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Troubles.. (1 Viewer)

Stimuli

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Hi,

I have a couple questions and would appreciate it if someone could help me!
1. Does the Choroid prevent light scattering? Or does it just suspend the Iris?
2. Are cataracts the results of protein denaturing or proteins clumping?
3. How do I set out the accommodation prac?
4. How much detail should I have on Fred Hollows?

Thanks!
 

BlueGas

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Hi,

I have a couple questions and would appreciate it if someone could help me!
1. Does the Choroid prevent light scattering? Or does it just suspend the Iris?
2. Are cataracts the results of protein denaturing or proteins clumping?
3. How do I set out the accommodation prac?
4. How much detail should I have on Fred Hollows?

Thanks!
1. The choroid absorbs and prevents light scattering to prevent false images forming on the retina.
2. Cataracts are the result of certain eye proteins called alpha-crystalline which fail to function properly (basically denaturation), when they fail to work, the normal clear lens proteins would clump together, clouding some part of the lens (cataract develops)
3. Take a look at this HSC question

4. Fred Hollows? lol where's the syllabus dot point that mentions him?
 

Stimuli

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Fred hollows links to "Process and analyse information from secondary sources to describe cataracts and the technology that can be used to prevent blindness from cataracts and use avaliable evidense to discuss the implications of this technology for society"?

Also, If i was to set out a prac for a question, would it be acceptable to draw some steps of my method to make it clear what i've done?

Thanks.
 
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BlueGas

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Fred hollows links to "Process and analyse information from secondary sources to describe cataracts and the technology that can be used to prevent blindness from cataracts and use avaliable evidense to discuss the implications of this technology for society"?

Also, If i was to set out a prac for a question, would it be acceptable to draw some steps of my method to make it clear what i've done?

Thanks.
Well if you can speak about Fred Hollows and maybe his work on cataracts as evidence then yeah you might be able to speak abut him.

Yes you can draw a diagram of the experiment to support your answer.
 

DepressedPenguino

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Hi,

I have a couple questions and would appreciate it if someone could help me!
1. Does the Choroid prevent light scattering? Or does it just suspend the Iris?
2. Are cataracts the results of protein denaturing or proteins clumping?
3. How do I set out the accommodation prac?
4. How much detail should I have on Fred Hollows?

Thanks!
1. Bluegas got a pretty good explanation.
2. yes, cataracts can result as a result of the denaturing of proteins and hence it would result in the clumping of them in the lens which causes the cloudiness (u see that in aged people)
3. Use comvex lenses w/ different thickness (i.e. different curvature) to measure the relationship between focal length and concavity. (The more round the lens, the shorter the focal length). You need to be able to identify the limitations of the experiment tho.
4. You should remember/know at least 2 statistics on the fred hollows foundations contribution to cataracts in terms of their successful impact on society.
 

DepressedPenguino

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Remember u can also mention other stuff besides fred hollows such as the World Cataract Foundation which also successfully decrease the rate of blindness
 

DepressedPenguino

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Fred hollows links to "Process and analyse information from secondary sources to describe cataracts and the technology that can be used to prevent blindness from cataracts and use avaliable evidense to discuss the implications of this technology for society"?

Also, If i was to set out a prac for a question, would it be acceptable to draw some steps of my method to make it clear what i've done?

Thanks.
Yes. U should :)
 

Stimuli

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What would the limitations be? Also, are the opsins in photreceptors (Rhodopsin for rods, photopsin for cones) the photopigment of the cells? I know that they're bonded with retinal but ive read information labelling the opsins as specifically, the photopigment.
 

BlueGas

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What would the limitations be? Also, are the opsins in photreceptors (Rhodopsin for rods, photopsin for cones) the photopigment of the cells? I know that they're bonded with retinal but ive read information labelling the opsins as specifically, the photopigment.
Basically photoreceptors contain photpigments. For Rods the photopigments would be Rhodopsin and for the Cones it would be Photopsin.
 

DepressedPenguino

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What would the limitations be? Also, are the opsins in photreceptors (Rhodopsin for rods, photopsin for cones) the photopigment of the cells? I know that they're bonded with retinal but ive read information labelling the opsins as specifically, the photopigment.
There are heaps of limitations lol. The eyes curvature is not just restricted to the ones (convex lenses) that you used. Another is that the convex lenses that was used only have a fixed focal length and that the lenses in our eyes can accommodate many focal lengths to focus light onto the retina (or fovea). There are many more.
question 2: Yeah. Light hits the photoreceptors (e.g. rods) and it initiate a series of decomposition reactions which includes the breakdown of rhodospin into retinal and opsin components. (I think it was 11-si-retina or whatever). The retinal segaments serves to absorb the light and activates the retinal component (which we generally read in textbooks as activated rhodopsin or active rhodopsin) which changes the charge of the rod cell etc.. (which moves away from ur question)
 

BlueGas

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I had a Biology exam today and I put iodopsins as the photopigments in cones, however this is what I found in 2014 HSC samples answers.



I don't think it matters though, I reckon it could be either photopsins or iodopsins...
 
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Flop21

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I had a Biology exam today and I put iodopsins as the photopigments in cones, however this is what I found in 2014 HSC samples answers.



I don't think it matters though, I reckon it could be either photopsins or iodopsins...

Photopsin is:
"The protein component of the pigment iodopsin in the cones of the retina of the eye."

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
Iodpsin is:

Any of three visual pigments, composed of 11-cis-retinal bound to an opsin, found in the cones of the retina.
So does that mean photopsin is the protein in iodopsin, and iodopsin is a name for the pigments within the cones ( erythrolabe, chlorolable, cyanolable)?

So would iodopsin be more correct??

I'm also confused since my notes use "iodopsin" multiple times, but don't mention photopsin, while the HSC answers do.
 

DepressedPenguino

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Photopsin is:


Iodpsin is:



So does that mean photopsin is the protein in iodopsin, and iodopsin is a name for the pigments within the cones ( erythrolabe, chlorolable, cyanolable)?

So would iodopsin be more correct??

I'm also confused since my notes use "iodopsin" multiple times, but don't mention photopsin, while the HSC answers do.
Yeah iodopsins are the pigments in cones. There are 3 kinds of the iodopsins and each of them are sensitive to one of the three primary colours of light, namely green, blue and red. U named the three types of iodopsin pigments.
 

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