ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: andrewloppol on February 26, 2010, 04:39:25 pm
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did the experiment last week and had 30 min SAC questions on it last night.
am pretty confident. :)
we just used cellulose tubing and a solution containing starch, protein, NaCl and glucose....and we put it in a beaker full of de-ion water with one of those flea-stirrer things to keep the conc. gradient high.
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umm, our teacher isn't following the textbook exactly.
she taught us about the organelles and phospholipid bilayer. last night we did lipids and carbohydrates. next week is proteins and nucliec acids. nice and easy if you do chem. :)
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^ you mean like glycerol and fatty acids and condensation reactions?
we've done that. we also did hexoses and pentoses last night. :)
we made glucose molecules with those chemistry sets and then we joined with another group and made manose lol.....
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Yes I've done my membrances SAC already, got 24/25 :)
Not sure where I stuffed up but I hopefully can have a look at it sometime soon...
I think my biology class is going so sloooowly, and the teacher doesn't even "teach". She's very pro about "self-directed learning", where we do the questions ourselves and "self-correct" using these sheets. I don't do it. Lmao too lazy. All she does is sit pretty in front of the class fiddling with her laptop T___T
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i already know like half of them...yay! i <3 bio....
and the other half i read them on the holidays but i sorta forget them haha.
and yeah i agree. pretty easy to teach yourself. but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
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Yes I've done my membrances SAC already, got 24/25 :)
Not sure where I stuffed up but I hopefully can have a look at it sometime soon...
I think my biology class is going so sloooowly, and the teacher doesn't even "teach". She's very pro about "self-directed learning", where we do the questions ourselves and "self-correct" using these sheets. I don't do it. Lmao too lazy. All she does is sit pretty in front of the class fiddling with her laptop T___T
Self directed learning :O?
Duuude..
Year 12 at school is all about spoon feeding :P. Getting given the answers on a sheet is good though!
Night time is for self directed!
Lazy teacher lol.
Bio's pretty easy to learn solo anyway, it's not very hard to understand! (There are a few hiccups though.)
I'm so glad that you can read from the Biology textbook and learn the content though, so phew! Yup I know... self directed learning T__T
but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
I'm glad I had another teacher explain to me that the textbooks aren't necessarily 100% true, and he told me about that :P
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Our class is doing a practical SAC using beetroot to explore our understanding of membranes. The main thing that we need to understand is why the solution (that the beetroot was placed in) changed colour.
So here are the different solutions: distilled water, pH 4, pH 7, pH 9.2, alcohol 1%, alcohol 25%, alcohol 50%, detergent 1%, detergent 5%.
Separate to this the beetroot was placed in temperatures of 0,10,25,40,50,60,70 degrees.
The results indicated that alcohol and detergent cause most pigment leakage (about 3-4/5 on a scale). Varying pH had a small effect, as did distilled water (about 2-3/5).
One interesting result was that pH 9.2 resulted in a colour leakage rating of 1 after 30 mins then change to 0 after 24 hours. What is an explanation for this?
For temperature, the colder, the more leakage and the warmer, also the more leakage. Temperatures 25 and 40 both showed little to no colour loss.
How do you explain these results?
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Mine was similar to stone colds.
Dialysis tubing was featured in all 3 experiments.
We only performed one ourselves and the other two were done as demonstrations due to time constraints and the gas not functioning because of the construction.
Experiment 1: Place a dialysis tube full of starch in a beaker full of water and Iodine solution. Leave for 30 minutes. (there may of been some heat involved.
Result: After 30 minutes the contents inside the dialysis tubing bag turned purple (indicating starch). This also proves that while iodine and water solution moved into the bag, hence reacting with the contents, no change was observed in the water outside the bag. This is because almost no starch made it through the dialysis tubing due to its size, while water solutions could fit through.
Experiment 2: Cut ~10 chunks of potato as equally as you can, place 2 into a cup, this way filling 5 cups. Label each cup 0%, 0.5% 1% 2% 5%. Weigh the potato contents of each cup and record. Fill each cup with matching concentration of NaCl (Salt water) and in the case of the 0% cup distilled water.
Leave for 30 minutes.
Remove and weigh the potato slices using the same procedure as before.
Figure out the change in weight, in absolute value and % wise.
Results: Cant remember exactly but the 0, 0.5, gained weight by a relative big amount. 1% barely changed with a little weight gain. 2% and 5% showed weight loss.
This can be explained by osmosis and the osmotic pressure causing water loss.
Experiment 3: ... if i remember ill write back.
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i already know like half of them...yay! i <3 bio....
and the other half i read them on the holidays but i sorta forget them haha.
and yeah i agree. pretty easy to teach yourself. but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
Root cells, for example, aren't exposed to sunlight, so it's really inefficient (waste of resources) to have chloroplasts in there.
Yes I've done my membrances SAC already, got 24/25 :)
Not sure where I stuffed up but I hopefully can have a look at it sometime soon...
I think my biology class is going so sloooowly, and the teacher doesn't even "teach". She's very pro about "self-directed learning", where we do the questions ourselves and "self-correct" using these sheets. I don't do it. Lmao too lazy. All she does is sit pretty in front of the class fiddling with her laptop T___T
Self directed learning :O?
Duuude..
Year 12 at school is all about spoon feeding :P. Getting given the answers on a sheet is good though!
Night time is for self directed!
Lazy teacher lol.
Bio's pretty easy to learn solo anyway, it's not very hard to understand! (There are a few hiccups though.)
I'm so glad that you can read from the Biology textbook and learn the content though, so phew! Yup I know... self directed learning T__T
but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
I'm glad I had another teacher explain to me that the textbooks aren't necessarily 100% true, and he told me about that :P
There is also a bit more to learn than just the textbooks!
E.g Cell membranes possess CHOLESTEROL for maintaining fluidity and stability!
That was on the exam last year, but don't remember reading it in Nature of Biology lol.
Oh what?! That's strange because the cholesterol in membranes was mentioned many times in Heinemann... and also in its workbook :)
Yeah I'm trying to hopefully get more resources for biology so I can go well :P
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Mine was similar to stone colds.
Dialysis tubing was featured in all 3 experiments.
We only performed one ourselves and the other two were done as demonstrations due to time constraints and the gas not functioning because of the construction.
Experiment 1: Place a dialysis tube full of starch in a beaker full of water and Iodine solution. Leave for 30 minutes. (there may of been some heat involved.
Result: After 30 minutes the contents inside the dialysis tubing bag turned purple (indicating starch). This also proves that while iodine and water solution moved into the bag, hence reacting with the contents, no change was observed in the water outside the bag. This is because almost no starch made it through the dialysis tubing due to its size, while water solutions could fit through.
Experiment 2: Cut ~10 chunks of potato as equally as you can, place 2 into a cup, this way filling 5 cups. Label each cup 0%, 0.5% 1% 2% 5%. Weigh the potato contents of each cup and record. Fill each cup with matching concentration of NaCl (Salt water) and in the case of the 0% cup distilled water.
Leave for 30 minutes.
Remove and weigh the potato slices using the same procedure as before.
Figure out the change in weight, in absolute value and % wise.
Results: Cant remember exactly but the 0, 0.5, gained weight by a relative big amount. 1% barely changed with a little weight gain. 2% and 5% showed weight loss.
This can be explained by osmosis and the osmotic pressure causing water loss.
Experiment 3: ... if i remember ill write back.
My SAC was like your experiment 2, with potato cylinders and but we had 10% NaCl solutions as well XD
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i already know like half of them...yay! i <3 bio....
and the other half i read them on the holidays but i sorta forget them haha.
and yeah i agree. pretty easy to teach yourself. but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
Root cells, for example, aren't exposed to sunlight, so it's really inefficient (waste of resources) to have chloroplasts in there.
Yes I've done my membrances SAC already, got 24/25 :)
Not sure where I stuffed up but I hopefully can have a look at it sometime soon...
I think my biology class is going so sloooowly, and the teacher doesn't even "teach". She's very pro about "self-directed learning", where we do the questions ourselves and "self-correct" using these sheets. I don't do it. Lmao too lazy. All she does is sit pretty in front of the class fiddling with her laptop T___T
Self directed learning :O?
Duuude..
Year 12 at school is all about spoon feeding :P. Getting given the answers on a sheet is good though!
Night time is for self directed!
Lazy teacher lol.
Bio's pretty easy to learn solo anyway, it's not very hard to understand! (There are a few hiccups though.)
I'm so glad that you can read from the Biology textbook and learn the content though, so phew! Yup I know... self directed learning T__T
but there a some things you need to be told. i.e. most textbooks don't really mention that not all plant cells have chloroplasts!
I'm glad I had another teacher explain to me that the textbooks aren't necessarily 100% true, and he told me about that :P
There is also a bit more to learn than just the textbooks!
E.g Cell membranes possess CHOLESTEROL for maintaining fluidity and stability!
That was on the exam last year, but don't remember reading it in Nature of Biology lol.
Oh what?! That's strange because the cholesterol in membranes was mentioned many times in Heinemann... and also in its workbook :)
Yeah I'm trying to hopefully get more resources for biology so I can go well :P
damn textbooks! heinemann talks about cholesterol in the membrane but doesn't mention anything about aquaporins. :(
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Aquaporins are relatively new though aren't they? Something like 2003 or so?
I doubt examiners will examine it though, due to many teachers lacking the knowledge of the discovery and not teaching it?
Biol textbooks will have to be re-written!
I know they have to be re-written!
LOL Andrew Douch's podcasts, I fell asleep during the first half of his podcast on enzymes as he attempted to use PacMan as an analogy for enzymes....
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aqua porins are just small water protein channels that span the whole membrane ....so yeah i don't think you guys need to learn about them specifically, but i think from bad memory...that you have to know the structure and function of the cell membrane
lol pacman......
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yep
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lol yeah, but i thought that the textbook co's would jump at the idea of making a few tiny changes and then releasing a brand new edition for $80 haha.
and what are these podcasts? i'm interested. :)
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ex bio student here who only got like 30 raw :P
good luck 2010 year 12 bio-ers
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Thanks first SAC is very soon! Weekends I'm going to hardcore study bio ;D
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i should probably note that water does move regardless of water channels via osmosis even though its charged or polar because of its small size...but the channels are needed to make it more efficient and faster..
ppl should also know the difference between osmolarity and tonicity..
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My prac is next week :) My teacher is going through the content of the prac in a single period class and then we have the next day's double for the prac.
Yeah my friend and I had a discussion about cholesterol in the plasma membrane, I had to rely on Douchy's podcast to understand what it's role is, because for some strange reason it isn't covered in the Nature of Biology book +_+ and my teacher explained it too :) And yeah the prac is in class test.
So we'll be tested on our knowledge of movements across the cell membranes, and perhaps also membrane structure right?
We may be asked to explain what causes the difference when placed in isotonic, hypertonic and hypotonic solutions etc. ?
I thought it might similar to the prac I did in Bio 1+2, we did potatoes.
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osmolarity and tonicity..
Oh.... lol..
lol you do right?
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
Sounds like chem :P.
I remember we did something like that
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hey when do you guys learn about the immune system? is that like the last topic?
or is it more dna, protein stuff now?+ transport mechanisms?
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i think immune system is towards the end of unit 3 yeah?
you mean like viruses and stuff?
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lol i dunno im asking you...
yea stuff like that....
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well it must be because unit 3 in my book is chapters 1-9, and i read up to chapter 7 on the holidayz and it still hadn't come haha.
so yeah must be right at the end of unit 3. :)
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ah okay lol
u read alot and hasn't it been like 1 month only?
well goodluck...learn about transcription/translation...all the cellular stuff... its important for later too (like uni and beyond..)
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thanks. :)
i'm listening to douchy podcast right now haha!
wish he would get to the damn point!!!!!
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lol.. i watched 5 seconds of the adp-atp podcast and then closed it.. he seems very chirpy and happy and excited..lol its funny..
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thanks. :)
i'm listening to douchy podcast right now haha!
wish he would get to the damn point!!!!!
LOL agreed, he likes to ramble
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Make sure you don't neglect immunity+ even though it's like the last topic!
I finished the course with a week to go - mistake lol - and pretty much left out immunity...
if you finished the whole course, how did u leave out immunity? u didn't study?
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
I did that exact SAC.
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Make sure you don't neglect immunity+ even though it's like the last topic!
I finished the course with a week to go - mistake lol - and pretty much left out immunity...
if you finished the whole course, how did u leave out immunity? u didn't study?
Obviously that's the best bit.
Yes, save it till the last :P
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Make sure you don't neglect immunity+ even though it's like the last topic!
I finished the course with a week to go - mistake lol - and pretty much left out immunity...
if you finished the whole course, how did u leave out immunity? u didn't study?
Obviously that's the best bit.
Yes, save it till the last :P
lol yeah
u doing it this year?
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oh i see ...bl u still got high 40 lol so wateva
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yeah u got high score- 40
anyway bio exams suck... 90 minutes is crap
uni so much better 3 hrs
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Make sure you don't neglect immunity+ even though it's like the last topic!
I finished the course with a week to go - mistake lol - and pretty much left out immunity...
if you finished the whole course, how did u leave out immunity? u didn't study?
Obviously that's the best bit.
Yes, save it till the last :P
lol yeah
u doing it this year?
Yep
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goodluck
does ur immunology go for two semesters or one?
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yeah u got high score- 40
anyway bio exams suck... 90 minutes is crap
uni so much better 3 hrs
Disagree, I enjoy examinations more than random assessments worth lots throughout the uni semesters.
Like I have to do in Arts. Psychology is a 3 hour exam for me though, so there's that.
Anyway if you mean that it's better because you have more time, it's really not because it will just be more difficult/longer :)
I liked the midyear for Bio, as far as examinations or assessments go.
I thought the structure of it was simple to study for.
Aside from disease/immunity which was a bit all over the place for our class, and what I lost marks on in the exam.
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i like how theres more time because you don't have to rush
but 1st yr bio exam was simple because i believe it was all multiple choice (which can and may not be a good thing)
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goodluck
does ur immunology go for two semesters or one?
I have something called Principles of Microb & Immun in semester 1 and have a whole subject dedicated to Immunology in third year
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i like how theres more time because you don't have to rush
but 1st yr bio exam was simple because i believe it was all multiple choice (which can and may not be a good thing)
I never had to rush in the mid year.
The end of year was long, so it was harder to complete the task in the given time, but all in all you should never truly be rushing.
If you think quickly, or prepare your mind to do so then you will have the time to construct a coherent answer and finish the paper with some left over time to go over what you have stated and make sure it is adequate.
But multiple choice is hard for many students, which is why I think it's a handy skill to perfect section A if you're partial to multiple choice.
I prefer long answer.
Too bad the Psychology exam is a computerized multiple choice test this year, I think?
Oh well, I can do multiple choice too, it requires considerably less effort and more chance of choosing the right answer if you're unsure.
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ah ok
yeah sorta like monash
i had two micro units and one imm unit in yr 2
but 3rd yr we have 4 units of imm and 4 units of micro
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i like how theres more time because you don't have to rush
but 1st yr bio exam was simple because i believe it was all multiple choice (which can and may not be a good thing)
I never had to rush in the mid year.
The end of year was long, so it was harder to complete the task in the given time, but all in all you should never truly be rushing.
If you think quickly, or prepare your mind to do so then you will have the time to construct a coherent answer and finish the paper with some left over time to go over what you have stated and make sure it is adequate.
But multiple choice is hard for many students, which is why I think it's a handy skill to perfect section A if you're partial to multiple choice.
I prefer long answer.
Too bad the Psychology exam is a computerized multiple choice test this year, I think?
Oh well, I can do multiple choice too, it requires considerably less effort and more chance of choosing the right answer if you're unsure.
if ur talking bout yr 12 ... i just remember that i was rushed for time
yeah psych is full mc exam
but because its mc, they usually make it dodgy or the answers are similar
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
I did that exact SAC.
Omg if you did can you help me? The method my teacher wrote out makes NO sense, and it's tomorrow :S
Apparently you get 5 test tubes, place hydrogen peroxide in each, and then various pH solutions of 1,4,7,9 and 14 into each one. Record "height of bubbles". It's meant to be recording the effect of the enzyme catalase (which breaks down hydrogen peroxide into water and oxygen), but I am confused as there is no catalase IN the pH solution OR the hydrogen peroxide, so how on earth am I meant to measure the "bubbles" caused by the release in oxygen? o.o
With 5 more test tubes, I am meant to put liver in each, and then the various pH solutions again. Measure "bubbles" again. This also doesn't make sense, there isn't any hydrogen peroxide so how am I meant to measure the effect of the enzyme catalase? Sorry if I'm not clear here, if someone replies I will actually get out my sheet and retype it.
Any help please?
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
I did that exact SAC.
Omg if you did can you help me? The method my teacher wrote out makes NO sense, and it's tomorrow :S
Apparently you get 5 test tubes, place hydrogen peroxide in each, and then various pH solutions of 1,4,7,9 and 14 into each one. Record "height of bubbles". It's meant to be recording the effect of the enzyme catalase (which breaks down hydrogen peroxide into water and oxygen), but I am confused as there is no catalase IN the pH solution OR the hydrogen peroxide, so how on earth am I meant to measure the "bubbles" caused by the release in oxygen? o.o
With 5 more test tubes, I am meant to put liver in each, and then the various pH solutions again. Measure "bubbles" again. This also doesn't make sense, there isn't any hydrogen peroxide so how am I meant to measure the effect of the enzyme catalase? Sorry if I'm not clear here, if someone replies I will actually get out my sheet and retype it.
Any help please?
The first set of 5 test tubes are controls. They don't have any catalase in them in case the breaking down of hydrogen peroxide occurs without the presence of catalase anyway (and I think it does, albeit at a negligible rate - hence the need for the enzyme). You won't see any bubbles. For the second set, I'm not sure if it's a typo or if you misread the prac instructions, but there should be hydrogen peroxide in each set of test tubes unless that's another control of some sort and then there's another set of test tubes.
EDIT: Basically what should be happening is that the controls (hydrogen peroxide+pH solution) produce no bubbles, and then the experimental tubes (hydrogen peroxide+pH solution+liver which has catalase in it) will produce some. However, as the liver is around pH 7 and typically enzymes function at their maximum rate at the pH from where they're found, I'd assume that the bubbles would be produced fastest in the pH 7 tube, with the rate decreasing as you get further away from this from either side. So keep in mind that with this experimental design, you're not really measuring the effect of the enzyme catalase as you said; you're measuring the effect of pH on enzyme function.
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I have another Biology SAC coming up, on enzymes this time.
We have to put liver in various pH solutions, and then hydrogen peroxide in various pH solutions.We then graph the "height in bubbles" of the oxygen produced in the test tubes...
Hmmm...
I did that exact SAC.
Omg if you did can you help me? The method my teacher wrote out makes NO sense, and it's tomorrow :S
Apparently you get 5 test tubes, place hydrogen peroxide in each, and then various pH solutions of 1,4,7,9 and 14 into each one. Record "height of bubbles". It's meant to be recording the effect of the enzyme catalase (which breaks down hydrogen peroxide into water and oxygen), but I am confused as there is no catalase IN the pH solution OR the hydrogen peroxide, so how on earth am I meant to measure the "bubbles" caused by the release in oxygen? o.o
With 5 more test tubes, I am meant to put liver in each, and then the various pH solutions again. Measure "bubbles" again. This also doesn't make sense, there isn't any hydrogen peroxide so how am I meant to measure the effect of the enzyme catalase? Sorry if I'm not clear here, if someone replies I will actually get out my sheet and retype it.
Any help please?
The first set of 5 test tubes are controls. They don't have any catalase in them in case the breaking down of hydrogen peroxide occurs without the presence of catalase anyway (and I think it does, albeit at a negligible rate - hence the need for the enzyme). You won't see any bubbles. For the second set, I'm not sure if it's a typo or if you misread the prac instructions, but there should be hydrogen peroxide in each set of test tubes unless that's another control of some sort and then there's another set of test tubes.
EDIT: Basically what should be happening is that the controls (hydrogen peroxide+pH solution) produce no bubbles, and then the experimental tubes (hydrogen peroxide+pH solution+liver which has catalase in it) will produce some. However, as the liver is around pH 7 and typically enzymes function at their maximum rate at the pH from where they're found, I'd assume that the bubbles would be produced fastest in the pH 7 tube, with the rate decreasing as you get further away from this from either side. So keep in mind that with this experimental design, you're not really measuring the effect of the enzyme catalase as you said; you're measuring the effect of pH on enzyme function.
Hey thanks a lot for that, but no there is no typo, the method specifically says just to put liver and pH solution into the test tube, and no hydrogen peroxide which was why I was confused. It was a prac my teacher wrote up herself which was why I am wary (as she is prone to a lot of mistakes..)
But thank you again!
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wth yeah i dont think it makes sense... u need liver (this contains the catalase right? or u adding seperate?) and hydrogen peroxide...
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wth yeah i dont think it makes sense... u need liver (this contains the catalase right? or u adding seperate?) and hydrogen peroxide...
Yeah the stupid teacher didn't put it on the sheet :( I'm hoping the SAC to be easy because it's on enzymes :P
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Haha thanks for the tip! :)
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Hmm I didn't really know that those inhibitors were called competitive and non-competitive, but I've heard of them before.. what textbook did you use last year?
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Haha Andrew Douch. I use Heinemann, they really need to update the biology textbooks, they're getting old :P
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got my results back for my sac 25/30 cant say im to happy with that but hey most of the class failed.
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got my results back for my sac 25/30 cant say im to happy with that but hey most of the class failed.
Good shit man :) - it's the rank which is what you're after remember :).
Trueee.
I got my SAC back 24.5/25, lol lost the .5 of a mark because I described that the graph (that I had in my results) revealed a bell-shape curve. I think I lost the marks for not mentioning the variables haha :P
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Hmm I'm not sure what rank, but probably in the top 3 :P
It was strange last year, my 2 friends did biology, one did better on his SACs than my other friend, and also performed a whole grade better in his two exams than her. Strange thing is, she got A+ for her SACs (girl with lower exam mark and sac mark) and the guy got A for his SACs (despite higher ranking and exam mark). Error of the VCAA? Or could there be another explanation?
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Hmm I'm not sure what rank, but probably in the top 3 :P
It was strange last year, my 2 friends did biology, one did better on his SACs than my other friend, and also performed a whole grade better in his two exams than her. Strange thing is, she got A+ for her SACs (girl with lower exam mark and sac mark) and the guy got A for his SACs (despite higher ranking and exam mark). Error of the VCAA? Or could there be another explanation?
Are you sure that he had a higher ranking? If so, I have no explanation; from what I've read higher ranking=higher moderated mark.
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i doubt that is the case, because statistical moderation does not change the ranking of students in a cohort, only the grades.
highest ranking = highest sac mark
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I know which is odd, he didn't have the highest ranking but he was probably in the top 3. Unless there was a really close margin of the rankings between him and my other, but I agree with you m@tty and stonecold, it really doesn't make any sense.
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My class isnt doing fantastic... well the people that sit within a table of me that ive asked anyway
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GG for bio SACS this year :/
We have three periods to do it
1st- we do the experiment
2nd - he goes through EVERYTHING, tells the whole class all the answers basically
3rd - we do the actual test
I got 24/25 for the first SAC and that was somewhere in the top 10
the lowest mark in the class was basically an A/A+
Wow easy SACs or people are all really good?
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so how are bio students liking it (bio) so far?
hate it? like it? difficult? easy?
cause if i remember correctly unit 3 is more interesting than unit 4
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Loving it, and u3 is much better than u4, I can tell. U4 also looks harder but that's not why its less interesting.
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ha cool ... anything in particular? or u like everything... yeah u4 is like evolution boring..lol
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About time I'm up to Outcome 2! It sounds so interesting, the immune system etc :P
I quite like biology, except the parts where the textbook doesn't explain information very well (how proteins are made). Still a bit icky on that.
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Specific, non-specfic defence and all that jazz looks very nice. Respiration and photosynthesis are amazing as always. Can you remember what you liked?
What specifically don't you understand about proteins? Are you using NOB, because if so, I can see why the explanations are poor. NOB is over-rated, I borrowed Heinemann and it is much better.
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yeah immunity is very nice and the dna and protein stuff
respiration and photosynthesis i never really liked and i still don't like lol
yeah nature isn't that good..i had used that textbook
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i :smitten: biology.
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I used Heinemann, but how they first introduced how proteins are made was with some analogy (office, "photocopying", workers etc.) Grr okay, the analogy is fine, but I don't particularly like it :P
Hmm well... transcription occurs in the nucleus? mRNA is made and then goes out of the nucleus into the cytoplasm... to the ribsomes? tRNA then carries an anti-codon and something something something and then arranges the sequence of amino acids that fits into the coding of the mRNA? Oh god I'm so lost. I've looked up the meaning for translation multiple times but it doesn't seem to stick in my mind, probably because I still don't understand it :(
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in eukaryotes..
yep..yep..yep... ye..p....lol
translation is just making of the polypeptide chain from reading of the mrna
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Yeah, gotta love bio-lodgerino. Proteins are good too, agree with you on that.
Akira - I hate stupid analogies too. I'm not too sure yet about the exact way that proteins are made but I don't think you need to know at this stage. Your explanation seems okay, although I better learn what an anti-codon is :) My understanding so far is that: mRNA copies the required segment of DNA carrying the codons that represent AAs. tRNA transfers the specific AAs to the ribosome and rRNA helps by reading the mRNA instructions and directing assembly of the polypeptide chain.
The reason why I say you don't need to know anything more then simple information at the moment is this:
What should I cover about DNA in Unit 3?
Response:
In Unit 3 Outcome 1 (p. 22 of the study design) students should understand the structure of DNA a polymer made from monomers and that its functions as a store of information to code for proteins.
The nucleus holds the genetic code in its base sequence. The code is carried to ribosomes by mRNA which is complementary to the DNA codons. There the code specifies the order of amino acids to form polypeptides that are converted into proteins by folding and cross-chain bonding. The genetic code is based on the base pairs that form the code.
Students should understand that three bases in sequence (a triplet) code for a particular amino acid. A gene can be defined as a sequence of triplets.
The process by which the code assembles the amino acids is gene expression. The mechanism of gene expression involves transcription and translational. Knowledge of gene expression (transcription and translation) is required in Unit 4 Outcome 1 (p. 27 of the study design).
I took this from the VCAA's biology FAQ. It's actually a worthwhile read considering the broadness of the study design.
http://www.vcaa.vic.edu.au/vce/studies/biology/biologyfaqs.html
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Thanks a lot aleitu1! I'm actually fine with all of that stuff, so phew :P
(except not being 100% sure what translation was but now I do thanks to Truelight, I was too lazy to get out my textbook haha)
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Awesome. Smiles all round :)
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What SS are you guys aiming for?
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I used Heinemann, but how they first introduced how proteins are made was with some analogy (office, "photocopying", workers etc.) Grr okay, the analogy is fine, but I don't particularly like it :P
Hmm well... transcription occurs in the nucleus? mRNA is made and then goes out of the nucleus into the cytoplasm... to the ribsomes? tRNA then carries an anti-codon and something something something and then arranges the sequence of amino acids that fits into the coding of the mRNA? Oh god I'm so lost. I've looked up the meaning for translation multiple times but it doesn't seem to stick in my mind, probably because I still don't understand it :(
totally agree, their comparison of dna/rna to an office blows. i'm really confused over the whole transcription, translation and tRNA, mRNA and rRNA. might learn it properly over the weekend. :)
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I used Heinemann, but how they first introduced how proteins are made was with some analogy (office, "photocopying", workers etc.) Grr okay, the analogy is fine, but I don't particularly like it :P
Hmm well... transcription occurs in the nucleus? mRNA is made and then goes out of the nucleus into the cytoplasm... to the ribsomes? tRNA then carries an anti-codon and something something something and then arranges the sequence of amino acids that fits into the coding of the mRNA? Oh god I'm so lost. I've looked up the meaning for translation multiple times but it doesn't seem to stick in my mind, probably because I still don't understand it :(
totally agree, their comparison of dna/rna to an office blows. i'm really confused over the whole transcription, translation and tRNA, mRNA and rRNA. might learn it properly over the weekend. :)
I know the explanation needs your undivided attention to understand! Haha me too, I might sit down properly and have a good look at it :P
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What SS are you guys aiming for?
Hmm last year I would have been happy with 35+, but now that I'm into it, I'm hoping to get 40+ :P I was going to ask you the same question and realised it was already in your sig.. :)
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thanks andrew, will do. :)
i was always meaning to take douchies virtual biology classroom to the next level and introduce videos lol.
speaking of douchy, I wonder when the next podcast will be, there hasn't been one for a while now...
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Your explanation seems okay, although I better learn what an anti-codon is :) My understanding so far is that: mRNA copies the required segment of DNA carrying the codons that represent AAs. tRNA transfers the specific AAs to the ribosome and rRNA helps by reading the mRNA instructions and directing assembly of the polypeptide chain.
the DNA acts as a template for mrna synthesis... and that mrna sequence of nucleotides is read in codons (3 nucleotides at a time) by the ribosome, which brings the correct trna molecule (which has an anticodon) which recognises the complementary codon, and that then is what the amino acid sequence is based on... because the trna has the amino acid attached to its structure and thus as the ribosome moves down the mrna it, more amino acids are added covalently to the growing polypeptide chain...
but yeah i guess u don't have to worry since its unit 4?
but yeah watch some videos... its better to visualise it
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Your explanation seems okay, although I better learn what an anti-codon is :) My understanding so far is that: mRNA copies the required segment of DNA carrying the codons that represent AAs. tRNA transfers the specific AAs to the ribosome and rRNA helps by reading the mRNA instructions and directing assembly of the polypeptide chain.
the DNA acts as a template for mrna synthesis... and that mrna sequence of nucleotides is read in codons (3 nucleotides at a time) by the ribosome, which brings the correct trna molecule (which has an anticodon) which recognises the complementary codon, and that then is what the amino acid sequence is based on... because the trna has the amino acid attached to its structure and thus as the ribosome moves down the mrna it, more amino acids are added covalently to the growing polypeptide chain...
but yeah i guess u don't have to worry since its unit 4?
but yeah watch some videos... its better to visualise it
Hmm I actually knew and understood that, I think my only worry is not being able to word it very well (as seen in my attempt before :P)
Is it really unit 4? So all we need to know about proteins at unit 3 is what aleitu1 posted?
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hmm dunno...i thought u did ... maybe u dont
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Your explanation seems okay, although I better learn what an anti-codon is :) My understanding so far is that: mRNA copies the required segment of DNA carrying the codons that represent AAs. tRNA transfers the specific AAs to the ribosome and rRNA helps by reading the mRNA instructions and directing assembly of the polypeptide chain.
the DNA acts as a template for mrna synthesis... and that mrna sequence of nucleotides is read in codons (3 nucleotides at a time) by the ribosome, which brings the correct trna molecule (which has an anticodon) which recognises the complementary codon, and that then is what the amino acid sequence is based on... because the trna has the amino acid attached to its structure and thus as the ribosome moves down the mrna it, more amino acids are added covalently to the growing polypeptide chain...
but yeah i guess u don't have to worry since its unit 4?
but yeah watch some videos... its better to visualise it
ah i forgot ... premrna splicing ... and other things.. promoters, utr, start, intron, exon, open reading frame, terminator sequence, release... but thats beside the point lol
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I don't know what those are ^ Would I have to know? :S
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i dunno... but i reckon it will make it easier for u to understand the overall process ... if u understand what is actually going on..
but yeah i dunno
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I don't know what those are ^ Would I have to know? :S
Nah, that stuff is unit 4.
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I don't know what those are ^ Would I have to know? :S
Nah, that stuff is unit 4.
Thanks :)
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this board is quiet lol what u guys learning now or up to?
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It feels like I haven't had a biology class in ages! The last class we were looking at ... I don't even remember :O What was your favourite part of biology TrueLight? (I'm assuming you've finished it :P)
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yeah ive finished it a few years back
...bored now..waiting for echo to work!!!rrrr
um...i think...lol some of the experiments were good... i dunno which unit this was but i still remember this one where we had to spray the heck out of ppl and then put a fan on them and then after they were soaked with water and ice, they had to go in blankets and heater.. in terms of content i liked the molecular bio stuff...i remember hating the evolution stuff...i didn;t like the genetics stuff mendelian stuff... and immune system stuff was really cool.. lol i think thats what got my interest started in immunology... biotech stuff was good i think... yeah lol thats all i can remember i think..
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we are learning about cellular respiration and photosynthesis, and are also in the process of doing our enzyme prac/sac
also here is a vid i found really helpful on dna transcription, translation and protein synthesis
http://www.youtube.com/watch?v=983lhh20rGY&feature=related
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Cell replication - we're at the end of Unit 1 AOS 1.
yr 11 bio? mmm thats like meiosis and mitosis stuff... never liked that stuff...
dna replication by itself and that process is alright
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we are learning about cellular respiration and photosynthesis, and are also in the process of doing our enzyme prac/sac
also here is a vid i found really helpful on dna transcription, translation and protein synthesis
http://www.youtube.com/watch?v=983lhh20rGY&feature=related
ah atp production and stuff.... never liked that too.. lol
yeah that video is pretty basic.. theres some better more detailed videos
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We started AOS 2 the other day.
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We are going way too slowly... Only up to molecular bio in medicine. Really, AOS 1 should be completed in 5-6 weeks, it's mostly revision from year 11.
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We are going way too slowly... Only up to molecular bio in medicine. Really, AOS 1 should be completed in 5-6 weeks, it's mostly revision from year 11.
I swear my class is going far too slow as well! And definitely agree with you, it is basically year 11 revision, I don't see why it should take that long.
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ha man u go through stuff in like terms 3 months... at uni in 3 months we finish everything lol
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didn't wan't to start a new thread so i'll just ask here :)
basically we tested the reaction rate of an enzyme at different temperatures by testing for glucose conc at the end of the experiment. (we put starch in at the beginning)
our controls were a test tube of enzyme and a test tube of starch both at 22 degrees.
we tested all our other tubes (containing both enzyme and starch) at a range of temps including 4, 22, 37 and 60 degrees.
what do I say for this question:
explain whether the controls in the experiment served their purpose...
edit: and obviously there was no glucose present in either of the controls at the end. we were using amylase btw...
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okay thanks. but i'm confused. the control showed the difference of enzyme by itself and starch by itself giving nothing. then when they were together, glucose was produced.
our teacher said the purpose of the experiment was to test the variable 'temperature.'
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exactly. i get why you have amylase and glucose on their own, to ensure that they don't produce glucose on their own, but that is really a separate experiment.
In the context of this experiment, if we were testing for temp, then shouldn't all test tubes contain the same thing (amylase + starch) and the control (only one) has a set temp, and then all the other tubes are tested at a range of different temps, and the glucose conc. compared to the control to see how temperature alters the reactions rate?
but that would mean that the controls didn't serve their purpose, and i doubt that would be the answer.
it is a two mark question, so maybe you say no, and then explain why?
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Schools always stuff up their experiments. Mention the ambivalence in your answer.
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^its so annoying. the sac is on thursday, i guess i'll have to ask my teacher then...
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Yeah I suppose, very annoying stuff.
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umm, can someone quickly explain what are the functional differences between salivary amylase and pancreatic amylase.
Amylase:
-Digestive enzyme, that breaks down starch into simple sugars such as dextrin, maltose and glucose.
-Humans have alpha amylase, which makes random products, vs. beta amylase in plants which only produces maltose.
-Both salivary amylase and pancreatic amylase have optimal pH of ~6-7 and optimal temp of 37 degrees.
are there any functional properties of amylase I should know about, which are unique to either the pancreas or saliva...
thanks.
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haha yeah, but my sac tomorrow unfortunately does...
:P
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im going to copy what this textbook (Human physiology, Lauralee Sherwood) says..
'Digestion in the mouth involves the hydrolysis of polysaccharides into disaccharides by amylase. However, the most digestion by this enzyme is accomplished in the body of the stomach after the food mass and saliva have been swallowed. Acid inactivates amylase, but in the center of the food mass, where stomach acid has not yet reached, this salivary enzyme continues to function for several more hours.'
'Like salivary amylase, pancreatic amylase contributes to carbohydrate digestion by converting polysaccharides into disaccharides. Amylase is secreted in the pancreatic juice in an active form, because active amylase does not present a danger to the secretory cells. These cells do not contain any polysaccharides.'
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thanks TL.
i checked wiki but it was pretty general.
so basically it is the exact same amylase, which means the functional properties are the same.
if that is the case then whoever wrote this sac really screwed up!
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yep same pretty much ... break down starch to simpler sugars
read through this
http://en.wikipedia.org/wiki/Alpha-Amylase
although seriously... u dont need to know all that.. and personally i think its a stupid question lol
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Enzymes are a pretty cool topic.
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Enzymes are a pretty cool topic.
+1
Awesome as :D
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Nah seriously they were probably my favourite; hf with energy. Krebs cycle and electron transport chain are pretty great to get your head around.
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Yeah, im a fan of the enzymes section too.
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so so so so many enzymes to remember and what they do......dam u micro and ur little dog too!
but yes enzymes fun... and expensive..lol
anyway...
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Okay, I'm confused! Please help...
The electron transport chain in cellular respiration involves:
A. Cytochrome's on the inner mitochondrial membrane or
B. Cytochrome protein on the outer mitochondrial membrane.
there were two other answers but they were redundant.
now the ETC takes place along the cytochrome's in the cristae
isn't that the outer membrane?
the answer sheet says A. is the correct answer, but yeah, unless the outer membrane is the mitochondrial matrix. (which makes no sense as it is on the inside), then i don't see why I am wrong. also, i'm pretty sure cytochrome's are proteins.
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Okay, I'm confused! Please help...
The electron transport chain in cellular respiration involves:
A. Cytochrome's on the inner mitochondrial membrane or
B. Cytochrome protein on the outer mitochondrial membrane.
there were two other answers but they were redundant.
now the ETC takes place along the cytochrome's in the cristae
isn't that the outer membrane?
the answer sheet says A. is the correct answer, but yeah, unless the outer membrane is the mitochondrial matrix. (which makes no sense as it is on the inside), then i don't see why I am wrong. also, i'm pretty sure cytochrome's are proteins.
Mitochondria are structured so that they have an outer membrane, an inner membrane, an intermembrane space in between these two layers, and the matrix filling the inner membrane. The spaces created by the folds of the inner membrane are known as the cristae. This diagram will probably help visualising that. I'm not sure what level of detail you've learnt in VCE since I'm pretty sure you don't go very in-depth into the electron transport chain, but it seems like you already knew that the proteins are found on the cristae at least. Just keep in mind that the cristae are formed from the inner membrane then I guess; not outer.
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oh i think i get it. thanks shinny. basically the cytochrome's sit on the outside of the inner membrane(the intermembrane space)?
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Yeah correct answer is A - they are called crystae like you said and are the compartments formed by the inner membrane. The matrix is the fluid inside the mitochondrion. You could think about it similarly to photosynthesis - the grana being similar to the crystae and the matrix being similar to the stroma.
You are right about cytochromes as well, they are protein complexes.