ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: Daenerys Targaryen on March 16, 2012, 05:06:33 pm
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Hey guys, this is my official question thread where I will post all of my questions about biology.
Here are my first few:
1. In Photosynthesis, the light dependant stage, where the water is split into 2 electrons, 2 hydrogen ions and one oxygen molecule, and the hydrogen and electron meet each other in stroma and are then picked up by the NADP. What happens here exactly because this is my main confusion which applies for most for the Hydrogen and NADP parts of cellular respiration and photosynthsis. My teacher told me, in specific to the situation above, that the 2 Hydrogen and 2e are combined together and then are joined to the NADP but he wrote this as NADPH + H+. Like what happens to that extra electron... and does NADP carry two hydrogens?
I dunno i have many questions and confusion around this, if anyone could build on this or explain in further depth that would be GREAT! (Answered but can also be further answered if you like :))
2. In photosynthesis, Calvin Cycle, when the NADPH's drop off the H+, does it put a H on each carbon molecule or does it put two to create the C6H12O6
Thanks ~
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I'll talk about Cellular Respiration first.
So Cellular Respiration is basically Glycolysis (or Oxidative decarboxylation of Pyruvate) -> Citric Acid Cycle (TCA) -> Electron Transport/ATP Formation (Oxidative Phosphorylation)
What you're interested in is the Citric Acid Cycle - you will have a net gain of 6 NADH, 2 FADH2 and 2 GTP
Now, when these go through the electron transport chain, they will basically be oxidised to NAD+, FAD2+
So the reaction for NADH would be: NADH -> NAD+ H+ + e-
The electron is then transferred to oxygen, the proton is pushed into the middle of the mitochondrion membrane, where it estabishes a charge gradient and hence, will force itself back down ATP Synthase which will hence, produce ATP.
I have no idea regarding photosynthesis, I don't do plant biology.
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So in general, the NADP is only a carrier for one Hydrogen not two?
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Yep. NADP+ can carry one hydrogen ion. It's important to know that NADPH and ATP are produced during the light-dependent stage and that these are used along with carbon dioxide in the light-independent stage, but I wouldn't worry too much about how many of each electron acceptor are produced or how many hydrogen ions or electrons can be attached to each. Oh, and it's important to know that water is split in the light-dependent stage and that oxygen is produced as a "by-product".
Also, NAD+ and NADP+ aren't the same. NAD+ is used as an electron acceptor for cellular respiration (forming NADH), while NADP+ is used for photosynthesis (forming NADPH).
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:O great, was getting confused between the two!
thanks
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Heres my next question:
In photosynthesis, Calvin Cycle, when the NADPH's drop off the H+, does it put a H on each carbon molecule or does it put two to create the C6H12O6
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In the 2012, VCAA sample question about the metabolic rate and effect from evironmental temperture.
http://www.vcaa.vic.edu.au/vce/studies/biology/pastexams/sample/biol1sampv206.pdf
What would do you guys think is the most viable/correct answer?
I've chosen A or C partically because, and -50 the mammal would be shivereing to produces more heat, but could mammal B have tjomler insulation as it is able to maintain its heat within a stricter range?
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Also, this may seem a lil' stupid but what does it mean by arbitrary?
ive dictionary'd it and its says random. how does this make sense with graphs and such?
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I don't know either but they use arbritrary units just to make it simpler to reference to. Many people wouldn't understand if they reference mol or anything like that.
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would it be safe to assume that its just normal numbers increasing/decreasing?
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arbitrary refers to things you can't easily measure but where an increase in distance from the origin refers to an increase in the value along that axis. It is used when the specific numbers are of little / no importance and / are completely relative (e.g. absorbance)
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ah okay thanks.
for the question above:
In the 2012, VCAA sample question about the metabolic rate and effect from evironmental temperture.
http://www.vcaa.vic.edu.au/vce/studies/biology/pastexams/sample/biol1sampv206.pdf
What would do you guys think is the most viable/correct answer?
I've chosen A or C partically because, and -50 the mammal would be shivereing to produces more heat, but could mammal B have tjomler insulation as it is able to maintain its heat within a stricter range?
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I would actually choose A, because mammal B actually has a higher metabolic rate at a temperature closer to the optimum than mammal A, indicating mammal B is required to shiver earlier. Therefore mammal A most likely has better insulating fat.
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ah i see. thanks !
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Must we know the four man immunoglobulins? (IgM, IgE, IgA, IgG)
If so what are some possible definitions?
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we just need to know IgE and IgG im pretty sure
IgE = allergen antibody
IgG = 70% of the antibodies in the immune system (general ones that they talk about)
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We only need to know IgE, IgG and IgA. For IgD and IgM, we only need to recognise that it's one of the 5 heavy chains of antibodies.
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i see, ive been getting mixed info.
teacher reckons we need to know M and E, other teachers all 5, friends from other school all 5 expect D
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It's really easy to remember all 5, since they spell GAMED
oh right you mean function.
it's not too bad
IgG is the General purpose one that's in most of the serum
IgE is the allergy one.
IgD you never need to know anything about
IgA/IgM, whilst important aren't as important as the first 2 for you guys to know imo
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yeah, but i haven't got any definitions atm haha.
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I can write some for you :)
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Types of Antibodies:5 different kinds if heavy chains.
IgG: formed and present in milk. Active against bacteria & viruses capable of crossing the placenta.Greatest concentration of antibodies in blood serum.Activates complementary system & macrophages.
IgA: active against bacteria&viruses, present in milk, saliva, perspiration and tears. Does not cross placenta. Formed by mucuous membrane cells and prevents attachment of viruses.
IgE: the tails of IgE attach to mast cells & basophils, when triggered by antigen, cause the cells to release histamine and other chemicals that cause allergic reactions, it is very rare.
IgM&IgD
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thanks babe <3
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If you want to know IgM: First antibody formed, confined to blood plasma, early defence against bacteria and viruses in the bloodstream.
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IgG IgA IgM IgE for my school.