EBIO 1210 EXAM 4 QUESTIONS WITH CORRECT ANSWERS
1) What are the defining characteristics of viruses? -- Answer ✔✔ - Particles that
infect cells
- Nucleic acids with protein coats
- Obligate intracellular parasites
- Most have a well-defined host range
- Viruses are NOT considered to be living things.
2) What advantage can a virus gain by having an "envelope" derived from the host?
A) The virus can use the envelope to help in translation of its mRNA
B) The virus can use the envelope to hide from the host's immune system
C) The virus can use the envelope to make its own cells
D) The virus can use the envelope to send itself through the mail to new hosts
E) All of the above -- Answer ✔✔ B. The virus hides from the immune system
**Cannot be C because viruses don't have cells
3) How does a virus do its business? -- Answer ✔✔ 1. Virus enters the cell
2. Cell manufactures viral proteins and copies of virus's genome
3. Virus makes use of the host enzymes, ribosomes, tRNA, amino acids, ATP, etc.
4. Assembly of new viruses
5. New virus particles break out of the cell
4) Two key variables used to classify viruses that infect animals: -- Answer ✔✔ 1.
DNA or RNA?
2. Single or double stranded?
5) How do viruses make you sick? -- Answer ✔✔ 1. Damage or kill cells (with
enzymes)
, 2. Cause infected cells to produce toxins
3. Envelope proteins that are toxic
****However, most symptoms & damage come from your own immune system!!!
Apoptosis, inflammation, etc.
6) Why can't we take antibiotics to successfully cure ourselves of viral infections?
A) Viruses evolve resistance too quickly
B) Viruses use our own cellular machinery
C) Viruses are smarter than bacteria
D) Viruses get inside our cells
E) Viruses replicate too quickly -- Answer ✔✔ B. Viruses use our own cellular
machinery
7) Why are vaccines effective in preventing viral illnesses?
A) Vaccines are just like antibiotics
B) Vaccines teach your immune system how to recognize specific viruses
C) Vaccines make it impossible for a virus to enter your body
D) Vaccines change your cells so that no virus can enter them
E) Vaccines add "virus-fighting" genes to your genome -- Answer ✔✔ B.
Vaccines teach your immune system how to recognize specific viruses
8) Why don't all influenza A viruses readily jump back and forth between humans,
birds, pigs, dogs, etc.? -- Answer ✔✔ Most viruses are host specific; specializing to
infect one species can make a virus unable to infect another
9) How do different viruses get mixed up? -- Answer ✔✔ Reassortment: possible
when multiple virus types infect the same individual host and get into the same
cell.... think "viral sex"
10) What are vaccines? -- Answer ✔✔ Derivatives of pathogenic microbes that
stimulate the immune system to mount defenses against the actual microbe
11) A nucleotide consists of: -- Answer ✔✔ 1. A nitrogenous base
2. A sugar
3. A phosphate group
, 12) What are the three fundamental building blocks of DNA? -- Answer ✔✔ 1.
Nitrogenous base
2. 5-carbon sugar
3. Phosphate group
The sugar phosphate backbone is around the outside of a double stranded molecule
with nitrogenous bases in the middle
13) Name the 4 different nitrogenous bases: -- Answer ✔✔ 1. Thymine
2. Adenine
3. Cytosine
4. Guanine
Different sequences of the 4 possible nucleotides make up the different genetic
code of every living organism
14) What is Chargaff's Rule? -- Answer ✔✔ % Adenine = % Thymine
% Cytosine = % Guanine
15) Suppose that 22% of an organism's genome is the nucleotide guanine (G). What
else do you know about the organism?
A) Nothing
B) It must have 22% A
C) It must have 22% C, 22% T, 22%A, and 12% something else
D) It must have 22% C, 28% A, and 28% T
E) It must have 22% A, 28% C, and 28% T -- Answer ✔✔ D. 22% C, 28% A, and
28% T
16) The phosphate group in a single nucleotide is attached to the ____' carbon atom of
the sugar. -- Answer ✔✔ 5'
17) How do two strands of DNA form a double helix? -- Answer ✔✔ ****The strands
of DNA run in an antiparallel manner
- The phosphate group in a single nucleotide is attached to the 5' carbon atom
of the sugar
1) What are the defining characteristics of viruses? -- Answer ✔✔ - Particles that
infect cells
- Nucleic acids with protein coats
- Obligate intracellular parasites
- Most have a well-defined host range
- Viruses are NOT considered to be living things.
2) What advantage can a virus gain by having an "envelope" derived from the host?
A) The virus can use the envelope to help in translation of its mRNA
B) The virus can use the envelope to hide from the host's immune system
C) The virus can use the envelope to make its own cells
D) The virus can use the envelope to send itself through the mail to new hosts
E) All of the above -- Answer ✔✔ B. The virus hides from the immune system
**Cannot be C because viruses don't have cells
3) How does a virus do its business? -- Answer ✔✔ 1. Virus enters the cell
2. Cell manufactures viral proteins and copies of virus's genome
3. Virus makes use of the host enzymes, ribosomes, tRNA, amino acids, ATP, etc.
4. Assembly of new viruses
5. New virus particles break out of the cell
4) Two key variables used to classify viruses that infect animals: -- Answer ✔✔ 1.
DNA or RNA?
2. Single or double stranded?
5) How do viruses make you sick? -- Answer ✔✔ 1. Damage or kill cells (with
enzymes)
, 2. Cause infected cells to produce toxins
3. Envelope proteins that are toxic
****However, most symptoms & damage come from your own immune system!!!
Apoptosis, inflammation, etc.
6) Why can't we take antibiotics to successfully cure ourselves of viral infections?
A) Viruses evolve resistance too quickly
B) Viruses use our own cellular machinery
C) Viruses are smarter than bacteria
D) Viruses get inside our cells
E) Viruses replicate too quickly -- Answer ✔✔ B. Viruses use our own cellular
machinery
7) Why are vaccines effective in preventing viral illnesses?
A) Vaccines are just like antibiotics
B) Vaccines teach your immune system how to recognize specific viruses
C) Vaccines make it impossible for a virus to enter your body
D) Vaccines change your cells so that no virus can enter them
E) Vaccines add "virus-fighting" genes to your genome -- Answer ✔✔ B.
Vaccines teach your immune system how to recognize specific viruses
8) Why don't all influenza A viruses readily jump back and forth between humans,
birds, pigs, dogs, etc.? -- Answer ✔✔ Most viruses are host specific; specializing to
infect one species can make a virus unable to infect another
9) How do different viruses get mixed up? -- Answer ✔✔ Reassortment: possible
when multiple virus types infect the same individual host and get into the same
cell.... think "viral sex"
10) What are vaccines? -- Answer ✔✔ Derivatives of pathogenic microbes that
stimulate the immune system to mount defenses against the actual microbe
11) A nucleotide consists of: -- Answer ✔✔ 1. A nitrogenous base
2. A sugar
3. A phosphate group
, 12) What are the three fundamental building blocks of DNA? -- Answer ✔✔ 1.
Nitrogenous base
2. 5-carbon sugar
3. Phosphate group
The sugar phosphate backbone is around the outside of a double stranded molecule
with nitrogenous bases in the middle
13) Name the 4 different nitrogenous bases: -- Answer ✔✔ 1. Thymine
2. Adenine
3. Cytosine
4. Guanine
Different sequences of the 4 possible nucleotides make up the different genetic
code of every living organism
14) What is Chargaff's Rule? -- Answer ✔✔ % Adenine = % Thymine
% Cytosine = % Guanine
15) Suppose that 22% of an organism's genome is the nucleotide guanine (G). What
else do you know about the organism?
A) Nothing
B) It must have 22% A
C) It must have 22% C, 22% T, 22%A, and 12% something else
D) It must have 22% C, 28% A, and 28% T
E) It must have 22% A, 28% C, and 28% T -- Answer ✔✔ D. 22% C, 28% A, and
28% T
16) The phosphate group in a single nucleotide is attached to the ____' carbon atom of
the sugar. -- Answer ✔✔ 5'
17) How do two strands of DNA form a double helix? -- Answer ✔✔ ****The strands
of DNA run in an antiparallel manner
- The phosphate group in a single nucleotide is attached to the 5' carbon atom
of the sugar
