Viruses, Bacteria and Fungi

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INTERACTIVE MULTIPLE CHOICE QUESTIONS
Viruses, Bacteria and Fungi
The answers are provided. Explanations of why the
alternatives are unsatisfactory are also offered
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These multiple choice questions are similar to
the ones set by the GCSE and IGCSE Examination
Boards except that, in some cases, there may be
more than one acceptable answer.
For this reason, even if you select a correct
answer at your first attempt, it is worth looking
at all the alternatives
(a) to see if there is a better answer and
(b) to
see why some of the alternatives are unacceptable.
First slide
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Question 1
Which of the following are characteristics of a
virus?
(a) Respiration
(b) Growth
(c) Excretion
(d) Reproduction
Question 2
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No
Viruses do not respire
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No
Viruses do not grow but they do reassemble
themselves in the hosts cell
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No
Viruses do not excrete
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Yes
Viruses do reproduce inside the hosts cell.
Their DNA (or RNA) replicates and they assemble
new protein coats using the hosts resources
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Question 2
Viruses can reproduce only
(a) at certain temperatures
(b) inside a living cell
(c) in dry conditions
(d) inside bacteria
Question 3
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No
Reproduction of viruses is not dependent on
temperature. They will produce at any temperature
which does not damage their hosts cells
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Yes
Viruses can reproduce only in the cells of their
host organism
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No
Unless the host is harmed by dry conditions, the
virus reproduces in the cytoplasm of the hosts
cells
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No
There are certain viruses, called bacteriophages,
which reproduce inside bacteria but this does not
apply to all viruses
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Question 3
Which of the following diseases is caused by a
virus?
(a) Influenza
(b) Tuberculosis
(c) Syphilis
(d) Sore throat
Question 4
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Yes
Influenza (flu) is caused by a virus
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No
Tuberculosis is caused by a bacterium,
Mycobacterium tuberculosis
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No
Syphilis is caused by a spirochaete bacterium,
Treponema pallidum
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No
Sore throat is caused by a Streptococcus
bacterium.
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Question 4
A bacterial cell differs from a plant cell by
having
(a) no cell wall
(b) no central vacuole
(c) no nuclear membrane
(d) no cytoplasm
Question 5
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No
A bacterial cell does have a cell wall but,
unlike a plant cell wall, it does not contain
cellulose
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Yes
A bacterial cell has no central vacuole
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Yes
A bacterial cell has no nuclear membrane
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No
A bacterial cell does have cytoplasm
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Question 5
Most bacteria can be killed by
(a) cooking
(b) refrigeration
(c) freezing
(d) canning
Question 6
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Yes (within limits)
If the temperature is high enough and the cooking
reasonably prolonged, the majority of bacteria
will be killed. There will
probably be a residual population of bacteria but
not in sufficient numbers to cause disease.
However, if the cooked
food is left at room temperature, this small
population will multiply rapidly
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No
Refrigeration at 4oC does not kill bacteria but
slows down their rate of reproduction so that the
food remains safe for longer periods
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No
Freezing at about minus 18oC stops bacteria from
reproducing but does not kill them
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Yes
Food is canned at high temperatures and pressures
to kill bacteria
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Question 6
Which of the following is a bacterium?
(a) Penicillium notatum
(b) Candida albicans
(c) Plasmodium vivax
(d) Salmonella typhimurium
Question 7
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No
Penicillium notatum is a mould fungus. It grows
on decaying fruit and other organic matter and is
the source of the antibiotic, Penicillin
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No
Candida albicans is a yeast-like fungus. It
causes a disease called thrush
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No
Plasmodium vivax is a protozoan parasite which
causes malaria
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Yes
Salmonella typhimurium is a bacterium which
causes one form of food poisoning
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Question 7
Which of the following diseases is caused by
bacteria?
(a) Tinea
(b) The common cold
(c) Typhoid fever
(d) Diabetes
Question 8
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No
Tinea is a skin infection caused by one of a
number of fungal parasites which cause
inflammation between the toes (athletes foot),
on the scalp or in the pubic region
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No
The common cold is caused by a virus, (a
rhinovirus).
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Yes
Typhoid fever is caused by a bacterium,
Salmonella typhi.
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No
Diabetes is not an infectious disease. It arises
as a result of either (a) a failure of the
pancreas to produce sufficient insulin or (b) an
inability of the body to use insulin effectively
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Question 8
A fungus is made up of
(a) hyphae
(b) cells
(c) cytoplasm
(d) chitin
Question 9
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Yes
Hyphae are the living, thread-like structures
which form a fungus
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No
Fungi are made up of hyphae which have a wall,
cytoplasm and nuclei like plant cells but are in
the form of long threads
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No
A fungus is made up of hyphae which do contain
cytoplasm, but the fungus is not made solely of
cytoplasm
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No
Chitin is a component of the hyphal wall but the
fungus is not made up of chitin
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Question 9
A
The drawing represents a mushroom partly in
section. Which of the following structures
represents the mycelium?
B
C
soil level
(a) A
(b) B
(c) C
D
(d) D
Question 10
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No
This is the cap of the mushroom
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No
These are the gills of the mushroom. They carry
the spores.
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No
This is the mushrooms stalk
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Yes
This network of hyphae constitutes a mycelium
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Question 10
Fungi have the potential to produce large numbers
of offspring by ...
(a) producing many seeds
(b) sexual reproduction
(c) producing fruits
(d) producing many spores
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No
Fungi do not produce seeds
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No
Fungi do have methods of sexual reproduction but
they do not result in the production of large
numbers of offspring
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No
Mushrooms, toadstools and bracket fungi are
sometimes called the fruiting bodies of the
fungus but this is a misleading term. These
structures produce spores.
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Yes
Fungi produce a huge number of single-celled,
microscopic spores. Each one can produce a
mycelium if it lands in a suitable place, but
only a tiny minority succeed. The giant puffball
produces trillions of spores which appear as a
brown dust cloud if you tread on it.
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End of questions
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