MGY378 Exam Questions And
Complete Solution
What does hepatitis cause - Answer Liver malfunction from cirrhosis
What are the 5 types of hepatitis? - Answer Hep A, B, C, D, E
What is a Pararetrovirus - Answer A non-retrovirus that that still uses reverse
transcription for replication
What are the two types of Hepadnaviruses? - Answer 1. Orthohepadnavirus
2. Avihepadnavirus (infects birds)
What are the 8 major genotypes of HBV - Answer A-H, where they differ in at least 8% of
their sequences
What are the four major serotypes of HBV? - Answer adr, adw, ayr, ayw based on
antigens presented on its envelope.
What does it mean to be HBV infected? - Answer To have HBV antigen in your blood.
How many times is the HBV vaccine administered, and what does it do? - Answer It's
administered 3 times at 0, 1 and 6 months.
Its 95% effective for protecting liver cancer and cirrhosis due to hepatitis B.
What does the HBV vaccine contain? - Answer HBsAg particles (The antigen of hepatitis
B.
Why should we vaccine newborns? - Answer They are not able to clear infection, hence
high risk of dying due to infection.
How can you transmit HBV? - Answer 1. Parenterally - saliva, razors, toothbrushes,
needles
2. Mother to child
3. Sexual contacts.
How long can HBV survive outside the body? - Answer 7 days since its a DNA virus
making it much more resistant.
What are the two types of HPV infection - Answer 1. Acute - 95% of adults will fully
recover in a couple of weeks. 30% of younger individuals will completely lose this. 5%
for newborns
2. Chronic - 5% of those that never recover completely. This causes increase risk or
,developing hepatocellular carcinoma. 20-30% of those that have chronic will develop
liver cancer.
What are the serologic markers for acute and chronic Hep B? - Answer 1. Acute - HBsAg
levels undetectable after 6 months, followed by presence of HB antibodies. ALT and
HBV DNA are also undetectable after a while.
2. Chronic - HBsAg, ALT, HBV DNA levels remain high and doesn't drop
What are symptoms of hepatitis B? - Answer Jaundice, dark urine, fatigue, abdominal
pain, cirrhosis.
What is HBV life cycle? - Answer 1. Infects cell and gets into the cytoplasm
2. Disintegration causes viral DNA to enter the nucleus
3. Viral DNA converted to cccDNA
4. cccDNA creates pgRNA
5. pgRNA create polymerase.
6. Polymerase creates primer for RT to generate negative strand and DNA synthesis for
positive strand
7. gets incapsulated by core protein in the ER
8. Goes through golgi to be released
What are the two HBV particles? - Answer 1. Infectious Dane Particles
2. Non-infectious rods/filaments/Sphere
What does the Dane particle contain? - Answer 1. L, M, S protein and HBsAg in the
bilayer
2. The positive strand has an RNA primer at the 5' end
3. The negative strand has a polymerase at the 5' end
What does the non-infectious particle contain? - Answer 1. In rods/filaments - they
contain L, M ,S proteins and HBsAg
2. In sphere they contain M, S proteins and HBsAg
3. They both contain no genome or polymerase.
What does the HBV genome look like? - Answer Its a rcDNA where the negative strand is
full length, and the positive strand is partial length.
This results in 15-50% of the negative strand DNA to be single stranded
, Replication cycle of HBV - Answer 1. Enters the cell as rcDNA and gets repaired to
cccDNA in the nucleus.
2. cccDNA creates pgRNA which then creates more rcDNA which can go back to the
nucleus to create more cccDNA for amplification or be released for further infection.
3. Release is depended on binding to hNTCP
How do we convert rcDNA to cccDNA? - Answer 1. DNA polymerase finishes the
positive strand
2. Nuclease removes the 5' ends of both strand (containing RNA primer and
Polymerase).
3. DNA ligase close the ends together making a cccDNA.
What are the 5 mRNAs in HBV? - Answer PreC, pregeome, PreS1, PreS2, X.
What are the 7 proteins in HBV and what mRNA codes them? - Answer 1. PreC mRNA - E
protein
2. pregenome mRNA - C and P proteins (serves as template for DNA synthesis)
3. preS1 mRNA - L surface protein
4. preS2 mRNA - M, S surface proteins
5. X mRNA - X protein
How are the mRNA transcribed? - Answer Through leaky scanning, so there is no
frame-shifting, stopping.
This allows the generation of small proteins.
What are the 5 genes of HBV? - Answer 1. S gene - encodes preS1, preS2, and S. preS1
is made then preS2. Contains receptor binding domains to allow for infection
2. E gene - encodes E protein which is a capsid protein with a signal peptide to direct to
ER.
3. C gene - encodes the core protein
4. P gene - encodes P proteins used for polymerase
5. X gene - encodes X proteins associated with transcription activation
How are the HBV transcripts created? - Answer They each have different promoters but
they end in the same position so they are all capped in the 5' end.
Leaky scanning allows for production of the proteins
Explain what the HBV surface proteins do. - Answer The amino terminus of L protein
Complete Solution
What does hepatitis cause - Answer Liver malfunction from cirrhosis
What are the 5 types of hepatitis? - Answer Hep A, B, C, D, E
What is a Pararetrovirus - Answer A non-retrovirus that that still uses reverse
transcription for replication
What are the two types of Hepadnaviruses? - Answer 1. Orthohepadnavirus
2. Avihepadnavirus (infects birds)
What are the 8 major genotypes of HBV - Answer A-H, where they differ in at least 8% of
their sequences
What are the four major serotypes of HBV? - Answer adr, adw, ayr, ayw based on
antigens presented on its envelope.
What does it mean to be HBV infected? - Answer To have HBV antigen in your blood.
How many times is the HBV vaccine administered, and what does it do? - Answer It's
administered 3 times at 0, 1 and 6 months.
Its 95% effective for protecting liver cancer and cirrhosis due to hepatitis B.
What does the HBV vaccine contain? - Answer HBsAg particles (The antigen of hepatitis
B.
Why should we vaccine newborns? - Answer They are not able to clear infection, hence
high risk of dying due to infection.
How can you transmit HBV? - Answer 1. Parenterally - saliva, razors, toothbrushes,
needles
2. Mother to child
3. Sexual contacts.
How long can HBV survive outside the body? - Answer 7 days since its a DNA virus
making it much more resistant.
What are the two types of HPV infection - Answer 1. Acute - 95% of adults will fully
recover in a couple of weeks. 30% of younger individuals will completely lose this. 5%
for newborns
2. Chronic - 5% of those that never recover completely. This causes increase risk or
,developing hepatocellular carcinoma. 20-30% of those that have chronic will develop
liver cancer.
What are the serologic markers for acute and chronic Hep B? - Answer 1. Acute - HBsAg
levels undetectable after 6 months, followed by presence of HB antibodies. ALT and
HBV DNA are also undetectable after a while.
2. Chronic - HBsAg, ALT, HBV DNA levels remain high and doesn't drop
What are symptoms of hepatitis B? - Answer Jaundice, dark urine, fatigue, abdominal
pain, cirrhosis.
What is HBV life cycle? - Answer 1. Infects cell and gets into the cytoplasm
2. Disintegration causes viral DNA to enter the nucleus
3. Viral DNA converted to cccDNA
4. cccDNA creates pgRNA
5. pgRNA create polymerase.
6. Polymerase creates primer for RT to generate negative strand and DNA synthesis for
positive strand
7. gets incapsulated by core protein in the ER
8. Goes through golgi to be released
What are the two HBV particles? - Answer 1. Infectious Dane Particles
2. Non-infectious rods/filaments/Sphere
What does the Dane particle contain? - Answer 1. L, M, S protein and HBsAg in the
bilayer
2. The positive strand has an RNA primer at the 5' end
3. The negative strand has a polymerase at the 5' end
What does the non-infectious particle contain? - Answer 1. In rods/filaments - they
contain L, M ,S proteins and HBsAg
2. In sphere they contain M, S proteins and HBsAg
3. They both contain no genome or polymerase.
What does the HBV genome look like? - Answer Its a rcDNA where the negative strand is
full length, and the positive strand is partial length.
This results in 15-50% of the negative strand DNA to be single stranded
, Replication cycle of HBV - Answer 1. Enters the cell as rcDNA and gets repaired to
cccDNA in the nucleus.
2. cccDNA creates pgRNA which then creates more rcDNA which can go back to the
nucleus to create more cccDNA for amplification or be released for further infection.
3. Release is depended on binding to hNTCP
How do we convert rcDNA to cccDNA? - Answer 1. DNA polymerase finishes the
positive strand
2. Nuclease removes the 5' ends of both strand (containing RNA primer and
Polymerase).
3. DNA ligase close the ends together making a cccDNA.
What are the 5 mRNAs in HBV? - Answer PreC, pregeome, PreS1, PreS2, X.
What are the 7 proteins in HBV and what mRNA codes them? - Answer 1. PreC mRNA - E
protein
2. pregenome mRNA - C and P proteins (serves as template for DNA synthesis)
3. preS1 mRNA - L surface protein
4. preS2 mRNA - M, S surface proteins
5. X mRNA - X protein
How are the mRNA transcribed? - Answer Through leaky scanning, so there is no
frame-shifting, stopping.
This allows the generation of small proteins.
What are the 5 genes of HBV? - Answer 1. S gene - encodes preS1, preS2, and S. preS1
is made then preS2. Contains receptor binding domains to allow for infection
2. E gene - encodes E protein which is a capsid protein with a signal peptide to direct to
ER.
3. C gene - encodes the core protein
4. P gene - encodes P proteins used for polymerase
5. X gene - encodes X proteins associated with transcription activation
How are the HBV transcripts created? - Answer They each have different promoters but
they end in the same position so they are all capped in the 5' end.
Leaky scanning allows for production of the proteins
Explain what the HBV surface proteins do. - Answer The amino terminus of L protein
