Yeh I rushed that question but thats what I talked about, the action potential I said that a minimum threshold must be reached and that increasing the stimulus intensity has not much effect on how much the action potential goes, etc... did anyone else hate the drawings?! omg I kept on trying to draw!
Communication Option (2 Viewers)
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LauraHLH
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Yep, I talked about the experiment with the fat biconvex lens and the thin biconvex lens, where we anchored the lens and the paper to the desk and moved teh candle back and forth until the light focused on the paper, record the distance and repeat lol.
And the cochlear implant tech question was worth 7- I wrote a full page in the writing booklet, talking about understanding the structures in the ear and how this has helped us to build mechanical models that enhance (hearing aids) or translate (cochlear implant) sound.
With the visual communication, did everyone basically say that if they can see they can be a more functioning part of society, they can lead more independant lives etc?
well since since no one has really been confident with c) i'll tell you guys what i wrote, which i'm pretty sure is correct (yep at 2:30 in the morning because i cant sleep T_T)
I wrote about the "threshold" and explained what it meant, then explained how not all stimuli can generate an action potential (that is a response to stimuli) because they do not occur in the threshold. i explained using the diagram as the examples in my answer.
so referring to the diagram, the threshold is 2 or above, as there was only an action potential generated when the stimulus intensity was 2.
hope that clears things up a bit. I actually found our option quite easy and the fact only our option was one page as opposed to two and the other options had like 3 big mark questions whereas we only had 2.
looking in the forums, i think a lot of people found the exam easy (my biology teacher even said we got an easy paper) so the marking criteria will probably be harsher. they're probably gonna take of marks wherever they can. well there goes a the only possible band 6 i could get XD
I wrote about the "threshold" and explained what it meant, then explained how not all stimuli can generate an action potential (that is a response to stimuli) because they do not occur in the threshold. i explained using the diagram as the examples in my answer.
so referring to the diagram, the threshold is 2 or above, as there was only an action potential generated when the stimulus intensity was 2.
hope that clears things up a bit. I actually found our option quite easy and the fact only our option was one page as opposed to two and the other options had like 3 big mark questions whereas we only had 2.
looking in the forums, i think a lot of people found the exam easy (my biology teacher even said we got an easy paper) so the marking criteria will probably be harsher. they're probably gonna take of marks wherever they can. well there goes a the only possible band 6 i could get XD
BECBEC1992
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e) was worth 7 marks... i wrote 2 pages
wonmin
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Thought this section was okay. Had enough time to do a second section just incase. Supervisors laughed at me cause I did two. Ah well. Better safe than sorry.
For action potential I just wrote down the process of it and what is required for action potential to proceed. Then I just bsed the whole part about why didnt happen.
For action potential I just wrote down the process of it and what is required for action potential to proceed. Then I just bsed the whole part about why didnt happen.
truestar92
Member
I did the different lenses too. but I didn't really see how that modeled accommodation?
Cataract surgery!!! Ahh i wrote refractive. Pah! and that ear question was death.
I really thought i could've done better on the genetics question. I curse myself for not doing it!!!
=(
Cataract surgery!!! Ahh i wrote refractive. Pah! and that ear question was death.
I really thought i could've done better on the genetics question. I curse myself for not doing it!!!
=(
hey guys
For that 5 mark question about the potential
You had to talk about the electrochemical signals passing through the myelin shieth, the shwann cell and the axon
this must be demonstrated in the use of examples where the voltage of the interior sections of the nurone like Na+ and K+ ions which chagnge their positions by exchanging alternate ionic signals
this then gives the threshold for the minimum voltage required and the ability of the nurone to overcome this problem by changing the voltage potential, depolorise the actions and increase the voltage from -15mV to 50+mV
All these will earn you 5 marks
With the modelling of accommodation
It has nothing to do with myopia hyperopia
It is the thickness of 2 convex lenses that act like the human lens
and a ray box
and don't forget that accommodation is visual acuity and focus not a process of refraction which can be represented by myopia and hyperopia.
so u needed to draw 2 convex lenses both different interms of their thickness
and show how that can be realted to accommodation.
For that 5 mark question about the potential
You had to talk about the electrochemical signals passing through the myelin shieth, the shwann cell and the axon
this must be demonstrated in the use of examples where the voltage of the interior sections of the nurone like Na+ and K+ ions which chagnge their positions by exchanging alternate ionic signals
this then gives the threshold for the minimum voltage required and the ability of the nurone to overcome this problem by changing the voltage potential, depolorise the actions and increase the voltage from -15mV to 50+mV
All these will earn you 5 marks
With the modelling of accommodation
It has nothing to do with myopia hyperopia
It is the thickness of 2 convex lenses that act like the human lens
and a ray box
and don't forget that accommodation is visual acuity and focus not a process of refraction which can be represented by myopia and hyperopia.
so u needed to draw 2 convex lenses both different interms of their thickness
and show how that can be realted to accommodation.
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truestar92
Member
yeah i just want to know what people talked about for the action potential question??
Yer that was a tough one. I saved it for last actually.
I basically started by saying, to understand action potential. We must understand resting potential.
I spoke briefly about it. Basically, resting is when there is no pulse going through the nerve cell. The neurone is kept at a negative charge. This is done by the sodium pumps and Na ATPase, which pumps out Na ions outside cell. Potassium leak channels add the negativity which is around - 70mV.
So basically, action potential. I then went into it. When an impulse is passed either from a receptor (e.g mechanoreceptor ((cannot use example of a photoreceptor as they produce a generator potential which is different to action potential. Action is all or nothing, Generator is in ratio to stimulus) or the terminal branches from another axon, a pulse stimulates the neurone. If the stimulus depolarises the cell to around -35mV which is the threshold, the voltage gates (both the sodium and potassium gates) open and the built up Na ions outside cell rush in. Due to the fact it is an all or nothing response if this depolarisation does not reach the -35mV thresold and action potential does not occur.
Thus, this is reason why. I also spoke up mechnoreceptors being branched convergently ensuring the threshold is met even though the stimulus is smaller then the threshold.
I basically started by saying, to understand action potential. We must understand resting potential.
I spoke briefly about it. Basically, resting is when there is no pulse going through the nerve cell. The neurone is kept at a negative charge. This is done by the sodium pumps and Na ATPase, which pumps out Na ions outside cell. Potassium leak channels add the negativity which is around - 70mV.
So basically, action potential. I then went into it. When an impulse is passed either from a receptor (e.g mechanoreceptor ((cannot use example of a photoreceptor as they produce a generator potential which is different to action potential. Action is all or nothing, Generator is in ratio to stimulus) or the terminal branches from another axon, a pulse stimulates the neurone. If the stimulus depolarises the cell to around -35mV which is the threshold, the voltage gates (both the sodium and potassium gates) open and the built up Na ions outside cell rush in. Due to the fact it is an all or nothing response if this depolarisation does not reach the -35mV thresold and action potential does not occur.
Thus, this is reason why. I also spoke up mechnoreceptors being branched convergently ensuring the threshold is met even though the stimulus is smaller then the threshold.
Randomboy
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Accommodation question:
Materials:
Method:
As detailed below, set up practical mimicking the diagram:
I would then go on to relate this prac to the ciliary muscles manipulating the curvature of the lens to have a similar result...
Materials:
- Light box
- 3 x Blank A4 sheets of paper
- Two different shaped convex lenses of varying thickness and the widest point of the lens.
- Protractor
- Ruler
Method:
As detailed below, set up practical mimicking the diagram:
- Using the ruler draw two horizontal lines across the A4 page, one 5cm’s from the base line, and another 15cm’s from the base line.
- Draw a line vertically up the A4 page in the centre.
- Take the light box and place it on the 5cm mark.
- Place the tree slotted barrier over the end of the light box so you have three rays of light shinning onto your lens.
- Take your first lens and place it on the 15cm line.
- Turn the light box on and shine the beams of light through the lens using the vertical line drawn as a guide.
- Using the protractor measure the angle of refraction of the light as it enters the air/lens barrier. Use the line drawn as a guide to assist you.
- Record where the light converges to a point by marking it with a cross. Record the distance of the cross from the lens, in the table below. This should give you an indication of the focal length for the lens. The larger the distance from the cross to the lens, the larger the focal length.
- Trace the diagram of the behaviour of the light as it passes through the lens; record this on the white piece of paper.
- Repeat steps 5-9 with a lens of different thickness.
I would then go on to relate this prac to the ciliary muscles manipulating the curvature of the lens to have a similar result...
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boxhunter91
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Action potential-Threshold, "All or Nothing'' and wateva else.
Seriously wth 5 marks.
Seriously wth 5 marks.
dam i forgot to mention all or nothing response for the active potential question. For the first question id thought id be technical and put phakoemulsification for cataract surgery and i ended up spelling it wrong in the exam haha. I did the communication section first for some reason because i thought it was easy. wrote way too much for it tho