Biology 2013ers MARATHONN (4 Viewers)

[Cleverusername5321]

"Evaluate the current use of gene cloning in animals and plants." (7 marks)
Does anyone know the answer to this? It's from the 2003 HSC paper (genetics option); there are no sample answers.
I thought that gene cloning referred to processes such as the production of insulin? How would this be used in plants/animals?

Explain how both genetics and the environment can affect the phenotype of an organism.4M

Genetics determine the genotype which in the end determines phenotype via the production of polypeptides. Genotype refers to the types of alleles present in an organism for a particular gene (e.g. heterozygous for height in Mendel's pea plants - this will produce a tall phenotype).
Environment affects the genotype with mutagens. E.g. if a person experiences overexposure to sunlight (mutagen), skin cancers can arise (mutation, which is a variation from the original phenotype).

-------
Please don't come looking for me if that question comes up and if i mislead you or something, but I think that's right.

 

[bedpotato]

"Evaluate the current use of gene cloning in animals and plants." (7 marks)
Does anyone know the answer to this? It's from the 2003 HSC paper (genetics option); there are no sample answers.
I thought that gene cloning referred to processes such as the production of insulin? How would this be used in plants/animals?

- briefly (1 - 2sentences) describe what gene cloning is (recombinant DNA technologies, PCR)
- uses of gene cloning - insulin is right, but you need more examples
- advantages - relate this to its uses
- disadvantages - again, relate this to its uses
- evaluation (conclusion)

 

[Cleverusername5321]

- briefly (1 - 2sentences) describe what gene cloning is (recombinant DNA technologies, PCR)
- uses of gene cloning - insulin is right, but you need more examples
- advantages - relate this to its uses
- disadvantages - again, relate this to its uses
- evaluation (conclusion)

Yea, but what other examples would you use? Also, insulin production occurs in bacteria. I thought about using bacteria for that question, but I googled it and it's neither an animal or a plant. This asks for animals and plants. That's the part that I don't understand, how you'd use *gene cloning* in animals or plants, without referring to whole organism cloning.

 

[bedpotato]

Yea, but what other examples would you use? Also, insulin production occurs in bacteria. I thought about using bacteria for that question, but I googled it and it's neither an animal or a plant. This asks for animals and plants. That's the part that I don't understand, how you'd use *gene cloning* in animals or plants, without referring to whole organism cloning.

Don't think you understand the difference between gene cloning and whole organism cloning, which is quite self explanatory.
Whole organism cloning: a whole organism is cloned. produces identical offspring which are copies of the parent organism.
Gene cloning: produces multiple copies of only specific genes. e.g. only the gene that produces insulin is cloned.

Gene cloning is used to produce transgenic organisms such as:
- drought resistant crop
- bt cotton.
- frost-resistant strawberries
If you look at BOL, you should have some examples there as well.

Other examples:
- genes can be cloned for analysis and research (in forensic investigations)
- insulin/human growth hormone (insulin is used for humans - which are animals, bacteria is only used to produce insulin etc. the question isn't asking where gene cloning occurs, but what it's used for)

 

[Cleverusername5321]

Don't think you understand the difference between gene cloning and whole organism cloning, which is quite self explanatory.
Whole organism cloning: a whole organism is cloned. produces identical offspring which are copies of the parent organism.
Gene cloning: produces multiple copies of only specific genes. e.g. only the gene that produces insulin is cloned.

Gene cloning is used to produce transgenic organisms such as:
- drought resistant crop
- bt cotton.
- frost-resistant strawberries
If you look at BOL, you should have some examples there as well.

Other examples:
- genes can be cloned for analysis and research (in forensic investigations)
- insulin/human growth hormone (insulin is used for humans - which are animals, bacteria is only used to produce insulin etc. the question isn't asking where gene cloning occurs, but what it's used for)

Hmm.. I will use bt cotton and insulin production as examples. It makes sense now. I was focusing too much on where gene cloning occurs I guess.

 

[obliviousninja]

When in doubt, just go Bt cotton.

 

[fionarykim]

Genetics determine the genotype which in the end determines phenotype via the production of polypeptides. Genotype refers to the types of alleles present in an organism for a particular gene (e.g. heterozygous for height in Mendel's pea plants - this will produce a tall phenotype).
Environment affects the genotype with mutagens. E.g. if a person experiences overexposure to sunlight (mutagen), skin cancers can arise (mutation, which is a variation from the original phenotype).

-------
Please don't come looking for me if that question comes up and if i mislead you or something, but I think that's right.

This answer is pretty much right
except, environment affects the phenotype much more than the genotype. although it does due to mutations like you said. Environment can effect genetically identical twins, and allow them to look quite different. this is due to their life style, habitat, diet etc and these factors play a big role in affecting phenotype. Another example is the hydrangeas, where their flower colours can change depending on what type of soil it is, so even if it is the genetically same flower, it has a different phenotype due to the environment it grows in

in a first hand investigation you observed plant diseases and insect pests
name 3 features of plants which demonstrates they have diseases and suggest a cause (whether its bacterial or fungal etc) 5 mks

 

[bedpotato]

Lol, im not sure if my first two answers are correct (kinda guessing them)
a) for both animals the enzymatic activity increases from 0degrees to a certain point (when the enzyme is most efficient) then decreases with further increases in temperature. The enzyme activity is generally greater for animal B
b) B is the endotherm as it is able to regulate its core body temperature at an optimal level, despite changes in the ambient temperature, which allows for greater enzyme activity. A is the ectotherm as it's body temperature fluctuates with ambient temperature and hence efficient enzyme activity will be restricted to a much narrower optimal range.
c) Bilby; large ears with extensive blood capillaries facilitate an increased surface area over which the organism can lose heat to the environment. This allows it to cope with hot desert climates.
d) The red bellied black snake burrows under the ground and in vegetation to minimise exposure to sunlight, allowing it to keep cool.

Explain how both genetics and the environment can affect the phenotype of an organism.4M

Forgot to reply to this, haha sorry.

b is incorrect
A- endotherm
B - ectotherm

 

[Menomaths]

Forgot to reply to this, haha sorry.

b is incorrect
A- endotherm
B - ectotherm

Thank god, I was confused af lol

 

[Spiritual Bean]

all nighter here I come

ill check in later

 

[superSAIyan2]

Forgot to reply to this, haha sorry.

b is incorrect
A- endotherm
B - ectotherm

is it because endotherms can only function efficiently in a limited range of temperatures in which their strucutral/functional adaptations will work. but ectotherms' body temperature matches the external environment and so is less affected? im not sure about this lol

can someone explain that question please

 

[bedpotato]

is it because endotherms can only function efficiently in a limited range of temperatures in which their strucutral/functional adaptations will work. but ectotherms' body temperature matches the external environment and so is less affected? im not sure about this lol

can someone explain that question please

Yeah, something like that.

There was a question in 2012, and its answer will probably explain it better than I can.

 

[bangladesh]

in a first hand investigation you observed plant diseases and insect pests
name 3 features of plants which demonstrates they have diseases and suggest a cause (whether its bacterial or fungal etc) 5 mks

Can someone answer this plox?

 

[bedpotato]

If the plant leaf has dark growth spots on the stem, then that indicates that fungal infections have taken place. Sections of leaf that looked shredded or has holes indicates that caterpillars are responsible. Any rusting on surface leaves of plants indicate that bacteria have infested it. Insect gall are swollen spots on a leaf and are caused by various pest and insects. That is all I can think of, probably looking at 3 marks maximum.

A new product has been developed to kill pathogens in drinking water. Design an experiment to test the effectiveness of the product 4M (2008)

Just a quick outline;

1. - sterilise workbench area using methylated spirits.
2. - obtain 5 nutrient agar plates
3. - seal one plate with sticky tape and label as control
4. - obtain water samples from two different sources: pond water, river water
5. - sterilise innoculating loop
6. - dip the innoculating loop intro the pond water sample, lift the lid of a perti dish to 45deg and gently move the loop over the surface of the agar in an S shape.
7. - seal the dish with sticky tape and label as "pond water
8. - repeat steps 5-7 with the river water sample
9. - obtain fresh samples of pond water and river water, and add equal amounts of the new product to each.
10. - after 5 minutes, repeat steps 5 - 7 with with the new water samples.
11. - place all agar plates in the incubator at 30C for 3 days.
12. - after 3 days, record results in a table, identifying the number of colonies and types of microorganisms.

is this even right

 

[bangladesh]

Just a quick outline;

1. - sterilise workbench area using methylated spirits.
2. - obtain 5 nutrient agar plates
3. - seal one plate with sticky tape and label as control
4. - obtain water samples from two different sources: pond water, river water
5. - sterilise innoculating loop
6. - dip the innoculating loop intro the pond water sample, lift the lid of a perti dish to 45deg and gently move the loop over the surface of the agar in an S shape.
7. - seal the dish with sticky tape and label as "pond water
8. - repeat steps 5-7 with the river water sample
9. - obtain fresh samples of pond water and river water, and add equal amounts of the new product to each.
10. - after 5 minutes, repeat steps 5 - 7 with with the new water samples.
11. - place all agar plates in the incubator at 30C for 3 days.
12. - after 3 days, record results in a table, identifying the number of colonies and types of microorganisms.

is this even right

eh... Shouldn't the control be distilled water/boiled water ?

 

[Menomaths]

eh... Shouldn't the control be distilled water/boiled water ?

No, having nothing ensures the agar plates aren't contaminated.

 

[obliviousninja]

wat he said.

describe changes in blood composition as it moves around the body and identify tissues where changes occur

 

[bedpotato]

You got 2 marks:
- identification of independent variable (presence of product), dependent (amount of pathogens/colonies) and controlled variable (temperature, water source and volume)
- correct method for testing pathogen

You forgot to mention any risk identified and response lacked repetition of experiment/large sample size according to answer.

lol

i just wanted to know if this method was appropriate for this question.

risks:
- bunsen burner flame
- spread of pathogens: don't open the agar plates after incubation
- water samples are contaminated; don't consume

what would you write about sample size?

 

[obliviousninja]

when I saw the question...I legit forgot wat to relate to...tbh I was thinking about postulates. lol

 

[bedpotato]

It is rare to find a female with a sex-linked disease such as haemophilia or red-green colour blindless. Justify this statement. [3]