VCE Biology Question Thread

[Frozone]

If secretion of TSH by the pituitary gland is reduced, secretion of thyroxine by the thyroid gland will also reduce (since TSH stimulates the thyroid gland to secrete thyroxine). Normally, as thyroxine levels increase, secretion of TRH by the hypothalamus decreases (an example of negative feedback). As thyroxine levels decrease, secretion of TRH by the hypothalamus increases (which normally stimulates increased release of TSH by the pituitary gland and therefore increased release of thyroxine by the thyroid gland). Since, due to the pituitary gland tumour, thyroxine levels are reduced, release of TRH by the hypothalamus will increase (but will not lead to increased thyroxine production by the thyroid gland due to the pituitary gland tumour)

As a result of decreased thyroxine levels the overall metabolic rate of body cells would slow (since thyroxine stimulates an increased metabolic rate, as stated by the question)

The answer is wrong. Myelin increases the speed at which an action potential is propagated along the neural axon. Neurotransmitters are released at the axon terminals

I am sorry but the first answer you gave me is wrong(see attached file)

[alchemy]

I am sorry but the first answer you gave me is wrong(see attached file)

How so? I don't see anything wrong with Scooby's answer. It's essentially the same as the 'suggested answer' you posted.

[Frozone]

How so? I don't see anything wrong with Scooby's answer. It's essentially the same as the 'suggested answer' you posted.

Well that was embarrassing. Seems I hate a bit of a meltdown. Thanks for pointing that out!

[Scooby]

I was a bit worried for a second there ahaha

[Reus]

Immunology guys! Main topics that need to be known?
Any tips or such for the SAC?
Thanks!

[janettelxx]

Hello! Can anyone help me with the lymphatic system? Like what is it, how it works and what has it go to do with internal defence? Many thanks 

[katiesaliba]

How do planaria respond to gravity?

[The Usual Student]

What are globular proteins ?

[Marcas]

An example how living things can change or modify the abiotic environment in the ecosystem over
time?

[Reus]

What are globular proteins ?

This type of protein represents one of the three major protein groups. Globular proteins, also known as spheroproteins, are proteins formed by compacted amino acid chains, which are folded into intricate shapes, that sometimes roughly resemble spheres.

Globular protein molecules can play many roles. They can be enzymes, biological messengers and transport mechanisms, and they may also be found acting as structural proteins within animal cells.

Almost all enzymes are globular proteins that vary in size, shape, and complexity.

[grannysmith]

This type of protein represents one of the three major protein groups. Globular proteins, also known as spheroproteins, are proteins formed by compacted amino acid chains, which are folded into intricate shapes, that sometimes roughly resemble spheres.

Globular protein molecules can play many roles. They can be enzymes, biological messengers and transport mechanisms, and they may also be found acting as structural proteins within animal cells.

Almost all enzymes are globular proteins that vary in size, shape, and complexity.

Just to add to this, globular proteins are more or less water-soluble, as they contain hydrophilic amino acids (due to hydrophilic  R-variable groups). Note that the hydrophilic AA are situated on the outer surface of the protein (exposed to water).

[grannysmith]

In the body's response to raised blood glucose levels, would it be an increased production of glycogen or lowered blood glucose levels?
I thought it'd be the latter :/

[Reus]

In the body's response to raised blood glucose levels, would it be an increased production of glycogen or lowered blood glucose levels?
I thought it'd be the latter :/

The production of glycogen is lowering the blood glucose levels, so in turn both are correct. As the conversion of glucose to glycogen is just a storage mechanism.

[Fingerscrossed]

We did a practical on the effect of gibberellic acid on the growth of dwarf bean seedlings, and measured the plant growth of the seedlings over several days. We had two 10-day old seedlings at the beginning, and immersed them in either gibberellic acid solution or distilled water. I am confused as to what would the independent variable be - number of hours, or whether or not gibberllic acid was present???

[Reus]

We did a practical on the effect of gibberellic acid on the growth of dwarf bean seedlings, and measured the plant growth of the seedlings over several days. We had two 10-day old seedlings at the beginning, and immersed them in either gibberellic acid solution or distilled water. I am confused as to what would the independent variable be - number of hours, or whether or not gibberllic acid was present???

Independent variable would be the gibberellic acid solution and the dependent variable would be the growth factor of the seedlings.