Microbiology Chapter 13, Microbiology Chapter 4, Microbiology Chapter 12
Typically, most fungi grow ___.
Between 20 C to 35 C, in the presence of O2, in terrestrial environments
What term is used to describe a group of microbes co-existing in polymer-encased communities?
Biofilm
Which of the following descriptions of biofilms are true?
Biofilms are important in wastewater treatment facilities, biofilms are able to enhance many bioremediation efforts, biofilms are involved in dental plaque, which can lead to tooth decay and gum disease, bacteria in biofilms can be hundreds of time more resistant to disinfectants than their free-living counterparts
Replication of temperate phages and lytic phages have which steps in common?
Biosynthesis of viral components, release, genome entry, assembly, attachment
Which of the following viral release methods may not initially destroy the cell?
Budding
Enveloped viruses exit host cells be ___; non-enveloped viruses are released upon ___ of the host cell.
Budding, apoptosis
The number of phage particles released from a host cell is called the ___ size.
Burst
In the lytic cycle of the T4 page, lysozyme degrades a portion of the bacterial ___.
Cell wall
Enveloped viruses can derive their envelope from ___.
Certain host organelles, the host cytoplasmic membrane
Which term describes organisms which acquire their energy from chemical compounds?
Chemotrophs
Fungi differ from most other eukaryotic organisms in that their cell wall contains ___, and their cell membranes contain ___.
Chitin, ergosterol
An isolated ___ is a distinct mass of microorganisms appearing on a solid medium, arising from the multiplication of a single cell.
Colony
Bacteria that require growth factors and specific nutrients are called ___ organisms.
Fastidious
Which fact best supports the position that viruses are not living organisms?
Viruses cannot reproduce on their own
Regarding animal viruses, which of the following statements are true?
Viruses use their spike to attach to host cell receptors, some viruses require more than one host receptor for attachment, blocking a host receptor with a drug would prevent a virus from infecting that cell
A batch culture has which of the following characteristics
Wastes are not removed, nutrients are not renewed, it is a closed system, it typically involves growth of bacteria or archaea either on agar plates or in tubes or flasks of broth
Consider the following environmental factors. Which have the most impact on microbial growth?
Water availability, temperature, oxygen availability, pH
Asexual spores develop in sporangia, which are on the tips of aerial hyphae. Sporangia are found in which group of fungi?
Zygomycetes
HIV is describes as a ___ because it uses revers transcriptase to make a DNA copy from its RNA genome.
retrovirus
The ___ phase of the bacterial growth curve is when there are an equal number of cells dividing as there are dying.
stationary
A ___ medium means that the medium does not contain any viable microbes.
sterile
Match the genome of each type of RNA virus with its description of function
(+) strand genome -> serves as mRNA, (-) stand genome -> is the compliment to mRNA, double-stranded genome -> consists of both a (+) and (-) strand
Rank the following by size, from smallest to largest, starting with the smallest at the top.
Viruses Bacteria Human cells
The following are steps involved in obtaining a pure culture using the streak-plate method. Place them in the correct order.
1. A sterile inoculating loop is dipped into a microbe-containing sample 2. The inoculating loop is drawn several times across the surface of a sterile agar plate 3. The loop is sterilized, and a new series of parallel streaks is made across and at an angle to the original ones 4. The loop is sterilized, and a final set of parallel streaks is made, dragging into the area some organisms from the previous section 5. The Petri dish is incubated; distinct, well-isolated colonies form from cells that were separated sufficiently
Put the following phases in order for a normal bacterial growth curve
1. Lag, 2. Exponential, 3. Stationary, 4. Death
Put the stages of binary fission in the correct order.
1. The cell gets longer and DNA is replicated, 2. DNA is moved to each future daughter cell, and a cross wall forms, 3. The cell divides into two daughter cells, 4. The daughter cells separate
List the steps of an animal virus infection cycle in the correct order
1. attachment 2. penetration and uncoating 3. synthesis of viral proteins and replication of the genome 4. assembly 5. release
Place the five stages of a growth curve in the correct order.
1. lag phase 2. log or exponential phase 3. stationary phase 4. death phase 5. phase of prolonged death
Which of the following is most likely to be a pure culture?
A single colony growing on a streak plate
Algae ___.
Absorb sunlight to convert CO2 and H2O to organic material and O2
An ___ is an organisms that prefers a habitat where the pH is below 7.
Acidophile
A microbe that doesn't use O2 but can grow in environments containing O2 is described as an ___ anaerobe.
Aerotolerant
The polysaccharide found in marine algae that is commonly used to solidify culture media is called ___.
Agar
Which of the following are eukaryotes?
Algae, arthropods, fungi, multicellular worms
The term ___ is used to describe programmed cell death, a process some non-enveloped viruses trigger as a mean of release.
Apoptosis
The vast majority of protozoans live in a(n) ___ environment.
Aquatic
During the ___ or maturation step in viral multiplication, capsids and genetic material are packaged into virions.
Assembly
The ___ or maturation stage of the T4 phage lytic cycle is marked by the formation of new phage particles inside of the host cell.
Assembly
The binding of a bacteriophage surface protein to a host cell receptor is called ___.
Attachment
Viruses that infect bacteria are called ___.
Bacteriophages (phages)
In which phase of the growth curve are more cells dying than reproducing?
Death
Included in the microscopic algae are ___.
Diatoms, some green algae, euglenids, dinoflagellates
Consider interactions of mixed microbial communities. Match the descriptions in the left column with those that best correlate with them in the right column
Difficult to produce in the laboratory -> conditions in close microbial associations, Simpler to reproduce in the laboratory -> pure cultures, Inhibit competitors -> synthesis of toxic compounds, Nutrients for another microbe -> production of metabolic waste by one microbe, Creation of low O2 microenvironment -> consumption of O2 by aerobic growth
Bacteria growing in a natural environment experience ___.
Dynamic and complex conditions
Viral genomes can be ___.
Either single-stranded or double-stranded
The process by which a virus is taken up by a host cell as a result of the host cell's cytoplasmic membrane surrounding the virion to form a vesicle is called ___.
Endocytosis
All of the following statements about fungal hyphae are true EXCEPT ___.
Enzymes released by one hyphae attract the growth of other hyphae towards it
Ten cells of a pathogen may give rise to over 40,000 cells in only a matter of hours as a result of ___.
Exponential multiplication
Some microorganism live in harsh environments that kill most other organisms. The term used to describe an organisms with this characteristic is ___.
Extremophile
M13 particles are assembled during a process called ___, which the virus uses to exit the cell.
Extrusion
All non-cellular infection agents are viruses.
False
Enveloped and non-enveloped viruses all mature fully in the cytoplasm of the host cell.
False
Enveloped viruses enter the host cell by endocytosis only, while non-enveloped viruses can enter the host cell by fusion or endocytosis.
False
Lysogens are more susceptible to reinfection by the same type of phage.
False
The world would be better off with the extinction of all protists.
False
Which of the following are true regarding freezing?
Freezing is a common method used to preserve stock cultures of bacteria, freezing is a good method for preserving foods for long-term storage
___ transduction is the result of packaging errors during the assembly stage of phage replication.
Generalized
What term is used to describe the amount of time a particular microbial species takes to double in number?
Generation time
The molecules that viral spikes attach to on the host cell in order to gain entry are typically ___.
Glycoprotiens
An organism that must consume organic matter is called a ___.
Heterotroph
Which of the following require carbon from a source other than CO2?
Heterotroph
You would be most likely to find thermophiles in which of the following locations?
Hot springs, compost heaps
If a microorganism has a temperature optimum close to the boiling point of water, it is considered a ___.
Hyperthermophile, extremophile
A microorganism that has a temperature optimum close to the boiling point of water is a ___.
Hypterthermophile
Which of the following directs the incorporation of phage DNA into a bacterial chromosome?
Integrase
Which of the following describe a Petri dish?
It excludes airborne contaminants, a culture medium in a Petri dish can be referred to as a plate of that medium, it is a two-part covered container made of plastic or glass
Which of the following about classifying viruses is false?
It is not as important as classifying organisms since they are not living entities.
___ phase describes the initial phase after bacterial cells are placed into a new environment and are gearing up for cell division, but their numbers have not yet increased.
Lag
In which phase of the growth curve is the generation time measured?
Log
The term ___ is used to describe the rupture or bursting of a cell.
Lyse
Some pathogenic bacteria produce toxins that are encoded on prophage DNA, and these are examples of ___ conversion.
Lysogenic
___ is a change in the phenotype of a lysogen as a consequence of the specific prophage it carries.
Lysogenic conversion
The process by which the viral nucleic acid is released from the protective protein coat is ___.
Uncoating
Infection of bacteria by ___ phages always ends with the lysis of the host cell.
Lytic
In enveloped viruses, sandwiched between the nucleocapsid and the envelope is the ___.
Matrix protein
In the laboratory, a liquid or solid ___ provides nutrients for microbial growth.
Medium
Fungi are characterize by ___.
Membranes that contain ergosterol, cell walls that contain chitin
E. coli and most other common bacteria are ___.
Mesophiles
A microbe that requires small amounts of O2 (2-10%) for aerobic respiration but is inhibited by higher concentrations is called a ___.
Microaerophile
Unicellular algae, including diatoms, some green algae, dinoflagellates, euglenids, and a few red algae, can collectively referred to as ___.
Microscopic algae
A nuclear division in which each daughter cell receives the same number of chromosomes as the parent cell is ___.
Mitosis
Match each term with its definition
Mitosis -> Daughter cell contain the same number of chromosomes as parent cell, Meiosis -> Diploid cell produce haploid cells, Gamete -> A haploid sex cell, Diploid cell -> Contains 2n chromosomes, Haploid cell -> Contains n chromosomes
A ___ is a microbe that prefers environments near or at a pH of 7.
Neutrophile
Unlike sugar, proteins provide which of the following elements?
Nitrogen
One of the early proteins expressed in the T4 lytic cycle is an enzyme called a ___ that degrades the bacterial DNA.
Nuclease
Most animal DNA viruses replicate within the host cell's ___.
Nucleus
The primary defining characteristic of eukaryotes is that they possess a membrane-bound ___.
Nucleus
An ___ aerobe, or strictly aerobic organism, required O2 for survival.
Obligate
Bacteria that cannot multiply if O2 is present, and are often killed by even brief exposure to air, are termed ___.
Obligate anaerobes
A species grows most rapidly at its ___ growth temperature.
Optimal
Animals depend on organisms that fix carbon because without them the earth would run out of ___.
Organic carbon
Which of the following are considered major elements that make up cell constituents?
Oxygen, carbon, nitrogen, phosphorous, hydrogen
An autotrophic organism that uses light for energy and carbon dioxide as a carbon source is termed a ___.
Photoautotroph
Match up the following groups of prokaryotes according to the energy and carbon source they use.
Photoautotroph -> Energy: sunglight; Carbon: CO2. Photoheterotroph -> Energy: sunlight; Carbon: organic compounds. Chemolitoautotroph -> Energy: inorganic chemicals; Carbon: CO2. Chemoorganoheterotroph -> Energy: organic compounds; Carbon: organic compounds
Which term is used to describe organisms that can obtain energy directly from sunlight?
Phototrophs
A ___ is an infectious agent that lacks a capsid and consists only of RNA.
Viroid
If you searched around the world, where would you expect to find live prokaryotes?
Polar regions, temperatures above boiling, within animal hosts, ocean depths, volcanic vents
___ are the causative agents of transmissible spongiform encephalopathies.
Prions
Specialized transduction ___
Produced defective phage particles, transfers phage DNA and adjacent host genes, results from errors in excision of the prophage
All of the following are examples of the commercial contributions of fungi EXCEPT ___.
Production of toxins which can cause human disease
Match each possible outcome of phage replication with the correct definition.
Productive infection -> new viral particles are produced Latent state -> viral genome remains silent within the cell
RNA viruses have a higher mutation rate than DNA viruses because replicase lacks ___ ability.
Proofreading
At a minimum, all viruses are composed of ___.
Proteins, nucleic acids
Match the term on the left with the description of the optimum temperature environment
Psychophile -> cold Artic regions, psychrotroph -> refrigeration, mesophile -> human body, thermophile -> compost heap
Replicases are ___ polymerases.
RNA-dependant RNA
Metabolic reactions of fungi during decomposition include the ___.
Release of nitrogen compounds into the soil, release of CO2 into the atmosphere, ability to degrade both cellulose and lignin
The enzyme of RNA viruses that lack proofreading ability and thus makes many mistakes compared to the polymerase of DNA viruses is ___.
Replicase
Why are cells growing in a colony on solid media likely to be in many more different phases of growth than cells growing in a liquid culture?
Unlike cells on the edge of a colony, those in the center of a colony face depleted levels of nutrients and O2, yielding different phases of growth, cells in liquid culture experience a relatively uniform environment, so they are much more likely to be in the same phase of growth
To maintain the lysogenic state, a ___ protein prevents expression of the gene required for excision.
Repressor
The replication strategy of viruses can be divided into three general categories: those used by ___.
Reverse transcribing viruses, DNA viruses, RNA viruses
An enzyme that uses an RNA molecule as a template to make a complementary copy of DNA is called ___.
Reverse transcriptase
Fungi are ___, meaning they absorb nutrients from dead or decaying matter.
Saprophytes
Which of the following are diseases caused by prions?
Scrapie, Bovien spongiform encephalopathy, Creutzfeldt-Jakob disease
To obtain nutrients, fungi ___.
Secrete enzymes into the environment to break large molecules into smaller one they can absorb
Algae ___.
Serve as primary source of food in aquatic environments, may be microscopic or macroscopic, lack an organized vascular structure
Reassortment of gene segments that encode viral surface proteins that are recognized by the immune system can result in a loss of the immune system's ability to recognize and respond to the virus. This phenomenon is called antigenic ___.
Shift
___ transduction is the result of excision errors made as temperate phages transition from a lysogenic to a lytic cycle.
Specialized
What are the two types of transduction?
Specialized and generalized
The method of using a sterile loop to spread a small culture sample over a medium in a pattern that gradually thins out the sample, resulting in isolated colonies, is called which of the following?
Streak plate method
In nature, the source of energy that is used for photosynthesis come from the ___.
Sunlight
Phage DNA and proteins are made during the ___ stage of the T4 lytic cycle.
Synthesis
Which of the following are viral protein components that attach to specific receptors on host cells?
Tail fibers, spikes
Commercially important contributions attributed to fungi include ___.
Uses in the wine and cheese industries, the synthesis of antibiotics, genetically engineered production of insulin and vaccines
Which is most important for attachment of a virus to a host cell?
Viral specificity for host receptors
___ phages have the option of entering the prophage state, while ___ phages always burst the host cell shortly after infection.
Temperate, lytic
Which answer best explains the events in the figure leading to plasmolysis?
The solute concentration of the medium is greater than that in the cell, causing water to diffuse out of the cell due to osmosis.
Which of the following statements about viruses are true?
The viral capsid is composed of protein, viruses contain RNA or DNA but not both
The study of viruses is important because ___.
There are many medically important viruses that cause disease, viruses can be a vehicle for horizontal gene transfer in bacteria, bacteriophages play a significant ecological role in reducing bacterial populations in nature
Viruses are challenging to study because ___.
They are obligate intracellular parasites, they can only be seen using an electron microscope
Some arthropods and worms are included in the study of microscopic Eukarya because ___.
They are often carried or transmitted in forms that are microscopic, of their role in human disease
Which of the following describe aseptic techniques used in the laboratory?
They are used to keep containers, media, and instruments sterile prior to use, they are important to minimize the chance of contaminating pure cultures
Which of the following correctly describes facultative anaerobes?
They can grow without O2, their growth is faster when O2 is available
All of the following describe why fungi are able to grow in a variety of habitats EXCEPT ___.
They typically survive only in conditions that bacteria can
Which of the following processes are required for production of virus particles in a host cell?
Transcription of viral genes, replication of viral genome, translation of viral genes
Bacteriophages play a fundamental role in which type of horizontal gene transfer?
Transduction
What mechanisms do newly assembled viruses use to leave their host cell?
Triggering apoptosis, budding
Bacteriophages are important medically because they can be used to prevent the growth of food-contaminating pathogens.
True
Ina growth curve, cell numbers increase exponentially during the log phase and decrease exponentially during the death phase.
True
