VCE Biology Question Thread

[cosine]

For the attached image, the question says chemical composition. So I went ahead and wrote the chemicals that the phospholipids were composed of: Hydrogen, Oxygen, Carbon and Phosphorus. But in their answer it only had phospholipids or phospholipid bilayer. How is this a chemical composition? Is this a badly worded question?

[cosine]

Apologies for the influx of questions, but is rational drug design required for VCE Bio?

[heids]

For the attached question, I was able to deduce that the answer is either A or B as neurotransmitters, hormones and plant regulators are all signalling molecules. However, I would have thought that neurotransmitters and hormones would be grouped together, because they're both not found in plant systems? So I chose option B as gibberellins was isolated but still under signalling molecules. Answer is A

'Plant growth regulators' are also called 'plant hormones' (plant systems do have hormones).  Gibberellins are a type of plant hormones, so they come under the hormone category.  However, as neurotransmitters are not a type of hormone (they're from the nervous not endocrine system), they're obviously not within the hormone subset.  A.

Are we required to know the differences between fibrous and globular proteins?

No.  (I think that's in the FAQs? that distinction was in old SD, not current)

For the attached image, the question says chemical composition. So I went ahead and wrote the chemicals that the phospholipids were composed of: Hydrogen, Oxygen, Carbon and Phosphorus. But in their answer it only had phospholipids or phospholipid bilayer. How is this a chemical composition? Is this a badly worded question?

I've been caught out by that before .  I assume the question was on the chemical composition of the plasma membrane?  I think it's perfectly legit, and you'll meet a number of similar questions, but it's ~impossible to know whether they mean the molecules involved or the elements involved.  Get someone else to help you there.

Apologies for the influx of questions, but is rational drug design required for VCE Bio?

...and the inhibition of the action of enzymes both naturally and by rational drug design

The SD is your best friend, use it to structure your notes.

[Reus]

Apologies for the influx of questions, but is rational drug design required for VCE Bio?

Yes.

[cosine]

'Plant growth regulators' are also called 'plant hormones' (plant systems do have hormones).  Gibberellins are a type of plant hormones, so they come under the hormone category.  However, as neurotransmitters are not a type of hormone (they're from the nervous not endocrine system), they're obviously not within the hormone subset.  A.
No.  (I think that's in the FAQs? that distinction was in old SD, not current)
I've been caught out by that before .  I assume the question was on the chemical composition of the plasma membrane?  I think it's perfectly legit, and you'll meet a number of similar questions, but it's ~impossible to know whether they mean the molecules involved or the elements involved.  Get someone else to help you there.
The SD is your best friend, use it to structure your notes.

So does that mean not all hormones are secreted by endocrine glands? (assuming plants have hormones, but not any glands?)

Also as for the chemical composition, the question was from VCAA 2008, a picture of the bilayer and it said what is the chemical composition of structure A (it was the bilayer, not just one phospholipid highlighted). I mean 'chemical' 'composition' means the chemicals that its composed of, right? Otherwise if they wanted the answer of phospholipid, they would say what is the name of the structure, right?

Im just trying to be specific because in Bio, wording is vital, so just in case it comes up in this year's exam..

Thank you

[cosine]

Are protein channels only involved in facilitated diffusion?
Can facilitated diffusion occur through carrier proteins?
Is active transport only done through carrier proteins?

Thank you

[vox nihili]

Are protein channels only involved in facilitated diffusion?
Can facilitated diffusion occur through carrier proteins?
Is active transport only done through carrier proteins?

Thank you

Yes
Yes
Yes




Although protein channels can also be involved in osmosis, but osmosis of that type is still a form of facilitated diffusion.

[cosine]

Yes
Yes
Yes




Although protein channels can also be involved in osmosis, but osmosis of that type is still a form of facilitated diffusion.

Thank you
Thank you
Thank you

Would you also be able to answer my question from before?

So does that mean not all hormones are secreted by endocrine glands? (assuming plants have hormones, but not any glands?)

Also as for the chemical composition, the question was from VCAA 2008, a picture of the bilayer and it said what is the chemical composition of structure A (it was the bilayer, not just one phospholipid highlighted). I mean 'chemical' 'composition' means the chemicals that its composed of, right? Otherwise if they wanted the answer of phospholipid, they would say what is the name of the structure, right?

Im just trying to be specific because in Bio, wording is vital, so just in case it comes up in this year's exam..

Thank you

[pi]

Although protein channels can also be involved in osmosis, but osmosis of that type is still a form of facilitated diffusion.

Yeah I wouldn't even call it osmosis haha, assuming you're referring to aquaporins.

[vox nihili]

Thank you
Thank you
Thank you

Would you also be able to answer my question from before?

Not entirely sure about the endocrine one. My knowledge of plant stuff is absolutely shocking, so I'll leave that to someone else.

As for the membrane, it's fairly straight-forward. If they ask you what the chemical composition of the membrane is, say phospholipid. A phospholipid is a chemical. The membrane is not made up of phosphate and fatty acids, it is made up of the phospholipids. The phospholipid itself is formed when phosphate and fatty acids join together.

Yeah I wouldn't even call it osmosis haha, assuming you're referring to aquaporins.

Yeah I am referring to aquaporins. It is still referred to as osmosis, but eh, semantics, who cares?

[vanessa14]

Stuck on a practice exam question?

Question 10
Taenia saginata is the beef tapeworm which spends the adult part of its life cycle in the intestine of humans. It is reasonable to suggest that features important to the parasitic lifestyle of the adult beef tapeworm include
A. a digestive system with specialised regions for digesting different foods.
B. production of both male and female gametes by each individual.
C. a body shape with a high volume to surface area ratio.
D. well-developed sensory organs.

So the answer is B  but I dont fully understand it, can anyone help?

[sunshine98]

Stuck on a practice exam question?

Question 10
Taenia saginata is the beef tapeworm which spends the adult part of its life cycle in the intestine of humans. It is reasonable to suggest that features important to the parasitic lifestyle of the adult beef tapeworm include
A. a digestive system with specialised regions for digesting different foods.
B. production of both male and female gametes by each individual.
C. a body shape with a high volume to surface area ratio.
D. well-developed sensory organs.

So the answer is B  but I dont fully understand it, can anyone help?

-A: the question says the tapeworm lives in the intestine, meaning it has access to already digested food. If the tapeworm has access to already digested food it wouldn't need a highly complex digestive system , hence A is wrong
-C: is wrong because in biology you' re always after high SA to Volume (rather than the other way around)
-D : Because the tapeworm is inside the organism , it wouldn't be reasonable to have well developed sensory organs (I'm actually assuming a bit on  this one , because sensory organs are eyes, nose  etc ), maybe someone else clarify?
And so the answer is B. And B makes sense because the tapeworm is clearly a parasite and parasites reproduce in their hosts
 

[cosine]

So does that mean not all hormones are secreted by endocrine glands? (assuming plants have hormones, but not any glands?)

Also as for the chemical composition, the question was from VCAA 2008, a picture of the bilayer and it said what is the chemical composition of structure A (it was the bilayer, not just one phospholipid highlighted). I mean 'chemical' 'composition' means the chemicals that its composed of, right? Otherwise if they wanted the answer of phospholipid, they would say what is the name of the structure, right?

Im just trying to be specific because in Bio, wording is vital, so just in case it comes up in this year's exam..

Thank you

Can anyone help on this one?

Also what is meant by endocrine system?

[EspoirTron]

Can anyone help on this one?

Also what is meant by endocrine system?

The specific structure of a phospholipid is a glycerol backbone with two fatty acids acid attached, and in the third position there is a negatively charged phosphate group attached to the glycerol backbone. The fatty acids don't have to be the same, they can be different, in fact one could be monounsaturated and the other could be polyunsaturated, as an example.

The Endocrine system essentially is involved in the sequestration of hormones that travel far distances and act on tissue that is at distance to the secretion tissues. Conversely in the paracrine system  the molecule  travel a short distance, and in the exocrine system the molecule secreted acts on the tissue that secreted it. Usually the term "hormone" is more generally attached to the molecules that operate within the endocrine system.

Not everything in the Endocrine system is a "gland" per-say. For example, the testis, ovaries, thymus and pancreas all secrete hormones and are part of the endocrine system but they're not "glands" by their anatomical definitions.

[Sine]

A couple of questions on U3 AOS2

Do need to know about specific types of regulation?
AND
What knowledge are we required of Action Potentials?