HSC Biology Marathon 2015 (4 Viewers)

[tfw english]

Living cells work best in an isotonic environment, where the concentration of solutes inside the cell is the same as outside the cell. Any change to the concentration of solutes will result in a change in the levels of water and will lead to death.

Nice, could also mention that a change in the concentration of water in cells could interfere with the functioning of enzymes and metabolism would be disrupted
Might be too much for 3, but it's another reason

 

[TQuadded]

Explain why the concentration of water in cells should be maintained within a narrow range for optimal function. (3)

Water is essential in human survival as it is not only used to transport nutrients around the body, but also used for body regulation. When there is too little water in a cell, it shrivels. When there is too much water in a cell, it may explode. Both results in killing cells. It is therefore important to maintain the concentration of water within cells for optimal function.

 

[TQuadded]

Living cells work best in an isotonic environment, where the concentration of solutes inside the cell is the same as outside the cell. Any change to the concentration of solutes will result in a change in the levels of water and will lead to death.

Hit them with the blunt "may lead to death"!

 

[Mr_Kap]

During a first-hand investigation, a student acquired three photographs of cross-sections of the human brain. The student then lost the labels and mixed up the photographs. What structural features of the cerebrum, cerebellum and medulla oblongata could the student use to identify each photograph correctly. 3 MARKS

 

[Queenroot]

During a first-hand investigation, a student acquired three photographs of cross-sections of the human brain. The student then lost the labels and mixed up the photographs. What structural features of the cerebrum, cerebellum and medulla oblongata could the student use to identify each photograph correctly. 3 MARKS

3ez

 

[TQuadded]

During a first-hand investigation, a student acquired three photographs of cross-sections of the human brain. The student then lost the labels and mixed up the photographs. What structural features of the cerebrum, cerebellum and medulla oblongata could the student use to identify each photograph correctly. 3 MARKS

the big wrinkly thingy is the cerebrum and smaller wrinkly thingy is the cerebellum and the long thingy at the bottom of the brain is the medulla thingy

band 7 here I come

 

[Mr_Kap]

3ez

help then plz

Or someone give a proper description.

 

[Queenroot]

help then plz

Or someone give a proper description.

Not sure how much detail you guys have learnt it in. Did bio ages ago so forgot lol.

Either way some distinguishing features of the cerebrum include separation into lobes, larger in comparison to the cerebellum and sulci/gyri. Cerebellum is smaller in comparison to the cerebrum and has ridges on it, located towards the back of the brain. Medulla oblongata as the name suggests is oblong in shape, part of the greater brainstem which includes the diencephalon, midbrain and pons.

 

[Queenroot]

It's a good question though, how would you describe those parts of the brain? Not an easy task. If you listed their functions it would make it a whole lot easier, but describing their visual features alone is pretty hard.

 

[TQuadded]

It's a good question though, how would you describe those parts of the brain? Not an easy task. If you listed their functions it would make it a whole lot easier, but describing their visual features alone is pretty hard.

Maybe their location as well? Because the question did suggest that the brain was whole as he took photos of the parts.

 

[Mr_Kap]

Cerebrum: folded surface with white matter in the inner layer and grey in the outer layer
Cerebellum: Smaller folds on surface
Medulla: Grey matter in the inner layer a and white matter in the outer layer, extension of spinal cord.

This was in excel success one --> I didn't realise this was a past HSC question from early 2000's

 

[Queenroot]

Cerebrum: folded surface with white matter in the inner layer and grey in the outer layer
Cerebellum: Smaller folds on surface
Medulla: Grey matter in the inner layer a and white matter in the outer layer, extension of spinal cord.

This was in excel success one --> I didn't realise this was a past HSC question from early 2000's

That's correct but then you would have to assume that the person has a sliced cross section of the brain. Can't really see the matter on the inside of those structures.

 

[Stimuli]

Is sex-linked inheritance (Either dominant or recessive) restricted to one gender? E.g can a male carry a recessive sex linked characteristic, then his daughters will carry it. Then, will the daughters sons get the trait (If they inherit that X chromosome of course)

 

[tfw english]

Discuss the use and limitations of models when illustrating biological concepts. (3)

 

[Squar3root]

Discuss the use and limitations of models when illustrating biological concepts. (3)

too many pretty colours in models can be distracting and take away attention behind then main idea of the concept

 

[BlueGas]

Describe a first-hand investigation you performed to either, test the increase in temperature, change in pH or change in substrate concentration of the activity of enzymes. (3 marks)

 

[TQuadded]

Describe a first-hand investigation you performed to either, test the increase in temperature, change in pH or change in substrate concentration of the activity of enzymes. (3 marks)

That's three marks only? Ok then.

1.) Get enzymes.
2.) Change substrate concentration, temperature and pH.
3.) ???
4.) Profit.

 

[TQuadded]

Discuss the use and limitations of models when illustrating biological concepts. (3)

Models are widely used to simplify complex biological concepts. Instead of interpreting strings of information about biological concepts, a models pairs this information with a visual aspect. Because it makes use of our sense of sight, it allows for better interpretation. While models can be too simple in that it can be wrongly interpreted, the potential of models in giving us a better insight into biological concepts outweighs this.

 

[Queenroot]

Is sex-linked inheritance (Either dominant or recessive) restricted to one gender? E.g can a male carry a recessive sex linked characteristic, then his daughters will carry it. Then, will the daughters sons get the trait (If they inherit that X chromosome of course)

It's not restricted to one gender. Both genders can be affected, females are usually carriers and males are usually affected.

 

[BlueGas]

That's three marks only? Ok then.

1.) Get enzymes.
2.) Change substrate concentration, temperature and pH.
3.) ???
4.) Profit.

Fair enough, 6 marks then.