BIOLOGY 123 FINAL EXAM QUESTIONS
AND 100% VERIFIED CORRECT
ANSWERS!!!
How big are viruses compared to bacteria?
Viruses are 10-100 times smaller than bacteria, typically 20-300 nm in size. Bacteria are usually
0.2-2 µm (200-2000 nm).
What unit is used to measure viruses and how does it relate to micrometers?
Viruses are measured in nanometers (nm). 1000 nm = 1 micrometer (µm)
What type of microscope is required to observe viruses?
Electron microscopes—either Transmission Electron Microscope (TEM) or Scanning Electron
Microscope (SEM).
Why can't viruses be seen with a light microscope?
Because they are sub-microscopic—too small (20-300 nm) to be resolved by light microscopy.
hat type of microscope is commonly used to observe bacteria?
Light microscopes (compound microscopes), often with staining techniques.
What is the basic structure of a virus?
A virus consists of a protein capsid and genetic material (DNA or RNA), and sometimes an
envelope.
Are viruses considered living organisms?
No. Viruses are non-living; they cannot replicate or carry out metabolism without a host cell.
What are the major structural differences between viruses and other microbes like
bacteria?
Viruses lack cellular structures—no cytoplasm, membrane, or ribosomes—unlike bacteria, which
are full cells.
, How do viruses replicate?
They rely entirely on a host cell's machinery to replicate their genome and produce proteins.
hat are two types of electron microscopy used to study viruses?
Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).
What two macromolecules are viruses primarily made of?
Nucleic acids (DNA or RNA) and proteins.
hat is the capsid, and what is it made of?
protein shell that protects the viral genome. It is made of protein.
What is a nucleocapsid composed of?
the capsid (protein) and the viral genome (nucleic acid).
What is the viral genome made of?
nucleic acid, either DNA or RNA, and can be single- or double-stranded.
What is a viral envelope and what is it made of?
a lipid membrane surrounding some viruses, made of lipids from the host cell
membrane and viral proteins (like glycoproteins).
Which viral structure helps with host cell attachment?
Viral envelope proteins (especially glycoproteins)
What is the lytic cycle in bacteriophages?
A replication cycle where the phage destroys the host cell by lysing it to release new virus
particles.
What are the 5 steps of the lytic cycle?
Attachment
Entry
Replication & protein synthesis
AND 100% VERIFIED CORRECT
ANSWERS!!!
How big are viruses compared to bacteria?
Viruses are 10-100 times smaller than bacteria, typically 20-300 nm in size. Bacteria are usually
0.2-2 µm (200-2000 nm).
What unit is used to measure viruses and how does it relate to micrometers?
Viruses are measured in nanometers (nm). 1000 nm = 1 micrometer (µm)
What type of microscope is required to observe viruses?
Electron microscopes—either Transmission Electron Microscope (TEM) or Scanning Electron
Microscope (SEM).
Why can't viruses be seen with a light microscope?
Because they are sub-microscopic—too small (20-300 nm) to be resolved by light microscopy.
hat type of microscope is commonly used to observe bacteria?
Light microscopes (compound microscopes), often with staining techniques.
What is the basic structure of a virus?
A virus consists of a protein capsid and genetic material (DNA or RNA), and sometimes an
envelope.
Are viruses considered living organisms?
No. Viruses are non-living; they cannot replicate or carry out metabolism without a host cell.
What are the major structural differences between viruses and other microbes like
bacteria?
Viruses lack cellular structures—no cytoplasm, membrane, or ribosomes—unlike bacteria, which
are full cells.
, How do viruses replicate?
They rely entirely on a host cell's machinery to replicate their genome and produce proteins.
hat are two types of electron microscopy used to study viruses?
Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).
What two macromolecules are viruses primarily made of?
Nucleic acids (DNA or RNA) and proteins.
hat is the capsid, and what is it made of?
protein shell that protects the viral genome. It is made of protein.
What is a nucleocapsid composed of?
the capsid (protein) and the viral genome (nucleic acid).
What is the viral genome made of?
nucleic acid, either DNA or RNA, and can be single- or double-stranded.
What is a viral envelope and what is it made of?
a lipid membrane surrounding some viruses, made of lipids from the host cell
membrane and viral proteins (like glycoproteins).
Which viral structure helps with host cell attachment?
Viral envelope proteins (especially glycoproteins)
What is the lytic cycle in bacteriophages?
A replication cycle where the phage destroys the host cell by lysing it to release new virus
particles.
What are the 5 steps of the lytic cycle?
Attachment
Entry
Replication & protein synthesis
