2016 OCR Biology A Breadth - Unofficial Mark Scheme

x=cell wall
y=plasma membrane as during plasmolysis the plasma membrane is drawn away from cell wall
z=tonoplast/vacoule as they never made that clear so could allow either.

The questions 21ai) was there was no consistency of sucrose concentration (from table it went from 0.4 to 0.45 where as throughout it was a difference of 0./1)
the second answer was size\amount of potato disc was not stated or controlled.

21aii) The question where you explain how it shows the water potential within the potato discs. You had to use the figures and explain that the percentage decreased in mass as concentration increased as concentration of sucrose increased so therefore higher water potential was in potato and by osmosis water left potato sacs(whatever they called them) resulting in decrease of mass of potato disc.

Guanine was 28% method= 22x2=44
100-44/2=28

The question based upon red blood cells lacking cell content answer was: increased surface area to volume ration and therefore maximum level of 02 can be transported to respiring tissues.

Then the one about why red blood cells never used up 02 was because they never contained double membrane bound organelles such as mitochondria which uses 02 for aerobic respiration. (dont know if im correct)

The question about the conservation when asking about small groups were isolated advantages where:
if a disease arise will not wipe out whole population
isolated therefore protected from predators and human hunted rhinos.

Another question was filling in missing gaps went in order like this : KINGDOM=ANIMALIA
Phylum, Class, Order, Fishes, Genus, Species=(in the question it said D.S... it was to copy the s part of name)
the second part to questions was why is binomial system helpful this was because it avoids confusion across the world when classifying species.

Last question was= bohr effect.

ii) active respiring tissues have lower saturation of 02 because aerobic resp. takes place releasing more co2 at faster rate which in return reacts with water to form carbonic anhydrase which then dissociates to form h+ ions causing haemoglobin to unfold as the bonds are broken such as hydrogen and ionic and 02 is released. Or active tissues have low p02 so Hhb dissociates to release 02.

cant remember the letters for the question after.

last question was based on mass flow. Cotransportation occurs where sap is actively loaded companion cell then diffuse through plasmodesmata, at top of sieve tube elements theres high hydrostatic pressure therefore creates a pressure gradient and moves along gradient towards sink where they are unloaded. Mention flow of sap in one direction to gain mark for mass flow.


(DONT KNOW IF ITS RIGHT)

x=cell wall
y=plasma membrane as during plasmolysis the plasma membrane is drawn away from cell wall
z=tonoplast/vacoule as they never made that clear so could allow either.

The questions 21ai) was there was no consistency of sucrose concentration (from table it went from 0.4 to 0.45 where as throughout it was a difference of 0./1)
the second answer was size\amount of potato disc was not stated or controlled.

21aii) The question where you explain how it shows the water potential within the potato discs. You had to use the figures and explain that the percentage decreased in mass as concentration increased as concentration of sucrose increased so therefore higher water potential was in potato and by osmosis water left potato sacs(whatever they called them) resulting in decrease of mass of potato disc.

Guanine was 28% method= 22x2=44
100-44/2=28

The question based upon red blood cells lacking cell content answer was: increased surface area to volume ration and therefore maximum level of 02 can be transported to respiring tissues.

Then the one about why red blood cells never used up 02 was because they never contained double membrane bound organelles such as mitochondria which uses 02 for aerobic respiration. (dont know if im correct)

The question about the conservation when asking about small groups were isolated advantages where:
if a disease arise will not wipe out whole population
isolated therefore protected from predators and human hunted rhinos.

Another question was filling in missing gaps went in order like this : KINGDOM=ANIMALIA
Phylum, Class, Order, Fishes, Genus, Species=(in the question it said D.S... it was to copy the s part of name)
the second part to questions was why is binomial system helpful this was because it avoids confusion across the world when classifying species.

Last question was= bohr effect.

ii) active respiring tissues have lower saturation of 02 because aerobic resp. takes place releasing more co2 at faster rate which in return reacts with water to form carbonic anhydrase which then dissociates to form h+ ions causing haemoglobin to unfold as the bonds are broken such as hydrogen and ionic and 02 is released. Or active tissues have low p02 so Hhb dissociates to release 02.

cant remember the letters for the question after.

last question was based on mass flow. Cotransportation occurs where sap is actively loaded companion cell then diffuse through plasmodesmata, at top of sieve tube elements theres high hydrostatic pressure therefore creates a pressure gradient and moves along gradient towards sink where they are unloaded. Mention flow of sap in one direction to gain mark for mass flow.


(DONT KNOW IF ITS RIGHT)

x=cell wall
y=plasma membrane as during plasmolysis the plasma membrane is drawn away from cell wall
z=tonoplast/vacoule as they never made that clear so could allow either.

The questions 21ai) was there was no consistency of sucrose concentration (from table it went from 0.4 to 0.45 where as throughout it was a difference of 0./1)
the second answer was size\amount of potato disc was not stated or controlled.

21aii) The question where you explain how it shows the water potential within the potato discs. You had to use the figures and explain that the percentage decreased in mass as concentration increased as concentration of sucrose increased so therefore higher water potential was in potato and by osmosis water left potato sacs(whatever they called them) resulting in decrease of mass of potato disc.

Guanine was 28% method= 22x2=44
100-44/2=28

The question based upon red blood cells lacking cell content answer was: increased surface area to volume ration and therefore maximum level of 02 can be transported to respiring tissues.

Then the one about why red blood cells never used up 02 was because they never contained double membrane bound organelles such as mitochondria which uses 02 for aerobic respiration. (dont know if im correct)

The question about the conservation when asking about small groups were isolated advantages where:
if a disease arise will not wipe out whole population
isolated therefore protected from predators and human hunted rhinos.

Another question was filling in missing gaps went in order like this : KINGDOM=ANIMALIA
Phylum, Class, Order, Fishes, Genus, Species=(in the question it said D.S... it was to copy the s part of name)
the second part to questions was why is binomial system helpful this was because it avoids confusion across the world when classifying species.

Last question was= bohr effect.

ii) active respiring tissues have lower saturation of 02 because aerobic resp. takes place releasing more co2 at faster rate which in return reacts with water to form carbonic anhydrase which then dissociates to form h+ ions causing haemoglobin to unfold as the bonds are broken such as hydrogen and ionic and 02 is released. Or active tissues have low p02 so Hhb dissociates to release 02.

cant remember the letters for the question after.

last question was based on mass flow. Cotransportation occurs where sap is actively loaded companion cell then diffuse through plasmodesmata, at top of sieve tube elements theres high hydrostatic pressure therefore creates a pressure gradient and moves along gradient towards sink where they are unloaded. Mention flow of sap in one direction to gain mark for mass flow.


(DONT KNOW IF ITS RIGHT)

The only way I could think of this being evidence for translocation is that sucrose travelling through the apoplast pathway require a cotransport protein, at hight temps this protein may denature so therefore translocation through the apoplast pathway would decrease

The formula for percentage change is:

It's change over original, not other one over original which would give 6700%, though i did put 6700% in the exam as i didn't realize it until now

its not 98.5% larger, the difference between 20.1 and 0.3 as a percentage of 20.1 is 98.5%

i got my 2/70 yay. Wait lol6700% is absolutely stupid, who would write that down you literally divided 20.1 by 0.3 and multiplied by 100, now that's retarded.

damn i did the disadvantages of isolated populations :/

I wrote assimilates rather than sucrose solution. Would I still get the mark?? And I hated that exam. Probably my worse one so far ffs

Rightly so; the person who posted that must have made a typo/****ed up in the exam. The question asked why they could become extinct faster if isolated.