Can someone help me with this question pleasee. I am lost :/

Scientists investigated how damage to plants can affect gene expression. When the tomato hornworms bite the leaves of tomato plants, proteins are produced inside the leaf cells. Some of these proteins are enzyme inhibitors that prevent tomato hornworms from digesting the leaves.

Deduce how chemicals in the saliva of tomato hornworms can cause the leaf cells to produce these proteins (4)

Is this A-level? I would think look at epigenetic and gene expression. Think about how proteins are produced and what could happen to make the plant produce proteins when the leaves are bitten by the caterpillar.

A level
There is so much going on in that Idk what it is asking me
The question is worded so weirdly

All it's asking is how does the chemical in the saliva cause the leaf to start producing those proteins.

The preamble there is to tell you that the question is about gene expression and that the plant does something to adapt and protect itself from a hornworm that would otherwise eat its leaves (the protein makes the leaves undigestible by the hornworm, so they stop eating them). So, what must have happened to make the plant start producing this protein?

I'd look up gene expression and factors that regulate transcription and translation in your notes.

Genes can be inactivated/switched off by methylation
Prevents RNA polymerase binding + mRNA being produced
Histone modification can affect how tightly DNA wraps around the histones
If wrapped tightly, RNA polymerase can’t bind/if wrapped loosely, RNA polymerase can bind + produce mRNA??

Or Am I on wrong track

Right track. Genes are switched off by increased methylation or decreased acetylation of histones (for the reasons you mentioned).

Here, something is prompting the leaves to start producing this protein (question says a chemical in the saliva makes leaves start to produce the protein). So, it means a gene is switched on and transcription/translation is taking place (also look at transcription/translation regulators, i.e. transcription factors (activators and repressors)).

I know process of transcription and translation but putting it all together is a but hard for me

I genuinely don't know how to answer this question

Oh god, this is stressing me out so bad
I got A levels not even that far away

Don't panic, just take it step-by-step. Do you have the mark scheme for this question? What exactly are you finding hard, as I thought you had it above. As well as process of transcription/translation, do you know about their regulation via transcription factors (called activators/repressors) that bind to promoters? This will all be in your textbook/notes.

The question is asking how the chemical in the saliva is making leaves produce proteins i.e. how is the chemical switching on the gene or initiating transcription/translation?

this is the ms:
Chemical stimulus from the tomato hornworm activates a gene in the plant.
Gene for enzyme inhibitor activated
Transcribed to produce mRNA mRNA translated at a ribosome to produce enzyme inhibitor


even by seeing this I am not 100% sure on what to include to gain the 4 marks
I cant just copy the MS

I feel like I am overcomplicating it

Yeah, I think you're overcomplicating it don't worry, it happens when we're stressed.

As I said, take it step-by step.

Question says chemical in saliva causes leaf cells to produce proteins.
1 - chemical in saliva must be switching on/activating a gene (or multiple genes) [arguably, you could go into detail here about how that takes place, from above]
2 - one of these genes that is activated is the one that codes for the enzyme inhibitor (mentioned in the question)
3 - therefore, the gene is now transcribed to produce mRNA
4 - mRNA is then translated by ribosome to produce the enzyme inhibitor

All of this ^^ you have said above.

I agree copying is bad, and you won't the mark scheme in an exam, but look at how the mark scheme is structured and what they want from you. Most of the processes/systems in biology can be broken down into lists of 4 or 5 bullet points for exam purposes. You learn these, then use logic and what else you know about biological systems to make it coherent and describe how the process goes from step 1 > step 2 > step 3 etc.

Good luck - keep calm and break it down and you'll be fine.