Question Set 3
Is the polar OH group of cholestrol involved in the rigidity of the phospholipids?
Not really. The rigidity as mentioned is contributed by the steriod rings. The hydroxyl group orient itself such that it is beside the polar head grps of adjacent phospholipids and thus allowing the rings to (interact and) immobilise the regions of the HC chains closer to the polar heads. =)
Next Up: Let's talk about Water Potential.
Graph on Water Potential...
For one class, I have already gone through the theory of water potential while the other awaits. But really, what usually have us scratched our heads off is the graph and that, I shall try my best to explain it. Stay with me, imagine with me and see me if need to.
Clarification for 3L: when I meant turgid today, I meant full turgor. Nothing less.
Common misunderstanding : solute potential = turgor pressure.
Solute potential within and outside cell will determine the direction of flow of water. After incipient plamoslysis in the 2nd half of the graph when surrounding medium becomes more dilute, more water will enter the cell. (note that the solute potential is increasing -> increasing dilution in the cell)
Turgor pressure is the resultant of the influx of water, determined by the difference in solute potential within and outside cell as mentioned above. The influx of water leads to the expansion of vacuole and the pressing of the cell membrane against cell wall.
Conclusion: turgor pressure is not the equivalent of solute potential and is only somewhat related.
Why is the graph of pressure potential a curve and not a straight line like solute potential.
1) Turgor pressure = pressure potential (Newton's 3rd Law). But since there is no immediate relationship between turgor pressure and solute potential, the graph of pressure potential does not have to follow a straight line.
So why is it a curve?
2) I think this is best explained by imagining blowing a balloon.
As you blow more and more air into the balloon, it becomes harder and harder to make it bigger even though you are sure you have blew in the same cheek-ful. The limitation comes from the elasticity of the balloon and past a certain limit, you are straining the bonds that keep the balloon intact and the reaction force becomes stronger. And even though the same cheekful of air is blew in, the balloon may not expand as much but the molecules are now closer in the balloon than expected.
The same idea can be applied to pressure potential graph and thus the curve. =)
Not really. The rigidity as mentioned is contributed by the steriod rings. The hydroxyl group orient itself such that it is beside the polar head grps of adjacent phospholipids and thus allowing the rings to (interact and) immobilise the regions of the HC chains closer to the polar heads. =)
Next Up: Let's talk about Water Potential.
Graph on Water Potential...
For one class, I have already gone through the theory of water potential while the other awaits. But really, what usually have us scratched our heads off is the graph and that, I shall try my best to explain it. Stay with me, imagine with me and see me if need to.
Clarification for 3L: when I meant turgid today, I meant full turgor. Nothing less.
Common misunderstanding : solute potential = turgor pressure.
Solute potential within and outside cell will determine the direction of flow of water. After incipient plamoslysis in the 2nd half of the graph when surrounding medium becomes more dilute, more water will enter the cell. (note that the solute potential is increasing -> increasing dilution in the cell)
Turgor pressure is the resultant of the influx of water, determined by the difference in solute potential within and outside cell as mentioned above. The influx of water leads to the expansion of vacuole and the pressing of the cell membrane against cell wall.
Conclusion: turgor pressure is not the equivalent of solute potential and is only somewhat related.
Why is the graph of pressure potential a curve and not a straight line like solute potential.
1) Turgor pressure = pressure potential (Newton's 3rd Law). But since there is no immediate relationship between turgor pressure and solute potential, the graph of pressure potential does not have to follow a straight line.
So why is it a curve?
2) I think this is best explained by imagining blowing a balloon.
As you blow more and more air into the balloon, it becomes harder and harder to make it bigger even though you are sure you have blew in the same cheek-ful. The limitation comes from the elasticity of the balloon and past a certain limit, you are straining the bonds that keep the balloon intact and the reaction force becomes stronger. And even though the same cheekful of air is blew in, the balloon may not expand as much but the molecules are now closer in the balloon than expected.
The same idea can be applied to pressure potential graph and thus the curve. =)
Questions from past and present
Today, I finally remembered to tell another class to come by here. The implied response was my apparent lack of life beyond school. Arrgh. Only if you realised that this place is specially 4 you and so that you can understand the subject better, otherwise I guess I wouldn't be here
1) Amino acids are supposed to have buffering abilities... even the acidic and basic ones.
But can acidic amino acids help to prevent solution from being acidic?
At physiological pH, acidic aa will have 1 NH3+ and 2 COO- so if there is more H+ ions in the bloodstream, the H+ will be attracted to COO- to form COOH and thus the buffering effect. So the concern could be what about the extra H+ released into the bloodstream upon ionization. Well, it may be removed, be contained within bldstream to maintain pH or taken up by cells for use.
2) What is the monomer in HIV protease referring to? The entire polypeptide chain?
HIV is protease is a dimer; made up of 2 monomers - 2 folded polypeptide chains.
Monomer = subunit; thus the protease has a quaternary structure.
3) Are saturated fats made from saturated fatty acids completely? OR do they have a small % of unsaturated fatty acids?
When we talked about saturated fats in food, we are referring to the presence of a high % of saturated fat. Similarly for olive oil, we say that it has unsaturated fats but we are not excluding the presence of saturated fats but in relative much lower amt.
4) How does the specificity of enzyme apply in the induced fit model?
I am going to discuss this in class. Complementary shape is applicable.
5) If the phosphate heads are polar/charged, wouldn't there be repulsion.
Yup, there will be but there is also attraction btw the hydrophobic tails so equilibrium of opposing forces will be established.
6) In facilitated diffusion, it is a passive process yet there is conformation change of carrier proteins when transport solutes across the lipid bilayer. Should there be energy expenditure for the conformation change?
There is energy involved but it is inherent when the solutes move from a region of high conc to low conc - loss of potential energy/ free energy which is utilised. This explains why the movement of solutes is bi-directional.
On the other hand, active transport goes against conc gradient and thus requires external input of energy usually in the form of ATP.
7) diagram in Enzyme notes: graph of Y never reaches zero (% of unreacted molecules)
Due to fdbk inhibition lah. With sufficient amt of product, all enzymes can be inhibited
1) Amino acids are supposed to have buffering abilities... even the acidic and basic ones.
But can acidic amino acids help to prevent solution from being acidic?
At physiological pH, acidic aa will have 1 NH3+ and 2 COO- so if there is more H+ ions in the bloodstream, the H+ will be attracted to COO- to form COOH and thus the buffering effect. So the concern could be what about the extra H+ released into the bloodstream upon ionization. Well, it may be removed, be contained within bldstream to maintain pH or taken up by cells for use.
2) What is the monomer in HIV protease referring to? The entire polypeptide chain?
HIV is protease is a dimer; made up of 2 monomers - 2 folded polypeptide chains.
Monomer = subunit; thus the protease has a quaternary structure.
3) Are saturated fats made from saturated fatty acids completely? OR do they have a small % of unsaturated fatty acids?
When we talked about saturated fats in food, we are referring to the presence of a high % of saturated fat. Similarly for olive oil, we say that it has unsaturated fats but we are not excluding the presence of saturated fats but in relative much lower amt.
4) How does the specificity of enzyme apply in the induced fit model?
I am going to discuss this in class. Complementary shape is applicable.
5) If the phosphate heads are polar/charged, wouldn't there be repulsion.
Yup, there will be but there is also attraction btw the hydrophobic tails so equilibrium of opposing forces will be established.
6) In facilitated diffusion, it is a passive process yet there is conformation change of carrier proteins when transport solutes across the lipid bilayer. Should there be energy expenditure for the conformation change?
There is energy involved but it is inherent when the solutes move from a region of high conc to low conc - loss of potential energy/ free energy which is utilised. This explains why the movement of solutes is bi-directional.
On the other hand, active transport goes against conc gradient and thus requires external input of energy usually in the form of ATP.
7) diagram in Enzyme notes: graph of Y never reaches zero (% of unreacted molecules)
Due to fdbk inhibition lah. With sufficient amt of product, all enzymes can be inhibited
Happier Things
Camp ended today. Sometimes i wondered if I have gotten stricter this year or are the kids just so different? Alas, let me think of the happier things this year.
R-C-LF ended with a bomb. In the midst of managing all the logistics and endless nights at NACLI where I stayed (on alternate nights) with the international delegates, I had fun working with the 8 Liaison Officers who sticked it out with me through the 7 days in handling the well-being of the international delegates. And then there is my special teams of log, farewell dinner and SIGs whom I had worked closely with especially in the last few months leading up to the event. And not forgetting the group of teachers who braved everything to make the event possible. It had been a pleasure to work with everyone who took care of me and joined me in my silliness and out-of-the-blue jokes. And of cos,m I hoped it was the same for them too because I can be such a pain when I have too many things at hand and need to settle them fast.
A's. In an exam like this, there will be pple who are disappointed and others beaming with joy. There is 100% pass for my classes and I felt relieved - because I got really worried for a handful when the news of 2 failure came through.
As I sneaked out of the ops room to the canteen, braving the waves of students, words of thanks were passed around from my students as well as students from other classes whom i have sticked out with at the last stretch, clocking up countless consultation hours. For me, there was a whole sense of relief not because of the numbers of A's and B's that were chalked up but the simple knowledge that some of these kids whom I had stayed in school with, sitting down late into the nights explaining and reminding, and all the awkward moments of consultation....these efforts of theirs were not wasted and they had reaped fruits from all those to be able to move on comfortably into the next phase of their life. A few times I was just so overwhelmed (and still is when I recalled those instances)and had to blinked off those fluid that came out in a gush... and I think some kids just say the darnest things.
But somewhere out there, I know that some of you may not have done as well as you expected. Some B's, some C's and D's. Know that the only person you need to convince that you have done your best in that moment in the hall is yourself. Your teacher is not disappointed because I believed you had given your best shot then.
With all said and done, besides the grades, I hope that throughout those times in the classrooms and beyond what I had imparted is not just biology-related knowledge but more.
Post-Expedition
It is back to Chiang Mai immediately after Rc-L-F and we took back water samples before and after filtration (over 3 days) for testing. And even without chemical analysis, we knew that we have made a difference in the villagers' lives. (see comparison of water below)
R-C-LF ended with a bomb. In the midst of managing all the logistics and endless nights at NACLI where I stayed (on alternate nights) with the international delegates, I had fun working with the 8 Liaison Officers who sticked it out with me through the 7 days in handling the well-being of the international delegates. And then there is my special teams of log, farewell dinner and SIGs whom I had worked closely with especially in the last few months leading up to the event. And not forgetting the group of teachers who braved everything to make the event possible. It had been a pleasure to work with everyone who took care of me and joined me in my silliness and out-of-the-blue jokes. And of cos,m I hoped it was the same for them too because I can be such a pain when I have too many things at hand and need to settle them fast.
A's. In an exam like this, there will be pple who are disappointed and others beaming with joy. There is 100% pass for my classes and I felt relieved - because I got really worried for a handful when the news of 2 failure came through.
As I sneaked out of the ops room to the canteen, braving the waves of students, words of thanks were passed around from my students as well as students from other classes whom i have sticked out with at the last stretch, clocking up countless consultation hours. For me, there was a whole sense of relief not because of the numbers of A's and B's that were chalked up but the simple knowledge that some of these kids whom I had stayed in school with, sitting down late into the nights explaining and reminding, and all the awkward moments of consultation....these efforts of theirs were not wasted and they had reaped fruits from all those to be able to move on comfortably into the next phase of their life. A few times I was just so overwhelmed (and still is when I recalled those instances)and had to blinked off those fluid that came out in a gush... and I think some kids just say the darnest things.
But somewhere out there, I know that some of you may not have done as well as you expected. Some B's, some C's and D's. Know that the only person you need to convince that you have done your best in that moment in the hall is yourself. Your teacher is not disappointed because I believed you had given your best shot then.
With all said and done, besides the grades, I hope that throughout those times in the classrooms and beyond what I had imparted is not just biology-related knowledge but more.
Post-Expedition
It is back to Chiang Mai immediately after Rc-L-F and we took back water samples before and after filtration (over 3 days) for testing. And even without chemical analysis, we knew that we have made a difference in the villagers' lives. (see comparison of water below)
DRained
So many things have happened for the past 2 wks or so and personally I felt drained both physically and emotionally. 2 colleagues pointed out that I got thinner. So I was actually glad to have slept in late this morning and recuperate even though I would have love to go down to Padang to support the A girls in their final softball match. Anyway I eventually did get down in the afternoon to watch the boys' match - which I still did not manage to catch because one of the kids threw a ball, it flew through a hole in the net and hit an elderly pedestrian on the thigh. The lady collapsed and lied on the sidewalk for 15mins while waiting for the ambulance. A lifeguard was there to check the pulse and the daughter got a little hyper. In the end I went to the hospital and waited with them at the A&E for 2 hours plus and tried to work the matter out. Things got better at the hospital when I made small talk with the daughter about biology, medicines and etc. So typical of bio teacher but because she is in the Chinese Med industry, it was really interesting.And in doing so, I was trying to defuse the situation.
Anyway I sent them home after the lady was discharged and only got home at 9:30 to have dinner. I guess I was really not very good at responding to this kind of situations and my brain was still in a stupor so I am glad that my teacher was there to help at the scene and again, I have learnt much from her.
Yet, this is not the reason why I am typing now although it was a major incident. What preoccupied me since yesterday was really my inadequacy in teaching and I felt miserable enough to just took off to the staff lounge, drink coke and read a storybk. I am not sure but I think it was largely due to fatigue when I felt an inability to engage my students earlier and a tiredness to scold. ok maybe not scold but to remind. And it always feel lousy when you cannot give your best in that 50-110 mins of their time and knowing that you are terrible and they are not benefiting. Am I too harsh on myself? Maybe. Because I remembered that when I took over my classes two years back, some of the students' foundations were really flimsy and they never recover from it so I told myself I am going to take this batch through this and isn't going to let that happen again. Or at least tries. Am I demanding? Of cos. There are things which I just cannot compromise. Enuff said. I just wasn't feeling it then.
But let me get my bearing amidst all the clutter around me now. There is always another day to look forward to. Once I have rested. I will probably blog more tml. Tml I am running the softball camp over the wkend. but right now, I better go to bed because I would like to send some students off at 630 tml T1 as part of a collaboration with ITE and which I am in charge of.
Til later.
Anyway I sent them home after the lady was discharged and only got home at 9:30 to have dinner. I guess I was really not very good at responding to this kind of situations and my brain was still in a stupor so I am glad that my teacher was there to help at the scene and again, I have learnt much from her.
Yet, this is not the reason why I am typing now although it was a major incident. What preoccupied me since yesterday was really my inadequacy in teaching and I felt miserable enough to just took off to the staff lounge, drink coke and read a storybk. I am not sure but I think it was largely due to fatigue when I felt an inability to engage my students earlier and a tiredness to scold. ok maybe not scold but to remind. And it always feel lousy when you cannot give your best in that 50-110 mins of their time and knowing that you are terrible and they are not benefiting. Am I too harsh on myself? Maybe. Because I remembered that when I took over my classes two years back, some of the students' foundations were really flimsy and they never recover from it so I told myself I am going to take this batch through this and isn't going to let that happen again. Or at least tries. Am I demanding? Of cos. There are things which I just cannot compromise. Enuff said. I just wasn't feeling it then.
But let me get my bearing amidst all the clutter around me now. There is always another day to look forward to. Once I have rested. I will probably blog more tml. Tml I am running the softball camp over the wkend. but right now, I better go to bed because I would like to send some students off at 630 tml T1 as part of a collaboration with ITE and which I am in charge of.
Til later.
Cross Fingers
I am not sure who will be in the mood to look here but my dear Ss, Qs and Ls, I am crossing my fingers for you all. Tomorrow I will be tied down with RC-LF and because I am not a CT then, I could not be at the MPH/ISH to share the emotions (I will try to sneak in k?).
Somehow we will catch each other I hope. I will be at level 4 classrooms tho =P
Rest well and let's hope for the best tml!
Somehow we will catch each other I hope. I will be at level 4 classrooms tho =P
Rest well and let's hope for the best tml!
Questions of the Term
2 months are almost over and the results are almost out. As I struggled through this last stretch of the term with many things on my plate, be the multiple roles I play in the upcoming forum or as i/c for sci camp in term 2, I think it about time to start blogging in biological terms. I missed it really. hahah and I actually have been accumulating questions throughout the 2 months =P. But now that my classes have settled down and I am ready to start afresh, here goes:
Irreversible: Competitive or Non-Competitive?
This question had sparked off a furore of discussion so let me summarize and make some adjustment to the statement made in class.
Under the concept of enzymes, we recognise that competitive inhibition refers to competition at the active site of an enzyme betw an inhibitor and the substrate.
Non-competitive inhibitor refers to an inhibitor that binds to a site other than the active site (allosteric site) to inhibit the catalysis process.
I think that much we got it. Weak bonds (H- and ionic bonds) are involved above and thus all interactions are transient and thus reversible.
What is the issue with Irreversible Binding?
Irreversible binding by an inhibitor, because of the formation of strong covalent bonds, regardless of whether it is at the active site or allosteric site, will effectively render the enzyme non-functional (a decrease in enzyme no.) And in this situation, we may also refer the binding as non-competitive.
I suppose this kind of binding usually do occur at the active site because most enzymes do not have an allosteric site anyway . But if we extrapolate, a irreversible binding at the allosteric site will have the same effect.
PS: This whole idea is not uncommon in proteins really (not only enzymes). In most other proteins, there is usually just a BINDING site (NOT 'active site' which is specifically used for enzymes)
----------------------------
Allosteric Site & Allosteric Enzyme - Are they the same?
Nope. Shocked?
An allosteric site is just a site other than the active site and which an inhibitor can bind to. And we call the inhibitor a non-competitive one.
Such an inhibitor can bind to both the enzyme and enzyme-substrate complex. The main idea here is that the inhibitor does not prevent the binding of substrate but prevent catalysis from taking place (diagram in notes is very accurate/clear) and thus can also bind to the ES complex to prevent catalysis. This will explain why you can never reach Vmax.
An allosteric enzyme is simply an enzyme whose activity is affected by an activator or inhibitor binding to its allosteric site. When I wrote "affected", i refer to whether the reaction is enhanced or impeded. Do you think the Vmax will be reached then?
(do not have to worry about this. we will not be touching on this)
Thus an enzyme with an allosteric site may not be an allosteric enzyme.
----------------------
Acid-Base Catalysis
As I mentioned to some of you and I am convinced myself on:
"...facilitate the transfer of reactants to and from the reactants"
I think it is best rephrased to
"....facilitate the transfer of charges to stabilize the formation of a transition state (nucleophile or electrophile) in reactants"
Such a transition state is necessary so that catalysis in the presence of other molecule e.g. water can take place (you will learn it all in chemistry later :) so just take note first!!)
See Diagram (Zn ion is involved as the charged particle but the idea is the same):
Hydrophobicity
According to thermodynamics, matter seeks to be in a low-energy state, and bonding reduces chemical energy. Water is electrically polarized, and is able to form hydrogen bonds internally, which gives it many of its unique physical properties. But, since hydrophobes are not electrically polarized, and because they are unable to form hydrogen bonds, water repels hydrophobes, in favour of bonding with itself. It is this effect that causes the hydrophobic interaction — which in itself is incorrectly named as the energetic force comes from the hydrophilic molecules.[2] Thus the two immiscible phases (hydrophilic vs. hydrophobic) will change so that their corresponding interfacial area will be minimal. This effect can be visualized in the phenomenon called phase separation.
http://en.wikipedia.org/wiki/Hydrophobic
Equation for Fehling’s Test
The chemical test is best looked upon at the half-eqn level for simplicity.
Aliphatic aldehyde reduces Cu(II) to Cu(I). Ketones and aromatic aldehyde give no reaction.
Half Eqn: 2Cu2+ + OH- + 2e → Cu2O + H+
RCHO + H2O → RCOOH + 2H+ + 2e
Overall : RCHO + 2Cu2+ + 5OH- + H2O → RCOOH + 2H+ + 2e [+4OH-]
Fructose can undergo keto-enol tautomeric shift to exist as an aldehyde under basic conditions.
Isn't milk alkaline? Aren't we recommend to drink milk when experiencing gastric?
Gastric juice, which consists of hydrochloric acid and an enzyme, pepsin, which breaks down protein, can digest any living tissue, including your stomach and duodenum. Normally, both your stomach and duodenum are bathed constantly in gastric acid. But protective mechanisms, including the work of prostaglandins, which govern secretion of mucus from your stomach lining, and your food and saliva's ability to dilute acid, prevent your stomach from digesting itself. The pH of the human stomach is about 1.8. The pH of fresh milk is between 6.5 and 6.75. After drinking a glass of milk, the stomach's acidity changes. A powerful acid environment is buffered up to a 6.0, so that everything ferments and putrefies for the next four hours. Initially, milk does dilute stomach acid -- but then, acting on the rebound, it prompts the production of even more.
For years, ulcer patients had to survive on a bland diet of boiled fish, rice, milk, and cream. Now we know that while milk coats your stomach and may relieve the ulcer pain temporarily, it may retard the ulcer's healing. The calcium in milk can make you feel worse in the long run by stimulating the production of gastric acid. So can fried foods, citrus fruits, alcohol, caffeine in beverages or in chocolate, decaffeinated coffee, and smoking. Tea seems to particularly stimulate production of gastric juice.
http://www.otherhealth.com/homeopathy-discussion/2364-x-c-2.html
Fat and Carbohydrate as Energy Source
If we take a look at the diagram, we will realise that carbohydrates and triglycerides undergoes different pathways to yield ATP although both will converge at Krebs Cycle. Thus in comparison, carbo has to undergo more reactions (in glycolysis) where energy can be lost before getting to Krebs Cycle. Having C-H rather than C=O and C-OH bonds avoid that pathway.
Mistakes? Pls check
General formula of polysaccharides: Cn(H2O)n-1
Why glutamine is polar and not basic?
Despite the presence of NH2, we have to look at the neighboring molecules as well. If you notice, there is a C=O beside the NH2. Thus we are actually looking at an amide group and not an amine side group and former is not basic because C=O draws electrons away from NH2, thus the lone pair on N is less likely to be donated to a H+.
That's all folks!
Irreversible: Competitive or Non-Competitive?
This question had sparked off a furore of discussion so let me summarize and make some adjustment to the statement made in class.
Under the concept of enzymes, we recognise that competitive inhibition refers to competition at the active site of an enzyme betw an inhibitor and the substrate.
Non-competitive inhibitor refers to an inhibitor that binds to a site other than the active site (allosteric site) to inhibit the catalysis process.
I think that much we got it. Weak bonds (H- and ionic bonds) are involved above and thus all interactions are transient and thus reversible.
What is the issue with Irreversible Binding?
Irreversible binding by an inhibitor, because of the formation of strong covalent bonds, regardless of whether it is at the active site or allosteric site, will effectively render the enzyme non-functional (a decrease in enzyme no.) And in this situation, we may also refer the binding as non-competitive.
I suppose this kind of binding usually do occur at the active site because most enzymes do not have an allosteric site anyway . But if we extrapolate, a irreversible binding at the allosteric site will have the same effect.
PS: This whole idea is not uncommon in proteins really (not only enzymes). In most other proteins, there is usually just a BINDING site (NOT 'active site' which is specifically used for enzymes)
----------------------------
Allosteric Site & Allosteric Enzyme - Are they the same?
Nope. Shocked?
An allosteric site is just a site other than the active site and which an inhibitor can bind to. And we call the inhibitor a non-competitive one.
Such an inhibitor can bind to both the enzyme and enzyme-substrate complex. The main idea here is that the inhibitor does not prevent the binding of substrate but prevent catalysis from taking place (diagram in notes is very accurate/clear) and thus can also bind to the ES complex to prevent catalysis. This will explain why you can never reach Vmax.
An allosteric enzyme is simply an enzyme whose activity is affected by an activator or inhibitor binding to its allosteric site. When I wrote "affected", i refer to whether the reaction is enhanced or impeded. Do you think the Vmax will be reached then?
(do not have to worry about this. we will not be touching on this)
Thus an enzyme with an allosteric site may not be an allosteric enzyme.
----------------------
Acid-Base Catalysis
As I mentioned to some of you and I am convinced myself on:
"...facilitate the transfer of reactants to and from the reactants"
I think it is best rephrased to
"....facilitate the transfer of charges to stabilize the formation of a transition state (nucleophile or electrophile) in reactants"
Such a transition state is necessary so that catalysis in the presence of other molecule e.g. water can take place (you will learn it all in chemistry later :) so just take note first!!)
See Diagram (Zn ion is involved as the charged particle but the idea is the same):
Hydrophobicity
According to thermodynamics, matter seeks to be in a low-energy state, and bonding reduces chemical energy. Water is electrically polarized, and is able to form hydrogen bonds internally, which gives it many of its unique physical properties. But, since hydrophobes are not electrically polarized, and because they are unable to form hydrogen bonds, water repels hydrophobes, in favour of bonding with itself. It is this effect that causes the hydrophobic interaction — which in itself is incorrectly named as the energetic force comes from the hydrophilic molecules.[2] Thus the two immiscible phases (hydrophilic vs. hydrophobic) will change so that their corresponding interfacial area will be minimal. This effect can be visualized in the phenomenon called phase separation.
http://en.wikipedia.org/wiki/Hydrophobic
Equation for Fehling’s Test
The chemical test is best looked upon at the half-eqn level for simplicity.
Aliphatic aldehyde reduces Cu(II) to Cu(I). Ketones and aromatic aldehyde give no reaction.
Half Eqn: 2Cu2+ + OH- + 2e → Cu2O + H+
RCHO + H2O → RCOOH + 2H+ + 2e
Overall : RCHO + 2Cu2+ + 5OH- + H2O → RCOOH + 2H+ + 2e [+4OH-]
Fructose can undergo keto-enol tautomeric shift to exist as an aldehyde under basic conditions.
Isn't milk alkaline? Aren't we recommend to drink milk when experiencing gastric?
Gastric juice, which consists of hydrochloric acid and an enzyme, pepsin, which breaks down protein, can digest any living tissue, including your stomach and duodenum. Normally, both your stomach and duodenum are bathed constantly in gastric acid. But protective mechanisms, including the work of prostaglandins, which govern secretion of mucus from your stomach lining, and your food and saliva's ability to dilute acid, prevent your stomach from digesting itself. The pH of the human stomach is about 1.8. The pH of fresh milk is between 6.5 and 6.75. After drinking a glass of milk, the stomach's acidity changes. A powerful acid environment is buffered up to a 6.0, so that everything ferments and putrefies for the next four hours. Initially, milk does dilute stomach acid -- but then, acting on the rebound, it prompts the production of even more.
For years, ulcer patients had to survive on a bland diet of boiled fish, rice, milk, and cream. Now we know that while milk coats your stomach and may relieve the ulcer pain temporarily, it may retard the ulcer's healing. The calcium in milk can make you feel worse in the long run by stimulating the production of gastric acid. So can fried foods, citrus fruits, alcohol, caffeine in beverages or in chocolate, decaffeinated coffee, and smoking. Tea seems to particularly stimulate production of gastric juice.
http://www.otherhealth.com/homeopathy-discussion/2364-x-c-2.html
Fat and Carbohydrate as Energy Source
If we take a look at the diagram, we will realise that carbohydrates and triglycerides undergoes different pathways to yield ATP although both will converge at Krebs Cycle. Thus in comparison, carbo has to undergo more reactions (in glycolysis) where energy can be lost before getting to Krebs Cycle. Having C-H rather than C=O and C-OH bonds avoid that pathway.
Mistakes? Pls check
General formula of polysaccharides: Cn(H2O)n-1
Why glutamine is polar and not basic?
Despite the presence of NH2, we have to look at the neighboring molecules as well. If you notice, there is a C=O beside the NH2. Thus we are actually looking at an amide group and not an amine side group and former is not basic because C=O draws electrons away from NH2, thus the lone pair on N is less likely to be donated to a H+.
That's all folks!
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