Category: Microorganisms

Bacteria Study Guide

%CODE1%

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

 

HIVOrganisation 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

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 StanleyTobacco 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?