F215 - Revision thread 13th June 2011
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what textbook are you all using for revision? I'm currently using the Biology 2 for OCR (cambridge) book and the CGP revision guide ... the info in the former seems a little vague, I really need like an A or a solid B in this exam so my concern is whether I'm using the right resources. What textbook are you all finding the most useful?
Original post by FreeFly
what textbook are you all using for revision? I'm currently using the Biology 2 for OCR (cambridge) book and the CGP revision guide ... the info in the former seems a little vague, I really need like an A or a solid B in this exam so my concern is whether I'm using the right resources. What textbook are you all finding the most useful?
I just use that textbook - does seem like it misses out stuff, but along with my notes it seems to cover all the points on the specification. But I guess if you didn't have very good notes or handouts, you'd struggle!
Okay. so any predicitions anyone. Take a guess, 2 from each module. We did this for unit 1 of A2, and we predicted correctly. So come on guys, drop your predictions, or something that u feel has a strong chance of coming up, as it has not yet appeared on the new specification for a while.
Original post by tallysingh
Okay. so any predicitions anyone. Take a guess, 2 from each module. We did this for unit 1 of A2, and we predicted correctly. So come on guys, drop your predictions, or something that u feel has a strong chance of coming up, as it has not yet appeared on the new specification for a while.
I reckon:
Mod 1
- Meiosis and its significance - nice essay
Mod 2
- Cloning
Mod 3
- Galapagos
Mod 4
- Synovial Joint
- Muscle Contraction
I reckon the nitrogen cycle, electrophoresis, micropogation, signmodial growth curve! (He hopes)
Original post by sportycricketer
I reckon:
Mod 1
- Meiosis and its significance - nice essay
Mod 2
- Cloning
Mod 3
- Galapagos
Mod 4
- Synovial Joint
- Muscle Contraction
Mod 1
- Meiosis and its significance - nice essay
Mod 2
- Cloning
Mod 3
- Galapagos
Mod 4
- Synovial Joint
- Muscle Contraction
have these been tested before
Original post by tallysingh
have these been tested before
nope therefore the prediction
thats good, can you give me a list of what has not been tested so far, a list of the big main topics.
Original post by 786girl
helloooooo im joining this crew from today!
lets doo thissssssssssssssssssssssss 50% of A2 !!!
im gonna put the AS behind me now and focus on this and hopefully do well!
ok, for the succession, do we need to know the names of plants and species at every stage? there are so many!
lets doo thissssssssssssssssssssssss 50% of A2 !!!
im gonna put the AS behind me now and focus on this and hopefully do well!
ok, for the succession, do we need to know the names of plants and species at every stage? there are so many!
Yep you do.. there are two example for it on the book by Mary jones.One is based on succession near poles and other is of the sand dunes.
The one which I sat in jan. had no meiosis or chi square! Make sure you go through it,chances of it coming again are highly likely..
(edited 12 years ago)
Original post by ibysaiyan
Yep you do.. there are two example for it on the book by Mary jones.One is based on succession near poles and other is of the sand dunes.
The one which I sat in jan. had no meiosis or chi square! Make sure you go through it,chances of it coming again are highly likely..
The one which I sat in jan. had no meiosis or chi square! Make sure you go through it,chances of it coming again are highly likely..
ooh okay, meiosis and chi squared-thats what ill do tonight! thanx
Original post by 786girl
ooh okay, meiosis and chi squared-thats what ill do tonight! thanx
Np =]
Original post by 786girl
helloooooo im joining this crew from today!
lets doo thissssssssssssssssssssssss 50% of A2 !!!
im gonna put the AS behind me now and focus on this and hopefully do well!
ok, for the succession, do we need to know the names of plants and species at every stage? there are so many!
lets doo thissssssssssssssssssssssss 50% of A2 !!!
im gonna put the AS behind me now and focus on this and hopefully do well!
ok, for the succession, do we need to know the names of plants and species at every stage? there are so many!
I don't think you need to know specifics, more like 'climax community is woodland including...' But according to the specification, you only need to know one. So either sand dune, or exposed rock etc
Original post by tallysingh
thats good, can you give me a list of what has not been tested so far, a list of the big main topics.
Haha, there's only been a couple of past papers - look for yourself :P
No but seriously, its such a long paper, I'd expect a little bit of everything. They'll manage to put a random question for each thing in I'm sure.
Ok I've learnt the basics of succession. Succession is the changes that occur in a community over time. There are many stages to this proceeding succession, more commonly known as 'seres'. Succession occurs until a relatively stable state is reached known as the Climax Community- this is balanced equilibrium.
Primary Succession
This is when succession occurs on relatively lifeless area and the organisms that are formed are known as 'Pioneer species' which are adapted to hostile conditions. An example of where primary succession may occur is volcanic land.
An example is bare rock. The steps that occur are as follows:
1. Bare rock begins to erode and these mineral ions allow soil to form
2. Pioneer species die and decay, and this humus allows the water carrying capacity of the soil to increase and the soil volume to increase.
3. Over time, this would lead to plants such as mosses and ferns growing. They would take root in the soil and mask that of the pioneer species.
4. Succession goes through a series of different communities known as seres until eventually ending in the climaz community which is stable- balanced equilibrium and in the UK usually oak beach woodland.
Characteristic of pioneer species
1. Tolerant of extreme conditions e.g. Wind, salinity, lack of soil and water,
2. Easily dispersed-usually by wind
3. Not good competitors.
4. Not influenced by or dependant on animal species.
5. May be legumes and able to fix nitrogen.
6. E.g. Marram grass, lichens, algae and mosses.
Characteristuc of climax community species
1. Have a specialised niche
2. Unable to tolerate fluctuations in soil water content,
Secondary succession
This occurs when an existing community has been cleared by some disturbance that leaves the soil intact. Examples are Fire, flood and deforestation.
It takes place much faster than primary succession simply because the soil is already present.
Deflected succession.
This occurs when the normal changes in the succession are stopped by grazing or mowing of grass, ploughing of land; draining of woodland. It can lead to an increase in biodiversity- creation of greater variety of niches.
NITROGEN CYCLE
1. Nitrogen gas from the atmosphere is used by rhizobium bacteria. These bacteria living in the nodules of the legume species convert nitrogen gas into ammonia then amine compounds. The plants transport these amine compounds from the nodules and are used to make amino acids then proteins. Rhizobium bacteria gain carbohydrates from the plants so both organisms benefit and this is known as mutualism. This is known as NITROGEN FIXATION.
2. Plants support food webs, throughout which excretion, production of faeces and death takes place. These resources are of huge benefit to the ecosystem, but first decomposition by saprobiotic bacteria has to take place and a waste product of this is ammonia.
3. Ammonia is needed by nitrosomonas bacteria for a special type of nutrition (chemo-autotrophic) and a waste product of this is nitrite.
4. Nitrite is needed by nitrobacter bacteria for again chemoautotrophic nutrition. Another waste product is formed called nitrate. Nitrate is of huge benefit to plants making amino acids and therefore proteins, thus aid in growth. Plants absorb much nitrate through their roots. This is NITRIFICATION.
5. Finally, nitrogen gas is returned to the atmosphere by denitrifying bacteria such as pseudomonas. Some nitrate is converted back to nitrogen gas by these bacteria. this is DENITRIFICATION.
Meiosis 1(ill give it a go but aint revised it yet)
The first stage is PROPHASE 1. In this stage the chromatin consense and supercoil and the chromosomes from each homologous pair come together to form a bivalent. Next chiasmata form between the non sister chromatids and sections swapped during crossing over. The nucleolus dissapears and the nuceur envelope disintegrates. A spindle of protein microtubules form. The next stage is METAPHASE 1. During this stage, the bivalents line up on the equator and are attched to the spindle at the centromere. The bivalents randomly assort themselves on the equator. This allows the chromosomes to independantly segregate when they are pulled apart in anaphase 1. Next is ANAPHASE 1. In this stage the homologous chromosomes in each bivalent are pulled apart by the shortening of the spindle fibres to opposite poles. The centromeres stay undivided. The chiasmata seperate and new combination of alleles are formed. Next is TELOPHASE 1. In this the two nucleur envelopes form. The cells divide by cytokinesis to form to haploid daughter nucei.
Meiosis 2
First is PROPHASE 1. During this stage if the nucleur envelope has reformed it breaks down again. The nucleolus dissapears, chromosomes consense and spindle form. Next is METAPHASE 11. In this stage the chromosomes arrange themselves on the equator of the spinle and are attached to the spindle at the centromeres. The chromatid of each chromosome are randomly assorted. Furthermore, the next stage is that of ANAPHASE 11. During this stage the centromeres divide and the chromatids are pulled to opposite poles by the spindle fibres. The chromatids are randomly segregated. Finally is TELOPHASE 11. During this stage the nucleur membrane reforms around the haploid daughter nuclei. In animals the two daughter cells now divide to give four haploid cells. In plants a tetrad of fource haploid cells is formed.
( I cheated a bit on that hehehe)
Primary Succession
This is when succession occurs on relatively lifeless area and the organisms that are formed are known as 'Pioneer species' which are adapted to hostile conditions. An example of where primary succession may occur is volcanic land.
An example is bare rock. The steps that occur are as follows:
1. Bare rock begins to erode and these mineral ions allow soil to form
2. Pioneer species die and decay, and this humus allows the water carrying capacity of the soil to increase and the soil volume to increase.
3. Over time, this would lead to plants such as mosses and ferns growing. They would take root in the soil and mask that of the pioneer species.
4. Succession goes through a series of different communities known as seres until eventually ending in the climaz community which is stable- balanced equilibrium and in the UK usually oak beach woodland.
Characteristic of pioneer species
1. Tolerant of extreme conditions e.g. Wind, salinity, lack of soil and water,
2. Easily dispersed-usually by wind
3. Not good competitors.
4. Not influenced by or dependant on animal species.
5. May be legumes and able to fix nitrogen.
6. E.g. Marram grass, lichens, algae and mosses.
Characteristuc of climax community species
1. Have a specialised niche
2. Unable to tolerate fluctuations in soil water content,
Secondary succession
This occurs when an existing community has been cleared by some disturbance that leaves the soil intact. Examples are Fire, flood and deforestation.
It takes place much faster than primary succession simply because the soil is already present.
Deflected succession.
This occurs when the normal changes in the succession are stopped by grazing or mowing of grass, ploughing of land; draining of woodland. It can lead to an increase in biodiversity- creation of greater variety of niches.
NITROGEN CYCLE
1. Nitrogen gas from the atmosphere is used by rhizobium bacteria. These bacteria living in the nodules of the legume species convert nitrogen gas into ammonia then amine compounds. The plants transport these amine compounds from the nodules and are used to make amino acids then proteins. Rhizobium bacteria gain carbohydrates from the plants so both organisms benefit and this is known as mutualism. This is known as NITROGEN FIXATION.
2. Plants support food webs, throughout which excretion, production of faeces and death takes place. These resources are of huge benefit to the ecosystem, but first decomposition by saprobiotic bacteria has to take place and a waste product of this is ammonia.
3. Ammonia is needed by nitrosomonas bacteria for a special type of nutrition (chemo-autotrophic) and a waste product of this is nitrite.
4. Nitrite is needed by nitrobacter bacteria for again chemoautotrophic nutrition. Another waste product is formed called nitrate. Nitrate is of huge benefit to plants making amino acids and therefore proteins, thus aid in growth. Plants absorb much nitrate through their roots. This is NITRIFICATION.
5. Finally, nitrogen gas is returned to the atmosphere by denitrifying bacteria such as pseudomonas. Some nitrate is converted back to nitrogen gas by these bacteria. this is DENITRIFICATION.
Meiosis 1(ill give it a go but aint revised it yet)
The first stage is PROPHASE 1. In this stage the chromatin consense and supercoil and the chromosomes from each homologous pair come together to form a bivalent. Next chiasmata form between the non sister chromatids and sections swapped during crossing over. The nucleolus dissapears and the nuceur envelope disintegrates. A spindle of protein microtubules form. The next stage is METAPHASE 1. During this stage, the bivalents line up on the equator and are attched to the spindle at the centromere. The bivalents randomly assort themselves on the equator. This allows the chromosomes to independantly segregate when they are pulled apart in anaphase 1. Next is ANAPHASE 1. In this stage the homologous chromosomes in each bivalent are pulled apart by the shortening of the spindle fibres to opposite poles. The centromeres stay undivided. The chiasmata seperate and new combination of alleles are formed. Next is TELOPHASE 1. In this the two nucleur envelopes form. The cells divide by cytokinesis to form to haploid daughter nucei.
Meiosis 2
First is PROPHASE 1. During this stage if the nucleur envelope has reformed it breaks down again. The nucleolus dissapears, chromosomes consense and spindle form. Next is METAPHASE 11. In this stage the chromosomes arrange themselves on the equator of the spinle and are attached to the spindle at the centromeres. The chromatid of each chromosome are randomly assorted. Furthermore, the next stage is that of ANAPHASE 11. During this stage the centromeres divide and the chromatids are pulled to opposite poles by the spindle fibres. The chromatids are randomly segregated. Finally is TELOPHASE 11. During this stage the nucleur membrane reforms around the haploid daughter nuclei. In animals the two daughter cells now divide to give four haploid cells. In plants a tetrad of fource haploid cells is formed.
( I cheated a bit on that hehehe)
(edited 12 years ago)
Hello all,
If anyone expertise in Epsitasis or know something regards to this question please help!
Q: Suggest how you could do a breeding experiment to determine if an agouti mouse was heterozygous for C/c alleles.
Basically the context: cc= no colour (so albino can be ccAA / ccAa/ ccaa)
Agouti: CcAa / CCAA / CCAa/ CcAA
Black : Ccaa/ CCaa
I reckon the pathway goes like this:
Precursor substance (colourless) ---gene C/c---> black pigment----gene A/a---------> agouti pattern
If anyone expertise in Epsitasis or know something regards to this question please help!
Q: Suggest how you could do a breeding experiment to determine if an agouti mouse was heterozygous for C/c alleles.
Basically the context: cc= no colour (so albino can be ccAA / ccAa/ ccaa)
Agouti: CcAa / CCAA / CCAa/ CcAA
Black : Ccaa/ CCaa
I reckon the pathway goes like this:
Precursor substance (colourless) ---gene C/c---> black pigment----gene A/a---------> agouti pattern
(edited 12 years ago)
Original post by V.sey
Hello all,
If anyone expertise in Epsitasis or know something regards to this question please help!
Q: Suggest how you could do a breeding experiment to determine if an agouti mouse was heterozygous for C/c alleles.
Basically the context: cc= no colour (so albino can be ccAA / ccAa/ ccaa)
Agouti: CcAa / CCAA / CCAa/ CcAA
Black : Ccaa/ CCaa
I reckon the pathway goes like this:
Precursor substance (colourless) ---gene C/c---> black pigment----gene A/a---------> agouti pattern
If anyone expertise in Epsitasis or know something regards to this question please help!
Q: Suggest how you could do a breeding experiment to determine if an agouti mouse was heterozygous for C/c alleles.
Basically the context: cc= no colour (so albino can be ccAA / ccAa/ ccaa)
Agouti: CcAa / CCAA / CCAa/ CcAA
Black : Ccaa/ CCaa
I reckon the pathway goes like this:
Precursor substance (colourless) ---gene C/c---> black pigment----gene A/a---------> agouti pattern
I think you could breed two agouti mice to see what the phenotypic ratio of the offspring. So if two mice were CcAa x CcAa you'd get some individuals with just ccAa or ccaa which would show that some of the agouti mice were heterzygotes.
otherwise, no idea
Original post by Waqar Y
Original post by Waqar Y
I think you could breed two agouti mice to see what the phenotypic ratio of the offspring. So if two mice were CcAa x CcAa you'd get some individuals with just ccAa or ccaa which would show that some of the agouti mice were heterzygotes.
otherwise, no idea
otherwise, no idea
Thanks!
Can someone explain how you do crosses? I can't do them -_-
I need to confirm the difference of the terms: epistatic and hypostatic.
In the example:
Colourless substance------gene1-------> Red pigment-------gene 2-------> Purple pigment
So is gene 1 the epistatic and gene 2 hypostatic?
N.B- 'The gene which supresses the expression of another gene at a different locus is said to be epistatic, while the supressed locus said to be hypostatic.'
Sounds simple but just to check...
In the example:
Colourless substance------gene1-------> Red pigment-------gene 2-------> Purple pigment
So is gene 1 the epistatic and gene 2 hypostatic?
N.B- 'The gene which supresses the expression of another gene at a different locus is said to be epistatic, while the supressed locus said to be hypostatic.'
Sounds simple but just to check...
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