Wenhao's Biology 3/4 Ques Thread!!!

[Panicmode]

Haha that's fine.

Osmosis is the diffusion of water molecules from a region of low solute concentration to a region of high solute concentration across a semi-permeable membrane. Anything to add or change? Please give me the best definition that I could get.
Do I have to add "water movement "to this osmosis definition?

With osmosis you must always refer to the water molecules. I would say the definition should be:

Osmosis is the passive net movement of water molecules from a region of high water concentration (low solute) to a region of low water concentration (high solute) across a selectively permeable membrane

*I would not use diffusion but rather 'passive net movement' (net=overall; net is important because if there is no overall movement of molecules [because maybe it is in an isotonic solution] there is no osmosis)

So add  "passive net movement" instead of diffusion? What exactly is passive net movement?

Are you asking these questions because you skipped 1/2 bio?

Yeah I did skipped 1/2 Bio and haven't done any yr9-10 bio(just focus on physics and chem).
So I assume you know this?
If yes you might be able to explain the cellular respiration and photosynthesis to me. Thanks

I'll explain it when we go to the library together.

Please explain it here as I want to write down some info now. ThankQ

I'll make sure to give you a more comprehensive definition later using diagrams but for now:

The way diffusion works is that the solvent particles randomly collide (and pass through) the semipermeable membrane. The side with more particles obviously has more particles colliding (and passing through) the membrane. AT THE SAME TIME however, particles on the opposite side are colliding with this same membrane and passing through to the side with the higher concentration. But because more particles are going from the high solvent concentration to the low solvent concentration, the net solvent movement is in this direction. This is an example of a dynamic equilibrium. When the concentration becomes equal on both sides, water doesn't stop passing through the membrane, but there is overall no net water movement as the movement through the membrane is the same on both sides.

Does that make it easier to understand? 

[LOLs99]

That's quite a good explanation. But I have no idea what you're talking about. Haha gonna fail Bio

EDIT: I understand some after reading it couples of time. ty

[Truck]

I think the best thing you can do is start reading NOB, I think Osmosis is in chapter 1 or 2. Maybe take notes on chapter 1-2 and try understand how it works from the textbooks explanation, then look up youtube video's of Osmosis if you nee to, and then if you still need more help ask someone here. Personally, NOB was the most concise (opposite of a lot of other things lol).

[LOLs99]

Just a clarifying that do I have to know more than 1 definition for osmosis as there can be different definitions.
Yeah great idea Thanks.

[Truck]

It's really not a big part of the course, I wouldn't worry so much about it . Just about any of the definitions people have posted here will get you full marks if it was an exam question (albeit that's unlikely), just use Panic's or ggxoxo's one.

[LOLs99]

Wondering what would the first,second....sacs or outcomes would they be.
Can anyone explain them with more details a bit although schools may be doing different sacs.
ty very much

EDIT: Can someone also explain the cellular respiration and photosynthesis(some understandable basic language details)

[paulsterio]

I'll hit up Photosynthesis first. This is basically the storage of light energy in a form that the cell can access. It occurs in anything that is green (because that means that chlorophyll is present). The end aim of photosynthesis is to convert sunlight into Glucose and essentially ATP later on.

There are two phases of photosynthesis. There's the light-dependent phase and the light-independent phase. In the light-dependent phase, basically the chlorophyll will react with the light in the choloroplast to form a high energy compound. For every 12 water molecules used up in this process, 6 carbon dioxide molecules are used. The oxygen in water is converted into oxygen gas and is excreted as waste.

The light-independent phase takes the high energy compounds produced before and converts them into glucose. So for every glucose formed, 6 oxygen and 6 water molecules are produced, thus we have the equation: 6CO₂ + 12H₂O -> C₆H₁₂O₆ + 6O₂ + 6H₂O. This can be simplified to give: 6CO₂ + 6H₂O -> C₆H₁₂O₆ + 6O₂.

[duquesne9995]

I'll hit up Photosynthesis first. This is basically the storage of light energy in a form that the cell can access. It occurs in anything that is green (because that means that chlorophyll is present). 

Not just green, also red/blue/other coloured algae which have pigments that can capture different wavelengths of light. The chlorophyll captures red and blue light the best, but not green, so it reflects green.

[paulsterio]

Not just green, also red/blue/other coloured algae which have pigments that can capture different wavelengths of light. The chlorophyll captures red and blue light the best, but not green, so it reflects green.

True that actually

[ggxoxo]

Wondering what would the first,second....sacs or outcomes would they be.
Can anyone explain them with more details a bit although schools may be doing different sacs.
ty very much

EDIT: Can someone also explain the cellular respiration and photosynthesis(some understandable basic language details)

1st SAC- osmosis
2nd SAC- enzymes; investigate enzyme activities under diff conditions
3rd SAC- homeostasis
4th SAC- immunity (make a poster)

[LOLs99]

Thanks guys, greatly helpful..

So SAC 1 is coming soon and I need to know what's happening, so it's about what stuff in osmosis.
    and SAC 2 is about the roles of enzymes and the activities,right?
I get the others. Thanks

So basically light dependent requires light energy while light independent requires?high energy compound as in?
Btw do I have to know the chemical formula for the photosynthesis,cellular respiration, glucose(C6H12O6)

[HERculina]

Btw do I have to know the chemical formula for the photosynthesis,cellular respiration, glucose(C6H12O6)

definitely

[LOLs99]

Thanks and is there a way to remember them?by chemical names or formula or both?

[ggxoxo]

Thanks guys, greatly helpful..

So SAC 1 is coming soon and I need to know what's happening, so it's about what stuff in osmosis.
    and SAC 2 is about the roles of enzymes and the activities,right?
I get the others. Thanks

SAC1- my school put potato pieces into different concentrations (i.e. hypertonic, hypotonic, isotonic solutions) and observe their effects on the mass of the potato pieces; the SAC started off with questions directly from the experiment (e.g. aim, hypothesis, results, graphs, conclusion, what was the control, sources of error) and then got into more general questions (i.e. define osmosis, questions on different contexts (e.g. what would happen if you put a fresh-water fish into a salty environment))

Good luck!!! You should be fine!

[paulsterio]

Thanks and is there a way to remember them?by chemical names or formula or both?

Both, you'll need to know them for Unit 3 Chemistry anyway