BIO 215 Exam 2 Review UPDATED
ACTUAL Exam Questions and CORRECT
Answers
T/F: Viruses can only infect a few types of cells. - CORRECT ANSWER - False, they can
infect every type of cell, including bacteria, algae, fungi, protozoa, plants, and animals
How many viruses per milliliter can seawater contain? - CORRECT ANSWER - 10
million
Who proposed the term virus for the "living thing" smaller than bacteria that he hypothesized
caused rabies? - CORRECT ANSWER - Louis Pasteur
What is virus latin for? - CORRECT ANSWER - poison
Who showed that a disease in tobacco was caused by a virus? - CORRECT ANSWER -
Ivanovski and Beijerinck
Who discovered an animal virus that causes foot-and-mouth disease in cattle? - CORRECT
ANSWER - Loeffler and Frosch
What did those early researchers find when they passed fluid from host organisms through
porcelain filters designed to trap bacteria? What did this prove? - CORRECT ANSWER -
The filtrate remained infectious; proved that an infection could be caused by a fluid containing
agents smaller than bacteria
What are the two sides of the viral debate? - CORRECT ANSWER - 1: Viruses are not
living things, but rather infectious molecules, because they cannot multiply independently from
host cell.
2: Even though viruses do not exhibit most of the life processes of cells, they can direct them, so
they're more than inert and lifeless
,Vital role of viruses in Evolution - CORRECT ANSWER - Infect cells and influence their
genetic makeup
Shape the way cells, tissues, bacteria, plants, and animals have evolved
8% of the human genome consists of sequences that come from viruses
10 - 20% of bacterial DNA contains viral sequences
Obligate intracellular parasites - CORRECT ANSWER - cannot multiply unless they
invade a specific host cell and instruct its genetic and metabolic machinery to make and release
new viruses
7 properties of viruses - CORRECT ANSWER - 1. obligate intracellular parasites
2. ubiquitous in nature
3. ultramicroscopic in size
4. not cells
5. don't independently fulfill characteristics of life
6. nucleic acid can be DNA or RNA
7. lack enzymes for most metabolic processes
Estimate for number of virus particle on earth - CORRECT ANSWER - 10³¹
Range of size of viruses - CORRECT ANSWER - 20 nm to 1000nm in diameter
Basic structure of virus - CORRECT ANSWER - protein shell (capsid) surrounding
nucleic acid core
What gives viruses high specificity for attachment to host cell - CORRECT ANSWER -
molecules on virus surfaces
,How do viruses multiply? - CORRECT ANSWER - by taking control of host cell's genetic
material and regulating the synthesis and assembly of new viruses
T/F: viruses can synthesize proteins - CORRECT ANSWER - False, they lack the
machinery to do so
How did animal viruses used to be classified? - CORRECT ANSWER - On the basis of
their hosts and diseases they caused
What do newer classification systems emphasize? - CORRECT ANSWER - -hosts and
diseases they cause
-structure
-chemical composition
-similarities in genetic makeup
International committee on the taxonomy of viruses - CORRECT ANSWER - 8 orders and
38 families (another 84 families not yet assigned to any order)
Which of the following best describes viruses?
A. Heterotrophic
B. Saprobic
C. Obligate intracellular parasites
D. Chemoautotrophic
E. Photosynthetic - CORRECT ANSWER - C. Obligate intracellular parasites
What are the smallest infectious agents? - CORRECT ANSWER - viruses
What are the smallest viruses? - CORRECT ANSWER - parvoviruses (around 20 nm in
diameter)
, What are the largest viruses? - CORRECT ANSWER - herpes simplex virus (around 150
nm in length)
T/F: Longer viruses (800 nm) can be seen without an electron microscope. - CORRECT
ANSWER - False. They are cylindrical viruses with a narrow diameter (15nm)
T/F: Viruses somewhat resemble cells and have some of the protein-synthesizing machinery
found in cells. - CORRECT ANSWER - False. Viruses bear no resemblance to cells and
lack any of the protein-synthesizing machinery found in cells.
What gives rise to the crystalline appearance of viruses? - CORRECT ANSWER - Viral
structure is composed of regular, repeating subunits.
Viral structure contains only those parts needed to what? What are these parts? - CORRECT
ANSWER - Invade and control a host cell. External coating, core containing one or more
nucleic acid strains of DNA or RNA, sometimes one or two enzymes
Capsid - CORRECT ANSWER - -protein shell that surrounds the nucleic acid
-most prominent feature of viruses
-constructed from identical protein subunits called capsomeres
How do capsomeres form capsid? - CORRECT ANSWER - spontaneously self-assemble
into the finished capsid
Two types of capsids - CORRECT ANSWER - helical and icosahedral
Helical capsids - CORRECT ANSWER - have rod- shaped capsomers that bond together
to form a series of hollow discs resembling a bracelet. during the formation of the nucleocapsid,
these discs link with the other discs to form a continuous helix into which the nucleic acid strand
is coiled
ACTUAL Exam Questions and CORRECT
Answers
T/F: Viruses can only infect a few types of cells. - CORRECT ANSWER - False, they can
infect every type of cell, including bacteria, algae, fungi, protozoa, plants, and animals
How many viruses per milliliter can seawater contain? - CORRECT ANSWER - 10
million
Who proposed the term virus for the "living thing" smaller than bacteria that he hypothesized
caused rabies? - CORRECT ANSWER - Louis Pasteur
What is virus latin for? - CORRECT ANSWER - poison
Who showed that a disease in tobacco was caused by a virus? - CORRECT ANSWER -
Ivanovski and Beijerinck
Who discovered an animal virus that causes foot-and-mouth disease in cattle? - CORRECT
ANSWER - Loeffler and Frosch
What did those early researchers find when they passed fluid from host organisms through
porcelain filters designed to trap bacteria? What did this prove? - CORRECT ANSWER -
The filtrate remained infectious; proved that an infection could be caused by a fluid containing
agents smaller than bacteria
What are the two sides of the viral debate? - CORRECT ANSWER - 1: Viruses are not
living things, but rather infectious molecules, because they cannot multiply independently from
host cell.
2: Even though viruses do not exhibit most of the life processes of cells, they can direct them, so
they're more than inert and lifeless
,Vital role of viruses in Evolution - CORRECT ANSWER - Infect cells and influence their
genetic makeup
Shape the way cells, tissues, bacteria, plants, and animals have evolved
8% of the human genome consists of sequences that come from viruses
10 - 20% of bacterial DNA contains viral sequences
Obligate intracellular parasites - CORRECT ANSWER - cannot multiply unless they
invade a specific host cell and instruct its genetic and metabolic machinery to make and release
new viruses
7 properties of viruses - CORRECT ANSWER - 1. obligate intracellular parasites
2. ubiquitous in nature
3. ultramicroscopic in size
4. not cells
5. don't independently fulfill characteristics of life
6. nucleic acid can be DNA or RNA
7. lack enzymes for most metabolic processes
Estimate for number of virus particle on earth - CORRECT ANSWER - 10³¹
Range of size of viruses - CORRECT ANSWER - 20 nm to 1000nm in diameter
Basic structure of virus - CORRECT ANSWER - protein shell (capsid) surrounding
nucleic acid core
What gives viruses high specificity for attachment to host cell - CORRECT ANSWER -
molecules on virus surfaces
,How do viruses multiply? - CORRECT ANSWER - by taking control of host cell's genetic
material and regulating the synthesis and assembly of new viruses
T/F: viruses can synthesize proteins - CORRECT ANSWER - False, they lack the
machinery to do so
How did animal viruses used to be classified? - CORRECT ANSWER - On the basis of
their hosts and diseases they caused
What do newer classification systems emphasize? - CORRECT ANSWER - -hosts and
diseases they cause
-structure
-chemical composition
-similarities in genetic makeup
International committee on the taxonomy of viruses - CORRECT ANSWER - 8 orders and
38 families (another 84 families not yet assigned to any order)
Which of the following best describes viruses?
A. Heterotrophic
B. Saprobic
C. Obligate intracellular parasites
D. Chemoautotrophic
E. Photosynthetic - CORRECT ANSWER - C. Obligate intracellular parasites
What are the smallest infectious agents? - CORRECT ANSWER - viruses
What are the smallest viruses? - CORRECT ANSWER - parvoviruses (around 20 nm in
diameter)
, What are the largest viruses? - CORRECT ANSWER - herpes simplex virus (around 150
nm in length)
T/F: Longer viruses (800 nm) can be seen without an electron microscope. - CORRECT
ANSWER - False. They are cylindrical viruses with a narrow diameter (15nm)
T/F: Viruses somewhat resemble cells and have some of the protein-synthesizing machinery
found in cells. - CORRECT ANSWER - False. Viruses bear no resemblance to cells and
lack any of the protein-synthesizing machinery found in cells.
What gives rise to the crystalline appearance of viruses? - CORRECT ANSWER - Viral
structure is composed of regular, repeating subunits.
Viral structure contains only those parts needed to what? What are these parts? - CORRECT
ANSWER - Invade and control a host cell. External coating, core containing one or more
nucleic acid strains of DNA or RNA, sometimes one or two enzymes
Capsid - CORRECT ANSWER - -protein shell that surrounds the nucleic acid
-most prominent feature of viruses
-constructed from identical protein subunits called capsomeres
How do capsomeres form capsid? - CORRECT ANSWER - spontaneously self-assemble
into the finished capsid
Two types of capsids - CORRECT ANSWER - helical and icosahedral
Helical capsids - CORRECT ANSWER - have rod- shaped capsomers that bond together
to form a series of hollow discs resembling a bracelet. during the formation of the nucleocapsid,
these discs link with the other discs to form a continuous helix into which the nucleic acid strand
is coiled
