Biology 101 Ch. 13

Classify the protists as having either beneficial or harmful ecological effects.

Beneficial: zooxanthellae, saprobic protists Harmful: large algal blooms, Plasmodium species

Classify the characteristics based on whether or not they describe how fungi obtain nutrition.

Characteristics describing fungal nutrition: heterotrophic, do not have digestive tracts, cannot move around their environment to find food Characteristics not describing fungal nutrition: autotrophic, have digestive tracts, can move around their environment to find food

Which of these organelles is not found in a fungal cell?

chloroplast

There are several methods by which genetic material can be exchanged between bacteria. Which of the terms describes direct cell‑to‑cell DNA transfer between bacterial cells?

conjugation

What is a distinguishing characteristic of all microbial mats?

Each layer in the mat consists of those bacteria or other microorganisms that are able to use the resources available in the layer.

Which statement describes all organisms that are extremophiles?

thrive in extreme environmental conditions

Why was it necessary to put these organisms in two different domains?

- Archaean ribosomal RNA is more like the ribosomal RNA of eukaryotes than of bacteria. - Several aspects of protein synthesis in archaea are different from bacterial protein synthesis. - The cell walls of archaea have no peptidoglycan, which is present in the cell walls of all bacteria.

Which of the statements are ways that fungi interact with the environment?

- absorb heavy metals from soil caused by human pollution - release nutrients contained in dead organisms back to the soil - form symbiotic relationship with algae to improve both species' chances of obtaining nutrients

Identify which conditions or substances related to fungi contribute to human disease.

- black mold caused by Aspergillus spp. - yeast infections caused by Candida spp.

In the last few decades, the use of antibiotics and antibacterial cleaning products has increased. What consequences are being seen now as a result of the overuse or misuse of antibiotics?

- increase in virulence of once‑controlled bacteria - appearance of bacteria that are immune to antibiotics

Why is it advantageous for some species of basidiomycetes (club fungi) to produce a showy and fleshy fruiting bodies?

- increases spore dispersal by being desirable to animals - signals the toxicity of the fruiting body to animals

Select the constituents of a biofilm.

- microorganisms - proteins - carbohydrates - extracellular DNA

Which traits are characteristics of fungi?

- obtain nutrients from other organisms - cells lack chloroplasts

Select all of the ways humans use protists.

- providing a food source, such as seaweed - serving as a model organism for studying cell interactions - acting as an abrasive in cleaning products - breaking down human sewage waste and bacteria

In which ways do fungi damage crops?

- release harmful mycotoxins that contaminate plant tissues - spread in moist conditions and cause roots to rot

Which describe how lichens interact with their environment?

- sequester toxins - colonize barren areas

Which of the following are ways that humans use fungi?

- source of food - production of therapeutic proteins - genetic research

Bacteria are grouped as either gram‑positive or gram‑negative. Which features are found in gram‑positive bacteria, and which are found in gram‑negative bacteria?

Gram‑positive bacteria: have thick cell walls, have no membrane on the outside of cell walls, belong to a single phylum, have cells walls that are anchored to the cell membranes by lipoteichoic acid Gram‑negative bacteria: have thin cell walls, have membranes of lipoproteins and lipopolysaccharides on the outer side of cell walls, found in many phyla

Determine which protist causes each of the given diseases in humans.

Leishmaniasis= leishmania spp malaria= plasmodium spp beaver fever= guardia lamblia Toxoplasmosis= toxoplasma gondii African sleeping sickness= trypanosome brucei

Identify the role of saprobe protists in an ecosystem.

They feed on dead organisms, returning nutrients to the ecosystem.

Antibiotics became widely used in the 20th century. Classify the statements about human use of antibiotics as true or false.

True: It is possible to treat many life‑threatening illnesses with antibiotics.Some disease‑causing bacteria are resistant to several types of antibiotics. Antibiotics kill both harmful and beneficial bacteria. False: Taking antibiotics helps the immune system build antibodies to infection. Antibiotics released into water bodies become inactive immediately and cannot kill bacteria in the environment. Supplementing livestock feed with antibiotics decreases the number of strains of antibiotic-resistant bacteria among the livestock.

What was responsible for enriching Earth's atmosphere with oxygen?

photosynthesis by cyanobacteria