biol+4+exam+revision

Ok biolclan, it is getting down to crunch time.


 * THIS PAGE IS FILLING UP SO I HAVE CREATED A NEW PAGE FOR EXAM QUERIES. USE THE LINK BELOW FROM NOW ON. **

biol 4 exam queries

You have two folders of trial exams.
 * The green folder contains exams (2000-2007) that you can write on if you wish. **
 * The red folder contains trial exams (2006, 2007 and 2008) that you must not write on. **

You will also be doing a trial exam in class on **Friday 10th October**. Come prepared!

You can use the exams in a number of ways. and and
 * do one exam completely without assistance
 * work out if there is an area that you were particularly weak in
 * for your weak area, do some revision and then do questions from a variety of exams on that area only
 * practise doing questons on a certain topic, including use of notes etc so that it become a way of learning an area better
 * leave about 2 or 3 exams, inlcuding the 2006 and 2007 VCA exams to do under exam conditions

The following questions you needn't worry about from the 2000-2005 exams.


 * > ** VCAA exam ** ||> ** Multiple choice ** ||> ** Short answer ** ||
 * > 2000  ||>  10  ||>   ||
 * > 2001  ||>   ||>  2c  ||
 * > 2002  ||>  25  ||>   ||
 * > 2003  ||>  11  ||>   ||
 * > 2004  ||>  4, 5  ||>   ||
 * > 2005  ||>  9  ||>   ||

Any questions relating to the exams can be posted below.
 * MAKE SURE YOU TELL ME WHICH EXAM YOU ARE TALKING ABOUT! **

Well i was just wondering if there is a certain amount of exams we should aim to complete by the end of these holidays? LM //A. As much as you can. It is difficult to put a number on it. If you do an average of 1.5 hour of biology per day that is 15 hours of biology before term starts. I would say that at least half of that time should be doing exam questions. So that is at least 7.5 hours. Depending on how you use the exams, that would be the equivalent of 5 full exams. I suggest you use a selection from the non-VCAA ones first and the 2000-2005 VCAA to start of with.Leave yourself 2 or 3 exams to do in the week prior to the exam. VM //

Vojtech there's a question that's kinda weirding me out a little, on one of the practise exams. It says: A. Anaphase I of mitosis B. Anaphase II of meiosis C. Prophase I of meiosis D. Metaphase I of mitosis**
 * Independent assortment or random segragation can occur during

The answers says that the correct option is B, which confuses me... I know that A and D are incorrect because they talk about mitosis. And I always assumed independent assortment occured during metaphase I and random segragation during anaphase I - both of which aren't there. AP

//A. First of all, please let me know which exam you are talking about, so that I can check the question myself. Secondly, these trial exams do have mistakes in them. I think I know which question you are referring to and it seems to me that they have the wrong answer or that the question is ambiguous/unclear/badly worded. The two laws: Law of independent assortment and Law of segregation are two separate things. You need to be clear on the difference between them. There is no question that independent assortment (of chromosomes) occurs during meiosis I (analphase) and that according to the law of segregation each gamete will receive only one of the two alleles (ie one chromosome from a homologous pair of chromosomes). So, in my view their is no correct answer from the options. VM //

Oh ok, well makes sense a bit now. The question was from the 2006 IARTV exam (question 3 of M.C). But it doesn't really say anything that I haven't already written.


 * NEW QUESTION: This isn't in relation to the same question, but just independent assortment in general. You mentioned that it occurs in anaphase I of meiosis, but wouldn't it occur in metaphase? I read that each pair of homologous chromosomes assorts independently of all other pairs. Wouldn't the assorting occur at metaphase I because this is where they line up? That's something I haven't fully cleared up yet. AP**

//A. When it comes to meiosis and the naimg of stages, the boundaries can sometimes be blurry. This is why it is more important to know what happens, rather than names of stages. When it comes to indpendent assortment, you could say that it is in anaphase because until they have started to move towards the centrioles and therefore becoming spearated from their homologous partner, they haven't yet assorted. Although you could also say that it occurs in metaphase because they are lining up independent of each other. So, I don't think I can clear this up for you because you will probably find different sources say different things. In some ways it doesn't really occur at any particular point but is rather the explanation for inheritance patterns. Hence the **Law** of independent assortment. VM //


 * Q. Is there a difference between artificial selection and selective breeding? Or do they both mainly mean the same thing?**

//A. Selective breeding really only relates to the human context whereby we choose the traits we want (in a particular organism) and only allow those individuals to breed, so yep this is what we would also describe as artificial selection. VM //


 * Q. I'm really confused about M.C question 13 on the 2006 IARTV exam. I just don't know how to infer anything from what I've been given - how is the boy heterozygous for the HD gene?** **AP**

//A. Ok this is a question that requires careful thought about the information. First of all you are told that the HD allele is longer than the normal allele, so this means that gel electrophoresis will be able to pick up this difference (presence of HD allele will result in a band closer to the start). Hence the banding pattern will vary depending on whether you are homozygous dominant, heterozygous or homozygous recessive.THIS IS THE CRITICAL PIECE OF UNDERSTANDING THAT IS REQUIRED. Now sometimes you have to discount other possibilities before you get to the answer that is most likely to be correct, although that is not really the case here. Given the mother has only one band and it is has moved further than a band present in the boy and father, she must be homozygous recessive and have two normal alleles. Hence B and D cannot be correct. Now both the boy and father have two bands thus they must be heterozygous! The reason A is not correct is because he is not a carrier (ie he will suffer the disease). This question really is based about interpeting a banding pattern that relates to different types of alleles (as a result of a mutation). These types of questions I think are really good because they involve several different key areas of the course. VM //


 * Q. In terms of cultural evolution, what are the differences between Homo neanderthalensis and Homo sapiens? I've only found one, which is that Homo sapiens used symbols and neanderthalensis didn't. Are there any other important ones we should know? AP**

//A. Hmmm... I cannot think or know of any other difference. I would be very surprised if a question asked you to have to recall such a notion. Neanderthals are a bit of an enigma. It is likely they were a distinct species that became extinct (but not because they sort of became part of the Homo sapien gene pool). They coexisted with Homo sapiens (at least early forms) and were physically different in small ways (larger cranial capacity, no forehead). But they did use tools and had culture. They were the first to bury their dead, including flowers and artefacts. I would not worry about any more detail. VM //
 * Q. From NEAP 2007 - 'Index' fossils are the same as 'indicator' fossils, right? As in their age can be determined and they are found in many layers of rock, thereby allowing the ages of these rock layers to be determined if these particular fossils are found in them? AH**

//A. Yep, you are right another point is that they are ideally abundant, found in many places around the world and always found in the same layers. The shorter time period they represent the better as it allows for more "accuracy" in the determination of that rock layer. VM //


 * Q. Voij. Am I better off doing practise exams from the companies, or the VCAA ones from the old study design?**

//A. It depends on what you want to get out of them. The more VCAA you do the more familiar you become with the way they ask questions, and almost all the questions are still valid from the older ones. I suggest you use the other ones for questions on areas that are new to the course, eg applications of gene technology and experimental type questions. Another possibility is that you give yourself a 90 minute time limit and answer as many of the old VCAA MC questions, starting 2000 (aim for doing four exams worth). See how you go on these and any weaknessess can be addressed by doing short answer questions on these areas or further study. Just leave yourself a couple of full exams to do next week. VM // okkkkk thanks!:)


 * Q. This has been really confusing me. I've read from some sources that mtDNA mutates more slowly than DNA, which is the reason it is used. But other sources say since segments of mtDNA mutate more quickly, they can be used to examine recent human evolution. Maybe I'm interpreting it wrong or something, but I just don't understand if it mutates quickly or slowly... AP**

//A. You are not the only one that is confused about this. So much so that on last year's exam there was a MC question that had ambiguity that resulted in everyone getting a mark for it. Quite a bit is known about mtDNA, such as the size, how it replicates, how it is inherited, how many genes there and what they do. In terms of mutation rates, it appears some regions mutate faster than others. There are two hypervariable regions that appear to mutate "much faster" than the protein coding sections of the mtDNA. So these can be used as a source for phylogentic relationships. Obviously, it is good that the coding regions mutate slower because then diseases would be more prevalent. It therefore becomes confusing when comparing mutation rate in nuclear DNA to mtDNA. I cannot give you a 100% clear answer on this. What is important also is when you compare changes in nuclear DNA compared to mtDNA. If we look at changes nuclear DNA changes much more quickly compared to mtDNA from generation to generation because of recombination and paternal and maternal inputs. So when comparing the DNAs we have to be clear on whetehr we are talking about mutations rates or changes. My advice is read the question carefully on the exam, think about the facts associated with each type of DNA and choose the least likely incorrect answer if in doubt. Hope this makes sense. Now if we are trying to establish recent evolutionary relationships it is better if more mutations have occurred becuase differences will be seen more easily, this is the way I see it. Don't dwell too much on mtDNA, other than knowing its relevance and some of the facts about it. VM //


 * ohhhh, I think I understand. So when it says mtDNA changes more slowly than nuclear DNA, it refers to the changes nuclear DNA goes through such as recombination. But when it talks specifically about mutations, then mtDNA mutates faster the nuclear DNA. Is this right?**

// A. Yeah but remember only certain regions of the mtDNA mutate faster. I wish I could clarify this more for you but my expertise in this area is lacking. VM //

hi Voj, in the 2007 VCAA exam question 8c, when it asks if the number of pseudogenes will change in monkeys which can distinguish colour, how would you go about answering this question? I would think not but i dont know why hehe

// A. Ok, not easy to make sense of this question (no pun intended) hence the poor score by students only 20% got it right. If some apes and monkeys distinguish colour then sight is more important to them than smell. Therefore apes and monkey are less reliant on smell and therefore more of the smell genes will become pseudogenes. ie if a gene is not as important to survival then perhaps there is more possibility of it becoming a pseudogene (non-functional). VM //

and also q 8c on the same exam; why would pseudogenes genes accumilate mutations, is it becoz in DNA replication there are things that correct mutations if there occur, it is becoz this doesnt happen to pseudogenes? :0

// A. I assume you mean 8d. Now this is a really challenging question in that you need to be thinking the right way to make the link. Mutations occur all along the DNA but if a gene is important to the survival of an individual and therefore the offspring, then mutations cannot build up in that gene because it won't funtion properly and therefore the individual doesn't survive. But a gene that has become a pseudogene can have as many mutations occur in it, it won't matter because the individual doesn't need the gene for survival, it's just there stuck in the DNA but will still be passed on to offspring allowing more mutations to occur over time. VM //

Hi again hehe, in the same exam (VCAA 2007), Q 3b the answere is ' the trabnscription of all gene is stopped, but isnt gene 3 onwards stopped as tryptophan only repressors gene 3, and was i still right if i wrote that. thanx

// A. From the diagram pathway X leads to tryptophan affecting all the genes as shown by the arrows going to all five genes. So saying only gene 3 is not enough and would not get you the mark I would think. VM //