HSC Biology Marathon 2015 (1 Viewer)

[Flop21]

Yeh, usually i try and write as much as i can as well. Just try to make sure its relevant though, even if you write heaps.

And yeh, I thought they were the same thin but i was just checking in case i was wrong.

Yeah true, good tip. Also be careful when writing a lot, make sure it is actually correct. In biology they can hold off from giving you full marks if your answer contradicts itself of says something that's wrong, even though most of the answer is correct.

 

[Mr_Kap]

a) Use an example to explain why hybridisation within a species is carried out. 2 MARKS.

b) Use an example of a named transgenic species to discuss the social and environmental impact of this technology. 5 MARKS.

 

[Mr_Kap]

a) Use an example to explain why hybridisation within a species is carried out. 2 MARKS.

b) Use an example of a named transgenic species to discuss the social and environmental impact of this technology. 5 MARKS.

bump

 

[BlueGas]

a) Use an example to explain why hybridisation within a species is carried out. 2 MARKS.

b) Use an example of a named transgenic species to discuss the social and environmental impact of this technology. 5 MARKS.

bump

I feel so tired to answer the question but:

a) The triticale is an example of a hybrid species (bro this is in the notes you're using lol), the reason why it's carried out is because it's drought tolerant, disease resistant, high yeilding and fertile

b) Bt Cotton is an example of a transgenic species, environmental impact speak about if there is a disease either the entire species gets wiped out or they all live, genetic diversity is reduced as there's not much genetic variation, for social issues I'm not sure what they mean by this, do they mean ethical issues? Ethical and social issues are quite different.

 

[Khan.Paki]

a) Use an example to explain why hybridisation within a species is carried out. 2 MARKS.

b) Use an example of a named transgenic species to discuss the social and environmental impact of this technology. 5 MARKS.

a) Hybridization is carried out in order to combine favorable characteristics within the fertilisation of a gamete of one species with the gamete of another. An example of this are the cows 'Brahman' and 'Hereford'. The Brahman produces higher quality of milk whilst the Hereford produces large qunatities of milk. Hence, by hybridisation, the 'Bradford' is produced possessing both these features.

b) A transgenic species is the BT Crops. An environmental impact suggests that since all the crops around the world have been inserted with the bacterium BT, this, in essence, reduces genetic diversity as all the crops are genetically identical. Should a disease outbreak occur, there is a risk all crops can be wiped out into extinction. A social impact speaks that the use of the BT crops can succumb to the power of large corporations, an ethical issue as such power if controlled by large companies, can allow them to play as 'God'.

I hope I can join in on the fun!

 

[Mr_Kap]

1) Describe ONE theory about the processes responsible for the movement of materials through phloem tissue. 3 MARKS

2) Compare the changes in the chemical composition of blood as it passes through the lungs, the small intestine, and the brain. 4 MARKS

 

[Khan.Paki]

1) Describe ONE theory about the processes responsible for the movement of materials through phloem tissue. 3 MARKS

2) Compare the changes in the chemical composition of blood as it passes through the lungs, the small intestine, and the brain. 4 MARKS

1) One theory is the Pressure Flow Theory. The movement of materials in phloem is called translocation. It has 3 main steps: 1. Unloading from source to phloem, usually against a concentration gradient, hence requiring energy expenditure. 2. Movement in phloem due to osmotic pressure. 3. Movement from phloem to sink, again requiring active transport.

2) As blood passes the lungs, a decrease in CO2 and an increase in O2 can be attributed. However as blood passes through the brain and small intestine, a decrease in O2 and an increase in CO2 can be noted. Furthermore, in the small intestine, blood will have a higher concentration of nutrients . However it can also increase the amount of nitrogenous wastes. (is this right?)

Am I missing anything?

 

[Mr_Kap]

2) Small Intestines:
Blood entering ---> Less glucose, less amino acid, less vitamin, more oxygen
Blood Leaving ----> More glucose, more amino acid, more vitamin, less oxygen
(from excel success one)

1) Not sure. I never learnt phloem

 

[Khan.Paki]

I see. When answering these type of questions, is it necessary I state the composition of blood before it enters the organ? Or can I simply state the changes that occur after it has passes the organ?

 

[BlueGas]

I see. When answering these type of questions, is it necessary I state the composition of blood before it enters the organ? Or can I simply state the changes that occur after it has passes the organ?

Just mention that the blood is "deoxygenated" when it enters the heart.

 

[Mr_Kap]

Public health programs, pesticides, and genetic engineering are used to control and/or prevent disease.
Using an example, explain how ONE of these strategies have been used to control or prevent disease within the community. 3 MARKS

 

[Khan.Paki]

Aren't we only supposed to choose one? I think it says in the syllabus "how one of the following..."?

 

[Mr_Kap]

Aren't we only supposed to choose one? I think it says in the syllabus "how one of the following..."?

I fixed it. lol. Its only three marks now.

"Public health programs, pesticides, and genetic engineering are used to control and/or prevent disease.
Using an example, explain how ONE of these strategies have been used to control or prevent disease within the community. 3 MARKS "

 

[Chris_S]

Yeah! I only learnt about Public health programs! However, you might need to know about the others briefly in a multiple choice question?

 

[Mr_Kap]

does using pesticide such as DDT on mosquitos to prevent malaria count.

what did you do for public health programs

 

[BlueGas]

does using pesticide such as DDT on mosquitos to prevent malaria count.

what did you do for public health programs

Of course it counts lol.

 

[Mr_Kap]

For communication:

What is the role of the dendrites?

 

[BlueGas]

For communication:

What is the role of the dendrites?

Picks up messages using their extensive branches to increase the surface area of the 'receiving end' of the nerve cell.

 

[Mr_Kap]

do we have to know about the sodium channel shit? Or just the graph.

 

[BlueGas]

do we have to know about the sodium channel shit? Or just the graph.

It's not that hard to remember anyway, electrical changes are caused as sodium ions move into the neurone (deploratisation), after the signal has been transmitted, potassium ions move to the outside of the cell to restore the original charge of the neurone (polarisation).