AQA BIOL2 Biology Unit 2 Exam - 26th May 2011
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Original post by Master.K
I've done three. But seriously, some answers in the mark schemes are just RIDICULOUS! 
Yep; not like anything we've been taught, but I guess it's the same for everyone
Original post by DoaaK
how are plants, fish and insects adapted for gas exchange?
quote me please
quote me please
Hey, I hope this is enough detail for you...
Plants:
Stomata on the underside of the leaf-> Allows 02 in and out easily (without as much water loss as if they were on the top of the leaf,) (Here transpiration factors come in that affect rate of diffusion into the leaf-PM if you want to know more and I'll post it.)
Maram grass is curled inside (again to prevent as much water loss) and has large surfce area's with numerous somata.
The leaves are thin -> The 02 dosn't have to diffuse very far so it gets to where it is needed quickly.
Fish:
Large Surface area of the gills -> There are lots of gill fillaments and they have additional Lamellae to increase the S.A further.
Counter-flow system-> water flow in the opposite direction to the blood so a concentraion gradient can be maintanied which means a consistent fast rate of diffusion as no equilibruim is reached.
High blood flow through the gills-> The 02 that diffuses in is quickly removed and taken to where it is needed with the oxygen in it. There are lots of capillaries in the gills to do this.
Insects:
Lots of spiracles -> open and close to allow air in and out of the body.
Rhytmic abdominal movements -> Oxygen diffuses down a concentration gradient into the trachea and then the tracheoles as the volume is increased and decseased changing the pressure (like the way we breath out-See unit 1)Numerous trachea and tracheoles -> Increased Surface area
Thin Permeable walls of Tracheoles -> Short diffusion path and 02 diffuses directly into cells (Its circulatory system does not do this)
All of the above can be related to ficks law some how, which if anyone who is reading this has forgotten, it is:
Diffiusion is directly proportional to
(Surface area x Difference in concentration) / Distance of diffusion path
Sorry for any spelling mistakes-Computer won't let me check them and I'm useless with identifying mistakes... :P
Also does anyone else have four exams on 26th? I'm really beginning to freak out about this... (I have Biology Unit 2, C2, an R.E. retake and the Old Testemant part of my R.E. course...) Urgh. My total exam time comes to 5 and 3/4 hours, not quite the six hour limit so I have to do all four in one day.
Original post by Elliekate1
Hey, I hope this is enough detail for you...
Plants:
Stomata on the underside of the leaf-> Allows 02 in and out easily (without as much water loss as if they were on the top of the leaf,) (Here transpiration factors come in that affect rate of diffusion into the leaf-PM if you want to know more and I'll post it.)
Maram grass is curled inside (again to prevent as much water loss) and has large surfce area's with numerous somata.
The leaves are thin -> The 02 dosn't have to diffuse very far so it gets to where it is needed quickly.
Fish:
Large Surface area of the gills -> There are lots of gill fillaments and they have additional Lamellae to increase the S.A further.
Counter-flow system-> water flow in the opposite direction to the blood so a concentraion gradient can be maintanied which means a consistent fast rate of diffusion as no equilibruim is reached.
High blood flow through the gills-> The 02 that diffuses in is quickly removed and taken to where it is needed with the oxygen in it. There are lots of capillaries in the gills to do this.
Insects:
Lots of spiracles -> open and close to allow air in and out of the body.
Rhytmic abdominal movements -> Oxygen diffuses down a concentration gradient into the trachea and then the tracheoles as the volume is increased and decseased changing the pressure (like the way we breath out-See unit 1)Numerous trachea and tracheoles -> Increased Surface area
Thin Permeable walls of Tracheoles -> Short diffusion path and 02 diffuses directly into cells (Its circulatory system does not do this)
All of the above can be related to ficks law some how, which if anyone who is reading this has forgotten, it is:
Diffiusion is directly proportional to
(Surface area x Difference in concentration) / Distance of diffusion path
Sorry for any spelling mistakes-Computer won't let me check them and I'm useless with identifying mistakes... :P
Also does anyone else have four exams on 26th? I'm really beginning to freak out about this... (I have Biology Unit 2, C2, an R.E. retake and the Old Testemant part of my R.E. course...) Urgh. My total exam time comes to 5 and 3/4 hours, not quite the six hour limit so I have to do all four in one day.
Plants:
Stomata on the underside of the leaf-> Allows 02 in and out easily (without as much water loss as if they were on the top of the leaf,) (Here transpiration factors come in that affect rate of diffusion into the leaf-PM if you want to know more and I'll post it.)
Maram grass is curled inside (again to prevent as much water loss) and has large surfce area's with numerous somata.
The leaves are thin -> The 02 dosn't have to diffuse very far so it gets to where it is needed quickly.
Fish:
Large Surface area of the gills -> There are lots of gill fillaments and they have additional Lamellae to increase the S.A further.
Counter-flow system-> water flow in the opposite direction to the blood so a concentraion gradient can be maintanied which means a consistent fast rate of diffusion as no equilibruim is reached.
High blood flow through the gills-> The 02 that diffuses in is quickly removed and taken to where it is needed with the oxygen in it. There are lots of capillaries in the gills to do this.
Insects:
Lots of spiracles -> open and close to allow air in and out of the body.
Rhytmic abdominal movements -> Oxygen diffuses down a concentration gradient into the trachea and then the tracheoles as the volume is increased and decseased changing the pressure (like the way we breath out-See unit 1)Numerous trachea and tracheoles -> Increased Surface area
Thin Permeable walls of Tracheoles -> Short diffusion path and 02 diffuses directly into cells (Its circulatory system does not do this)
All of the above can be related to ficks law some how, which if anyone who is reading this has forgotten, it is:
Diffiusion is directly proportional to
(Surface area x Difference in concentration) / Distance of diffusion path
Sorry for any spelling mistakes-Computer won't let me check them and I'm useless with identifying mistakes... :P
Also does anyone else have four exams on 26th? I'm really beginning to freak out about this... (I have Biology Unit 2, C2, an R.E. retake and the Old Testemant part of my R.E. course...) Urgh. My total exam time comes to 5 and 3/4 hours, not quite the six hour limit so I have to do all four in one day.
omg good luck! you'll be fine!
but i think you're plant gas-exchange thing is wrong, isn't that how a plant reduces transpiration?
i thought plants have efficient gas exchange because:
- air spaces in the leaf = large sa
- mesophyll cells are thin & flat = large sa
- stomata - open and close to control co2 diffuion into cell and o2 out
- o2 produces from photosynthesis is reused in respiration
and probably more? i don't know :l
can someone please email me the january 2011 paper? i can't find it anywhere!
thanks
thanks
Meiosis produces gametes with haploid chromosome number. Haploid (23 chromosomes) is half of diploid (46 chromosomes) and every cell produced by mitosis has the diploid number.
The haploid number is needed so at fertilization, 2 gametes combine to give a cell with the diploid number again.
In meiosis there are 2 nuclear divisions. I remember it by "Heht C4", which doesn't make much sense but is helpful nonetheless.
H- Homologous chromosomes pair up randomly
E- Equivalent portions of the chromatids cross over and recombine (see notes)
H- Homologous chromosomes separate
T- This is called independent segregation (see notes)
C- Chromatids separate during anaphase of the second nuclear division
4- 4 daughter cells with haploid number of chromosomes are formed
Notes
There are two ways of meiosis producing genetic variation that you must know.
Independent segregation- The homologous chromosomes line up randomly, so when they separate for the first time, there are new combination of maternal and paternal chromosomes in the daughter cells.
Recombination of sister (identical) chromatids- This is where chromatids in the homologous pair get twisted around one another, break off, and recombine onto the other chromosome. XX- it only happens between the parts next to each other, and you need to know that it is a rare occurrence.
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
The diploid number is sometimes referred to as "2n" and the haploid as "n". So you may get a diagram with a cell, which would be 2n, then after meiosis, this you would write n.
I think that covers it. We don't go into much detail on meiosis, just the main events and their results.
The haploid number is needed so at fertilization, 2 gametes combine to give a cell with the diploid number again.
In meiosis there are 2 nuclear divisions. I remember it by "Heht C4", which doesn't make much sense but is helpful nonetheless.
H- Homologous chromosomes pair up randomly
E- Equivalent portions of the chromatids cross over and recombine (see notes)
H- Homologous chromosomes separate
T- This is called independent segregation (see notes)
C- Chromatids separate during anaphase of the second nuclear division
4- 4 daughter cells with haploid number of chromosomes are formed
Notes
There are two ways of meiosis producing genetic variation that you must know.
Independent segregation- The homologous chromosomes line up randomly, so when they separate for the first time, there are new combination of maternal and paternal chromosomes in the daughter cells.
Recombination of sister (identical) chromatids- This is where chromatids in the homologous pair get twisted around one another, break off, and recombine onto the other chromosome. XX- it only happens between the parts next to each other, and you need to know that it is a rare occurrence.
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
The diploid number is sometimes referred to as "2n" and the haploid as "n". So you may get a diagram with a cell, which would be 2n, then after meiosis, this you would write n.
I think that covers it. We don't go into much detail on meiosis, just the main events and their results.
Original post by ChessMister
Meiosis produces gametes with haploid chromosome number. Haploid (23 chromosomes) is half of diploid (46 chromosomes) and every cell produced by mitosis has the diploid number.
The haploid number is needed so at fertilization, 2 gametes combine to give a cell with the diploid number again.
In meiosis there are 2 nuclear divisions. I remember it by "Heht C4", which doesn't make much sense but is helpful nonetheless.
H- Homologous chromosomes pair up randomly
E- Equivalent portions of the chromatids cross over and recombine (see notes)
H- Homologous chromosomes separate
T- This is called independent segregation (see notes)
C- Chromatids separate during anaphase of the second nuclear division
4- 4 daughter cells with haploid number of chromosomes are formed
Notes
There are two ways of meiosis producing genetic variation that you must know.
Independent segregation- The homologous chromosomes line up randomly, so when they separate for the first time, there are new combination of maternal and paternal chromosomes in the daughter cells.
Recombination of sister (identical) chromatids- This is where chromatids in the homologous pair get twisted around one another, break off, and recombine onto the other chromosome. XX- it only happens between the parts next to each other, and you need to know that it is a rare occurrence.
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
The diploid number is sometimes referred to as "2n" and the haploid as "n". So you may get a diagram with a cell, which would be 2n, then after meiosis, this you would write n.
I think that covers it. We don't go into much detail on meiosis, just the main events and their results.
The haploid number is needed so at fertilization, 2 gametes combine to give a cell with the diploid number again.
In meiosis there are 2 nuclear divisions. I remember it by "Heht C4", which doesn't make much sense but is helpful nonetheless.
H- Homologous chromosomes pair up randomly
E- Equivalent portions of the chromatids cross over and recombine (see notes)
H- Homologous chromosomes separate
T- This is called independent segregation (see notes)
C- Chromatids separate during anaphase of the second nuclear division
4- 4 daughter cells with haploid number of chromosomes are formed
Notes
There are two ways of meiosis producing genetic variation that you must know.
Independent segregation- The homologous chromosomes line up randomly, so when they separate for the first time, there are new combination of maternal and paternal chromosomes in the daughter cells.
Recombination of sister (identical) chromatids- This is where chromatids in the homologous pair get twisted around one another, break off, and recombine onto the other chromosome. XX- it only happens between the parts next to each other, and you need to know that it is a rare occurrence.
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
The diploid number is sometimes referred to as "2n" and the haploid as "n". So you may get a diagram with a cell, which would be 2n, then after meiosis, this you would write n.
I think that covers it. We don't go into much detail on meiosis, just the main events and their results.
What do you mean when you say
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
This happens in both Meiosis and Mitosis I'm quite sure. I think in Meiosis the chromosomes line up in their homlogous pairs along spindle fibres and in Mitosis the chromosomes line up with one spindle fibre to each chromosome.
Correct me if I'm wrong
Original post by Insanity514
What do you mean when you say
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
This happens in both Meiosis and Mitosis I'm quite sure. I think in Meiosis the chromosomes line up in their homlogous pairs along spindle fibres and in Mitosis the chromosomes line up with one spindle fibre to each chromosome.
Correct me if I'm wrong
If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid.
This happens in both Meiosis and Mitosis I'm quite sure. I think in Meiosis the chromosomes line up in their homlogous pairs along spindle fibres and in Mitosis the chromosomes line up with one spindle fibre to each chromosome.
Correct me if I'm wrong
"If you get a diagram of anaphase, make sure you identify whether an entire chromosome is being pulled to the poles (as this would make it meiosis) or just a chromatid."
Meiosis occurs in 2 divisions. What you said is correct. First division in anaphase, you won't see the chromosomes lined up, but you will see entire chromosomes being pulled to opposite poles. The question would be, "what stage is this", and the answer would be Anaphase I (meiosis).
If you just get chromatids moving to the poles you don't need to specify whether this is meiosis 2 or anaphase of mitosis, so the answer to "what stage is this" would just be anaphase
Original post by DoaaK
omg good luck! you'll be fine!
but i think you're plant gas-exchange thing is wrong, isn't that how a plant reduces transpiration?
i thought plants have efficient gas exchange because:
- air spaces in the leaf = large sa
- mesophyll cells are thin & flat = large sa
- stomata - open and close to control co2 diffuion into cell and o2 out
- o2 produces from photosynthesis is reused in respiration
and probably more? i don't know :l
but i think you're plant gas-exchange thing is wrong, isn't that how a plant reduces transpiration?
i thought plants have efficient gas exchange because:
- air spaces in the leaf = large sa
- mesophyll cells are thin & flat = large sa
- stomata - open and close to control co2 diffuion into cell and o2 out
- o2 produces from photosynthesis is reused in respiration
and probably more? i don't know :l
Thanks. At least myy exam officer has promised my a nice invidulator to supervise me all day..
I have to say, I think your right but I believe that there are large spaces within the leaf in the "spongy layer" to allow air with O2 to go get where it needs to be easily, (but on another note i think it's to allow water movement too.) But the whole re-using of 02 to make it C02 and vice versa I don't think is actually an adaption as such. I wonder if anyone else can help?
Sorry if this bit isn't very clear, I can check it out with my teacher after my Stats exam... (I need to see her anyway so I might as as well ask.)
Also, this whole Homolougs pair thing...
Can somebody break this down for my becaus I don't get it. Do we have 23 Homolougous pairs so 46 chromosones so 92 chromatids because there are 2 in every pair of chromosones? (My teacher managed to really confuse me with using chromosones and chromatids almost interchangably...) or is it we only have 23 Homolougus pairs when the DNA has been replicated? or is a homolougs pair one X? Because I assumed a Homolouus pair is two X X so do with regards to Allesles, is it the homologous pairs that have the different versions or the individual pairs in a chromosone?
Does that make sense? Because it dosen't to me... Please help!
Original post by Elliekate1
Thanks. At least myy exam officer has promised my a nice invidulator to supervise me all day..
I have to say, I think your right but I believe that there are large spaces within the leaf in the "spongy layer" to allow air with O2 to go get where it needs to be easily, (but on another note i think it's to allow water movement too.) But the whole re-using of 02 to make it C02 and vice versa I don't think is actually an adaption as such. I wonder if anyone else can help?
Sorry if this bit isn't very clear, I can check it out with my teacher after my Stats exam... (I need to see her anyway so I might as as well ask.)
Also, this whole Homolougs pair thing...
Can somebody break this down for my becaus I don't get it. Do we have 23 Homolougous pairs so 46 chromosones so 92 chromatids because there are 2 in every pair of chromosones? (My teacher managed to really confuse me with using chromosones and chromatids almost interchangably...) or is it we only have 23 Homolougus pairs when the DNA has been replicated? or is a homolougs pair one X? Because I assumed a Homolouus pair is two X X so do with regards to Allesles, is it the homologous pairs that have the different versions or the individual pairs in a chromosone?
Does that make sense? Because it dosen't to me... Please help!
I have to say, I think your right but I believe that there are large spaces within the leaf in the "spongy layer" to allow air with O2 to go get where it needs to be easily, (but on another note i think it's to allow water movement too.) But the whole re-using of 02 to make it C02 and vice versa I don't think is actually an adaption as such. I wonder if anyone else can help?
Sorry if this bit isn't very clear, I can check it out with my teacher after my Stats exam... (I need to see her anyway so I might as as well ask.)
Also, this whole Homolougs pair thing...
Can somebody break this down for my becaus I don't get it. Do we have 23 Homolougous pairs so 46 chromosones so 92 chromatids because there are 2 in every pair of chromosones? (My teacher managed to really confuse me with using chromosones and chromatids almost interchangably...) or is it we only have 23 Homolougus pairs when the DNA has been replicated? or is a homolougs pair one X? Because I assumed a Homolouus pair is two X X so do with regards to Allesles, is it the homologous pairs that have the different versions or the individual pairs in a chromosone?
Does that make sense? Because it dosen't to me... Please help!
i'm sure you'll have a really nice one
don't worry!what did your teacher say btw?
okay so basically in total humans have 46 chromosomes
we have 23 from our mother and 23 from our father
each chromosome from our mother matches up/pairs up with a chromosome from our father
these matching chromosomes are known as homologous pairs
homologous pairs determine the same genetic characteristics i.e. in a homologous pair the paternal chromosome and the maternal chromosome will have alleles for hair colour (using hair colour as a random example) in it so they determine the same genetic characteristics but they are not genetically similar because they have different alleles
does that make sense?
okay this whole chromosome/chromatid thing is awfully confusing and the book doesn't really explain it...
okay so do you understand that dna replicates in interphase (s1) and does that whole semi-conservative replication thing
well okay before it replicates it looks like a line (l) <-- the thing in brackets is meant to be a chromosome :')
when it replicates it forms two lines, which we refer to as two chromatids held together by a centromere (l-l) but we still call the whole thing a chromosome
okay if we skip through the some of the phases to anaphase, the spindles contract pulling apart the chromosome (l-l) by it's centromere so each chromatid (l) migrates to opposite poles
these chromatids are now refered to as chromosomes
did that make sense? :P
edit: homologous pair can be represented as:
l l OR X X
(edited 12 years ago)
Can someone please explain everything we need about exchange in the capillaries? Like tissue fluids and stuff. Im quite stuck on that.
Original post by DoaaK
i'm sure you'll have a really nice one don't worry!
what did your teacher say btw?
okay so basically in total humans have 46 chromosomes
we have 23 from our mother and 23 from our father
each chromosome from our mother matches up/pairs up with a chromosome from our father
these matching chromosomes are known as homologous pairs
homologous pairs determine the same genetic characteristics i.e. in a homologous pair the paternal chromosome and the maternal chromosome will have alleles for hair colour (using hair colour as a random example) in it so they determine the same genetic characteristics but they are not genetically similar because they have different alleles
does that make sense?
okay this whole chromosome/chromatid thing is awfully confusing and the book doesn't really explain it...
okay so do you understand that dna replicates in interphase (s1) and does that whole semi-conservative replication thing
well okay before it replicates it looks like a line (l) <-- the thing in brackets is meant to be a chromosome :')
when it replicates it forms two lines, which we refer to as two chromatids held together by a centromere (l-l) but we still call the whole thing a chromosome
okay if we skip through the some of the phases to anaphase, the spindles contract pulling apart the chromosome (l-l) by it's centromere so each chromatid (l) migrates to opposite poles
these chromatids are now refered to as chromosomes
did that make sense? :P
edit: homologous pair can be represented as:
l l OR X X
don't worry!what did your teacher say btw?
okay so basically in total humans have 46 chromosomes
we have 23 from our mother and 23 from our father
each chromosome from our mother matches up/pairs up with a chromosome from our father
these matching chromosomes are known as homologous pairs
homologous pairs determine the same genetic characteristics i.e. in a homologous pair the paternal chromosome and the maternal chromosome will have alleles for hair colour (using hair colour as a random example) in it so they determine the same genetic characteristics but they are not genetically similar because they have different alleles
does that make sense?
okay this whole chromosome/chromatid thing is awfully confusing and the book doesn't really explain it...
okay so do you understand that dna replicates in interphase (s1) and does that whole semi-conservative replication thing
well okay before it replicates it looks like a line (l) <-- the thing in brackets is meant to be a chromosome :')
when it replicates it forms two lines, which we refer to as two chromatids held together by a centromere (l-l) but we still call the whole thing a chromosome
okay if we skip through the some of the phases to anaphase, the spindles contract pulling apart the chromosome (l-l) by it's centromere so each chromatid (l) migrates to opposite poles
these chromatids are now refered to as chromosomes
did that make sense? :P
edit: homologous pair can be represented as:
l l OR X X
For meiosis, i do not understand how it halves the chromosomes and i i just find it all very annoying lol
any explanations please?
hit and miss if it comes up
Basically cappilaries are designed to have a large surafce area
They are so thin that a red blood cell is flattened against the wall and thus, reducing diffusion distance so carbon dioxide diffusses out quickers and oxygen diffuses in quicker.
Also becasue rate of blood flow is slow this allows more time for diffusion.#
The diameter of lumen is very narrow thuis slowing down rate of flow of blood.
The epithelium of capilari is 1 cell thick thus reducing the difusion distance.
Tissue fluid is a water substnce which contains respiaratory substances such as glucose and fatty acids and etc. This bathes all cells, so basically cells recieve the nutrients and what ever tissue fluid carries.
Then ine xcchange it gets waste prodicst back and CO2. Cells could pass one by one thorugh cappilaries to gain oxygen but it would take soo longg so simply the cells are bthed with tissue fluid it makes the job shorter.
Anyways, the composition of the tissue fluid is controlled by haemostatic systems.
Tissue fluid cannt move out the cappialries through the aarterial end becasue of two opposing forces.
Fiirst being the hydrostatic pressure. The hydrostatic pressure is higher outside capilaires than inside. Like everything pressure always move down concentration gradient. So tissue fludi moves from outside cappialrie to inside. That one reason tissue fluid dosent move out.
Another reason it cant move out is that there are loot of plasma proteins in the cappialrie so iit moves back in kuz of osmotic forces(i think coorect me if im wrong)
They are so thin that a red blood cell is flattened against the wall and thus, reducing diffusion distance so carbon dioxide diffusses out quickers and oxygen diffuses in quicker.
Also becasue rate of blood flow is slow this allows more time for diffusion.#
The diameter of lumen is very narrow thuis slowing down rate of flow of blood.
The epithelium of capilari is 1 cell thick thus reducing the difusion distance.
Tissue fluid is a water substnce which contains respiaratory substances such as glucose and fatty acids and etc. This bathes all cells, so basically cells recieve the nutrients and what ever tissue fluid carries.
Then ine xcchange it gets waste prodicst back and CO2. Cells could pass one by one thorugh cappilaries to gain oxygen but it would take soo longg so simply the cells are bthed with tissue fluid it makes the job shorter.
Anyways, the composition of the tissue fluid is controlled by haemostatic systems.
Tissue fluid cannt move out the cappialries through the aarterial end becasue of two opposing forces.
Fiirst being the hydrostatic pressure. The hydrostatic pressure is higher outside capilaires than inside. Like everything pressure always move down concentration gradient. So tissue fludi moves from outside cappialrie to inside. That one reason tissue fluid dosent move out.
Another reason it cant move out is that there are loot of plasma proteins in the cappialrie so iit moves back in kuz of osmotic forces(i think coorect me if im wrong)
Guys what is the role of root pressure?
Original post by aleema1992
Guys what is the role of root pressure?
It basically contributes to pushing water up the xylem, although it only really plays a key role in small plants. For example, transpiration causes a greater pull than the root pressure's push in a tree
So how far has ur revision gone
ive dun the 4 aqa papers onb io 2
and then gone over the actual aqa book
wat else shall i do
ive dun the 4 aqa papers onb io 2
and then gone over the actual aqa book
wat else shall i do
guys hows ur revisionn now?
Can somebody please go over haemoglobiin? i get really confused with 'high affinity for oxygen' and 'high partial pressure' :/
Really worried about this exam as it's worth 47%, hoping i manged at least a C on unit 1, and a B on my isa!
Really worried about this exam as it's worth 47%, hoping i manged at least a C on unit 1, and a B on my isa!
Original post by xkate1019x
Can somebody please go over haemoglobiin? i get really confused with 'high affinity for oxygen' and 'high partial pressure' :/
Really worried about this exam as it's worth 47%, hoping i manged at least a C on unit 1, and a B on my isa!
Really worried about this exam as it's worth 47%, hoping i manged at least a C on unit 1, and a B on my isa!
Partial pressure of oxygen is basically a complicated way of saying amount of oxygen in the air.
High affinity for oxygen is how much of the haemoglobin is saturated with oxygen.
What actually is root pressure? It just salts being actively transported into the xylem and so water moves in by osmosis?????????
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