Exam 2

• What is a protist?  Provide a good definition for this group of organisms:

  • Protists are single celled organisms in the Kingdom Protista.
  • Can be grouped into water molds, protozoans, or algae.
  • They have many mechanisms for reproduction and need water to move. 
• What are the ecological functions of protists?

  • Nitrogen, carbon, and phosphorus cycling.
  • Primary producers.
  • Selective feeders.
  • Decomposers.
• What is the difference between a protist and a protozoan?

  All protozoan are protists
• Historically, how are protists classified?

  • water molds (fungus-like)
  • protozoans (animal-like)
  • algae (plant-like)
• These are the two main developmental stages of most protists

  Trophozoit and cyst
• Define trophozoite


  Feeding and growth
• Define cyst

  Resistant form, protective wall
• These are the main strategies of asexual reproduction in protists

  Binary fission, budding, and schizogony
• What is schizogony and what are its characteristics?

  Asexual reproduction where the nucleus divides.
• Sexual reproduction does occur among protists, while syngamy can be seen in many protist groups, protist conjugation has only been reported in:

  Ciliates
• What are the morphological categories used to classify fungi?

  Molds (multicellular), mushrooms (multicellular), yeasts ( unicellular), and dimorphic.
• What is a dimorphic fungi?

  Can change shape depending on the conditions of the environment.
• How do scientist call the type of hyphae made by yeast connecting with each other?

  pseudohyphae
• This group of organisms are heterotrophic and major sources of antibiotics such as penicillin.

  Fungi such as Penicillium
• List the main kinds of enzymes released by fungi and their function

  Lignocellulose- degradation of plant biomass

  Cellulases, xylanases, amylases, proteases- Polymeric compounds
• Why are fungi considered microbial organisms even though many members of this kingdom are multicellular?

  Because many unicellular yeast and spores of macroscopic fungi are microscopic
• What differentiates water/slime molds (protists) from fungal molds?

  The cell wall of fungi is made of chitin and the one from slime/water molds is made of cellulose
• This Division of the kingdom fungi reproduces exclusively through sexual reproduction

  Basidiomycota
• The Division Glomeromycota includes most known mycorrhizal fungi, and like the Microscoporidia, reproduces exclusively through this mechanism:

  Asexual reproduction
• What benefits do mycorrhizal fungi (arbuscular and ectomycorrhizal) provide to their host plant in exchange for plant metabolites?

  Protection against pathogens, access to phosphorus and water
• True or false: hyphae can form a network (mycelium) that forms the body of fleshy fungi

  True
• These are some of the main ecological roles of protists in the environment

  Primary production, mixotrophy, bacterivory, parasitism, symbiosis
• Protists mixotrophy refers to:

  The capacity of a protists to obtain energy from phototrophy and heterotrophy
• A protist whose C: N (carbon to nitrogen) ratio is 30:1, decided to eat eight bacterial cells. Each bacterial cell has a C: N ratio of 5:1. How much N and C will the protist have to release after digestion?

  10 carbon and 7 nitrogen
• Besides releasing N to the environment, grazing of bacteria by protists may contribute to?

  Horizontal gene transfer between engulfed bacteria
• What is a virus?

  Genetic material surrounded by a capsid or envelope.
• What are the main categories for the classification of viruses according to the Baltimore classification?

  DNA viruses, RNA viruses, and retro-transcribing viruses.
• What is the envelope of viruses that contain it made of?

  Lipids derived from the host cell and proteins.
• What type of viruses are considered as the most abundant biological entities in Earth?

  bacteriophages
• Describe the process of bacteria infection by phage

  • EPS degradation
  • Host recognition, takeover, and genome replication
  • Virion assembly
  • Host lysis
• What are the main strategies used to study viruses (abundance, diversity)?

  Metagenome sequencing, isolation, microscopy.
• Do some research: Describe the process of transduction as mediated by viruses (phage). 

  The phage transfers non-viral DNA from one host to another. 
• What are the ecological dynamics that can mediate phage-bacteria interactions?

  red queen dynamics, kill-the-winner dynamics, and piggyback-the-winner dynamics.
• Virome composition is unique among humans. What are the main factors that can potentially influence the gut virome?

  Health of the gut, inflammation, genetics, maternal dissemination, and diet.
• This command allows you figure out your location in your computer

  pwd
• This command allows you to move between directories

  cd
• What command do you use when creating a new directory?

  mkdir
• Define species richness

  The number of species in a specified area.
• Define evenness

  The distribution of abundance of a species across an area.
• Define the species problem

  Explains the difficulty scientists have in defining what a species is.