I am having extra biology lessons on last year's work every Thurs (since we have barely picked off for the recent installations)for this term.
I will be going through some past year's TYS questions which some of you had done in the hols or are doing now but I will open the session to students who are interested to drop in.
This wk questions:
Cell membrane and function:
2001 November P3/Q8
2002 June P2/Q3
I will also be doing biomolecules which most would not have done (if time permit)
2004 November P2/Q7
2005 June P2/Q4
Attendance is compulsory for those who I have asked to do the work in Dec.
For those dropping in , it would be greater if you could look at the question and think about the answers and jot them down to see if you are hitting the right concepts.
Venue : C61
there are two slots: 2-3 and 3:15-4:15
I have printed out the answers if you have not already done so. Scripts will also be returned.
FLY
Sometimes you think they are ready to take flight but only to find them floundering desperately as they make their way out of the nest.
Your heart broke at the sound of their silent anguish and frustration before you went ahead to pick up the little shattered pieces so that you can better bring them back into safety and guide them again for the big flight when the winter approaches
Your heart broke at the sound of their silent anguish and frustration before you went ahead to pick up the little shattered pieces so that you can better bring them back into safety and guide them again for the big flight when the winter approaches
Game Phewed
Day 1 of Game.
It did not work as well as I envision.
As usual, I have always been a little bit too ambitious with my game plan. There was just too much to showcase within too little a time.
Not everyone left class with the learning in tow, that I am sure.
I need to modify and simplify the game plan.
And I guess some game plan cannot be used with biology ;)
Well, hope it takes the monday blues away tho.
It did not work as well as I envision.
As usual, I have always been a little bit too ambitious with my game plan. There was just too much to showcase within too little a time.
Not everyone left class with the learning in tow, that I am sure.
I need to modify and simplify the game plan.
And I guess some game plan cannot be used with biology ;)
Well, hope it takes the monday blues away tho.
Questions of the Week_26 Jan 06
Why does the following equation have an extra H+ on both sides?
NAD+ + 2H+ + 2e- → H+ + NADH
Can we simplify it to NAD+ + H+ + 2e- → + NADH ?
Yes, you can simplify the chemical equation as you would for chemistry.
The original equation is given to show you what actually happen/ what are needed for the reaction to occur.
* There is no need for you to memorize the equation for exam purpose.
Can we just write the following abbreviations without making reference to the actual terms: NAD+/NADH , FAD/FADH2 , RuBP, Rubisco
Not for all.
Yes to NAD+/NADH , FAD/FADH2 because they are ubiquitous
FYI:
NAD+ (nicotinamide adenine dinucleotide)
FAD (flavin adenine dinucleotide)
NADH or FADH2 is referred to as the reduced form of the above mentioned.
However for RuBP and Rubisco, please give the full term first before launching into their respective short forms e.g. Ribulose 1,5-bisphosphate (RuBP) and RuBP carboxylase (Rubisco)
NAD+ + 2H+ + 2e- → H+ + NADH
Can we simplify it to NAD+ + H+ + 2e- → + NADH ?
Yes, you can simplify the chemical equation as you would for chemistry.
The original equation is given to show you what actually happen/ what are needed for the reaction to occur.
* There is no need for you to memorize the equation for exam purpose.
Can we just write the following abbreviations without making reference to the actual terms: NAD+/NADH , FAD/FADH2 , RuBP, Rubisco
Not for all.
Yes to NAD+/NADH , FAD/FADH2 because they are ubiquitous
FYI:
NAD+ (nicotinamide adenine dinucleotide)
FAD (flavin adenine dinucleotide)
NADH or FADH2 is referred to as the reduced form of the above mentioned.
However for RuBP and Rubisco, please give the full term first before launching into their respective short forms e.g. Ribulose 1,5-bisphosphate (RuBP) and RuBP carboxylase (Rubisco)
Clarification
Please note that for the intracellular signaling cascasde,
When a protein kinase phosphorylates a downstream protein kinase, the phosphate group does not get passed from one to another. Instead, the preceding protein kinase will make use of the phosphate group from ATP/GTP found in cytoplasm to add to the next protein kinase for activation.
------------------
I realised taht I would crack silly comments/jokes in LT4 but barely in LT1
I guess the latter isn't very conducive for my rumblings. Hahaah- too noisy for silly things to filter through.
------------------
Lectures by me is over for now. Thank you for listening.
And now pple can concentrate =)
Pro And U Questions Asked In Class & Random Thoughts
1) Proto-oncogenes promotes cell growth. Checked.
But did you realise cell growth is related to cell division because the growth of a cell is limited by the cell size due to the surface area:volume ratio. Thus once it has reached a certain size, cell will undergo cell division.
Proto-oncogenes promotes cell growth and cell division.
*2) What happen to the telomeres of the template strand during replication (somatic cells).Do they get shorten or do they remain in length?
Bravo! you are right! Those that get shorter are the daughter strands due to "end replication problem". Thus we have a blunt end and one with a 3' overhang.
But do we have a problem here as some of you had thought about - the template strand will remains just as long regardless of the number of replications - so has the original first-ever cell achieve immortality?
The status of immortality is given if a cell has the capacity to undergo unlimited cell divisions and is, of course, closely associated with the activation of telomeres (telomerase activity is found in ~90% of cancer) . But even those cells can die.
Cell are suscepticle to chemical or physical insults and older cells also tend to accumulates more DNA damages or mutations that will trigger off apoptosis and thus the original cell does not persist in our body but give way to new cells (why cells undergo mitosis?)
Nonetheless, cancer cells are more persistant because they are more resistance to various insults due to possible defects in the apoptotic pathway etc
Thus, after successive cell divisions, we will eventually get to a daughter cell with telomeres of a critical length and will not undergo mitosis (cell senescence/arrested cell growth). That limits the no. of cell divisions a cell can undergo.
http://en.wikipedia.org/wiki/Hayflick_limit
If replication does ever happen beyond the critical length, the cell will undergo apoptosis because the telomeres/chromosomes are damaged.
Consensus Sequences
Are consensus sequences only found in prokaryotes?
Nope. Although we only briefly talked about it under prokaryotes, consensus sequences are also found in TATA box, CAAT and GC boxes of the eukaryotes as well.
In fact gene mutation can alter the correlation with the consensus sequence.
Does plastid contains DNA?
Plastids is a general term that includes chloroplasts. So yes to that question but it is more appropriate at this level to talk simply about chloroplasts than involves plastids.
Are 30nm fiber and solenoid the same?
Yes. They are the same thing. The 30nm fiber is so called because of its size. Solenoid is a model that is attributed to the 30nm fiber. There is also a cross-linker model.
To be sure, we will make reference to 30nm fiber.
But did you realise cell growth is related to cell division because the growth of a cell is limited by the cell size due to the surface area:volume ratio. Thus once it has reached a certain size, cell will undergo cell division.
Proto-oncogenes promotes cell growth and cell division.
*2) What happen to the telomeres of the template strand during replication (somatic cells).Do they get shorten or do they remain in length?
Bravo! you are right! Those that get shorter are the daughter strands due to "end replication problem". Thus we have a blunt end and one with a 3' overhang.
But do we have a problem here as some of you had thought about - the template strand will remains just as long regardless of the number of replications - so has the original first-ever cell achieve immortality?
The status of immortality is given if a cell has the capacity to undergo unlimited cell divisions and is, of course, closely associated with the activation of telomeres (telomerase activity is found in ~90% of cancer) . But even those cells can die.
Cell are suscepticle to chemical or physical insults and older cells also tend to accumulates more DNA damages or mutations that will trigger off apoptosis and thus the original cell does not persist in our body but give way to new cells (why cells undergo mitosis?)
Nonetheless, cancer cells are more persistant because they are more resistance to various insults due to possible defects in the apoptotic pathway etc
Thus, after successive cell divisions, we will eventually get to a daughter cell with telomeres of a critical length and will not undergo mitosis (cell senescence/arrested cell growth). That limits the no. of cell divisions a cell can undergo.
http://en.wikipedia.org/wiki/Hayflick_limit
If replication does ever happen beyond the critical length, the cell will undergo apoptosis because the telomeres/chromosomes are damaged.
Consensus Sequences
Are consensus sequences only found in prokaryotes?
Nope. Although we only briefly talked about it under prokaryotes, consensus sequences are also found in TATA box, CAAT and GC boxes of the eukaryotes as well.
In fact gene mutation can alter the correlation with the consensus sequence.
Does plastid contains DNA?
Plastids is a general term that includes chloroplasts. So yes to that question but it is more appropriate at this level to talk simply about chloroplasts than involves plastids.
Are 30nm fiber and solenoid the same?
Yes. They are the same thing. The 30nm fiber is so called because of its size. Solenoid is a model that is attributed to the 30nm fiber. There is also a cross-linker model.
To be sure, we will make reference to 30nm fiber.
keep your eyes out
The current tutorial posed a lot of challenges because of the scope it covers.
The challenge to the teachers have always been how to simplify something that is ever so confusing and monsterous in proportion.
Keep your eyes peeled for the end of wk when I will pose up answers to a series of interesting questions in class!
The challenge to the teachers have always been how to simplify something that is ever so confusing and monsterous in proportion.
Keep your eyes peeled for the end of wk when I will pose up answers to a series of interesting questions in class!
That's it
The day went on well until the 2nd lecture of the day.
Ridiculous things came as a package as I went from one issue to another.
Looking back there is so much to learn from it.
I have no idea why but I always find myself bursting into laughter in that lecture grp while I remained more firm in the other. Maybe it is because two of my classes are there and in such close promixity that I reverts immediately back to the corny and silly me that tends to manifest in classroom. Not exlcuding the fact that some in my classes make their attempts to bring a smile to my face (or poke at my laughing acupoint), espeicially the five warriors who are such posers *faint*.
My new year resolution: less laughter more work. That I already did in classroom and there is more of a balance. Laughter, the best medicine is also my bane because thoughts dispersed when my brain get hysterics overdrive and teaching becomes so haywired. And I get upset because of a lesson not as well delivered as I possible could. (And of course I do need to redeem for the above lecture, after such a fiasco)
I need to find that cool and collected me that existed before when I gave presentation instead of launching myself ever so readily into friendster mode. When I am focused, living in suspended, solipsistic time, words come in flow rather than in staccato and my pronunication can be clear and accented. I lost all that after working with my youth outside because that will never cut it with them but that is no excuse and I really enjoying working with them so it is of no issue. Thus there is a line I still need to cut mentally when I give lectures. I mean what will other classes think? That my classes suffer under an eccentric teacher? That will be the start of a series of unfortunate events. =)
Ridiculous things came as a package as I went from one issue to another.
Looking back there is so much to learn from it.
I have no idea why but I always find myself bursting into laughter in that lecture grp while I remained more firm in the other. Maybe it is because two of my classes are there and in such close promixity that I reverts immediately back to the corny and silly me that tends to manifest in classroom. Not exlcuding the fact that some in my classes make their attempts to bring a smile to my face (or poke at my laughing acupoint), espeicially the five warriors who are such posers *faint*.
My new year resolution: less laughter more work. That I already did in classroom and there is more of a balance. Laughter, the best medicine is also my bane because thoughts dispersed when my brain get hysterics overdrive and teaching becomes so haywired. And I get upset because of a lesson not as well delivered as I possible could. (And of course I do need to redeem for the above lecture, after such a fiasco)
I need to find that cool and collected me that existed before when I gave presentation instead of launching myself ever so readily into friendster mode. When I am focused, living in suspended, solipsistic time, words come in flow rather than in staccato and my pronunication can be clear and accented. I lost all that after working with my youth outside because that will never cut it with them but that is no excuse and I really enjoying working with them so it is of no issue. Thus there is a line I still need to cut mentally when I give lectures. I mean what will other classes think? That my classes suffer under an eccentric teacher? That will be the start of a series of unfortunate events. =)
New Year New Start
Walking down to canteen for a simple meal can sometimes lead to ambush by your students and 4 rounded me up a while ago.
From them spewed words of wisdom in the form of glycolysis, link reaction, oxidative phosphorylation and why total ATPs might not be 38 or the importance of oxygen. I do not know my expression then but I was amazed by their ready integration of knowledge and everyone did pay attention in the lecture after all. N it was a tough-going lecture with information astrewn. Their enthusiam was ....touching..?
Of course nothing beat M.S' final comment which really got me tickled throughout my lunch break and now. Sounds like such a movie liner.
From them spewed words of wisdom in the form of glycolysis, link reaction, oxidative phosphorylation and why total ATPs might not be 38 or the importance of oxygen. I do not know my expression then but I was amazed by their ready integration of knowledge and everyone did pay attention in the lecture after all. N it was a tough-going lecture with information astrewn. Their enthusiam was ....touching..?
Of course nothing beat M.S' final comment which really got me tickled throughout my lunch break and now. Sounds like such a movie liner.
Pseudogenes
To read about Pseudogenes for extra information,
you can check out the Scientific American August 2006.
There is a small title in front: The Power of Pseudogenes. It should be in the library but I have a copy myself if you are interested.
you can check out the Scientific American August 2006.
There is a small title in front: The Power of Pseudogenes. It should be in the library but I have a copy myself if you are interested.
Telomerase: Why are they around? How they work?
Well, before school ended last year, I have already sourced these for you. But better to showcase them now since I know no one will bother about them until now. Perhaps.
Why are telomeres around?
How Telomeres work?
(I don't know why the pictures are upside down. Any help is welcome)
Why are telomeres around?
How Telomeres work?
(I don't know why the pictures are upside down. Any help is welcome)
Back in Business (Pro & Eu): Un-Spacey Satellites
If you have not heard of minisatellites and DNA fingerprinting or have forgetten about them, here is a link for you:
https://sciencegrants.dest.gov.au/scienceprize/Pages/Doc.aspx?name=previous_winners/Aust1998Jeffreys.htm
Genetic fingerprinting, DNA testing, DNA typing, and DNA profiling are techniques used to distinguish between individuals of the same species using only samples of their DNA. Its invention by Sir Alec Jeffreys at the University of Leicester was announced in 1985. Two humans will have the vast majority of their DNA sequence in common. Genetic fingerprinting exploits highly variable repeating sequences called minisatellites. Two unrelated humans will be likely to have different numbers of minisatellites at a given locus. By using PCR enough DNA is obtained to then detect the number of repeats at several loci. It is possible to establish a match that is extremely unlikely to have arisen by coincidence, except in the case of identical twins, who will have identical genetic profiles. (Wikipedia)
However DNA fingerprinting is not 100% foolproof. The term "fingerprinting" is actually a misnomer. Read about it in http://www.sciencewatch.com/interviews/sir_alec_jeffreys.htm under subtitle: Fingerprinting has been subject to a lot of controversy, something you have alluded to in some of your papers. Do you personally have any reservations about its reliability?
While both satellites are similar in nature, other than sizes.....
The advantage of microsatellites over minisatellites is that the size of each allele is much smaller and they are therefore more amenable to PCR analysis. Their small size also means that they are more likely to remain intact in highly degraded DNA such as that from forensic samples or from ancient DNA - for example from Egyptian mummies. - thus better for linkage mapping of genome as noted in your notes although minisatellites have also been used in linkage mapping.
WHY Satellites?
http://en.wikipedia.org/wiki/Satellite_DNA
https://sciencegrants.dest.gov.au/scienceprize/Pages/Doc.aspx?name=previous_winners/Aust1998Jeffreys.htm
Genetic fingerprinting, DNA testing, DNA typing, and DNA profiling are techniques used to distinguish between individuals of the same species using only samples of their DNA. Its invention by Sir Alec Jeffreys at the University of Leicester was announced in 1985. Two humans will have the vast majority of their DNA sequence in common. Genetic fingerprinting exploits highly variable repeating sequences called minisatellites. Two unrelated humans will be likely to have different numbers of minisatellites at a given locus. By using PCR enough DNA is obtained to then detect the number of repeats at several loci. It is possible to establish a match that is extremely unlikely to have arisen by coincidence, except in the case of identical twins, who will have identical genetic profiles. (Wikipedia)
However DNA fingerprinting is not 100% foolproof. The term "fingerprinting" is actually a misnomer. Read about it in http://www.sciencewatch.com/interviews/sir_alec_jeffreys.htm under subtitle: Fingerprinting has been subject to a lot of controversy, something you have alluded to in some of your papers. Do you personally have any reservations about its reliability?
While both satellites are similar in nature, other than sizes.....
The advantage of microsatellites over minisatellites is that the size of each allele is much smaller and they are therefore more amenable to PCR analysis. Their small size also means that they are more likely to remain intact in highly degraded DNA such as that from forensic samples or from ancient DNA - for example from Egyptian mummies. - thus better for linkage mapping of genome as noted in your notes although minisatellites have also been used in linkage mapping.
WHY Satellites?
http://en.wikipedia.org/wiki/Satellite_DNA
Fat Invasion
Holding on to my cup of hot Friday afternoon tea that usually accompanies a long day in school, a group of freshmen jaunted past me and trooped into the 7-11 with glee.
The first and almost funny thought flashed through my mind: our kids are getting FAT!!!
Studies with the American schools had been done to evaluate the health status of their high school canteen and environment, especially with their high obseity rate. Although I can be assured of the more healthy choices in our canteen food, I also remembered that one of the first measure carried out to fight obesity was the removal of soft drink vending machines throughout the school and replace them with water coolers. That move was a success and the students did have a healthy option without glucose-laden drinks as a staple in their daily lives.
Then I turned around to look at the Big Gulp that was brought out, and wondered about the effects of a 7-11 in school.
Perhaps the consolation is the high metabolism of our growing students, who are constantly burning up their brain cells (metaphorically) and muscle glycogen. But some things are best not to be developed into an acquired taste becaues when senescence sets in like what is happening to me now, eating habits do have to change.
Mmm..perhaps I should be more worried about the teachers who choose to frequent 7-11 more =).
7-11 felt like a thing of the past. I can still remember when it first open its flagship store and my first surplee sundae and their expired hip-ness. Nevertheless, when you ever go Japan, the original 7-11 are definitely more cool. =)
The first and almost funny thought flashed through my mind: our kids are getting FAT!!!
Studies with the American schools had been done to evaluate the health status of their high school canteen and environment, especially with their high obseity rate. Although I can be assured of the more healthy choices in our canteen food, I also remembered that one of the first measure carried out to fight obesity was the removal of soft drink vending machines throughout the school and replace them with water coolers. That move was a success and the students did have a healthy option without glucose-laden drinks as a staple in their daily lives.
Then I turned around to look at the Big Gulp that was brought out, and wondered about the effects of a 7-11 in school.
Perhaps the consolation is the high metabolism of our growing students, who are constantly burning up their brain cells (metaphorically) and muscle glycogen. But some things are best not to be developed into an acquired taste becaues when senescence sets in like what is happening to me now, eating habits do have to change.
Mmm..perhaps I should be more worried about the teachers who choose to frequent 7-11 more =).
7-11 felt like a thing of the past. I can still remember when it first open its flagship store and my first surplee sundae and their expired hip-ness. Nevertheless, when you ever go Japan, the original 7-11 are definitely more cool. =)
First Week
The first week has passed.
While it was only three days, it felt like a month with the pace we started with and not forgetting a nagging need to get everything ready for my concurrent lectures next week for H1 & possibly 2.
But then work aside, it felt good to be back, to see everyone again - students and teachers alike. Standing in front of the class, peering at those familiar faces, there was a warm sensation of happiness to know that we can journey together for a little while more - thus I am going to ignore those silly wisecracks for a little while more.
Respect for each other and self should not be nelgected.
----------------------------
Here is a little info for some
I managed to grab hold of the timetable for H3 biology LSM 1102
Directions:
What is the fastest way to NUS science?
If you are going to Lt like LT26
Exit school from the side gate beside the sheltered carpark (behind canteen)
Cross the road via overhead bridge and take 93.
Get ready to alight when you see Queensway Shopping Centre on your right. The bus will make a huge turn to the right at a X-junction. No idea about Queensway Shopping Centre? It is near IKEA. Alight then (1st stop after the turn)
Take 197 from the bus stop (you are now across the road from Queensway Shopping Centre). It will bring you to NUH on about the 4-5th stops. You will be able to see NUH although you don't stop in front of it and the bus-stop has an overhead bridge.
From there you can get to NUS science via walking for 5 minutes.
If you miss this stop, don't worry. The next stop is fine too although slightly further up. It is beside the school field which makes it very conspicious. If you are going for lab or university hall for the first day, this stop beside the field is your best bet for proximity.
Cross the track/field to reach the hall/lab.
The above is not the only way. There are several variations which I did not post unless you need
Mmm...the Spinelli cookies is really great so if you are there, either at Science canteen or Uni Hall, get one for a treat haahah. If you find this useful, you can treat me too ahahahah
While it was only three days, it felt like a month with the pace we started with and not forgetting a nagging need to get everything ready for my concurrent lectures next week for H1 & possibly 2.
But then work aside, it felt good to be back, to see everyone again - students and teachers alike. Standing in front of the class, peering at those familiar faces, there was a warm sensation of happiness to know that we can journey together for a little while more - thus I am going to ignore those silly wisecracks for a little while more.
Respect for each other and self should not be nelgected.
----------------------------
Here is a little info for some
I managed to grab hold of the timetable for H3 biology LSM 1102
Directions:
What is the fastest way to NUS science?
If you are going to Lt like LT26
Exit school from the side gate beside the sheltered carpark (behind canteen)
Cross the road via overhead bridge and take 93.
Get ready to alight when you see Queensway Shopping Centre on your right. The bus will make a huge turn to the right at a X-junction. No idea about Queensway Shopping Centre? It is near IKEA. Alight then (1st stop after the turn)
Take 197 from the bus stop (you are now across the road from Queensway Shopping Centre). It will bring you to NUH on about the 4-5th stops. You will be able to see NUH although you don't stop in front of it and the bus-stop has an overhead bridge.
From there you can get to NUS science via walking for 5 minutes.
If you miss this stop, don't worry. The next stop is fine too although slightly further up. It is beside the school field which makes it very conspicious. If you are going for lab or university hall for the first day, this stop beside the field is your best bet for proximity.
Cross the track/field to reach the hall/lab.
The above is not the only way. There are several variations which I did not post unless you need
Mmm...the Spinelli cookies is really great so if you are there, either at Science canteen or Uni Hall, get one for a treat haahah. If you find this useful, you can treat me too ahahahah
Welcome Back 2 School. It is 2007!!
It is back to school day!
Before we realise it, the holidays had went ahead and left us behind to begin a new year and start the mugging for a challenging year ahead.
What is going to happen this year?
It will be the same old routine of tutorials, lectures, PE lessons but without any PW nagging in the background and asking mr chan to act out a script about BBQ school. But also that the syllabus will be due for completion in about 6 months' time before the teachers round up their preaching and nagging as the exams loom overhead. 6 months. A pretty short time. For the students and teachers who forsee the remedials and extra lessons beyond that.
For me, I am already looking into a 6-month plan to get things kicking although I am almost sure that most students did not realised the limited time left before intensive mugging start. Well, at least I never did when I was still in my uniform years back. =) Yet, if you did, beside studying, do cherish the time you have in school with your friends, class and everyone else. I remembered my JC2 as clear as yesterday and my JC frens are still with me after all these years. =)
-----------------
How did my holidays go?
The first month was spent invilgilating and preparing notes, answers and powerpoints, all the way up before the day I left for China.
I went backpacking again this year and the thrill is still there when you explore new grounds on your feet with limited funds and a heavy sack behind you. But I do think I should take a break next year from the excitement for a while. Time perhaps to bring my parents out, especially my dad to see snow.
Unlike young pple nowsdays, I never did fly a plane until very late in life and I supposed with the past few years of backpacking, I am making up for those missed experiences as curosity of foreign lands got the better of me. And personally, it was an important growing phase for me as well. But be warned that dangers lurked all over so while the ideas of backpacking sounds absolutely fanciful, certain considerations and maturation will be great.
Anyway, my parents never really got out of the country especially my dad so perhaps next year is a good time to bring them out if they can pry themselves away from my baby niece. =)
Oh. I never did find my kiddo based on the direction I got. The place was just too big and I hunted from place to place, even seeking help from the local teachers. It was a mini adventure on my own met with disappointment but we needed to pick up and move on as each day of the holiday is always different.
Stories have to be set aside for now and if i get get around telling because , I am rather tired from all the running around and setting issues on this brand new school day. =)
Well, one thing for sure, this blog is back in business and I will be posting educational materials soon kekekeek.
Hope you all have a great holidays and are recharged.
Really happy to see you all again =)
Oh btw, prepare your tutorial. we are ready to start. Or at least I am so be ready. =P
PS: mmm...who is reading this blog? Apparently this blog has gone beyond my class. mmmm...
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