nexttttt (3 Viewers)

[Undermyskin]

Ew, I think the neg. impacts of using pesticides are:
- Resistance renders these chemicals ineffective
- Poisonous to humans and other animals/plants
- Cause mutations to both human and animals and bacteria
- If appearing effective at first, farmers are tempted to overuse them

Pos. impacts:
- Quite good if monitored correctly

Biological control: they use birds, yeah?
- Safe, very effective, environmentally friendly, not troublesome in monitoring

Problems:
I remember they said about how they used birds to kill locusts but when they consumed all of the insects, their populations were too big and they got hungry --> acted like locusts and even destroyed orchards.

PS dol: I suppose they are similar.
Not sure, I just know that ribosome provides an active site for the synthesis and can accommodate two tRNAs at a time. (hence two proteins)

 

[dolbinau]

Is there any other way to identify xylem/phloem from a transverse section other than:

1. Xylem have thing cell walls

2. Phloem are surrounded by companion cells

?

 

[midifile]

Also, a few more questions regarding polypeptides.

In DNA replication, corresponding nucleotides are brought from the nucleoplasm. Is this the same for the formation of mRNA?

Is the function of the ribosome to read the codons and call for a corresponding tRNA molecule?

Yep. But in replication free nucleotides join to both stands of nucleotides, while in transcription nucleotides only join to one strand.

 

[midifile]

Is there any other way to identify xylem/phloem from a transverse section other than:

1. Xylem have thing cell walls

2. Phloem are surrounded by companion cells

?

3. Xylem are wider in diameter

 

[hoochiscrazy]

Also, a few more questions regarding polypeptides.

In DNA replication, corresponding nucleotides are brought from the nucleoplasm. Is this the same for the formation of mRNA?

Is the function of the ribosome to read the codons and call for a corresponding tRNA molecule?

The DNA chain doesnt unravel all the way only section that is to be copied is( in the mRNA). Also in mRNA uracil replaces thymine.

 

[Undermyskin]

But aren't those two effective?

Q: Investigators gathered data on a group of 100 smokers for a period of 10 years. During this time, 12 developed lung cancer, two died in traffic accidents, 3 of heart attacks. They concluded smoking causes lung cancer. How could it be improved. (4m)

I mention:
- Increase the number of "guinea pigs" to more than 1000
- Frequently survey if they quit smoking, how much they smoke
- Gather info about their lifestyles (diets, sports, etc), where they live (if near mining areas or industrial compounds)
- Are they under medications? Are there anyone in their families have the disease?
- Their ages (?) and jobs.

Anything else? My teacher says we need 6-7 points. Gross!

PS: why are xylems bigger in diameter? Aren't they derived from dead phloem?

 

[imqt]

But aren't those two effective?

Q: Investigators gathered data on a group of 100 smokers for a period of 10 years. During this time, 12 developed lung cancer, two died in traffic accidents, 3 of heart attacks. They concluded smoking causes lung cancer. How could it be improved. (4m)

I mention:
- Increase the number of "guinea pigs" to more than 1000
- Frequently survey if they quit smoking, how much they smoke
- Gather info about their lifestyles (diets, sports, etc), where they live (if near mining areas or industrial compounds)
- Are they under medications? Are there anyone in their families have the disease?
- Their ages (?) and jobs.

Anything else? My teacher says we need 6-7 points. Gross!

- have a control group to compare against
- increase survey over a longer time period
- survey other smoking groups from different areas

 

[Undermyskin]

Cool, except for the longer time. 10 yrs are enough, I think. Or well we die before we get the results, lolz.

Q: for 'environmental affects on phenotypes', we didn't do an experiment but use 2ndary data, still first hand investigation, to see how genes and environments act on certain diseases to different extents on lots of twins. Is it counted? I mean, everyone is doing a proper experiment with either plants or whatever. I'm so worried.

 

[frogbutt]

1. single strands of chromosomes double to form homologous pairs of chromosomes.
2. first meiotic division, the homologous pairs separate, but the double strands of the chromosomes are still joined.
3. 2nd division, the chromatids separate to form 4 gamates/daughter cells

Youtube explains it better than I do:
http://au.youtube.com/watch?v=D1_-mQS_FZ0

that's a very good video. the music especially. it's terribly emotional I nearly cried at the end. meiosis. what a beautiful thing.

 

[Undermyskin]

Q: practising Australian scientist and his/her research???

 

[gloworm14]

Cool, except for the longer time. 10 yrs are enough, I think. Or well we die before we get the results, lolz.

Q: for 'environmental affects on phenotypes', we didn't do an experiment but use 2ndary data, still first hand investigation, to see how genes and environments act on certain diseases to different extents on lots of twins. Is it counted? I mean, everyone is doing a proper experiment with either plants or whatever. I'm so worried.

we learnt about siamese kittens in changing temp
also hydrangea plants in changing pH soils

you can easily create an experiment with the hydrangeas using different pH soils

 

[imqt]

Cool, except for the longer time. 10 yrs are enough, I think. Or well we die before we get the results, lolz.

Q: for 'environmental affects on phenotypes', we didn't do an experiment but use 2ndary data, still first hand investigation, to see how genes and environments act on certain diseases to different extents on lots of twins. Is it counted? I mean, everyone is doing a proper experiment with either plants or whatever. I'm so worried.

no 10 years isnt enough...you need minimum 20 years. This is due to the fact that you may be surveying people in their late teens who just started smoking compared to those in their late thirties who've been smoking for 10 years. You need to give sufficient time for these early smokers in order to effectively assess the effects of smoking on a population as a whole. And if they die before the results? well you are not surveying them to give them the results. You could assess their death and see if it is smoking related. This will further evidence for your studies. Its not unusual for people to pass away during surveys...

 

[hoochiscrazy]

Cool, except for the longer time. 10 yrs are enough, I think. Or well we die before we get the results, lolz.

Q: for 'environmental affects on phenotypes', we didn't do an experiment but use 2ndary data, still first hand investigation, to see how genes and environments act on certain diseases to different extents on lots of twins. Is it counted? I mean, everyone is doing a proper experiment with either plants or whatever. I'm so worried.

We didnt do this experiment but got a sheet on a experiment you could do and just answered questions on it. Pretty much took 4 cutting from a hydrangeas they grew these in similar conditions( pH of soil=5, same amount of water, same times in sun ect). They becames established with a root system. Four months before they bloomed they changed the pH balance of the soil. They kept one plant as the control with soil pH =5. To one pot they added aluminium sulfate to make the soil more acidic and to the other 2 pots they added different amounts of dolomitic lime to make the soil more alkaline. they maintained the pH of the soil in the pots so that:
pot 1= pH 5 (control)
pot 2= pH 4 (acidic)
pot 3= pH 6.5
pot 4= pH 7.5
when the plants bloomed the students recorded the following results
pot 1= blue flowers
pot 2= darker blue
pot 3=pink
pot 4=pink and plant was slightyl chlorotic

 

[boony3]

I still havent looked at Blueprint of life and communication....my two worst topics :S
uh ohhhh anyways questionn

A standard NSW vaccination schedule for diptheria/pertussis/tetanus (DPT) is shown:

AGE
2 months
4 months
6 months
18 months
4 years

Propose reasons for the frequent vaccination between 2months and 4years.

 

[pbillabong]

hey for ppl doing human story, any ideas for examples in dot point 6.1?

 

[Undermyskin]

Thanks guys!

To boony: I suppose it's to boost and reboost the immune systems. Since the kids are still weak and immature, the memory cells can be insufficient and inefficient. It's a way to test their immune system and train the cells, I suppose.

Like when I had the hepatitis vaccination, I had to go there 4 times! after one month, after 6 months, after a year. Ouch.

 

[pooja_107]

Somebody....could you please have a look at the 2003 HSC paper Q 16 (a) --------------------------------i dont get it....they say its ectothermic but shouldnt it be endo???

 

[midifile]

Somebody....could you please have a look at the 2003 HSC paper Q 16 (a) --------------------------------i dont get it....they say its ectothermic but shouldnt it be endo???

Do you mean the solutions in success one?

if so, im pretty sure the answer is wrong

 

[pooja_107]

Yeah even i think sooo

 

[imqt]

hey for ppl doing human story, any ideas for examples in dot point 6.1?

yeh ...what do you not get about it?