VCE Biology Question Thread

[thatdumbstudent]

Monoclonal and suppress (:

ahh thank you!!
so one more question... would a "relatively harmless antigen that can cause the release of histamine by mast cells" be allergens?

[darkz]

ahh thank you!!
so one more question... would a "relatively harmless antigen that can cause the release of histamine by mast cells" be allergens?

Yep, sounds good to me.

[Strawbery47]

How do skeletal muscle movements help to maintain the flow of blood around the body??

[Coolmate]

How do skeletal muscle movements help to maintain the flow of blood around the body??

Hey Strawbery47!

I just found this website which hopefully answers your question, including a diagram:
https://courses.lumenlearning.com/boundless-ap/chapter/blood-flow-through-the-body/#:~:text=Skeletal%20muscles%20also%20play%20a,the%20blood%20towards%20the%20heart.

You just need to scroll down to the part that says, "Skeletal Muscle Pump"

Hope this helps!
Coolmate

[Strawbery47]

Ok thanks!

how does the beating of the heart help to maintain the flow of blood around the body?

And why are the capillaries called the connectors between systemic and pulmonary circulations

[Coolmate]

Ok thanks!

how does the beating of the heart help to maintain the flow of blood around the body?

And why are the capillaries called the connectors between systemic and pulmonary circulations

The beating of the heart helps to maintain the flow of blood around the body because, each beat provides consistent blood pressure and the resulting pressure from this pumping, pushes blood through the arteries through the systemic circulation. This will ensure oxygen and nutrients are passed around the body.

The capillaries are called the connectors between systemic and pulmonary circulations because capillaries allow gas diffusion and due to their size, allow a large surface area for this diffusion. Once the blood exits the right atrium, it enters pulmonary circulation (pulmonary artery --> pulmonary capillaries where gas exchange occurs --> pulmonary vein which feeds into the left atrium). Once entering the left atrium it enters the left ventricle, where it is expelled into the systemic circulation. Thus, capillaries can be called the connectors between systemic and pulmonary circulations.

I hope this helps!
Coolmate

[Strawbery47]

Thank you coolmate!

For this question: meiosis consists of 2 cell divisions. At the end of meiosis 1 the 2 daughter cells have half the number of chromosomes as the parent cell but the same amount of DNA. Are these cells diploid or haploid.

Would I be correct if I said these cells are haploid because they have half the number of chromosomes but the same amount of DNA

[Strawbery47]

When glucose molecules join is it a condensation reaction

Also what are the sub units that make up a triglyceride

When glucose molecules join together it is a condensation reaction and releases a water molecule.

Is it fatty acids and glycerol?

[Coolmate]

Thank you coolmate!

For this question: meiosis consists of 2 cell divisions. At the end of meiosis 1 the 2 daughter cells have half the number of chromosomes as the parent cell but the same amount of DNA. Are these cells diploid or haploid.

Would I be correct if I said these cells are haploid because they have half the number of chromosomes but the same amount of DNA

That's ok

That's a very interesting question, for that question though, I would say you are correct because, at the end of Meiosis 1, it results in 2 daughter cells, each having half the number of chromosomes (n), but the same amount of DNA as the parent cell.

This is just my guess, so I hope this helps!
Coolmate

[Strawbery47]

Ok thanks!

This is a similar question to that one just not sure if my answer is correct

At the end of meiosis 2 the four daughter cells have half the number of chromosomes as the original parent cell and half the amount of DNA.
Are the cells diploid or haploid and why.

The cells are still haploid right? Because they have half the number of chromosomes even though they have half the amount of DNA.

[Coolmate]

Ok thanks!

This is a similar question to that one just not sure if my answer is correct

At the end of meiosis 2 the four daughter cells have half the number of chromosomes as the original parent cell and half the amount of DNA.
Are the cells diploid or haploid and why.

The cells are still haploid right? Because they have half the number of chromosomes even though they have half the amount of DNA.

Yep, that's correct, the 4 resulting daughter cells are haploid, each containing 23 chromosomes (n), which is half from the parent cell which is (2n)

Coolmate

[PhoenixxFire]

*Brushes off cobwebs* Been way too many pages without a post from me.

Could you say the light dependent reaction takes place in the grana or would that be incorrect and do you have to say thylakoid membranes

2012 exam suggested answer was grana so that should be fine.

What is a good definition for exocrine signalling and neurotransmitters? And what points should I make when describing what a second messenger is? Thanks

Hi! Does anyone know a really good definition for vaccinations?

Hey,
Trying to memorise other people's definitions is a bit hard - a better way for you to learn is for you to come up with your own definition and then edit it to be as concise as possible. If you'd like to have a go at coming up with a definition, feel free to post it here for feedback

would it be correct if for ribosomes relating structure to function you said
RNA bind to mRNA to produce protein via the process of translation. translate an mRNA sequence into a polypeptide.

If you're relating structure to function then you'll probably need to be more specific and talk about the EPA sites and how they allow for the production of the polypeptide - how much detail you need will depend on how many marks the question is worth.

Also for vacuoles relating structure to function would it be correct if you said they are involved in intracellular digestion and release of cellular waste products. maintain water balance in cells.

Thanks!

You're not really explaining how the structure relates to the function here. You could talk about their shape or them being membrane bound.

Hello

For the question of leaves are removed transpiration stops. Explain why this is so

Would this be a sufficient answer:
Transpiration is the evaporation of water from the leaves of a plant through the stomata. The stomata are present on the underside of the leaf therefore if leaves are removed there will be no stomata and transpiration will not be able to occur

Yep, this shoud be fine.

Hello!

Hope you all are doing well. I have a question on apoptosis.

List two examples of situations that could trigger the mitochondrial pathway of apoptosis and List three examples of situations that could trigger the external death receptor pathway of apoptosis.

The first one I can answer with things like 'the viral infection of a cell can cause it to perform apoptosis to prevent any further spread' and 'When a cell's genome is damaged'. However, I cannot think of enough answers for the second question. I'm not even sure if the questions were asking for these answers. 

Any help would be appreciated

Cancer (causing changes to the mhc marker or polypeptide fragments), transplanted tissue, or viral infection (identified by Tc cell) could cause external apoptosis

Also is co2 involved with the Photolysis of water or it it just used in the light independent stage?

Just in the light independent stage.

Is the difference between cytosol and cytoplasm that cytoplasm is the fluid and organelles  surrounding except the nucleus whereas cytosol is just the fluid without the organelles

Yep.
Please let me know if anything seems a bit off - it's been a while since I've thought about bio. Also let me know if I've missed any questions!

[Amelia257]

Hello

Coat colour inheritance in certain cats is sex linked and codominant
Male cats can have yellow or black coat colours . Female cats may be yellow, black or tortoiseshell in colour. What would be the probability of having yellow female offspring if a tortoiseshell  female is crossed with a yellow male?
A 0%
B 25%
C 50%
D 75%
Why is the answer for this question B
Can’t work it out

Thank you

How do you work out what the alleles are for the tortoiseshell female and the yellow male

[GodNifty]

How do you work out what the alleles are for the tortoiseshell female and the yellow male

You were given the information that coat colour inheritance is co-dominant (and sex-linked).

Let A = Black
Let a = Yellow
Note that the question doesn't signify which allele is the dominant one, but it doesn't matter as you'll produce the same answer if you made 'A = Yellow' and 'a = Black'

If it were homozygous, you'd be producing one colour only, so what genotype will co-dominance give?

Try the question out yourself, it can definitely trip you up, but make sure you note that it is sex-linked - this piece of information is important.

Let me know if you need further assistance, I just did it and I'm very impressed with the question itself.

[Amelia257]

Ohh ok. Thanks

So I did X^A x a crossed with x ^a y

there’s only 1 x^a xa  which is yellow so it’s 25%