Practice Questions (Multiple Choice) Flashcards
Please choose the correct answer regarding viruses:
A.Viruses belong to the microbial kingdom; however, they form separate domain of life that is distinct from Bacteria, Archaea and Eukaryotes.
B. Viruses belong to the infectious agents that have no kingdom membership; however, viruses contain genetic information (DNA or RNA) surrounded by a protein coat termed a capsid.
C. One of viral characteristics is that its microcellular structure established a parasitic mode of life.
D. Correct are A and C
E. Correct are B and C
B
Q2. Which hypothesis suggests that viruses evolved from replicative elements preceding early life forms?
A. The ‘virus early’ hypothesis
B. The ‘regression’ hypothesis
C. The ‘escaped genes’ hypothesis
D. The ‘viral ancestor’ hypothesis
A
Q3. Why do viruses have no kingdom membership?
A. They are too small to be classified.
B. They lack genetic material.
C. They do not belong to any cellular organism.
D. They have characteristics of both plants and animals.
C
Q4. Chose correct answer regarding viral envelopes:
A. Viral envelope is rigid membranous layer that is coded by viral genome.
B. Viral envelopes are flexible membranous structures that originate from the host cell in animal viruses.
C. Viral envelopes are used as viral ID; they can have enzymatic activities and play the role in viral nucleic acid replication.
D. Correct are B and C
E. All the above
D
Q5. How do viruses reproduce?
A. Through binary fission
B. By meiosis
C. By invading a host cell and taking over its machinery.
D. Through mitosis
C
What is NOT correct about viral genome and replication?
A.Viruses have variety of shapes and symmetries (Helical, Icosahedral. Complex symmetry); however, they can ONLY have DNA as genetic information storage.
B. Nucleic acid inside of viral capsid can be DNA (single stranded or double stranded) or RNA (single stranded or double stranded); however, most viruses contain RNA as genetic information storage.
C. In DNA viruses, the nucleic acid is linear, with some exceptions of circular double stranded DNA
D. Incorrect are B and C
E. All the above is incorrect.
A
Q7. Chose the correct answer regarding viral replication:
A.The viral nucleic acid and proteins copies are manufactured by the cell’s machinery; A virus cannot reproduce by itself, it must invade a host cell and take over the cell activities, eventually causing destruction of the cell and killing it.
B. During lytic infection, the viral DNA gets integrated with the host cell DNA where it gets copied with the host cell DNA.
C. During lysogenic infection, a virus enters the host cell, makes a copy of itself, and causes the cell to burst, or lyse.
D. Viruses cannot survive out of host cell at all. As soon as a virus gets in contact with water and hard surface, it will burst and die.
E. A cold virus cannot survive on indoor surfaces while flu viruses can survive in the air for several hours, especially at lower temperatures; enteric viruses, viruses that affect our gut microbiome can survive for weeks on a surface if conditions are suitable.
A
How do enveloped viruses obtain their envelope?
A. They produce it using their own machinery.
B. It is inherited from the host cell.
C. It forms during viral replication.
D. They steal it from other viruses.
B
Which method is NOT used for penetration or viral entry?
A. Fusion of the viral envelope with host membrane
B. Endocytosis in vesicle
C. Injection of nucleic acid
D. Encapsulation in a protein coat
D
Which organelles in eukaryotic cells are thought to be derived from bacteria and have their own DNA?
A. Nucleus and Golgi apparatus
B. Mitochondria and chloroplasts
C. Endoplasmic reticulum and lysosomes
D. Ribosomes and peroxisomes
B
Which group of protists is correctly matched with its characteristics?
a. Euglenozoans - contain hydrogenosomes.
b. Alveolates - form red tides in unpolluted coastal zones
c. Stramenopiles - exclusively marine and form shell-like structures
d. Diplomonads - have a single large mitochondrion and feed on bacteria via phagocytosis
b
What is the primary role of diatoms among the stramenopiles?
A. Cause malaria in humans
B. Form red tides in polluted coastal zones
C. Major components of planktonic microbial communities
D. Form shell-like structures exclusively in marine environments
C
. Chose the correct answer regarding primary and secondary endosymbiotic theory:
A. Primary endosymbiosis gave rise to the chloroplast in the common ancestor of green algae, red algae, and plants.
B. Cells of green and red algae were engulfed, and their chloroplasts were stably retained (new cells become phototrophic).
C. New phototrophic cells of euglenids and chlorarachniophytes is the result of secondary endosymbiosis in green algae.
D. Correct are A and B
E. All the above is correct (A, B, and C).
E
Chose correct answer regarding Euglenozoans:
A. Euglenozoans are divided into two groups, kinetoplastids and euglenids; euglenids are characterized by large mass of DNA in single large mitochondrion.
B. Euglenozoans are divided into two groups, kinetoplastids and euglenids; euglenids are characterized by two flagella, chloroplasts, and phagocytosis of bacterial cells.
C. Euglenozoans are divided into two groups, kinetoplastids and euglenids; kinetoplastids are characterized by large mass of DNA in single large mitochondrion.
D. Correct are B and C
E. None of the above
D
According to the RNA world theory, which molecule catalyzed the formation of first simple peptides?
a) Proteins
b) RNA
c) Lipids
d) DNA
e) Both, RNA and DNA
b