Bio HL Papers 1 & 2 May 2010

[soadquake981]

I did TZ1! Sweetnsimple, I'm going to try to pull some of the focus to TZ1 here, rather than all TZ2, haha.

I put mostly the same answers as you said. For the question asking why the lactase reaction is performed at lower temperatures, I suggested that higher temperatures are avoided so that beneficial enzymes in milk products are not denatured, and possibly also so that the milk products do not spoil before they reach the consumer.

All three papers in TZ1 were super easy! It was great.

[102jon]

i found paper 1 extremely easy. paper 2 was fairly straightforward although the data analysis section made some of us feel quite uneasy. as for the long answer, i answered question 4, about homeostasis and processes in the kidney, and question 5 about plants. hopefully i pulled enough marks out of the mark scheme to come away with a 7.

i also mentioned denaturation for the lactase question, and i also said that it allows for easier control of the amount of products produced. some people in my class talked about costliness of high temperatures, which also seems valid.

[soadquake981]

i also mentioned denaturation for the lactase question, and i also said that it allows for easier control of the amount of products produced. some people in my class talked about costliness of high temperatures, which also seems valid.

High cost for high temperatures would make sense, but the question mentioned that the reaction is typically carried out at a temperature of 5 degrees Celsius. Wouldn't there be a corresponding high cost with maintaining a very low (almost freezing) temperature?

One of my friends also suggested that with a lower temperature, you have better control over the reaction. I think that seems feasible.

For the extended-response questions, I chose 4 (homeostasis and blood glucose level) and 7 (DNA and DNA profiling). They were both really easy/good questions!

[sweetnsimple786]

I did TZ1! Sweetnsimple, I'm going to try to pull some of the focus to TZ1 here, rather than all TZ2, haha.

I put mostly the same answers as you said. For the question asking why the lactase reaction is performed at lower temperatures, I suggested that higher temperatures are avoided so that beneficial enzymes in milk products are not denatured, and possibly also so that the milk products do not spoil before they reach the consumer.

All three papers in TZ1 were super easy! It was great.

I think I said something along those lines as well. Can't talk about P3 yet... but wow I was surprised.

i found paper 1 extremely easy. paper 2 was fairly straightforward although the data analysis section made some of us feel quite uneasy. as for the long answer, i answered question 4, about homeostasis and processes in the kidney, and question 5 about plants. hopefully i pulled enough marks out of the mark scheme to come away with a 7.

i also mentioned denaturation for the lactase question, and i also said that it allows for easier control of the amount of products produced. some people in my class talked about costliness of high temperatures, which also seems valid.

What about the data analysis? A friend of mine said the same thing as you. I remember thinking I was happy it was related to respiration because we all had insight into that. It wasn't some obscure plant function or something

I did 4 & 5 as well

For 4c, how much did you write? How did you go about doing it? I said that conc of glucose in filtrate was greater than conc in blood plasma. Is that right? And by glomerular filtrate, did it only refer to the filtrate as it was in Bowman's Capsule or filtrate as it went through the Loop and the tubules? When does filtrate turn into urine? Once it reaches the collecting duct? Once it's past the collecting duct? Oh dear.

[soadquake981]

For 4c, how much did you write? How did you go about doing it? I said that conc of glucose in filtrate was greater than conc in blood plasma. Is that right? And by glomerular filtrate, did it only refer to the filtrate as it was in Bowman's Capsule or filtrate as it went through the Loop and the tubules? When does filtrate turn into urine? Once it reaches the collecting duct? Once it's past the collecting duct? Oh dear.

I know you weren't asking me, but I'll answer anyway: I wrote almost two full pages for 4c. Glomerular filtrate refers only to the liquid in the glomerulus. Urine is formed in the collecting duct.

[ABC123456]

OMG Bio!

What'd you think of it?

I'm TZ1.

I thought Paper 1 was pretty nice!

I looked at the question w/ + and - as the answers, and I was like what the heck?

But I got - and - as my answer.

And I spent way too long on the pedigree one. The only one that could have made sense was the X linked, recessive, right? I wanted to make sure that it was right...

What you get on the backwards recombinant one? I finally put A as my answer. Can't recall exactly what it was, but I remember it took me a while to get the answer.

And I hadn't studied long-day short-day enough. I read about it, but when it got to the P red and P far red, I zoned out because I didn't understand... eek.

I answered it as D.. which had something to do with one of the P acting as an inhibitor. Anyone else know what I'm talking about?

I also couldn't quite remember what HCG did. I said it kept up the corpus leutum...? I should go study that for tomorrow...

And for Paper 2, I thought I did fine. I wish there was more room for data analysis, but whatever.

For the lactose one, a lot of stuff from IB1 came back to me. Thank goodness. What did you say were the three reasons for galactose and glucose instead of lactose? I said something about lactose intolerance, making a thicker substance [because of hydrolysis], and one other thing.. can't remember...

But when it asked about why they put it in such low temperatures, I started BSing What'd you guys say, if you answered it?

And what'd you choose for Section B? I went with 4 and 5. I was 95% done with 4 when I realized that I didn't have 90 minutes left--I had only 30! So I freaked and started writing about the leaves for #5 [it was either that or the last one with DNA, but I didn't know how to add detail to the unique versus highly repetitive, so I went with 5. I just knew I wasn't going to do #6 haha]

So I had like 10 minutes after I'd just about finished number 5, and I went back to #4. Turns out my part C for #4 was 3 sides long. I wasted way too much space on that. But overall I had 5 pages for Section B. I was just glad I finished!

How bout you?

sweetnsimple, I was definitely too busy cramming for Paper 3 this morning to reply to your post =) So whoever said that (Sandwich? I don't remember) was right.

I feel like if I was even more prepared I would have felt better on biology. I think I should have done okay though. Hopefully.

I put - and - for that question too. I didn't get why they didn't just use words or something. And I think I also put X-linked, recessive for the pedigree question. I have to say I absolutely hate pedigree charts. I don't know which one you mean by the backwards recombinant one, the one where they give you the test cross and then you have to say which one was the parents? I think I put C for that one. Eek on the long-day flower one. I remember reading it but completely forgot everything.

As for Paper 2 what did you say was the importance of the long-term survival of that mollusc?

For that question about lower temperatures, I totally BSed it. I think I wrote down something totally wrong. Like since it's at lower temperatures the reaction won't be as rapid and energy won't be lost so quickly. I think that's definitely wrong. haha.

I picked I think 4 and 6? The one on blood and the one on translation and such? I think I did better on 4 that 6 because I knew about processes of the kidney but couldn't go that much in detail about translation and the whole process.

[soadquake981]

Speaking of the recombinants question... here's what I did. They gave you that the recombinants were tB/tb and Tb/tb (or other letters, but same sequences), and asked you to find the original parents' genotypes. My textbook actually had an example with the same exact recombinants, so I remembered that the parents' genotypes would be TB/tb and tb/tb. I'm pretty sure that's correct.

[sweetnsimple786]

For 4c, how much did you write? How did you go about doing it? I said that conc of glucose in filtrate was greater than conc in blood plasma. Is that right? And by glomerular filtrate, did it only refer to the filtrate as it was in Bowman's Capsule or filtrate as it went through the Loop and the tubules? When does filtrate turn into urine? Once it reaches the collecting duct? Once it's past the collecting duct? Oh dear.

I know you weren't asking me, but I'll answer anyway: I wrote almost two full pages for 4c. Glomerular filtrate refers only to the liquid in the glomerulus. Urine is formed in the collecting duct.

I was asking anyone who did that question. Thanks Yeah, I wrote 2.5 pages for it, and after I finished, I realized that was too much for 8 or whatever points.

sweetnsimple, I was definitely too busy cramming for Paper 3 this morning to reply to your post =) So whoever said that (Sandwich? I don't remember) was right.

I feel like if I was even more prepared I would have felt better on biology. I think I should have done okay though. Hopefully.

I don't know which one you mean by the backwards recombinant one, the one where they give you the test cross and then you have to say which one was the parents? I think I put C for that one. Eek on the long-day flower one. I remember reading it but completely forgot everything.

As for Paper 2 what did you say was the importance of the long-term survival of that mollusc?

For that question about lower temperatures, I totally BSed it. I think I wrote down something totally wrong. Like since it's at lower temperatures the reaction won't be as rapid and energy won't be lost so quickly. I think that's definitely wrong. haha.

Haha me too! I arrived at the testing site at 750, but I had to study more so I crammed for 8 more minutes and ended up a couple of minutes late, but they hadn't started. But the information I got in those last minutes saved my butt in P3

I can't remember how I got A for the recombinant one. I remember I had work scrawled all over that page and the last page where there was just empty space. It took me a good bit, but that was because I assumed something wrong first, I think. And I might have still gotten that wrong. Oh well.

Speaking of the recombinants question... here's what I did. They gave you that the recombinants were tB/tb and Tb/tb (or other letters, but same sequences), and asked you to find the original parents' genotypes. My textbook actually had an example with the same exact recombinants, so I remembered that the parents' genotypes would be TB/tb and tb/tb. I'm pretty sure that's correct.

Here's what I finally ended up doing: I went through each of the answer choices and assumed they were right. I'd make the crossing over combinations and then look at it. For the answer that you remembered, this would have been what resulted from crossing over: Tb//tB tb//tb

Then I assumed that each offspring would get a chromosome from the first set and a chromosome for the second set. So the first offspring would get Tb and the second would get tB from the 1st parent. From the second parent, both would get a tb. and that matched with the answer?

[ABC123456]

For 4c, how much did you write? How did you go about doing it? I said that conc of glucose in filtrate was greater than conc in blood plasma. Is that right? And by glomerular filtrate, did it only refer to the filtrate as it was in Bowman's Capsule or filtrate as it went through the Loop and the tubules? When does filtrate turn into urine? Once it reaches the collecting duct? Once it's past the collecting duct? Oh dear.

I know you weren't asking me, but I'll answer anyway: I wrote almost two full pages for 4c. Glomerular filtrate refers only to the liquid in the glomerulus. Urine is formed in the collecting duct.

I was asking anyone who did that question. Thanks Yeah, I wrote 2.5 pages for it, and after I finished, I realized that was too much for 8 or whatever points.

sweetnsimple, I was definitely too busy cramming for Paper 3 this morning to reply to your post =) So whoever said that (Sandwich? I don't remember) was right.

I feel like if I was even more prepared I would have felt better on biology. I think I should have done okay though. Hopefully.

I don't know which one you mean by the backwards recombinant one, the one where they give you the test cross and then you have to say which one was the parents? I think I put C for that one. Eek on the long-day flower one. I remember reading it but completely forgot everything.

As for Paper 2 what did you say was the importance of the long-term survival of that mollusc?

For that question about lower temperatures, I totally BSed it. I think I wrote down something totally wrong. Like since it's at lower temperatures the reaction won't be as rapid and energy won't be lost so quickly. I think that's definitely wrong. haha.

Haha me too! I arrived at the testing site at 750, but I had to study more so I crammed for 8 more minutes and ended up a couple of minutes late, but they hadn't started. But the information I got in those last minutes saved my butt in P3

I can't remember how I got A for the recombinant one. I remember I had work scrawled all over that page and the last page where there was just empty space. It took me a good bit, but that was because I assumed something wrong first, I think. And I might have still gotten that wrong. Oh well.

Speaking of the recombinants question... here's what I did. They gave you that the recombinants were tB/tb and Tb/tb (or other letters, but same sequences), and asked you to find the original parents' genotypes. My textbook actually had an example with the same exact recombinants, so I remembered that the parents' genotypes would be TB/tb and tb/tb. I'm pretty sure that's correct.

Here's what I finally ended up doing: I went through each of the answer choices and assumed they were right. I'd make the crossing over combinations and then look at it. For the answer that you remembered, this would have been what resulted from crossing over: Tb//tB tb//tb

Then I assumed that each offspring would get a chromosome from the first set and a chromosome for the second set. So the first offspring would get Tb and the second would get tB from the 1st parent. From the second parent, both would get a tb. and that matched with the answer?

Well I don't know if my method was correct, but it seemed correct when I did it. I just took each of the answers and did punnett squares for them with the Ts and then the Bs and then added the Ts and Bs together in their proper sequences so get what genotypes the result would be and I remember I did this process for all four answers and put down C. I just did it now using the genotypes of the parents that soadquake981 said (TB/tb and tb/tb) and got what sweetnsimple said (Tb//tB tb//tb) from it. I am not sure though.

[soadquake981]

I'm looking at my book right now, and here's what it says (with T and B substituted for the letters in the book):

One parent has genotype TB//tb and the other has genotype tb//tb. The four possible genotypes for offspring are TB//tb, tb//tb, tB//tb, and Tb//tb. The latter two are the ones asked for in the question.

[ABC123456]

The question about long-day plants and flowering and I think I put the answer that said something about Red light P® converts to P(fr) which promotes flowering? I looked it up and I think this is right? Does anyone else know?

[soadquake981]

The question about long-day plants and flowering and I think I put the answer that said something about Red light P® converts to P(fr) which promotes flowering? I looked it up and I think this is right? Does anyone else know?

My textbook says that is correct. I guessed that too.

[dexter]

The plasmid question: 1.E.Coli OR Prokaryote. I think they will accept them both.

2.Plasmid

3.DNA code

4.Transgenic organism/Gentically Modified Organism

As for the Database question, the first site is better than site 2 same reasoning a few posts ahead me said (because of storage of fats) and the Advantage: Can be very accurate. As for the Disadvantage: Since birds fly around countires they may contract diseases and using the blood testing may contaminate you, or through contact basically any argument of fear of dieases.

[D. C.]

Back to the TZ2 paper really quickly - did anyone find that the essay questions this year were really strangely hard?

I mean, generally all of the questions require you to draw a diagram for the first part. This year, there was only one question (asking you to draw a sperm)! I spent the entire day before learning diagrams. I was so annoyed.

Also, what happened to staple questions such as DNA replication, gene transfer etc. again, I spent ages on those the day before and none came up.

[IB_delusion]

Back to the TZ2 paper really quickly - did anyone find that the essay questions this year were really strangely hard?

I mean, generally all of the questions require you to draw a diagram for the first part. This year, there was only one question (asking you to draw a sperm)! I spent the entire day before learning diagrams. I was so annoyed.

Also, what happened to staple questions such as DNA replication, gene transfer etc. again, I spent ages on those the day before and none came up.

I agree with you. the question were ridiculous , the whole section B of paper 2

[pomoni]

Back to the TZ2 paper really quickly - did anyone find that the essay questions this year were really strangely hard?

I mean, generally all of the questions require you to draw a diagram for the first part. This year, there was only one question (asking you to draw a sperm)! I spent the entire day before learning diagrams. I was so annoyed.

Also, what happened to staple questions such as DNA replication, gene transfer etc. again, I spent ages on those the day before and none came up.

I agree with you. the question were ridiculous , the whole section B of paper 2

OMG thank God other people who share my opinion! I found section B soooo annoying! The questions were ridiculous!

I hope they lower the boundaries or something, because it really makes you lose points! (section B is over 36)

Edited May 19, 2010 by pomoni

[D. C.]

Back to the TZ2 paper really quickly - did anyone find that the essay questions this year were really strangely hard?

I mean, generally all of the questions require you to draw a diagram for the first part. This year, there was only one question (asking you to draw a sperm)! I spent the entire day before learning diagrams. I was so annoyed.

Also, what happened to staple questions such as DNA replication, gene transfer etc. again, I spent ages on those the day before and none came up.

I agree with you. the question were ridiculous , the whole section B of paper 2

OMG thank God other people who share my opinion! I found section B soooo annoying! The questions were ridiculous!

I hope they lower the boundaries or something, because it really makes you lose points! (section B is over 36)

Oh I know, unfortunately section B is usually the make-or-break one as well. So frustrating.

[IB_delusion]

section B worth 40 points T_T

[pomoni]

section B worth 40 points T_T

No it's worth 36 points.

[Sponge123]

I believe that section B is actually worth 38 points. It's 36 points of content (18 per question), and then at the top it says that an additional two points are available for the structuring of your answer. (Not sure how they mark that, exactly.)

Also, quick question about TZ1 Section A: what was the pattern of inheritance for the traits Aa Bb and Cc? I said something about them being linked genes, but I don't know if that's what the question was asking.