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1.1 The study of life Read Online
Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.
Chapter 21: Viruses MCQ Multiple Choices Questions Quiz Test Bank
21.1 Viral Evolution, Morphology, and Classification
21.2 Virus Infections and Hosts
21.3 Prevention and Treatment of Viral Infections
21.4 Other Acellular Entities: Prions and Viroids
Question: Which statement is true of reverse transcriptase?
Choices:
It is a nucleic acid.
It infects cells.
It transcribes RNA to make DNA.
It is a lipid.
Question: Viruses_______.
Choices:
all have a round shape
cannot have a long shape
do not maintain any shape
vary in shape
Question: The viral ________ plays a role in attaching a virion to the host cell.
Choices:
core
capsid
envelope
both b and c
Question: Which statement is not true of viral replication?
Choices:
A lysogenic cycle kills the host cell.
There are six basic steps in the viral replication cycle.
Viral replication does not affect host cell function.
Newly released virions can infect adjacent cells.
Question: Which of the following is NOT used to treat active viral disease?
Choices:
vaccines
antiviral drugs
antibiotics
phage therapy
Question: Which statement is true?
Choices:
A virion contains DNA and RNA.
Viruses are acellular.
Viruses replicate outside of the cell.
Most viruses are easily visualized with a light microscope.
Question: Vaccines_______.
Choices:
are similar to viroids
are only needed once
kill viruses
stimulate an immune response
Question: Which is true of DNA viruses?
Choices:
They use the host cell's machinery to produce new copies of their genome.
They all have envelopes.
They are the only kind of viruses that can cause cancer.
They are not important plant pathogens.
Question: A bacteriophage can infect ________.
Choices:
the lungs
viruses
prions
bacteria
Question: Which statement is true of viral replication?
Choices:
In the process of apoptosis, the cell survives.
During attachment, the virus attaches at specific sites on the cell surface.
The viral capsid helps the host cell produce more copies of the viral genome.
mRNA works outside of the host cell to produce enzymes and proteins.
Question: Oncogenic virus cores can be_______.
Choices:
RNA
DNA
neither RNA nor DNA
either RNA or DNA
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