nexttttt (3 Viewers)

[Takuto]

thanks for confirming that guys, lol

it was from a q in the 2007 MC

 

[Jt2008]

Yeah thats exactly right about xylem ( water and dissolved mineral ions) and its also a passive process.
where as phloem actively transports water and sugars (sucrose) via translocation around the... tree haha. Hope that helps...


One Q: About techology in relation with evolutionary relationships...

Are DNA sequencing and Amino acid sequencing the same?
And what other examples are there besides these and carbon dating?

Cheers

Ps. I cant wait to finsh my hsc and have a beer or three...or 700 haha

 

[Lordie]

I'm thinking there might be a bit on B and T cells, as well as the structure of nerves and neurons...just hasn't been asked TOO much lately. The last two years in Communication, there's been questions on the brain...so I think this year the experiment will be the Oscilloscope/amplifier? Just my opinion!

 

[LiL-Azn]

Yeah thats exactly right about xylem ( water and dissolved mineral ions) and its also a passive process.
where as phloem actively transports water and sugars (sucrose) via translocation around the... tree haha. Hope that helps...


One Q: About techology in relation with evolutionary relationships...

Are DNA sequencing and Amino acid sequencing the same?
And what other examples are there besides these and carbon dating?

Cheers

Ps. I cant wait to finsh my hsc and have a beer or three...or 700 haha

I am pretty sure DNA sequencing and amino acid sequencing isnt the same. Coz amino acids are made from 3 codes of DNA bases (A.T.C.G.). The DNA is sequenced in terms of the bases and are connected by a backbone of sugars and phosphates.

U can also use haemoglobin sequencing and cytochrome-c sequencing.

thats all i can pull outa my head lol

 

[hoochiscrazy]

Name a disease caused by a macro-parasite.

 

[midifile]

Name a disease caused by a macro-parasite.

taenaisis caused by tapeworm (tanaea)

 

[LiL-Azn]

Name a disease caused by a macro-parasite.

lol easy way to remember is to think of worms, lots and lots of worms!!

tapeworm = hydatid disease

 

[lil-monkey]

Yep thats right, except the water has minerals dissolved in it, so thats why takuto said "water and mineral ions"

ok thanks that makes sence now lol.
and the phloem moves water and sugars? i think im good now...with that anyways. oh god the test is tomorrow BAHH!!!

 

[gloworm14]

Name a disease caused by a macro-parasite.

lice infestation from lice haha
easy to remember


my brain hurts from too much bio info to remember eeeeeeeeeep

 

[dolbinau]

Who wants to post communication questions, if a lot of you (and statistically you probably are) doing that option

 

[hoochiscrazy]

Provide a definition and distinguish between the terms allele and gene?

 

[JosephW]

Who wants to post communication questions, if a lot of you (and statically you probably are) doing that option

How does an eye accommodate for objects of varying distances?

 

[lil-monkey]

Who wants to post communication questions, if a lot of you (and statistically you probably are) doing that option

yea i am. but just finishing stuff off for search for a better health atm. god damn t & b cells. lol

 

[Takuto]

Provide a definition and distinguish between the terms allele and gene?

A gene refers to the position on a chromosome which codes for a particular characteristic e.g. eye colour

while

An allele refers to alternative forms of the gene or characteristic e.g. brown or blue eye colour

 

[Takuto]

Hey, out of curiosity, how many of you guys have actually studied for the HSC and the Prelim course?

prelim? whats prelim?

 

[gloworm14]

i havent really studied the prelim. do we have to?
i think we just have to know vaguely about photosynthesis/respiration/omsosis umm what else ...


im getting the shakes... i dont know if its from nerves or the coldness

 

[bekmay]

i thought the xylem transported water up the stem from the roots to the leaves. and its passive transport. the transpiration-cohesion-tention mechanism.

or it that the phloem???


EDIT: yeah it does transport both water and minerals... but is above still correct ?
im so confused about the xylem and phloem.
could someone say
what each transports,
what each mechanism is called and how they work.
thanks =]

hmm.
for water, the transpiration-tension-cohesion mechanism. the process by which water and minerals are transported in the xylem to the leaves (which require water) is called transpiration. As water is evaporated from the stomata in the leaves (using energy from the sun), water molecules move up the xylem to replace the space left by the molecules being evaporated. this is the tension aspect- water moves from where it is low pressure to where it is low pressure. weak bonds between molecules of water are held together by cohesive force. water is adhesive to xylem walls. oh and also maybe consider root presure.

translocation moves sucrose in the plant via phloem from the source (storage cells or photosynthetic cells where sucrose is glucose... later converted) to the sink (plant cells). this requires active transport (whereas transpiration only uses passive transport). because substances are being transported (rather than just water), they are diffused over a concentration gradient, and the substances move to where there is the lowest pressure. thus, they don't just move up the plant, rather to where they are needed.

 

[lil-monkey]

How does an eye accommodate for objects of varying distances?

thats from the contracting(for close objects) and relaxing( for far objects) of the ciliary muscle, causing the slackening(for close objects) or tention(for far objects) of the ligaments attached to the lens, forcing the lens to become more spherical (for close objects) or flatter( for far objects)


i hope that kind of makes sence to you. lol if not sorry

 

[hoochiscrazy]

Its not like maths where the exam can be like 20% of the prelim course or anything like that so no havnt studied for it at all.

 

[dolbinau]

How does an eye accommodate for objects of varying distances?

Accommodation is achieved by changing the refractive power of the lens. At close distances, light diverges and the lens must have maximum refractive power to focus the light on the retina. This is achieved when the ciliary muscles contract; the ciliary ligaments become loose and the lens has a rounded shape. For light at long distances, the waves are almost parallel and minimum refractive power is needed. The muscles relax, the ciliary muscles tense and the lens is pulled flat, allowing light to be focused on the retina. This insures visual acuity for light at varying distances.

Q: What is a sound shadow?