Running list of key examples for Bio Trials/HSC (3 Viewers)

[SadCeliac]

Hi all,

I am making this thread as a mind dump of key examples for Bio trials based on questions seen in papers. Feel free to give some feedback and add examples!

Thanks!

THIS IS NOT A CLOSED THREAD - IF ANYONE HAS ANY OTHER USEFUL EXAMPLES PLEASE ADD AND ALSO PROVIDE FEEDBACK AND SUGGESTIONS

EDIT: ORIGINAL POSTS HAVE BEEN UPDATED

 

[SadCeliac]

"Identify the cause and effect of a named nutritional disease you have studied"
Scurvy
- Cause: lack of vitamin C (e.g., in citrus fruits)
- Effect: bleeding, swollen gums, loose teeth, bruising

 

[SadCeliac]

"Describe two features of a named Australian plant that help it conserve water"
Eucalyptus leaves
- waxy cuticle help retain water
- vertical leaves prevent over exposure to sun due to reduced surface area

 

[SadCeliac]

"With the aid of a specific example, assess the impact of the process of artificial pollination on the composition. and continuity of a population" (4)

example from another thread: "wheat hybrids were created in Australia in the 1870's by William Farrer. 'Purple Straw' variety was crossed with an Indian wheat variety, 'Yandilla', to create a new variety called 'Federation Wheat'. This new variety had increased disease resistance (from the indian variety) and was more tolerant of Australian climatic conditions (from the purple straw)"

edit;
bananas and panama disease
vanilla and how it is grown by artificial pollinaation

see thread for more details im not bothered to summarise here <3

 

[SadCeliac]

"Discuss the social, economic and cultural considerations surrounding the use of GM plants, with reference to this tomato plant [provided in a stimulus] and another example of a GM plant" (7)

BT cotton
- made in the 1990s
- GM cotton that contains DNA for a protein that is poisonous to a specific cotton-eating caterpillar
- required to be produced because the caterpillar had developed resistance to regular insecticides and was being a nasty pest
- gene used is from Bacillus Thuringiensis bacteria (now say it out loud)
- decrease in genetic diversity of the cotton plant --> GM plants are clones of each other for ease of production and therefore have no variation

edits;
- recombinant plasmid vector used to transfer BT gene into cotton
- as the cotton "germinates" it produces the gene and thus acquires the resistance
- decreased variation and genetic diversity allows increases the risk of a single disease wiping out an entire population, as there is no room for healthy mutations and resistances to generate and occur

- social considerations: allows for greater cotton products to be made and therefore benefits humanity OR general public is scared of GM
- economic: due to greater production by farmers, they can earn more + creates more jobs in the economy for retailers to sell cotton
- ethical: monocultures - not good for other plants who dont have resistance (they are outcompeted and die rip) OR general public is scared of GM and how it could be unethical to feed the developing countries a possibly 'harmful' genetically engineered product tbh

 

[SadCeliac]

Summary of SCNT (Somatic Cell Nuclear Transfer)
1) take a tissue (somatic cell) from a donor (A)
2) remove the diploid nucleus from the tissue cell
3) take unfertilised eggs from another animal (B) and remove the haploid nucleus
4) insert the diploid nucleus from the donor (A) into the empty egg from animal (B) --use heat shock and enzymes (e.g., telomerase) to insert the egg into the nucleus
5) allow the egg to grow in a surrogate (C)

offspring has the DNA of (A) but is birthed from (C)

confirmatory step: if surrogate (C) is recessive for the traits that donor (A) is dominant for, then you can have an extra layer of confirmation that the child is actually a clone of (A) and not just a child of (C), assuming that they show the same dominant traits as (A)

 

[Big_Kev]

"Describe two features of a named Australian plant that help it conserve water"
Eucalyptus leaves
- waxy cuticle help retain water
- vertical leaves prevent *** {I have no idea}

someone help with this example?

vertical leaves prevent excess sunlight from reaching the plant, coz think about it less of the plant itself is exposed to the sun due to it being vertical (not horizontal) and so it can ensure the plant doesnt die due to the excess sun

 

[Big_Kev]

"With the aid of a specific example, assess the impact of the process of artificial pollination on the composition. and continuity of a population" (4)

need help w this one

example from another thread: "wheat hybrids were created in Australia in the 1870's by William Farrer. 'Purple Straw' variety was crossed with an Indian wheat variety, 'Yandilla', to create a new variety called 'Federation Wheat'. This new variety had increased disease resistance (from the indian variety) and was more tolerant of Australian climatic conditions (from the purple straw)"

nice example - now u can mention how the resistance has (sadly for other plants) resulted in a "monoculture" due to these wheat hybrids being resistant to pests & such, and can allow for the hybrid plants' species to to "out-survive their counterparts" (counterparts being other plants without resistance) and so can ensure that these special plants are less susceptible to selection pressures & such

 

[Big_Kev]

"Discuss the social, economic and cultural considerations surrounding the use of GM plants, with reference to this tomato plant [provided in a stimulus] and another example of a GM plant" (7)

BT cotton
- made in the 1990s
- GM cotton that contains DNA for a protein that is poisonous to a specific cotton-eating caterpillar
- required to be produced because the caterpillar had developed resistance to regular insecticides and was being a nasty pest
- gene used is from Bacillus Thuringiensis bacteria (now say it out loud)
- decrease in genetic diversity of the cotton plant --> GM plants are clones of each other for ease of production and therefore have no variation

mention transduction vector agrobacterium tumifaciens which is used to transfer the BT gene into cotton
And also mention how as the cotton "germinates" it produces the gene and thus acquires the resistance
What is the result of decreased variation? Link this to higher change of succumbing to disease & env conditions
Slightly gory ik but say specifically that caterpillar dies upon ingestion of the plant

 

[SadCeliac]

nice example - now u can mention how the resistance has (sadly for other plants) resulted in a "monoculture" due to these wheat hybrids being resistant to pests & such, and can allow for the hybrid plants' species to to "out-survive their counterparts" (counterparts being other plants without resistance) and so can ensure that these special plants are less susceptible to selection pressures & such

maybe??

I was also thinking different examples:

1). Panama disease w bananas
Since the bananas are produced via artificial pollination (I'm not actually sure if they are tbh, it could be cloning) then they are susceptible to diseases --e.g., the Panama fungus that affected bananas

2). Vanilla bean is grown using artificial pollination, and is grown anywhere in the world --increases continuity but decreases diversity

 

[Big_Kev]

mention transduction vector agrobacterium tumifaciens which is used to transfer the BT gene into cotton
And also mention how as the cotton "germinates" it produces the gene and thus acquires the resistance
What is the result of decreased variation? Link this to higher change of succumbing to disease & env conditions
Slightly gory ik but say specifically that caterpillar dies upon ingestion of the plant

For social considerations id say it allows for greater cotton products to be made & so benefits humanity in that way
Economic - again due to greater production by farmers, they can earn more & it also creates more jobs in the economy for retailers & such to sell cotton
Ethical say monocultures - not good for other plants who dont have resistance

 

[Big_Kev]

maybe??

I was also thinking different examples:

1). Panama disease w bananas
Since the bananas are produced via artificial pollination (I'm not actually sure if they are tbh, it could be cloning) then they are susceptible to diseases --e.g., the Panama fungus that affected bananas

2). Vanilla bean is grown using artificial pollination, and is grown anywhere in the world --increases continuity but decreases diversity

yes Panama is good I use that too - if u can word it nicely then go for it

 

[SadCeliac]

mention transduction vector agrobacterium tumifaciens which is used to transfer the BT gene into cotton
And also mention how as the cotton "germinates" it produces the gene and thus acquires the resistance
What is the result of decreased variation? Link this to higher change of succumbing to disease & env conditions
Slightly gory ik but say specifically that caterpillar dies upon ingestion of the plant

a) isn't that just a fancy way of saying we use recombinant plasmids as a vector
b) yep okay didn't know that
c) decreased variation and genetic diversity allows increases the risk of a single disease wiping out an entire population, as there is no room for healthy mutations and resistances to generate and occur
d) fair, I was just going to leave it as "toxic to the caterpillar" haha

 

[SadCeliac]

Ethical say monocultures - not good for other plants who dont have resistance

but doesn't that just stem from the initial issue, where plants w/o resistance just die from the caterpillar? or do you mean that the plants w/o resistance are outcompeted by the ones with resistance...?

 

[Big_Kev]

Summary of SCNT (Somatic Cell Nuclear Transfer)
1) take a tissue (somatic cell) from a donor (A)
2) remove the diploid nucleus from the tissue cell
3) take unfertilised eggs from another animal (B) and remove the haploid nucleus
4) insert the diploid nucleus from the donor (A) into the empty egg from animal (B) --use heat shock and enzymes (e.g., telomerase) to insert the egg into the nucleus
5) allow the egg to grow in a surrogate (C)

offspring has the DNA of (A) but is birthed from (C)

GOOD but also ik im being a bit pedantic - towards the end just mention that even tho offspring is a clone of somatic donor, there still might be a bit of mitochondrial DNA from the egg cell of the mother, causing it to not be TRULY a clone of the dad (which you've already asserted at the end, but just extend it u know what mean) otherwise nice

 

[Big_Kev]

but doesn't that just stem from the initial issue, where plants w/o resistance just die from the caterpillar? or do you mean that the plants w/o resistance are outcompeted by the ones with resistance...?

yes those without resistance are outcompeted, which (bit of a stretch ik) but u can link this to how its unethical in a way coz it reduces the ability of other plants & species to survive

 

[SadCeliac]

GOOD but also ik im being a bit pedantic - towards the end just mention that even tho offspring is a clone of somatic donor, there still might be a bit of mitochondrial DNA from the egg cell of the mother, causing it to not be TRULY a clone of the dad (which you've already asserted at the end, but just extend it u know what mean) otherwise nice

theres also the extra step where I could say that if you have the surrogate (C) be recessive with traits that donor (A) is dominant for, then you can have an extra confirmation that the child is actually a clone of (A) and not just a child of (C)

 

[SadCeliac]

yes those without resistance are outcompeted, which (bit of a stretch ik) but u can link this to how its unethical in a way coz it reduces the ability of other plants & species to survive

nah that ethical issue is whack

much rather argue that the general public is scared of GM and how it could be unethical to feed the developing countries a possibly 'harmful' genetically engineered product tbh

 

[Big_Kev]

theres also the extra step where I could say that if you have the surrogate (C) be recessive with traits that donor (A) is dominant for, then you can have an extra confirmation that the child is actually a clone of (A) and not just a child of (C)

yuh thats good

 

[SadCeliac]

yuh thats good

cheers