Category: Microorganisms

Virus Study Guide

Javascript not enabled

Name: 

Virus Quiz

 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Viruses are considered nonliving because
a.
 they cannot reproduce by themselves.
b.
 they are not made up of cells.
c.
 they cannot carry out metabolism by themselves.
d.
 All of the above
 2.
The study of viruses is a part of biology because
a.
 they belong to the kingdom Eubacteria.
b.
 they are about to become extinct.
c.
 they are living organisms.
d.
 they are active inside living cells.
 3.
Biologists now know that viruses
a.
 are the smallest organisms.
b.
 consist of a protein surrounded by a nucleic acid coat.
c.
 contain RNA or DNA in a protein or lipid-protein coat.
d.
 all form the same crystalline shape.
 4.
The capsid of a virus is the
a.
 protective outer coat.
b.
 cell membrane.
c.
 nucleus.
d.
 cell wall and membrane complex.
 5.
Viruses are classified according to
a.
 whether they contain RNA or DNA.
b.
 the shape of their genome.
c.
 whether they have a membrane envelope.
d.
 All of the above
 6.
All viruses have
a.
 cytoplasm.
c.
 mitochondria.
b.
 ribosomes.
d.
 None of the above
 7.
Tobacco mosaic virus
a.
 is able to be crystallized.
b.
 causes disease in tobacco plants.
c.
 is smaller than a bacterium.
d.
 All of the above
 8.
Scientists first began to study viruses because they
a.
 were seen through a microscope.
b.
 could not be seen but caused disease.
c.
 formed crystals.
d.
 were made of cells.
 9.
Viruses that use reverse transcriptase to cause their host cells to transcribe DNA from an RNA template are called
a.
 bacteriophages.
c.
 retroviruses.
b.
 antibodies.
d.
 capsoviruses.
 10.
Which of the following contains only RNA?
a.
 a prion
c.
 a viroid
b.
 a virus
d.
 All of the above
 11.
Unlike viruses, prions
a.
 are capable of reproducing outside of a host cell.
b.
 are composed only of protein.
c.
 can cause brain infections.
d.
 can be treated with antibiotics.
 12.
A typical virus consists of
a.
 a protein coat and a cytoplasm core.
b.
 a carbohydrate coat and a nucleic acid core.
c.
 a protein coat and a nucleic acid core.
d.
 a polysaccharide coat and a nucleic acid core.
nar001-1.jpg
 13.
Refer to the illustration above. Which structure could possibly be made of RNA?
a.
 structure 2
c.
 structure 4
b.
 structure 3
d.
 structure 5
 14.
Refer to the illustration above. Which structure is found outside the cell after the cell is infected?
a.
 structure 1
c.
 structure 3
b.
 structure 2
d.
 structure 4
 15.
Viruses
a.
 are cellular organisms.
b.
 reproduce only in living cells.
c.
 have nuclei and organelles.
d.
 are surrounded by a polysaccharide coat.
 16.
Animal viruses often infect only specific host cells because
a.
 the virus must have the same DNA as the host cell.
b.
 the host cell must have specific receptors for proteins on the virus surface.
c.
 viruses have receptors for host cell glycoproteins.
d.
 the enzymes of the virus can attach only to specific host cells.
 17.
In which cell cycle(s) does viral DNA become integrated into the host cell’s DNA?
a.
 lytic
b.
 lysogenic
c.
 neither lytic nor lysogenic
d.
 both lytic and lysogenic
 18.
Antibiotics are ineffective against viral infections because
a.
 host cells protect the viruses.
b.
 viruses have enzymes that inactivate the antibiotics.
c.
 antibiotics interfere with cellular processes that viruses do not perform.
d.
 viral protein coats block the antibiotics from entering the virus.
 19.
Which of the following is not a viral disease of humans?
a.
 hepatitis
b.
 SARS
c.
 shingles
d.
 All of the above are viral diseases of humans.
 20.
Which of the following is not linked to cancer?
a.
 Ebola virus
c.
 hepatitis B virus
b.
 human papillomavirus
d.
 Epstein-Barr virus
 21.
Which of the following human activities is most closely associated with the emergence of viruses not previously seen in humans?
a.
 absence of a vaccination program
b.
 crowded living conditions
c.
 clearing of forests for housing
d.
 eating uncooked meat
 22.
Most scientists think that early viruses originated from
a.
 other viruses.
b.
 existing cell parts.
c.
 animals.
d.
 spontaneous generation.
 23.
HIV causes AIDS by
a.
 converting a proto-oncogene to an oncogene.
b.
 damaging a person’s blood vessels.
c.
 destroying the covering of a person’s nerves.
d.
 gradually destroying a person’s immune system.
 24.
Which of the following is not a vector of viral diseases?
a.
 mosquitoes
c.
 prions
b.
 ticks
d.
 humans
 25.
Which of the following has been the most successful at fighting viral diseases?
a.
 vaccination
c.
 drug therapy
b.
 vector control
d.
 Both a and b
 26.
Most scientists believe that viruses first appeared on Earth ____ living cells appeared.
a.
 after
b.
 a very long time before
c.
 at the exact time when
d.
 immediately before
 

Completion
Complete each statement.
 27.
The protein coat of a virus is called a(n) ____________________.
 28.
Viruses can vary in size and ____________________.
 29.
A virus that transcribes DNA from an RNA template is called a(n) ____________________.
 30.
An enzyme called _________________________ manufactures DNA that is complementary to a virus’s RNA.
 31.
____________________ are viruses that infect bacteria and have a polyhedral head and a helical tail.
 32.
All viruses reproduce by taking over the reproductive machinery of a(n) ____________________.
 33.
Viruses that infect a host cell and have their nucleic acid replicated but do not harm the host cell are in a(n) ____________________ cycle.
 34.
The replication of a temperate virus includes the ____________________ cycle.
 35.
The virus that causes AIDS is called _________________________.
 36.
Some viruses are thought to induce ____________________, a disease characterized by uncontrolled cell division.
 37.
The Ebola virus, the SARS virus, and hantavirus are examples of ____________________ viruses.
 38.
In the ____________________ cycle, viruses destroy the host cell.
 39.
Chickenpox and ____________________ are caused by the same virus.
 

Problem
 40.

A new disease has suddenly appeared and scientists are trying to determine whether the disease agent is a virus or a bacterium. They collect the following information:

1.      The disease can be transmitted through the air.
2.      The disease agent is too small to be seen under a light microscope.
3.      There are no known antibiotics that are effective against the disease.
4.      The genetic material of the disease agent is DNA.
5.      The disease agent cannot be cultured using any known culture medium.

Is the disease agent most likely a bacterium or a virus? Explain your answer. Write your answer in the space below.

 
Check Your Work     Start Over

Quiz Viruses

Name: 

Viruses

 

 

True/False
Indicate whether the sentence or statement is true or false.
1.
Although viruses do not consist of cells, biologists consider them to be living because they are capable of reproduction.
2.
Some viruses have a membranous envelope surrounding the protein coat that helps them gain entry into host cells.
3.
Viruses consist of RNA or DNA surrounded by a coat of protein.
4.
Prions are the smallest known particles that are able to replicate.
5.
A virus can only reproduce by controlling a cell.
6.
Once a virus enters either a lytic or a lysogenic cycle, it cannot change to the opposite type of cycle.
7.
Prophages and proviruses can both enter lytic cycles and destroy host cells.
8.
People can contract the influenza virus more than once because the virus tends to mutate rapidly, avoiding the actions of the immune system.
9.
Smallpox is caused by bacteria.
10.
Chickenpox and shingles are caused by the same virus.
 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
11.
The study of viruses is a part of biology because
a.
they belong to the kingdom Eubacteria.
b.
they are about to become extinct.
c.
they are living organisms.
d.
they are active inside living cells.
12.
The capsid of a virus is the
a.
protective outer coat.
c.
nucleus.
b.
cell membrane.
d.
cell wall and membrane complex.
13.
A membranous envelope surrounding some viruses may be composed of
a.
lipids.
c.
glycoproteins.
b.
proteins.
d.
All of the above
14.
viruses : nucleic acids::
a.
water : ice
c.
simplicity : complexity
b.
brick : wood
d.
a jigsaw puzzle : individual pieces
15.
A typical virus consists of
a.
a protein coat and a cytoplasm core.
b.
a carbohydrate coat and a nucleic acid core.
c.
a protein coat and a nucleic acid core.
d.
a polysaccharide coat and a nucleic acid core.
viruses_files/i0180000.jpg
16.
Refer to the illustration above. Which labeled structure could possibly be made of RNA?
a.
Structure “B”
c.
Structure “D”
b.
Structure “C”
d.
Structure “E”
17.
In which type of cell cycle(s) does viral DNA become integrated into the host cell’s DNA?
a.
lytic
c.
neither lytic nor lysogenic
b.
lysogenic
d.
lytic and lysogenic
18.
A prophage differs from a provirus in that
a.
a prophage contains DNA, while a provirus contains RNA.
b.
a prophage is formed during a lysogenic cycle, while a provirus is formed during a lytic cycle.
c.
a prophage contains DNA found in the infecting virus particle, while a provirus contains DNA produced from viral RNA.
d.
a prophage becomes integrated into a host cell’s DNA, while a provirus cannot become integrated into a host cell’s DNA.
19.
Which of the following is not a virus linked to cancer?
a.
Ebola
c.
hepatitis B
b.
human papillomavirus
d.
Epstein-Barr
20.
Which of the following human activities is most closely associated with emerging viruses?
a.
absence of a vaccination program
c.
clearcutting of forests
b.
crowded living conditions
d.
eating uncooked meat

 
Check Your Work     Reset

 

Protists Quiz

Simple Protists
  1. Plant-like protists are collectively called:
    protozoans
    algae
    diatoms
    pseudopodia
  2. Where would you find a paramecium?
    in quiet ponds
    in the human body
    in dirt
    on leaves
  3. Which of the following moves using pseudopodia?
    paramecium
    euglena
    diatoms
    ameba
  4. Which of the following is unicellular and heterotrophic?
    ameba
    paramecium
    algae
    both ameba & paramecium
  5. The word “pseudopodia” means:
    small cell
    fake eye
    false foot
    first animal

 

 

 

 

 

  1. Identify the organism pictured above.

ameba
paramecium
euglena
diatom

  1. Which organelle functions to remove excess water?
    micronucleus
    contractile vacuole
    pellicle
    gullet
  2. The ameba reproduces by:
    fusion
    endocytosis
    binary fission
    conjugation
  3. The paramecium belongs to the Kingdom ____ and the Phylum _____
    Ciliphora, Protista
    Protista, Ciliophora
    Protozoa, Protista
    Animalia, Protista
  4. Which of the following is autotrophic?
    paramecium
    foraminifera
    ameba
    euglena

Score =
Correct answers:

Protist Study Guide

Javascript not enabled

Name: 

Protist Quiz

 

 

Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.
 1.
The kingdom Protista contains the eukaryotes that are not plants, animals, or fungi. _________________________
 2.
Sexual reproduction with spores evolved in protists. _________________________
 3.
Tissues, organs, and organ systems evolved in unicellular protists. _________________________
 4.
Sexual reproduction allows Chlamydomonas to delay development of new organisms until environmental conditions are favorable. _________________________
 5.
Amoebas move by means of pseudopodia. _________________________
 6.
Diatoms are the only type of protists with single shells. _________________________
 7.
Paramecium takes in food through its contractile vacuole. _________________________
 8.
Cellular slime molds form a mass of cytoplasm that has many nuclei. _________________________
 9.
Protists have an important effect on humans because they cause disease. _________________________
 10.
Malaria is caused by the protist Plasmodium and is spread by the bite of certain fleas. _________________________
 11.
Carrageenan is a product made by protists that is used to flavor many food products. _________________________
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 12.
Which of the following is not true about some or all protists?
a.
 unicellular and heterotrophic
c.
 multicellular and autotrophic
b.
 unicellular and autotrophic
d.
 multicellular and prokaryotic
 13.
The kingdom Protista does not include
a.
 most of the single-celled eukaryotes.
c.
 multicellular seaweed.
b.
 slime and water molds.
d.
 prokaryotes.
 14.
Which of the following characteristics did not evolve in the Kingdom Protista?
a.
 unicellularity
c.
 membrane-bound organelles
b.
 gametes
d.
 complex cilia and flagella
 15.
sexual reproduction : diversity ::
a.
 flagella : cilia
c.
 green algae : flagella
b.
 multicellularity : tissues
d.
 unicellularity : protists
 16.
Eukaryotes that lack the features of animals, plants, or fungi are classified in the kingdom
a.
 Archaebacteria.
c.
 Protista.
b.
 Plantae.
d.
 Animalia.
 17.
You have been given an unknown organism to identify. You find that it is unicellular and has a cell wall. Which of the following must it also have?
a.
 chloroplasts
c.
 pseudopodia
b.
 asexual reproduction
d.
 one or more flagella
 18.
When Chlamydomonas reproduces sexually, it divides by mitosis, producing
a.
 zygospores.
c.
 haploid gametes.
b.
 diploid gametes.
d.
 zoospores.
 19.
Zoospores are
a.
 produced as a result of meiosis.
c.
 produced as a result of mitosis.
b.
 diploid.
d.
 all parasitic.
 20.
The haploid, gamete-producing phase in the life cycle of some multicellular protists is known as the
a.
 zygospore generation.
c.
 conjugation generation.
b.
 gametophyte generation.
d.
 sporophyte generation.
 21.
The marine green alga Ulva reproduces sexually by
a.
 alternation of generations.
c.
 mitosis.
b.
 conjugation.
d.
 aggregation.
 22.
Pseudopodia are used for
a.
 Paramecium conjugation.
c.
 Euglena reproduction.
b.
 movement by amoebas.
d.
 Paramecium mitosis.
 23.
Amoebas capture food by
a.
 engulfing it.
c.
 trapping it with flagella.
b.
 using cilia.
d.
 taking it into an oral groove.
 24.
When an individual diatom gets too small because of repeated division, it
a.
 grows to full size in its existing shell.
b.
 slips out of its shell, grows to full size, and regenerates a new shell.
c.
 slips out of its shell, grows to full size, and reinhabits its old shell.
d.
 slips out of its shell and lives the rest of its life without a shell.
 25.
Algae are
a.
 sometimes heterotrophic.
b.
 always microscopic in size.
c.
 found in fresh water, salt water, and damp soil.
d.
 found only in fresh water.
 26.
Red algae
a.
 are multicellular.
c.
 have eyespots.
b.
 are unicellular.
d.
 have double shells.
 27.
Euglenoids are examples of protists that
a.
 can be both autotrophic and heterotrophic.
b.
 are only parasitic heterotrophs.
c.
 are always autotrophic.
d.
 swim away from light.
 28.
dinoflagellates : flagella ::
a.
 amoebas : pseudopodia
c.
 ciliates : pseudopodia
b.
 sporozoans : flagella
d.
 amoebas : flagella
 29.
The process in which two Paramecia come together to exchange parts of their genetic material is called
a.
 mitosis.
c.
 pollination.
b.
 replication.
d.
 conjugation.
nar001-1.jpg
 30.
Refer to the illustration above. Excess water in the body of the Paramecium is forced back out by the structure labeled
a.
 A
c.
 D
b.
 C
d.
 E
 31.
Refer to the illustration above. The structure that contains the cell’s chromosomes is labeled
a.
 A
c.
 C
b.
 B
d.
 E
 32.
Refer to the illustration above. Structure C is the
a.
 macronucleus.
c.
 oral groove.
b.
 contractile vacuole.
d.
 micronucleus.
 33.
Refer to the illustration above. The structure that controls routine cellular functions is labeled
a.
 A
c.
 C
b.
 B
d.
 D
 34.
Funguslike protists reproduce by releasing
a.
 gametes.
c.
 zoospores.
b.
 spores.
d.
 plasmodia.
 35.
Giardiasis is a disease that is spread
a.
 by direct person-to-person contact.
c.
 through contaminated water.
b.
 through the air.
d.
 by the Anopheles mosquito.
 36.
Chagas disease is spread by
a.
 kissing bugs.
c.
 contaminated food.
b.
 mosquitoes.
d.
 contaminated water.
 37.
Which of the following is not a human disease caused by a protist?
a.
 amebic dysentery
c.
 malaria
b.
 toxoplasmosis
d.
 tuberculosis.
 38.
giardiasis : contaminated water ::
a.
 amebic dysentery : mosquito
c.
 malaria : mosquito
b.
 amebic dysentery : giardiasis
d.
 malaria : food contamination
 39.
The protist that causes malaria reproduces in the
a.
 intestine of a human.
c.
 red blood cells of a human.
b.
 red blood cells of a mosquito.
d.
 stinger of a mosquito.
 40.
Malaria is caused by several species of
a.
 Toxoplasma.
c.
 Giardia.
b.
 Phytophthora.
d.
 Plasmodium.
 41.
The stage in the life cycle of Plasmodium in which it lives in mosquitoes and is injected into humans is called the
a.
 gametophyte.
c.
 sporophyte.
b.
 sporozoite.
d.
 zoospore.
 42.
Symbiotic protists live in all of the following organisms except
a.
 termites.
c.
 cattle.
b.
 corals.
d.
 bacteria.
 43.
Protists that play an important role in aquatic food webs are called
a.
 plankton.
c.
 anchovies.
b.
 lichens.
d.
 cyanobacteria.
 44.
The evolution of the plant kingdom can be inferred by studying
a.
 green algae.
c.
 red algae.
b.
 brown algae.
d.
 dinoflagellates.
 45.
A mass of cytoplasm that has many nuclei is a(n)
a.
 spore.
c.
 colony.
b.
 plasmodium.
d.
 amoeba.
 46.
A protist that almost destroyed the entire potato crop in Ireland in 1846 is a
a.
 plasmodial slime mold.
c.
 dinoflagellate.
b.
 cellular slime mold.
d.
 water mold.
 47.
A downy mildew gets nutrients by
a.
 photosynthesis.
b.
 absorbing them from the environment.
c.
 making them from inorganic chemicals.
d.
 making them from organic building blocks.
 48.
When an algal bloom dies, the bacteria that decompose the algae
a.
 deplete carbon dioxide levels in the water.
b.
 kill the plankton population.
c.
 deplete oxygen levels in the water.
d.
 kill fish.
 49.
A protist used by scientists to study cell movement and cell signaling is a
a.
 dinoflagellate.
c.
 paramecium.
b.
 diatom.
d.
 slime mold.
 50.
Agar is a product used to grow bacteria. Agar comes from
a.
 bacteria.
c.
 diatoms.
b.
 algae.
d.
 amoebas.
 

Completion
Complete each statement.
 51.
Two important features that evolved in the protists were multicellularity and sexual reproduction with the production of ____________________.
 52.
The evolution of ____________________ allowed single-celled organisms to perform many functions at the same time.
 53.
When ______________________________ evolved, protists could become genetically diverse.
 54.
Although protists are diverse, they are all ____________________.
Life Cycle of Chlamydomonas
nar002-1.jpg
 55.
Refer to the illustration above. Arrow B is pointing to a ____________________ in the life cycle.
 56.
Refer to the illustration above. Arrow A is pointing to ____________________ in the life cycle.
 57.
According to the illustration above, Chlamydomonas reproduces both sexually and ____________________.
 58.
Some protists undergo sexual reproduction only at times of environmental ____________________.
 59.
Ulva is characterized by two distinct multicellular phases: a diploid, spore producing phase called the ____________________ generation and a haploid, gamete-producing phase called the ____________________ generation.
nar003-1.jpg
 60.
Refer to the illustration above. The organism shown in A moves and obtains food by means of ____________________.
 61.
Refer to the illustration above. The organism shown in C moves by means of ____________________.
 62.
Refer to the illustration above. The organism shown in B moves by means of ____________________.
 63.
Some amoeboid protists have porous shells called ____________________.
 64.
____________________ have double shells that resemble small boxes with lids.
 65.
The large brown algae that grow along coasts are called ____________________.
 66.
Protists that are strict photoautotrophs are called ____________________.
 67.
Poisonous “red tides” are caused by population explosions of ____________________.
 68.
Brown algae are the only algae that form more than one kind of ____________________.
 69.
Some protists have ____________________ that contain light-sensitive pigments.
 70.
____________________ disease is a protist-caused disease that is transmitted by kissing bugs.
 71.
Disease-causing protists are transmitted mainly by insects or by contaminated ____________________ and ____________________.
 72.
The stage of Plasmodium that infects the liver is called the ____________________; the second stage of the Plasmodium life cycle, which infects red blood cells, is called the ____________________.
 73.
Plantlike protists produce ____________________, which allows most forms of life to live on Earth.
 74.
____________________ are related to green algae and are thought to have evolved from them.
 75.
Funguslike protists resemble fungi in that they reproduce with ____________________ and they ____________________ nutrients from their environment.
 76.
Cellular slime molds usually exist as single-celled amoebas, but they form ____________________ and release ____________________ when food or water is scarce.
 77.
A water mold caused the great potato famine in ____________________ in 1846.
 78.
The empty shells of diatoms are used as ____________________ in cleaning agents.
 79.
Red algae produce carrageenan, which is used in the food industry to ____________________ foods such as ice cream and salad dressings.

 
Check Your Work     Start Over

Bacteria and Viruses

Javascript not enabled

Name: 

 

bacteria and Viruses

 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Many microscopic organisms or entities have been identified as pathogens, including all of the following except:
a.
 protozoa.
b.
 viruses.
c.
 fungi.
d.
 bacteria.
e.
 None of the above, all may be pathogenic.
 2.
Which of the following statements about bacteria is false?
a.
 A small percentage of bacteria are pathogenic.
b.
 Some bacteria can photosynthesize.
c.
 Bacteria are important decomposers.
d.
 Bacteria are not cellular and are sometimes not classified as life forms.
e.
 Bacteria convert atmospheric nitrogen into ammonia and then nitrates that can be used by plants.
 3.
Viruses were first identified:
a.
 because they caused an infection and formed colonies on nutrient agar plates.
b.
 because they were seen in the light microscope.
c.
 because they caused an infection and were small enough to pass through filters that trapped bacteria.
d.
 because they were smaller than bacteria and had all the properties of living organisms.
e.
 because they caused an infection and were seen in the electron microscope.
 4.
The protein coat of a virus is called the:
a.
 capsule.
b.
 capsid.
c.
 exospore.
d.
 phage.
e.
 pilus.
 5.
Viruses that attack bacteria are called:
a.
 phages.
b.
 bacteriods
c.
 prions.
d.
 virons.
e.
 viroids.
Figure 23-01
Use the figure below to answer the corresponding questions.nar001-1.jpg
 6.
The structure of the virus in Figure 23-01 that is common to all viruses is:
a.
 2.
b.
 3.
c.
 4.
d.
 5.
e.
 All of the above.
 7.
In Figure 23-01, the function of the structure labeled 3 is:
a.
 attachment to a host cell.
b.
 locomotion.
c.
 mate recognition.
d.
 replication.
e.
 to take over host cell mechanisms.
 8.
Viruses are classified by:
a.
 the sequence of their DNA.
b.
 structural similarities.
c.
 the sequence of their rRNA genes.
d.
 the traditional Linnaean binomial nomenclature system.
e.
 an international committee.
 9.
Viruses:
a.
 are very tiny cells on the order of 500 nm.
b.
 contain both RNA and DNA.
c.
 cannot independently perform metabolic activities.
d.
 have a standard morphology that includes a capsid, tail, and tail fibers.
e.
 All of the above.
 10.
Viruses:
a.
 are usually species-specific.
b.
 may have multiple origins.
c.
 are probably related to mobile genetic elements.
d.
 may have escaped from cells.
e.
 All of the above.
 11.
Phages are being considered for:
a.
 vectors in gene therapy experiments.
b.
 antibiotics in bacterial infections.
c.
 gene transfer vectors in animal cells.
d.
 being equivalent to the first living organisms.
e.
 All of the above.
 12.
Temperate viruses:
a.
 always destroy their host immediately.
b.
 are considered virulent.
c.
 do not always destroy their host.
d.
 do not undergo a lysogenic cycle.
e.
 undergo a lytic cycle.
 13.
Virulent (lytic) phages:
a.
 infect viruses.
b.
 destroy bacteria.
c.
 infect, but do not destroy bacteria.
d.
 infect virions.
e.
 infect prions.
 14.
The five stages of a lytic infection are attachment, penetration, _____________, assembly, and release.
a.
 lysis
b.
 prophage
c.
 lysogenesis
d.
 transduction
e.
 replication
 15.
A prophage:
a.
 is phage DNA that is integrated into viral DNA.
b.
 is phage DNA that is integrated into bacterial DNA.
c.
 replicates only when the eukaryotic cell it infects replicates.
d.
 is an underdeveloped lytic virus.
e.
 is a bacterial cell about to lyse.
 16.
The bacterium that causes botulism disease is harmless until it:
a.
 is infected by lytic bacteria.
b.
 is infected by certain retroviruses.
c.
 contains a certain prophage DNA.
d.
 is irradiated by UV radiation.
e.
 is infected by prions.
 17.
____________ conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics.
a.
 Transducing
b.
 Lysogenic
c.
 Prophage
d.
 Lytic
e.
 Reverse
 18.
The specificity of viruses to different types of cells is due to _____________ sites on the host cell.
a.
 prophage
b.
 receptor
c.
 transduction
d.
 penetration
e.
 transcription
 19.
Retroviruses differ from other RNA viruses by:
a.
 having reverse transcriptase instead of RNA-dependent RNA polymerase.
b.
 the shape of their capsid.
c.
 the way they infect their host cells.
d.
 the sugar coating on their capsids.
e.
 lytically destroying their hosts.
 20.
Which of the following diseases is not caused by a virus?
a.
 rabies
b.
 polio
c.
 warts in humans
d.
 chickenpox
e.
 Lyme disease
 21.
Which of the following identifies a group of DNA viruses?
a.
 retroviruses
b.
 herpesviruses
c.
 paramyxoviruses
d.
 filovirus
e.
 picornaviruses
 22.
Viral proteins can damage host cells by:
a.
 increasing the rate of fermentation within the host.
b.
 producing endotoxins.
c.
 causing a decline in coordination and increased irritability.
d.
 preventing transcription of viral nucleic acids.
e.
 overwhelming the host cell with a large number of viruses.
 23.
Viral infections in humans spread via the circulatory system. Viral infections in plants spread from cell to cell via:
a.
 endocytosis.
b.
 plasmodesmata.
c.
 infected seeds.
d.
 pili.
e.
 transformation.
 24.
Human viruses can enter human cells by fusion with the cell membrane or by:
a.
 diffusion into the cell.
b.
 passage through specific protein channels.
c.
 coating themselves with lipids that cloak their entrance into the cell.
d.
 endocytosis.
e.
 hitchhiking onto protein signals entering the cell.
 25.
Viroids cause a variety of plant diseases and are composed only of:
a.
 strands of RNA.
b.
 strands of DNA.
c.
 protein coats.
d.
 peptidoglycan.
e.
 a capsid.
 26.
Mad cow disease is an example of an infection caused by a:
a.
 bacterium.
b.
 bacteriophage.
c.
 retrovirus.
d.
 viroid.
e.
 prion.
 27.
_____________ is credited with the discovery of prions as a new biological principle of infection.
a.
 Stanley Prusiner
b.
 Anton van Leeuwenhoek
c.
 Dmitrii Ivanowsky
d.
 Stanley Brenner
e.
 Carl Woese
 28.
A symptom of a transmissible spongiform encephalopathy (TSE) is:
a.
 degeneration of the digestive tract.
b.
 progressive immune deficiency.
c.
 degeneration of the brain and central nervous system.
d.
 inflammation of the reproductive organs.
e.
 influenza-like symptoms.
 29.
The volume of a typical bacterium is about ____________ the volume of a typical eukaryotic cell.
a.
 equal to
b.
 a half
c.
 a tenth
d.
 a hundredth
e.
 a thousandth
 30.
A chain of round bacteria would be called:
a.
 spirilla.
b.
 diplococci.
c.
 bacilli.
d.
 streptococci.
e.
 streptobacilli.
 31.
Rod-shaped bacteria are called:
a.
 streptococci.
b.
 bacilli.
c.
 diplococci.
d.
 vibrio.
e.
 spirochete.
Figure 23-02
Use the figure below to answer the corresponding questions.nar002-1.jpg
 32.
The structure in Figure 23-02 labeled C is:
a.
 a ribosome.
b.
 the plasma membrane.
c.
 the capsule.
d.
 the cell wall.
e.
 the flagellum.
 33.
What is the function of the structure labeled A in Figure 23-02?
a.
 to adhere to surfaces or other bacteria
b.
 to prevent phagocytosis
c.
 support and protection in hypotonic conditions
d.
 transmission of DNA between bacteria
e.
 locomotion
 34.
Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on:
a.
 the nuclear membranes.
b.
 the endoplasmic reticulum.
c.
 the plasma membrane.
d.
 ribosomes.
e.
 the cell wall.
 35.
Most bacterial cells keep from bursting in a hypotonic environment by:
a.
 an efficient water pump.
b.
 a tough cell membrane.
c.
 pumping large quantities of salts into the cell.
d.
 a rigid cell wall.
e.
 a stiff capsule.
 36.
Gram-positive bacteria would stain __________ in a gram stain because of a thick layer of __________ in their cell walls.
a.
 green; peptidoglycan
b.
 purple; peptidoglycan
c.
 green; cellulose
d.
 purple; polysaccharides
e.
 red; polysaccharides
 37.
The walls of Eubacteria contain peptidoglycan, which is:
a.
 lipids crosslinked with sugars.
b.
 sugars crosslinked with proteins.
c.
 a protein.
d.
 a lipid.
e.
 a polysaccharide.
 38.
Penicillin works most effectively against gram-positive bacteria because:
a.
 penicillin affects cell membranes.
b.
 they have a thick peptidoglycan cell wall and penicillin affects the synthesis of peptidoglycans.
c.
 they have special protein channels that allow penicillin to enter the cell and halt the cell cycle.
d.
 they are smaller than gram-negative bacteria and, thus, easily take up penicillin by diffusion.
e.
 they contain prophages that negatively interact with penicillin.
 39.
Some bacteria avoid a host’s immune system by means of:
a.
 efficient use of their flagella.
b.
 ameboid motion.
c.
 their capsule.
d.
 changing their cell wall structure.
e.
 eliminating the use of a membrane.
 40.
Bacteria:
a.
 are incapable of locomotion.
b.
 move by means of pili
c.
 move by means of cilia.
d.
 move by means of a rotating flagella.
e.
 move by means of a whiplike flagella.
 41.
Small circles of DNA called ______________ exist in addition to the bacterial chromosome.
a.
 capsids
b.
 plasmids
c.
 chromatids
d.
 pili
e.
 centromeres
 42.
Small hairlike structures on the surface of bacteria are called:
a.
 capsids.
b.
 pili.
c.
 chromatids.
d.
 plasmids.
e.
 virons.
 43.
Plasmids of bacteria often have genes involved in:
a.
 reproduction.
b.
 motility.
c.
 viral resistance.
d.
 antibiotic resistance.
e.
 photosynthesis.
 44.
Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of __________ between bacteria.
a.
 ribosomes
b.
 cytoplasm
c.
 vectors
d.
 RNA
e.
 DNA
 45.
Prokaryotes have their genetic information stored in:
a.
 several small, circular pieces of DNA.
b.
 a single, small, circular piece of DNA.
c.
 a large, linear piece of DNA.
d.
 several small, linear pieces of DNA.
e.
 a large, circular piece of DNA.
 46.
_______________ is a form of genetic exchange in bacteria that involves contact between two cells.
a.
 Transformation
b.
 Transduction
c.
 Conjugation
d.
 Binary fission
e.
 Budding
 47.
_____________ are dormant structures formed by bacteria in response to adverse environmental conditions.
a.
 Capsids
b.
 Endospores
c.
 Exotoxins
d.
 Endotoxins
e.
 Heterocysts
 48.
Most bacteria are:
a.
 photoheterotrophs.
b.
 chemoheterotrophs.
c.
 autotrophs.
d.
 heterotrophs.
e.
 chemoautotrophs.
 49.
A bacterium that gains nourishment from dead organisms is referred to as:
a.
 an autotroph.
b.
 a parasite.
c.
 a saprotroph.
d.
 a chemoautotroph.
e.
 a pathogen.
 50.
A(an) ___________________ bacterium would not be able to survive in the presence of oxygen.
a.
 facultative aerobic
b.
 facultative anaerobic
c.
 facultative autotrophic
d.
 obligate aerobic
e.
 obligate anaerobic
 51.
The most common mode of reproduction in bacteria is:
a.
 binary fission.
b.
 transformation.
c.
 transduction.
d.
 conjugation.
e.
 mitosis.
 52.
The first indication that Archae were different from the Eubacteria came from differences noted in their:
a.
 cell wall.
b.
 preferred habitats.
c.
 16 S rRNA sequence.
d.
 protein synthesis machinery.
e.
 resistance to antibiotics.
 53.
The Archaea differ from the Eubacteria and eukaryotes by having different ____________ in their cell membranes, but they are similar to eukaryotes in their ____________ process.
a.
 sugars; replication
b.
 sugars; transcription
c.
 lipids; replication
d.
 lipids; transcription
e.
 proteins; transcription
Figure 23-03
Use the figure below to answer the corresponding questions.nar003-1.jpg
 54.
Which of the following groups from Figure 23-03 represents gram-negative bacteria?
a.
 Spirochetes
b.
 Protists
c.
 Methanogens
d.
 Halophiles
e.
 None of the above.
 55.
Which of the following groups from Figure 23-03 is a member of the Eubacteria domain?
a.
 Fungi
b.
 Halophiles
c.
 Chlamydias
d.
 Protists
e.
 More than one of the above.
 56.
About how many different species of bacteria have been classified?
a.
 200
b.
 2,000
c.
 4,000
d.
 20,000
e.
 40,000
 57.
The most significant difference between the Archaea and the Eubacteria is:
a.
 lack of a nuclear envelope in the Archaea.
b.
 the absence of the 70S ribosomes in the Eubacteria.
c.
 the presence of a single filament flagellum in the Eubacteria.
d.
 the absence of peptidoglycans in the cell walls of the Archaea.
e.
 All of the above.
 58.
One difference between the Archaea and the Eukarya is:
a.
 the lack of a nuclear envelope in the Archaea.
b.
 the absence of the 70S ribosomes in the Archaea.
c.
 the presence of membrane-bound organelles in the Archaea.
d.
 the presence of peptidoglycans in the cell walls of the Archaea.
e.
 the presence of simple RNA polymerase in the Archaea.
 59.
One unique characteristic associated with some of the extreme halophilic Archaea is:
a.
 that they are found at deep-sea vents on the sea floor.
b.
 that they are a source of most known antibiotics.
c.
 that they have photosynthetic ability involving a purple bacteriorhodopsin pigment.
d.
 that they fix atmospheric nitrogen that is then used by plants.
e.
 that most form symbiotic associations.
 60.
_____________ Archae are typically found in abnormally hot environments.
a.
 Extreme halophile
b.
 Extreme thermophile
c.
 Pyrrhanogen
d.
 Metanogen
e.
 Any of the above.
 61.
Most prokaryotes belong to the:
a.
 Fungi.
b.
 Archaea.
c.
 Protista.
d.
 Eubacteria.
e.
 Viroids.
 62.
Bacterial ____________ cause systemic symptoms such as fever, whereas bacterial ____________ cause more specific maladies.
a.
 phages; prophages
b.
 prophages; phages
c.
 endotoxins; exotoxins
d.
 exotoxins; endotoxins
e.
 exotoxins; phages
 63.
The bacterial reproductive parasite Wolbachia is known to:
a.
 eradicate males from a population.
b.
 convert males into females.
c.
 cause infected females to lay eggs that develop without fertilization.
d.
 reduce the number of males in a population.
e.
 All the above.
 64.
The symbiotic bacteria found in the root nodules of legumes:
a.
 supply the plant with the nitrogen it needs in the form of nitrates.
b.
 are motile, soil-dwelling bacteria.
c.
 belong to the genus Rhizobium.
d.
 are gram-negative Eubacteria.
e.
 All of the above.
 65.
Koch’s postulates include all the following except:
a.
 when a sample of a pure culture is injected into a healthy host causes the same disease.
b.
 a sample of the microorganism from a diseased host can be grown in pure culture.
c.
 the microorganism can be recovered from an experimentally infected host.
d.
 the microorganism must be visible in the electron microscope.
e.
 the pathogen must be present in every individual with the disease.
 66.
The first bacteria that was clearly identified as the cause of an infectious disease was:
a.
 Legionella pneumophila, which causes Legionnaires’ disease.
b.
 Chamydia sp., which causes pelvic inflammatory disease in women.
c.
 Clostridium botulinum, which causes botulism.
d.
 Vibrio cholerae, which causes cholera.
e.
 Bacillus anthracis, which causes anthrax.
 

Short Answer
 67.
Compare and contrast a virus and a bacterium.
 68.
List the characteristics of the following groups and identify examples for each: Archaea, Eubacteria, and Eukarya.
 69.

Compare and contrast the metabolic diversity of bacteria in one of the two groups below.

A. Obligate anaerobes, facultative anaerobes, and aerobes
B. Autotrophic and heterotrophic bacteria

 70.
Identify and briefly discuss two ecological roles filled by bacteria.
 

Essay
 71.
Describe the theory that attempts to explain the species specificity of viruses to their hosts.
 72.
Discuss the distinction between gram-negative and gram-positive bacteria. In the laboratory, how is this determined? What are differences between these two groups of bacteria?
 73.
Describe endotoxins and exotoxins. What effects do they each have on infected persons?

 
Check Your Work     Start Over

Bacteria Study Guide

Javascript not enabled

Name: 

Bacteria Study Guide

 

 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
The earliest known group of living organisms on Earth was
a.
 viruses.
c.
 bacteria.
b.
 fungi.
d.
 protists.
 2.
Bacteria and archaea are the only organisms characterized as
a.
 unicellular.
c.
 eukaryotic.
b.
 prokaryotic.
d.
 photosynthetic.
 3.
Bacteria can be classified according to their
a.
 type of cell walls.
b.
 methods of obtaining energy.
c.
 Gram-staining characteristics.
d.
 All of the above
nar001-1.jpg
 4.
Refer to the illustration above. Which of the organisms shown has the shape called bacillus?
a.
 organism 1
c.
 organism 3
b.
 organism 2
d.
 None of the above
 5.
Refer to the illustration above. The shape represented by organism 3 is called
a.
 coccus.
c.
 bacillus.
b.
 spirillum.
d.
 filamentous.
 6.
When tested with a Gram stain, Gram-positive bacteria are stained
a.
 green.
c.
 pink.
b.
 yellow.
d.
 purple.
 7.
Bacteria lack a true nucleus and membrane-bound organelles; therefore, they are classified as
a.
 prokaryotes.
c.
 anaerobes.
b.
 aerobes.
d.
 eukaryotes.
 8.
The cytoplasm of bacteria
a.
 contains numerous types of organelles.
b.
 is divided into compartments.
c.
 has varying numbers of chromosomes, depending on the species of bacteria.
d.
 contains a single chromosome.
 9.

Which of the following comparisons is incorrect?

PROKARYOTES      EUKARYOTES
a.
 smaller      larger
b.
 circular chromosomes      linear chromosomes
c.
 binary fission      mitosis
d.
 chloroplasts      mitochondria
 10.
One difference between human body cells and bacterial cells is that bacterial cells have
a.
 an outer cell wall made up of phosphates.
b.
 a cell wall made up of peptidoglycan.
c.
 no DNA.
d.
 no ribosomes.
 11.
Structures found in a eukaryotic cell but not in a bacterial cell are
a.
 cell nuclei.
b.
 multiple chromosomes.
c.
 membrane-bound organelles.
d.
 All of the above
 12.
Which of the following might be found in the cytoplasm of a bacterial cell?
a.
 chloroplasts
c.
 mitochondria
b.
 Golgi apparatus
d.
 None of the above
 13.
Bacterial cells
a.
 have a cell wall only.
b.
 have a cell membrane only.
c.
 have both a cell membrane and cell wall.
d.
 have a cell wall inside their cell membrane.
 14.
One thing that E. coli and other bacteria have in common with eukaryotes is the presence of
a.
 chloroplasts.
c.
 nuclei.
b.
 mitochondria.
d.
 DNA.
 15.
Bacterial endospores
a.
 occur where there is plenty of available food.
b.
 allow certain species to survive harsh environmental conditions.
c.
 are similar to human tumors.
d.
 can cause growth abnormalities in plants.
 16.
Which of the following are used by at least some bacteria for movement?
a.
 pili
b.
 flagella
c.
 cytoplasmic projections
d.
 All of the above
 17.
phototrophic bacteria : sunlight ::
a.
 chemotrophic bacteria : dead organisms
b.
 chemoautotrophic bacteria : inorganic molecules
c.
 photosynthesis : nitrification
d.
 heterotrophic bacteria : inorganic molecules
 18.
Which of the following conditions would be unsuitable for any kind of bacteria to grow?
a.
 temperature of 110ºC (230ºF)
b.
 absence of oxygen
c.
 pH of 5
d.
 None of the above
 19.
Prokaryotes can transfer pieces of genetic material in a process called
a.
 binary fission.
c.
 conjugation.
b.
 mitosis.
d.
 sexual reproduction.
 20.
During the process of transduction
a.
 a virus obtains DNA from a host bacterium.
b.
 a bacterial cell takes in DNA from the external environment.
c.
 one bacterium transfers DNA to another.
d.
 two bacteria exchange DNA.
 21.
A pathogen is an agent that is
a.
 beneficial to humans.
b.
 harmful only to plants.
c.
 harmful to living organisms.
d.
 nearly extinct.
 22.
Which of the following foods is not a fermentation product of bacteria?
a.
 sour cream
c.
 milk
b.
 a pickle
d.
 yogurt
 23.
Antibiotics
a.
 include penicillin and tetracycline.
b.
 may prevent bacteria from making new cell walls.
c.
 can be effective treatments for bacterial diseases.
d.
 All of the above
 24.
All of the following are habitats of archaea except
a.
 volcanic vents.
b.
 intestinal tract of cows.
c.
 salt lakes.
d.
 human skin.
 25.
Which of the following is not a way of preventing a foodborne illness at home?
a.
 washing kitchen utensils thoroughly in cold water
b.
 keeping cooked and raw foods separate during storage
c.
 washing fresh fruits and vegetables before eating them
d.
 refrigerating leftovers promptly
 

Completion
Complete each statement.
 26.
A spiral bacterium is called a(n) ____________________.
 27.
Spherical bacteria are called ____________________.
 28.
Rod-shaped bacteria are called ____________________.
 29.
The procedure used to distinguish between two types of bacterial cell wall composition is called ____________________.
 30.
Protective structures that some bacteria may form under harsh conditions are ____________________.
 31.
The cell walls of bacteria are composed of a combination of polysaccharide and polypeptide called ____________________.
 32.
Bacteria that obtain their energy from inorganic molecules, rather than from the sun, are called ____________________ bacteria.
 33.
In general, organisms that obtain their energy from sunlight are called ____________________.
 34.
Bacteria that get carbon from other organisms are called ____________________.
 35.
A(n) ____________________ is a substance that can be obtained from bacteria or fungi and can be used as a drug to fight pathogenic bacteria.
 36.
Many bacteria are ____________________ and must have oxygen to live, whereas other bacteria are ____________________ and cannot live where oxygen is present.
 37.
Bacteria that can survive either with or without oxygen are called _________________________.
 38.
Archaea are more closely related to ____________________ than they are to ____________________.
 39.
____________________ are poisons that can cause disease when bacteria secrete them into their environment.
 40.
The evolution of populations of pathogenic bacteria that antibiotics cannot kill is called _________________________.

 
Check Your Work     Start Over

Virus Model Instructions

Virus Models

Use viral pictures from your textbook or from a website to construct a 3-dimensional model of a virus. Your model must meet the following criteria:

  • Must be 3-dimensional
  • Must show the two main parts of the virus — nucleic acid core & protein coat or capsid
  • Model must have string attached & be ready to hang
  • Must include a label with your the name of the virus, your name, & class period

The following rules for constructing you model must also be followed:

  • Must be light enough & small enough to hang and not “bump” other students heads
  • Must be sturdy (use plenty of glue & securely attach your string)
  • Can’t be made out of food products
  • May not have sharp points (no toothpicks)
  • May not be made of anything flammable (no matches)
  • Should be made of inexpensive materials

Types of viruses that make good models:

 

Bacteriophage

 
Retrovirus

 
HIV Organisation of the HIV-1 Virion

 
Rabies

 
Tobacco Mosaic Virus

 
Adenovirus

 

 

Models will be graded based on the following:

  • Level of difficulty (will receive the most weight in grading)
  • Accuracy
  • Colorfulness
  • Creativity of building materials
Back

 

Virus

 

Viruses
All Materials © Cmassengale

Discovery of Viruses

  • Beijerinck (1897) coined the Latin name “virus”  meaning poison for  the substance infecting tobacco plants
  • Wendell Stanley (1935) crystallized sap from tobacco leaves infected with Tobacco Mosaic Virus (TMV) & found virus was made of nucleic acid & protein

 

Wendell Stanley Tobacco Leaf with Virus

 

  • Edward Jenner developed smallpox vaccine using milder cowpox viruses
  • Virology – study of viruses
  • Deadly viruses are said to be virulent
  • Viruses couldn’t be seen until electron microscope invented

Viral Characteristics

  • Not living organisms
  • Noncellular
  • Consist of a nucleic acid core (DNA or RNA) and a protein coat called the capsid
  • Capsid made of protein subunits called capsomeres
  • Cannot grow or replicate on their own (inactive particles)

 

 

  • Can only reproduce inside of a living host cell using its raw materials & enzymes
  • Lack ribosomes & enzymes needed for protein synthesis or metabolism
  • Are extremely small particles ranging from 20 – 400 nanometers on average
  • Largest virus is 1000 nanometers in dimension
  • Some can cause disease (smallpox, measles, mononucleosis, influenza, colds, AIDS, Ebola

Ebola Picture
Ebola Virus

  • Some may also cause cancers such as leukemias
  • Virus free cells are rare
  • Highly host specific (only infect certain cells)
  • Referred to as phages
  • Viruses are classified into 2 main groups by their nucleic acid — DNA or RNA Viruses
  •  DNA & RNA viruses are subdivided by capsid shape & whether they do or don’t have an envelope

Viral Structure

  • DNA or RNA core surrounded by protein sheath called capsid
  • Nucleocapsid  includes the viral nucleic acid & its capsid
  • Some form lipid rich covering around capsid called the envelope
  • Envelope usually formed from host cell membrane
  • Envelope may have spikes to help chemically recognize & attach to the host cell
  • Shaped determined by the arrangement of proteins making up the capsid
  • TMV is rod shaped

  • Adenovirus & polio viruses are icosohedral (20 sided)

Virus Structure

  • Measles & rabies viruses are helical
  • T -phages have a head & tail

Bacteriophage Structure

Bacteriophages or T-Phages

  • Among the most complex viruses
  • Attack bacterial cells
  • Composed of a icosohedral head, tail, base plate, & tail fibers
  • Long DNA molecule is inside the head 
  • Tail helps inject the viral DNA into host cell
  • Tail fibers used to attach to host

Retroviruses

  • Contain RNA
  • Have an enzyme called reverse transcriptase which helps use the RNA to make DNA
  • Use the host cell’s ribosomes & raw materials to make viral proteins
  • Cause some cancers & AIDS


HIV Virus

Viroids

  • Smallest particle able to replicate
  • Made of a short, single strand of RNA with no capsid
  • Cause disease in plants


Viroid Attack on Potatoes

Prions

  • No nucleic acid or capsids
  • Made of protein particles that have folded incorrectly
  • Attacks the central nervous system
  • Cause animal diseases in cows (Mad Cow disease), sheep, & humans

Lytic Cycle

  • Viral replication that rapidly kills the host cell causing it to lyse or burst
  • Involves 5 steps —– Adsorption, Injection, Replication, Assembly, & Lysis
  • Adsorption — phage attaches to cell membrane of host
  • Injection — nucleic acid (DNA) of virus injected into host cell
  • Replication — viral DNA inactivates host cell’s DNA & uses host’s raw materials & ribosomes to make viral DNA, capsids, tails, etc.
  • Assembly — new viral parts are combined to make new phages
  • Lysis — enzymes weaken & destroy the cell membrane causing it to lyse releasing new viruses that infect other cells

 

Phases of the Lytic Cycle of a Virulent Virus:

  • Absorption:
    1. Virus attaches itself to the cell.
  • Entry:
    1. Enzymes weaken the cell wall and nucleic acid is injected into the cell, leaving the empty caspid outside the cell. Many viruses actually enter the host cell intact.
  • Replication:
    1. Viral DNA takes control of cell activity.
  • Assembly:
    1. All metabolic activity of the cell is directed to assemble new viruses.
  • Release:
    1. Enzymes disintegrate the cell in a process called

lysis

    , releasing the new

 

 


Source: http://science.howstuffworks.com/virus-human.htm

Lysogenic Cycle

  • Replication in which the virus stays inactive inside of the host cell & doesn’t immediately kill it
  • Viruses are called temperate phages
  • Lysogenic steps include adsorption, injection, recombination, cell reproduction, activation, replication, assembly, & lysis
  • Recombination —Viral DNA joins with host cell DNA forming an inactive prophage
  • Host cell reproduces  normally until activated by an external stimuli 
  • External stimuli unknown, but could be ultraviolet radiation, carcinogens, etc.
  • Once activated, prophage forms new viruses & destroys host cell
  • HIV is an example of a temperate phage

 

The Lysogenic Cycle of a Temperate Virus:

  • The virus attaches itself and injects its DNA into the cell.
  • The viral DNA attaches itself to the host DNA, becoming a new set of cell genes called a prophage.
  • When the host cell divides, this new gene is replicated and passed to new cells. This causes no harm to the cell, but may alter its traits.
  • Now there are two possibilities:
    • The prophage survives as a permanent part of the DNA of the host organism.
    • Some external stimuli can cause the prophage to become active, using the cell to produce new viruses.

 

 

 


Source: http://science.howstuffworks.com/virus-human.htm

Viral Control

  • Interferon are proteins made by cells to fight viruses
  • Two types of viral vaccines exist — inactivated & attenuated
  • Inactivated virus vaccines don’t replicate in the host’s system
  • Attenuated viral vaccines have been genetically altered so they can’t cause disease
  • Antiviral drugs (AZT, acyclovir, & azidothymidine) interfere with viral DNA synthesis
  • Protease Inhibitors interfere with viral capsid production
  • New viruses emerge as rain forests are cleared (Ebola virus)
Back

Virus PPT Questions

Viruses, Viroids, & Prions
ppt Questions

Living or Nonliving?

1. Why might some people consider viruses alive?

 

2. Can viruses be “killed”?

3. Can a virus maintain homeostasis like cells?

4. Are viruses cellular or noncellular?

 

5. Define virus.

 

6. Name the 2 main things that make up a virus.

Viral History

7. Who coined the term virus and what does it mean?

8. Explain how viruses were first discovered.

 

9. What discovery did Wendell Stanley make about viruses? What type of virus was he studying?

 

10. __________ is an example of a viral disease.

11. Who found the vaccine against this viral disease? What milder virus was used to make the vaccine?

12. What is meant by a virulent virus?

13. Smallpox has been ________________ in the world today. What does this mean?

 

14. How does the size of a virus compare with that of a cell?

15. What metric units are used to measure the size of viruses?

16. What technology had to be developed before viruses can be seen?

17. Give the size of these viruses.

     a. bacteriophage

     b. polio virus

     c. adenovirus

     d. Ebola virus

Viral Structure 

18. Are viruses made of cells? Are they living?

19. What covers the outside of a virus and what is it called?

20. What is in the core of a virus?

21. When & how can a virus reproduce?

22. What protective covering is around the capsid of some viruses?

23. What is the purpose of spikes and do all viruses have them?

 

24. Viruses only attack ___________ host cells.

25. Sketch and label the parts of a virus.

 

 

 

26. Describe the capsid of viruses.

 

27. What are capsomeres?

28. Are all viruses the same shape?

29. Outside of a host cell, viruses are ______________.

30. Do viruses have ribosomes like cells?

31. Do viruses have enzymes like cells?

 

32. Viruses use the _________ __________ and ____________ of its host cell to be able to ________________.

33. Does the HIV virus have spikes for attachment?

34. Besides smallpox and AIDS, name 6 other viral diseases.

 

35. Name a type of cancer thought to be caused by viruses.

36. What is the shape of each of these viruses:

     a. ebola?

     b. influenza?

37. Label the parts of these viruses.

 

 

Taxonomy of Viruses 

38. Family names for viruses end in what suffix?

39. Genus names for viruses end in ___________.

40.What is meant by a viral species?

 

41. ____________ names are used for different species of viruses.

42. How is the subspecies for a virus designated?

43. Give the family, genus, and species for the HIV and Herpes viruses.

 

 

44. What virus causes blisters that may appear around the mouth?

45. What virus is responsible for the common cold?

46. What virus causes warts?

47. Name 4 things used to identify viruses.

     a.

     b.

     c.

     d.

Bacteriophages

48. What is a bacteriophage?

49. Give 3 characteristics of T-phages.

     a.

     b.

     c.

50. What are the most commonly studied T-phages?

51. T-phages often attack what bacterial cell? Where is the host cell found?

 

52. How does a bacteriophage attach to its host cell?

 

53. What is the only part of the virus that actually enters the host cell?

54. What is the shape of the bacterial host cell that bacteriophages attack?

55. How many sides does the head or capsid of a bacteriophage have? 

56. T-bacteriophages have what nucleic acid at their core?

57. What are the head and tail fibers made of?

Retroviruses

58. What nucleic acid do retroviruses contain?

59. What enzyme do retroviruses contain that let them make DNA from RNA?

60. What 2 things do retroviruses inject into their host cells when they attack them?

61. Give an example of a retrovirus.

Viroids and Prions

62. What is a viroid? 

64. What is the host for viroids?

65. Viroids are responsible for causing what major problem in Europe?

66. Viroids resemble ____________ pieces of DNA that are cut out because they do not code for any proteins.

67. Prions are infectious pieces of _____________.

68. Describe how prions occur.

 

69. Do prions have a nucleic acid core?

70. What protein is responsible for most mammalian prion diseases?

71. What happens when prions get into the brain?

 

72. What does BSE stand for and what is the common name for this prion disease?

 

73. Explain the prion disease caused kuru.

 

Viral Replication

74. Viruses are host specific. What does this mean?

 

75. Do the viruses that attack most animals also attack most humans?

76. What is the envelope of viruses often made from? What is the function of an envelope?

 

77. List the 5 steps of the Lytic cycle in viruses.

     (1)

     (2)

     (3)

     (4)

     (5)

78. What structures help a virus attach to a host cell?

79. What does the virus inject into its host?

80. What viral parts are made inside a cell? where do the raw materials come from?

 

81. What is meant by cell lyses?

82. Place these steps of the lytic cycle in order: maturation, penetration, release, biosynthesis, and attachment.

 

83. Label the stages of the lytic cycle. Also label the capsid, host cell, and DNA.

 

84. What are latent viruses?

85. How long can a latent virus remain inactive?

86. what activates latent viruses?

87. Give 2 examples of latent viruses.

88. During the lysogenic cycle of a virus, what happens to the viral nucleic acid after it is injected into the host cell?

 

89. What is a prophage?

 

90. What causes the phage or viral DNA to start replicating?

 

91. Does the prophage start replicating right after it is injected into the host cell? Explain.

 

92. Viral DNA along with the host cell DNA is replicated during each ___________ ___________.

93. After a long period of time, __________ cells form that contain ________________.

94. Once a prophage cell is activated, what happens?

 

95. Once a prophage is active, the host cell is ______________ making the virus deadly or _______________.

96. Label the viral DNA, host DNA, prophage, bacteriophage, host cell, lytic cycle, and lysogenic cycle.

 

97. Give an example of a virus that remains dormant in the nervous system tissues for many years.

98. This virus may reappear later in life as a disease called ___________. Describe the disease.

 

99. ___________ infections also remain dormant in the nervous system.

100. How long does a herpes infection last?

101. Genital herpes is called Herpes ______________, while cold sores or fever blisters are known as Herpes ______________.

102. Viruses make us sick because they ___________ healthy host cells.

Treatment for Viral Disease

103. What is an attenuated virus?

 

104. How are viruses attenuated?

105. How are some viral vaccines made?

 

106. How does an attenuated virus help protect us from disease?

 

107. What proteins do our cells make to help protect us from viruses?

108. What is AZT?

109. How do protease inhibitors work to stop viruses?