BIOC20 LECTURE 6 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED
How much of the genome does gene 1 occupy in CoV? What does it translate
into?
2/3, precursor polyproteins.
What does the other 1/3 of the genome consist of?
Structural, non-structural and packaging proteins.
Name the proteins of CoV.
HE: hemagglutinin estrase.
S: Spike
E: small envelope protein.
M: membrane protein.
N: nucleocapsid protein.
What is the structure of CoV?
Enveloped with helical nucleocapsids, +ssRNA.
What does S protein get cleaved to and what do they do?
S1: initiates attachment and contains the receptor binding domain.
S2: forms the stalk, hydrophobic transmembrane domain and exterior domain.
Name the three types of CoV.
Alpha, beta, gamma.
What do alpha CoV bind to?
, Aminopeptidase-N (a family of metalloproteinases), broadly distributed on epithelial and
fibroblast cells.
What does HE bind to?
Sialic acid (9C sugar).
What can beta CoV bind to?
ACE2: angiotensin converting enzyme - mediated by L-sign (lectin which can
agglutinate)
TMPRSS2: cleaves S2 to enter.
List the steps of CoV entry.
Attachment (S1), conformational changes, insert S2 into target, pulls membrane closer
to envelope, fusion.
What are the two routes CoV can use to enter?
Endosomal (endocytosis - capthesin-L), non-endosomal (fusion - TMPRSS2).
What is the first step after entry?
The synthesis of viral proteins that organize and catalyze viral RNA (early genes).
What are ORF1a and ORF1b?
Part of replicase (gene 1), have partially overlapping reading frames, when translating
ORF1a, ribosomes pause at pseudo-knot and frame shift, allowing for ORF1b to be
made, yielding pp1a and pp1b.
What are pseudoknots?
Secondary structures formed in RNA via H-bonds.
A frameshift slips by ____________ nt in the 5' strand and _____________ nt in
the 3' end.
WITH COMPLETE SOLUTIONS VERIFIED
How much of the genome does gene 1 occupy in CoV? What does it translate
into?
2/3, precursor polyproteins.
What does the other 1/3 of the genome consist of?
Structural, non-structural and packaging proteins.
Name the proteins of CoV.
HE: hemagglutinin estrase.
S: Spike
E: small envelope protein.
M: membrane protein.
N: nucleocapsid protein.
What is the structure of CoV?
Enveloped with helical nucleocapsids, +ssRNA.
What does S protein get cleaved to and what do they do?
S1: initiates attachment and contains the receptor binding domain.
S2: forms the stalk, hydrophobic transmembrane domain and exterior domain.
Name the three types of CoV.
Alpha, beta, gamma.
What do alpha CoV bind to?
, Aminopeptidase-N (a family of metalloproteinases), broadly distributed on epithelial and
fibroblast cells.
What does HE bind to?
Sialic acid (9C sugar).
What can beta CoV bind to?
ACE2: angiotensin converting enzyme - mediated by L-sign (lectin which can
agglutinate)
TMPRSS2: cleaves S2 to enter.
List the steps of CoV entry.
Attachment (S1), conformational changes, insert S2 into target, pulls membrane closer
to envelope, fusion.
What are the two routes CoV can use to enter?
Endosomal (endocytosis - capthesin-L), non-endosomal (fusion - TMPRSS2).
What is the first step after entry?
The synthesis of viral proteins that organize and catalyze viral RNA (early genes).
What are ORF1a and ORF1b?
Part of replicase (gene 1), have partially overlapping reading frames, when translating
ORF1a, ribosomes pause at pseudo-knot and frame shift, allowing for ORF1b to be
made, yielding pp1a and pp1b.
What are pseudoknots?
Secondary structures formed in RNA via H-bonds.
A frameshift slips by ____________ nt in the 5' strand and _____________ nt in
the 3' end.
