exhaustedstudent
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Can anybody help me with this? I don’t know what p60 in L. monocytogenes are, so I can’t really compare it..Name:  B2B1FD1A-4E03-466F-BA7D-42B9C27F17F6.jpg.jpeg
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macpatgh-Sheldon
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Hi "tired young man",

If this is an A level Q which it looks like from the layout, may I say that unless the first part of Q tells you that the L. in the generic name stands for Listeria, a genus of bacterium that causes a kind of gastro-intestinal infection in humans and animals, then this Q is grossly unfair.

If it is an A level Q, it is not expecting you to know anything about the physiology of Listeria monocytogenes but is rather testing you on your knowledge of prokaryotic and eukaryotic cell structure and protein synthesis.

The points I would predict would be in the mark scheme:-

a) the fact that the mammalian process would use its relevant chromosome for transcription while the bacterium would use its (circular) plasmid.
b) that in the mammalian cell, translation would occur in the RER, specifically ribosomes attached to it, while in the bacterium it would occur on free-standing ribosomes.
c) that the ribosome of a mammal would be an 80S one, while the bacterial one would be 70S.
d) the (smaller) subunit of the ribosome to which mRNA attaches would be a 40S subunit in the mammal and a 30S in the bacterium.
e) the release of the protein after synthesis in the mammal is likely to be after processing in the Golgi; not so in bacterium which has no Golgi apparatus.

I would probs bank on b), c) and e) for the two marks assigned to the Q.

Hope this helps!

M (specialist biology tutor)
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exhaustedstudent
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(Original post by macpatelgh)
Hi "tired young man",

If this is an A level Q which it looks like from the layout, may I say that unless the first part of Q tells you that the L. in the generic name stands for Listeria, a genus of bacterium that causes a kind of gastro-intestinal infection in humans and animals, then this Q is grossly unfair.

If it is an A level Q, it is not expecting you to know anything about the physiology of Listeria monocytogenes but is rather testing you on your knowledge of prokaryotic and eukaryotic cell structure and protein synthesis.

The points I would predict would be in the mark scheme:-

a) the fact that the mammalian process would use its relevant chromosome for transcription while the bacterium would use its (circular) plasmid.
b) that in the mammalian cell, translation would occur in the RER, specifically ribosomes attached to it, while in the bacterium it would occur on free-standing ribosomes.
c) that the ribosome of a mammal would be an 80S one, while the bacterial one would be 70S.
d) the (smaller) subunit of the ribosome to which mRNA attaches would be a 40S subunit in the mammal and a 30S in the bacterium.
e) the release of the protein after synthesis in the mammal is likely to be after processing in the Golgi; not so in bacterium which has no Golgi apparatus.

I would probs bank on b), c) and e) for the two marks assigned to the Q.

Hope this helps!

M (specialist biology tutor)
by the way, I’m not a man...

but thanks for the reply!
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