These structures are used by bacteriophages to attach to host cell receptors.

tail fibers

True or False: Prophages can be activated into viral replication and enter the lytic cycle.

True

Viruses with __________ sense RNA contain the correct message for translation, while viruses with _________ sense RNA must first be converted into a correct message.

positive, negative

The capsomers are made of

protein.

Which of the following will not support viral cultivation?

blood agar

Clostridium botulinum is made virulent by incorporated prophage genes encoding for the botulinum toxin. What term describes this process?

Lysogenic conversion

In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____.

nucleus, cytoplasm

Freshly isolated animal tissue that is placed in a growth medium and allowed to produce a cell monolayer is referred to as a cell culture.

primary

All of the following is correct about treating viral diseases except

viruses are killed by the same antibiotics that kill bacteria.

Viruses have all the following except

metabolism.

True or False: The International Committee on Taxonomy of Viruses has determined that there are only three orders of viruses.

False

True or False: Viruses are ultramicroscopic because they range in size from 2 mm to 450 mm.

False

The correct sequence of events in viral multiplication is

adsorption, penetration, uncoating, synthesis, assembly, release.

True or False: Bacteriophages do not undergo adsorption to specific host cell receptors prior to penetration.

False

Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes called

pocks.

Viruses belong to which of the following Kingdoms?

None of the choices are correct.

Oncogenic viruses include all the following except

Measles virus.

Which of the following viruses did D. Ivanovski and M. Beijerinck work with?

Tobacco Mosaic Virus

How do enveloped animal viruses exit their host?

Budding or exocytosis

True or False: Spikes are glycoproteins of the virus capsid.

False

Viruses that infect bacteria are specifically called _____.

bacteriophages

Virus capsids are made from subunits called

capsomeres.

Uncoating of viral nucleic acid

All of the choices are correct.

The virus-induced, specific damage to the host cell that can be seen in a light microscope is called

cytopathic effects.

Satellite viruses are

dependent on other viruses for replication.

Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called

plaques.

Creutzfeld-Jacob disease is

a spongiform encephalopathy of humans.

True or False: The adeno-associated virus (AAV) and the delta agent are prions.

False

Classification of viruses into families involves determining all the following characteristics except

biochemical reactions.

Which of the following represents a virus family name?

Herpesviridae

Host cells of viruses include

All of the choices are correct.

A(n) _____ is the protein shell around the nucleic acid core of a virus.

capsid

True or False: Viral spikes are inserted into the host cell membrane before budding or exocytosis occurs.

True

A naked virus does not have a(n) ________ .

envelope

True or False: No cases of variant Creutzfeldt-Jakob syndrome linked to eating infected cows have occurred in the United States.

True

True or False: When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell.

True

The core of every virus particle always contains

either DNA or RNA.

Which of the following is correct
about viruses?

cannot be seen with a light microscope

When a virus enters a lysogenic phase, it means

the virus is integrated into the DNA of the host cell and is latent.

All of the following pertain to virus envelopes except they

are located between the capsid and nucleic acid.

Two noncellular agents, smaller than viruses, are the infectious proteins called _______ , and the infectious RNA strands called ________ .

prions, viroids

Which of the following is a type of cytopathic effect?

All of the choices are correct.

T-even phages

infect Escherichia coli cells.

Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called

latent

True or False: Viral infections are easier to treat with drugs than bacterial infections.

False

Diagnosis of viral infections sometimes involves analyzing the patient's blood for specific _____ that the immune system produced against the virus.

Antibodies

True or False: A closed culture system is used to determine a population growth curve.

True

The E. coli that normally live in the human large intestines and produce vitamin K that the body uses would be best termed a _____ relationship.

Mutualistic

Organisms that feed on dead organisms for nutrients are called

Saprobes

The time interval from parent cell to two new daughter cells is called the

Generation time

What type of media is used to demonstrate oxygen requirements of microbes?

Thioglycollate

The methanogens, producers of methane gas, require environments that

Are anaerobic with hydrogen gas and CO2

The use of energy by a cell to enclose a substance in its membrane by forming a vacuole and engulfing it is called

Endocytosis

The toxic superoxide ion is converted to harmless oxygen by two enzymes,

Superoxide dismutase and catalase

An organism that cannot grow without oxygen is a(n)

Obligate aerobe

Aerobic respiration is an example of

Chemoheterotrophy

The movement of substances from higher to lower concentration across a semi permeable membrane that must have a specific protein carrier but no energy expenditure is called

Facilitated diffusion

True or False: A saprobe with a cell wall will utilize extracellular digestion.

True

The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the

Stationary phase

True or False: Anaerobes can be cultured in a CO₂ environment.

True

True or False: Obligate saprobes can adapt to a living host.

False

All of the following could find a location in or on body tissues suitable for growth except

Psychrophiles

A halophile would grow best in

Salt lakes

An organic nutrient that cannot be synthesized by the organism and must be provided is called a/an

Growth factor

The phase of the bacterial growth curve that shows the maximum rate of cell division is the

Log phase

True or False: Facilitated diffusion and active transport require a carrier protein to mediate the movement across the plasma membrane.

True

In _____ conditions, the cell wall will help prevent the cell from bursting.

Hypotonic

True or False: Whether an organism is an autotroph or heterotroph depends on its source of nitrogen.

False

True or False: After binary fission, daughter cells will differ genetically.

False

Microorganisms that live in severe habitats, such as very hot, acidic or salty environments, are called

Extremophiles

When it is important to count the number of cells, determine cell size and differentiate between dead and live cells a ___ is used.

flow cytometer

Cultures of a bacterial species were incubated on the shelf of a refrigerator, out on a lab bench top, on the shelf of a 37° C incubator and on the shelf of a 50° C incubator. After incubation, there was no growth at 37° C and 50° C, slight growth out on the bench top and abundant growth at refrigeration. What term could be used for this species?

Psychrophile

The production of antibiotics is a form of antagonism called

Antibiosis

True or False: The time that it takes for a freshly inoculated agar culture to develop visible colonies is principally governed by that species' generation time.

True

Bacteria living in a freshwater stream that are moved to salty seawater would

Shrivel

Contractile vacuoles are

Used to expel excess water from cells

Organisms called _____ live on or in the body of a host and cause some degree of harm.

Pathogens

When whole cells or large molecules in solution are engulfed by a cell, this endocytosis is specifically termed

Phagocytosis

An organism that can use gaseous oxygen in metabolism and has the enzymes to process toxic oxygen products is a(n)

Aerobe

True or False: Most microorganisms on earth can only live and survive in habitats that are similar to human body conditions.

False

Calcium is required for bacteria because

It stabilizes the cell wall

An important mineral ion that is a component of chloroplasts and stabilizer of membranes and ribosomes is

Magnesium

Cultures of a bacterial species were incubated out on the incubator shelf, in an anaerobic jar and in a candle jar. After incubation there was moderate growth of cultures in the candle and anaerobic jars, but heavy growth of the culture on the incubator shelf. This species is a/an

Facultative anaerobe

An organism that can exist in both oxygen and oxygen-less environments is a(n)

Facultative anaerobe

True or False: Inorganic nitrogen must be converted to ammonia to be used by a cell.

True

Growth factors

Cannot be synthesized by the organism

The movement of substances from lower to higher concentration across a semi permeable membrane that must have a specific protein carrier and cell expenditure of energy is called

Active transport

Diffusion of water through a semi permeable membrane is called

Osmosis

The phase of the bacterial growth curve in which newly inoculated cells are adjusting to their new environment, metabolizing but not growing is the

Lag phase

A microorganism that does not have catalase or superoxide dismutase would find it difficult to live in an environment with

Oxygen

Microorganisms require large quantities of this nutrient for use in cell structure and metabolism

Macronutrient

The term facultative refers to

The ability to exist in a wide range of conditions

Why are Archea as a group are not pathogens?

Because mammalian hosts do not meet their environmental requirements

The term phototroph refers to an organism that

Gets energy from sunlight

True or False: Bacteria have an average generation time of 24 hours.

False

True or False Whether an organism is a phototroph or a chemotroph depends on its source of energy.

True

What is a virus?

an infectious particle consisting of gene packaged in a protein coat

What did Ivanoski and Beijerink do?

discovered and isolated tobacco mosaic virus

Viruses have DNA ____(and/or)___ RNA

DNA or RNA NEVER BOTH

What is the most abundant microbe on earth?

viruses

Are viruses cellular or noncellular?

Noncellular meaning they are non living

Can viruses metabolize?

No viruses cannot metabolize

Are viruses capable of replicating without a cellular host?

No, viruses are obligate meaning they require a host to replicate

Can viruses form their own structures and receptors?

No, they have no machinery for protein synthesis

What is a capsid?

a viral protein coat

What is the capsid together with the nucleic acid called?

nucleocapsid

What are the identical protein subunits of a capsid called?

capsomeres

Give some examples of enveloped viruses

HIV, Coronavirus, Yellow fever, Rubella, Hepatitis C

What are the two structural capsid types

Helical - continuous helix of capsomers

Icosahedral - 3D, 20-sided with 12 corners

Why can enveloped viruses not survive long outside of a host?

The lipid bilayer is prone to drying out

What are the capsid and envelope responsible for?

transfer of the viral genetic material from one cell to another, resistance to chemical or physical inactivation

What are spikes essential for?

for attachment of viruses to the host cell

Give an example of a plant virus that is enveloped

Tomato spotted wilt virus

_____________ viruses possess great adaptability and can change in a short time in order to invade the immune system

Enveloped

What kind of virus uses bacteria as its host

bacteriophages

What are the general phases in animal virus multiplication cycle

Adsorption

Penetration

Uncoating

Synthesis

Assembly

Release

Give examples of DNA viruses

Papillomavirus, Herpesviruses, Epstein-Barr, Hepatitis B

Give examples of RNA viruses

HIV, COVID, FLU, Measles, Rabies

ssRNA genomes ready for immediate translation are

positive sense RNA

ssRNA genomes that must be converted into proper form are

negative sense RNA

what is needed to convert negative sense RNA to positive sense RNA

reverse transcriptase

Family names of viruses end in

viridae EX: Herpesviridae

Genus name of viruses ends in

-virus EX: Simplexvirus

What is endocytosis

entire virus is engulfed and enclosed in a vacuole or vesicle

What is fusion

envelope merges directly with membrane resulting in nucleocapsids entry into cytoplasm

Where are DNA viruses assembled

the nucleus

Where are RNA viruses assembled

the cytoplasm

What are the two ways viruses can leave a host

Budding - sheds viruses gradually, cell is not immediately destroyed

Lysis - released when cell dies and ruptures

Define Cytopathic effect (CPE)

virus induced specific damage to cell that alters its microscopic appearance

Define persistent infections and give examples

cell harbors the virus and is not immediately lysed, Measles, Herpes simplex, Herpes zoster

Define oncoviruses and give examples

Mammalian viruses capable of initiating tumors examples are Epstein Barr Virus, Hepatitis B, Hepatitis C, HIV

What are the stages of bacteriophage replication in order

Adsorption, Penetration, Replication, Assembly, Maturation, Lysis and Release

What are the two life cycles of a bacteriophage

lytic and lysogenic

What kind of phages undergo adsorption and penetration but don't replicate

temperate phages

The viral genome inserts into bacterial genome and becomes an inactive __________.

prophage

When a prophage is retained and copied during normal cell division resulting in the transfer of temperate phage genome to all host cell progeny is called?

lysogeny

______________ can occur resulting in activation of lysogenic prophage followed by viral replication and cell lysis

Induction

Lysogeny results in the spread of the virus without ___________ the host cell

killing

What is lysogenic conversion

phage genes in the bacterial chromosome can cause the production of toxins or enzymes that cause pathology

What methods can you use to grow viruses

cell (tissue) cultures

Birid embryos

Live animal inoculation

True or False: Viruses are obligate intracellular parasites

True

What are prions

proteinaceous infectious particles - infectious misfolded proteins, contain no nucleic acid

What are some prion diseases common in animals

Scrapie - in sheep and goats

Mad Cow Disease (Bovine spongiform encephalopathies)

Wasting disease - in elk

Give examples of Human prion diseases

Kuru

Creutzfeldt-Jakob disease (CJD)

Fatal familial insomnia (FFI)

Describe Satellite viruses

dependent on other viruses for replication

Describe viroids

tiny circular, single-stranded RNAs that are infectious pathogens. Have no protein coating, common in plants may also affect humans

What are essential nutrients

must be provided to an organism can not acquire denovo

96% of cell is composed of 6 elements name those elements

carbon

hydrogen

oxygen

phosphorous

sulfer

nitrogen

Heterotroph

depend on other living things

Autotroph

uses CO2 does not depend on other living things

Chemotroph

gain energy from chemical compounds

Phototroph

gain energy through photosynthesis

Saprobes

free-living microorganisms that feed on organic detritus from dead organisms

Parasites

derive nutrients from host

Passive Transport

does not require energy, higher concentration to lower EX: diffusion, osmosis, and facilitated diffusion

Active Transport

requires energy and carrier proteins EX: group translocation, bulk transport

Isotonic

equal inside and out in both Bacteria and Humans

Hypotonic

into cell causes; in Humans it causes it to burst or swell in Bacteria the wall prevents it from bursting

Hypertonic

out of cell; in Humans causes it to shrink and become distorted in Bacteria shrinks cell membrane away from cell wall

Endocytosis

bringing substances into the cell through a vesicle or phagosome

Phagocytosis

ingests substances or cells

Pinocytosis

ingests liquids

What is a niche when referring to bacteria

the totality of adaptions organisms make to their habitat including factors such as pH, temperature, oxygen requirements, osmotic pressure, and barometric pressure

psychrophiles

< 15 ℃

mesophile

20 - 40 ℃

thermophiles

> 45 ℃

Enzymes that function at high temperatures or other harsh conditions are called:

extremozymes

What does Thermoduric mean

survive for short time above maximum temperature for growth EX: are Bacillus, Microbacterium, Streptococcus

enzymes that kill toxic oxygen products

superoxide, dismutase, catalase

utilizes oxygen and can detoxify it

aerobe

cannot grow without oxygen aerobe EX: Micrococcus luteus

Obligate aerobe

utilizes O2 if it is available, but can also grow in the absence of O2 EX: Staphylococci

Facultative anaerobe

requires only a small amount of oxygen Helicobacter pylori

Microaerophilic

does not utilize oxygen

Anaerobe

lacks the enzymes to detoxify O2 so can not survive in an O2 environment EX: Clostridium

Obligate anaerobe

do not utilize O2 but can survive and grow in its presence EX: Lactobacilli

Aerotolerant anaerobes

Neisseria gonorrhoeae

example of facultative anaerobe Gram-negative coffee-bean "diplococci"

Capnophile

grows best at higher CO2 tensions than normally present in the atmosphere EX: Haemophilus influenza

require a high concentration of salt

Halophiles

do not require high concentration of solute but can tolerate it when it occurs

Osmotolerant

can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure

Basophiles

Biofilms

cooperative aggregate of microorganisms associated a surface and enclosed in a polymeric matrix

quorum sensing

communicate and cooperate in the formation and functions of biofilms

Beneficial biofilms

layers of normal microbiota lining the intestinal and respiratory mucosa help ward off infections by pathogens

Harmful biofilms

form on teeth can contribute to dental and periodontal diseases, forms on wounds causing infections that can spread

Microbial growth occurs at two levels growth at a cellular level with increase in ________ and increase in ____________.

size, population

Division of bacterial cells occurs mainly through ______________

binary fission

Time required for a complete fission cycle is called the ________________, or doubling time

generation

Each new fission cycle increases the population by a factor of ______.

2

Rate of population growth forumla

N_t = (N_i)2ⁿ

What are the 4 stages of the population growth curve

Lag phase, Log (exponential) phase, Stationary phase, Death phase

What stage is best for Gram staining

log (exponential) phase

What stage is best for motility testing

log (exponential) phase

What stage is best for endospore staining

death phase

Define metabolism

all chemical and physical workings of a cell

Define Anabolism

forms larger macromolecules from small molecules, biosynthesis, requires energy

Define Catabolism

breaks larger molecules to form smaller molecules, biodegeneration, releases energy

What is an enzyme

a biological catalyst

Define exoenzymes and give examples

transported extracellularly, where they break down large food molecules or harmful chemicals, play a role in toxins EX: cellulase, amylase, penicillinase

Define endoenzymes

retained intracellularly and function there, play a role in metabolic pathways (most enzymes fall into this category)

Define labile

chemically unstable enzymes

Define denaturation

weak bonds that maintain the shape of the apoenzyme are broken

Substances that resembles the normal substrate competes with the substrate for the active site

Competitive inhibition

enzymes are regulated by the binding of molecules other than the substrate away from the active site

Noncompetitive inhibition

What are the 3 linked pathways of catabolism

Glycolysis, Kreb's cycle, Electron transport chain

Bioenergetics

study of the mechanisms of cellular energy release

Aerobic respiration

glycolysis, the Kreb's cycle, respiratory chain (MOST ENERGY)

Anaerobic respiration

glycolysis, the Kreb's cycle, respiratory chain; O2 is not the final electron acceptor

Fermentation

glycolysis, organic compounds are the final electron acceptors (LEAST ENERGY)

limiting factors intensify, cells die exponentially

Death phase

grow at extreme acid pH

Acidophiles

grow at extreme alkaline pH

Alkalinophiles