lichen?

A symbiotic association between a fungus and a photosynthetic partner.

How do fungi contribute to soil formation?

By breaking down rock surfaces in barren areas.

What is the significance of fungi in bioremediation?

They help in breaking down pollutants and returning nutrients to the ecosystem.

What is the role of fungi in fermentation?

Yeast converts sugars into alcohol, aiding in beer and wine production.

What is the function of antibiotics produced by fungi?

To kill or inhibit the growth of bacteria.

What are some examples of unicellular fungi?

Yeasts like Baker's yeast and Candida.

What environments do fungi thrive in?

Moist, slightly acidic environments.

How do fungi reproduce?

They can reproduce sexually or asexually by producing spores.

What is the importance of decomposers like fungi in ecosystems?

They return nutrients locked in dead bodies into a usable form for other organisms.