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Difference Between a pathogen and parasite

Hey everyone :smile:

,
I am doing OCR Biology AS Level and in my text book came across the question:
describe the differences between a parasite and a pathogen?
I would answer it as follows:
A parasite lives on or within the host cell for all of or part of its life, may cause harm to the host or might just weaken it. However, pathogens are disease causing organisms that will definitely cause harm to the cell.

What do you think of this answer?
There are answers at the back and the answer provided word by word is:
A parasite is an organism that lives on or in its host for all or part of its life; it causes harm and gains nutrition from the host. A pathogen is any organism that causes diseases.

What I don't understand about this answer is why 'gains nutrition from the host' is mentioned as if it is exclusive to the parasite when in fact the pathogen also gains its host's nucelus?

Would much appreciate some help on this, thanks in advance :smile:

Reply 1

nexttime

No you're right. The question is stupid - its asking you to compare two completely different words.

A pathogen is just something that causes disease. It will inevitably get something from the thing it is causing disease to (although i'm not sure the nucleus counts as 'nutrition' per se), however, that is not a defining feature of a pathogen. Its purely about the disease it causes. Compare that to a parasite, where the defining feature is that it gains nutrients from its host. That is why it was emphasised.

Reply 2

arvin_infinity

Original post by cakefreak

Hey everyone :smile:

To me its a fair question would be interested to see where you found it textbook cause I havent seen it.
pathogen is any organism/parasite that causes diseases.

parasites: any organism that live in or on another living organism (the host)
parasite cause harm to the host
some parasite cause harm to the host by taking nutrients from the host-so not all

cant figure out your angle as to nucleus being nutrients

not all pathogen gain their host nucleus

wondered if you are thinking about virus?! :rolleyes:

Reply 3

cakefreak

Original post by arvin_infinity

Thanks for your response , the question comes from this book http://www.amazon.co.uk/Biology-Student-Book-Exam-CD-ROM/dp/0435691805 and yes sorry I meant nutrients lol. And so is a parasite a type of pathogen because you said "pathogen is any organism/parasite that causes diseases"?

Reply 4

arvin_infinity

Original post by cakefreak

All Pathogens are parasites not the other way around

I mean dont try to memorise it but think of it this way : all pathogens live either in or on another living organism and they also cause harm so yeh they are all parasites

got the same book cant find it tho :colondollar:

Reply 5

cakefreak

Original post by arvin_infinity

but pathogens definitely cause harm because that is their defining trait and parasites can live on or in its host for all or part of its life...

Reply 6

Larry31

Original post by cakefreak

Hey everyone :smile:

I also do OCR AS Bio, and the first thing that came to my head about the whole nutrients thing was that the female anopheles mosquito is a parasite because it lives off the host to provide protein for it's eggs...so that may be where the acquiring nutrients bit comes from :biggrin:

Reply 7

merrycled

An organism that infects its host and causes no harm is termed com
encal
If host and infective agent benefit- a symbiont.
If infective agent causes harm can be called a parasite or pathogen.
Pathogen is usually used for micro organisms, parasite for multicellular, I believe.
http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/ourselves/2_keeping_healthy1.shtm
cf parasite

A very interesting question which has puzzled Ph.D. qualified friends.

.

Reply 8

vshkla91

The way I see it, both pathogen and parasite live off the host by utilising the nutrients produced in/by the host. Primarily, the difference lies in the fact that a parasite will utilise all nutrients present, not leaving any nutrient behind for the host. Whereas, a pathogen utilises just enough for its survival. Secondly, the word pathogens are used to refer to microorganisms (unicellular) like Bacteria, Virus and Fungi and parasites for multicellular forms.