HSC Biology Marathon 2015 (5 Viewers)

[tfw english]

Maybe not the full 2 marks, but what you gotta mention is that in dominant-recessive cases, the hetrozygous animal gives the dominant trait, whereas in co-dominance this is not the case, as the "hetrozygous" roan cow (RW) gives the "roan" colour.

Ahhh that's what I was missing, thanks!

 

[BlueGas]

Co-dominance is an incomplete dominance in which both alleles are expressed in the heterozygous form.
In co-dominance the hybrid showing a different phenotype means there are 3 possible phenotypes and Mendel’s 3:1 does not account for a third phenotype.

Is this alright? I'm not 100%

If it was a "demonstrate" question and you backed up your question with a punnett square you'll get the full marks but in this question it's "explain".

 

[tfw english]

Outline how cell differentiation and specialisation assist in the maintenance of health? (3)

 

[BlueGas]

Outline how cell differentiation and specialisation assist in the maintenance of health? (3)

Cell differentiation and specialisation is the process in which different genes are activated in different cells. These two processes result in cells specialised for specific functions of the body eg. red blood cells, etc. Together, all the specialised cells work together in a coordinated way to maintain the proper functioning of an organism.

Who wants to do Maintaining a Balance questions?

 

[Mr_Kap]

Cell differentiation and specialisation is the process in which different genes are activated in different cells. These two processes result in cells specialised for specific functions of the body eg. red blood cells, etc. Together, all the specialised cells work together in a coordinated way to maintain the proper functioning of an organism.

Who wants to do Maintaining a Balance questions?

yes. Ive forgotten maintaining a balance a lot.

In your Biology course, you performed a first-hand investigation to gather information about structures in plants that assist in the conservation of water.
a) Describe the procedure followed. 4 MARKS
b) Identify TWO safe work practices needed during this investigation. 2 MARKS

 

[Khan.Paki]

Please. I'll start off.

Outline some problems with diffusion and osmosis within the human body [3 marks]

 

[Mr_Kap]

Please. I'll start off.

Outline some problems with diffusion and osmosis within the human body [3 marks]

Well the dotpoint is actually: explain why the processes of diffusion and osmosis are inadequate in removing dissolved nitrogenous wastes.

So here goes:

The process of diffusion and osmosis require no energy input, and consequently are both slow processes. Nitrogenous wastes are toxic hence need to be removed from cells. Since both osmisis and difusion rely on the concentration gradient, this process slows down as the gradient flattens out until it reaches equilibrium, and no more nitrogenous wastes can be removed. This would result in concentrations of nitrogenous wastes within the blood and urine being equalized, and no further waste could be removed and hence the waste would accumulate in the bloodstream, which would alter the pH and become toxic.
If urine contains large concentrations of nitrogenous wastes, water will be drawn into through osmosis to try to dilute and equalize the concentrations. To rid the body of these nitrogenous wastes, a large amount of water would be needed to dilute the urine which animals can not afford to have occur, hence why osmosis has problems.

 

[tfw english]

Please. I'll start off.

Outline some problems with diffusion and osmosis within the human body [3 marks]

Diffusion and osmosis are both examples of passive transport, this is too slow for the normal functioning, because the movement of molecules relies on differences in the concentration gradient between two solutions.
Diffusion offers further issues as toxins can accumulate in the body, and can only be removed if they are in water, hence they would only move if there was a higher concentration of toxins in the blood then the urine itself. And this would stop if the concentrations equalise.
More so osmosis would draw water continually be from the body to even out the conc. gradient. However, excretion of dilute urine means the loss of large amount of water from body, a loss too great for terrestrial animals.
These issues can be dangerous for the body's internal environment.


Bit too much for 3 marks (maybe)

 

[BlueGas]

yes. Ive forgotten maintaining a balance a lot.

In your Biology course, you performed a first-hand investigation to gather information about structures in plants that assist in the conservation of water.
a) Describe the procedure followed. 4 MARKS
b) Identify TWO safe work practices needed during this investigation. 2 MARKS

a) A microscope was set up appropriately to observe different types of leaves were picked around the school (typical environment) which were placed on prepared slides. The leaves were carefully looked at for different 'prominent' features that could inhibit water loss, these were then cross-checked with reliable sources.

b) - Sun has strong UV light outside, sunscreen and hats should be worn
- Leaves can be diseased and can have splinters and can be sharp, gloves should be worn

Please. I'll start off.

Outline some problems with diffusion and osmosis within the human body [3 marks]

Diffusion and osmosis are both passive transport (don't require energy), this is too slow for the normal functioning and the movements of molecules relies on the different in concentration gradient between two solutions. Also toxins such as drugs can accumulate in the body and can only be removed by water, which is a problem with diffusion. Further problems for osmosis include: Too much water is lost in urine, and osmosis only deals with the movement of water, so nitrogenous wastes can't be removed out of the body.

 

[BlueGas]

lol 2 minutes between each of our posts.

 

[tfw english]

Compare the structures of arteries and veins, relating them to their function. (3)

 

[Mr_Kap]

a) A microscope was set up appropriately to observe different types of leaves were picked around the school (typical environment) which were placed on prepared slides. The leaves were carefully looked at for different 'prominent' features that could inhibit water loss, these were then cross-checked with reliable sources.

Maybe mention the "prominent features", like sunken stomates, surface hair, thickness and type of cuticle.
Maybe also mention "collect a variety of leaves from different species recording type and location"

 

[BlueGas]

Compare the structures of arteries and veins, relating them to their function. (3)

Arteries are thick and contain muscle to withstand the pressures of pumping oxygenated blood away from the heart. Veins are thin-walled, don't contain muscle and rely on valves to pump dexoygenated blood to the heart. Capillaries are one cell thick for the rapid exchange of materials between body and blood cells.

 

[Mr_Kap]

Compare the structures of arteries and veins, relating them to their function. (3)

Arteries have a thick muscular walls in order to withstand high blood flow from the heart. Veins however, have valves which prevent backflow of blood to the heart. The walls arent very thick compared to arteries.

 

[Mr_Kap]

Arteries are thick and contain muscle to withstand the pressures of pumping oxygenated blood away from the heart. Veins are thin-walled, don't contain muscle and rely on valves to pump dexoygenated blood to the heart. Capillaries are one cell thick from the rapid exchange of materials between body and blood cells.

he/she didnt ask for that, but anyway, mention that it provides a large SA:V as well for cappilary

 

[tfw english]

Arteries have a thick muscular walls in order to withstand high blood flow from the heart. Veins however, have valves which prevent backflow of blood to the heart. The walls arent very thick compared to arteries.

Could also compare that arteries carry oxygenated blood whereas veins carry deoxygenated blood but that's about it

 

[BlueGas]

he/she didnt ask for that, but anyway, mention that it provides a large SA:V as well for cappilary

Oh I didn't read the whole question haha.

 

[Mr_Kap]

Discuss the imprtance of hormone replacement therapy for people who can't secret aldosterone. 4 MAKRS

 

[tfw english]

Discuss the imprtance of hormone replacement therapy for people who can't secret aldosterone. 4 MAKRS

Addison's disease is a rare endocrine disorder occurring when the adrenal glands, seated above the kidney, fail to produce enough aldosterone. Without aldosterone, the body would not be able to reabsorb salt (specifically sodium ions) this would cause severe dehydration and excessive potassium loss which may cause brain damage and death.

The treatment includes an artificial hormone called Fludrocortisone, a drug that decreases the amount of salt the body excretes. Patients are also advised by their doctors to increase their sodium intake along with this. This allows efficient salt re-absorption and therefore prevents issues associated with being unable to produce aldosterone.

 

[tfw english]

Distinguish between active and passive transport and relate these to the processes occurring in the mammalian kidney. (4)