HSC Biology Question Thread

[julia_warren13]

Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu

[Snew]

Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu

Hey fellow 2017er this is what Naomi's notes (one of the awesome atar notes hsc lecturers) has so definitely check that out! super helpful

Enzymes work best when water is at its optimal concentration, and any variation from this negatively impacts cell metabolism
Cells work best in an isotonic environment - the solute concentration is the same both inside and outside the cell
Example:
When water concentration in red blood cells is optimal, they are said to be at an 'isotonic state' they are the right shape and size and can function effectively.
When RBC have too little water (due to there being to much salt in the fluid around them) RCB shrivel up as water moves out, attempting to recreate balance between the inside of the cell and the outside.
When RBC have too much water (due to there being too little water in the fluid around them) RBC swell up as water moves in, attempting to recreate balance between the inside of the cell and the outside

[Rathin]

Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu

Firstly we need to know WHY water should be maintained:
- It is a medium that transports and distributes substances between cells.
- It is a universal solvent it acts as a medium where all metabolic reactions can occur in water.
- It provides osmotic pressure for movement of materials depending on the solutes dissolved in water.

So new we need to know why the concentration of water is only maintained in a narrow range for optimum function.

- For a cell to perform at its optimum level the water concentration outside the cell and inside the same. This is known as an Isotonic state. If there is too much water the cell will burst and if there is too little water the cell will shrivel, where in both cases due to the unbalanced water concentration the functioning of the cell is not at its optimum.   

[pikachu975]

Hey! I'm just having a bit of trouble with this MAB dotpoint: Explain why the concentration of water in cells should be maintained within a narrow range for optimal function What are the main things that I need to know for this dotpoint?? Thankyouu

To add on, here's some key terms for this dot point:

Animals/Humans:
Hypotonic - too much water in the cells (bursting/swelling of the cell)
Isotonic - balance between water inside and outside (good for humans/animals)
Hypertonic - too little water (shrivelling)

Plants:
Turgid - too much water in the plant cells (good for plants)
Flaccid - same amount inside and outside (not enough water)
Plasmolysed - too little water (death due to no photosynthesis)

[bananna]

Hi
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u

[pikachu975]

Hi
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u

The peppered moth should be good to use.

[Rathin]

Hi
Is the peppered moth of the industrial revolution considered a modern example of natural selection ?
Thank u

Yes Peppered Moth is an example of a physical change in the environment and DDT on mosquitoes is a chemical change in the environment which has led to the mechanism of Natural Selection.

[Thebarman]

Hey guys, do we need to know about IVF and genetic engineering for the first dotpoint of focus area 5? The dotpoint centres around current reproductive techniques and their impact on a population. My textbook is going into quite some detail on the two, but it's not one of the three listed techniques...

[diesxel]

Hello, I have an assessed biology exam coming up for module 1 and 2, and I was wondering if anyone had any links to good past papers or exams that I can use to study from?? I really really need to do well in this exam, I'm good with content but I need to apply it as well.

Exam's in only a few days so any help is appreciated!!

Thanks so much 

[pikachu975]

Hello, I have an assessed biology exam coming up for module 1 and 2, and I was wondering if anyone had any links to good past papers or exams that I can use to study from?? I really really need to do well in this exam, I'm good with content but I need to apply it as well.

Exam's in only a few days so any help is appreciated!!

Thanks so much 

Just some general tips to study for how to write answers:
- Use dot points! Markers will already be sighing if they see a large slab of a whole page answer with no dot points or structure whatsoever and using dot points can make it easier to read at least.
- Adding on to the first dot point, subheadings and underlining can give a lot of structure to answers.
- Writing important words in capital letters or underlining them could help the marker instantly see that you know your content because they may skip over it on a tiring night when they've read 20 other papers!
- Plan 4+ mark responses because often a logical and coherent answer is essential for the full marks, ESPECIALLY the 8 marker.
- Always look at the key verb and key terms and keep them in your mind. If it says compare, it could be useful to draw a table, etc. Alongside this, highlighting the key terms could help you remember to keep on track.
- Read marking criterias of HSC and trial papers to see the expectation of what they're looking for, but before that, try and predict the mark allocation so that in the exam you can easily tell what you need to include. Reading sample answers off of ARC or bostes examplar responses helps heaps.

[DalvinT]

Hello,

So I've a question on how exams are marked in Biology. So the marking guidelines, gives points in which students can include in there responses and also has standards for each range. Now, I said "can", does that mean that if we didn't  include those specific points they suggested, would we be disadvantaged? Even if the points mentioned, were valid and correct.

For example,
The question is, "Explain the advantage adaptations of haemoglobin" 2 marks
Marking guidelines:
- 4 oxygen molecules per haemoglobin, Approx. 200 haemoglobin. Large quantity (1)
- Able to transfer gases and other products efficiently to cells. (1)
- Allows proper functioning and maintains pH as well. (1)

And let's say that the answer did not include "transfer gases efficiently" but instead wrote "transfer chemicals efficiently"... would they still get a mark?
To me, I think they should cause gases are chemicals ... lol. Or does marking responses requires SPECIFIC details, in order to earn marks...

[Youssk]

Hi, I'm just confused on how to answer this question from 'the search for better health)
Describe the importance of protein production for maintaining and repairing body tissue?

Thanks 

[vox nihili]

Hi, I'm just confused on how to answer this question from 'the search for better health)
Describe the importance of protein production for maintaining and repairing body tissue?

Thanks 

-tissues sometimes get damaged and break down
-tissues are made out of protein
-to make new tissue to replace the damaged/old tissue, one needs to make protein

[pikachu975]

Hello,

So I've a question on how exams are marked in Biology. So the marking guidelines, gives points in which students can include in there responses and also has standards for each range. Now, I said "can", does that mean that if we didn't  include those specific points they suggested, would we be disadvantaged? Even if the points mentioned, were valid and correct.

For example,
The question is, "Explain the advantage adaptations of haemoglobin" 2 marks
Marking guidelines:
- 4 oxygen molecules per haemoglobin, Approx. 200 haemoglobin. Large quantity (1)
- Able to transfer gases and other products efficiently to cells. (1)
- Allows proper functioning and maintains pH as well. (1)

And let's say that the answer did not include "transfer gases efficiently" but instead wrote "transfer chemicals efficiently"... would they still get a mark?
To me, I think they should cause gases are chemicals ... lol. Or does marking responses requires SPECIFIC details, in order to earn marks...

I think for that example chemicals is a broad/vague term and if I saw it I'd think they don't know what haemoglobin is for, and are trying to write a vague term to hope for the best.

[DalvinT]

I think for that example chemicals is a broad/vague term and if I saw it I'd think they don't know what haemoglobin is for, and are trying to write a vague term to hope for the best.

Ahh I see, good point.