A level Biology: Post your doubts here!

[AKA1010]

When we did our bio practical paper 33, is it fine if we write the mean time in one decimal place but the recorded ones are whole numbers?

 

[kirzzz]

When we did our bio practical paper 33, is it fine if we write the mean time in one decimal place but the recorded ones are whole numbers?

all my values were written to two decimal places. i recall my teacher asking us to do so

 

[SohaibButt]

The composition of tissue fluid, blood n lymph is same?

 

[Hisham Khan]

all my values were written to two decimal places. i recall my teacher asking us to do so

Time is always noted upto to 1 d.p I guess

 

[SohaibButt]

Time is always noted upto to 1 d.p I guess

But in physics 2 decimal right?

 

[innovative_1]

But in physics 2 decimal right?

For the raw data 2 d.p n for the processed data 1

 

[kirzzz]

The composition of tissue fluid, blood n lymph is same?

um i think lymph has lipids as opposed to plasma and tissue fluid

 

[SohaibButt]

um i think lymph has lipids as opposed to plasma and tissue fluid

Protein conc remains same? Except in plasma have more

 

[kirzzz]

Protein conc remains same? Except in plasma have more

yes, plasma has a higher concentration of protein compared to tissue fluid and lymph

 

[SohaibButt]

yes, plasma has a higher concentration of protein compared to tissue fluid and lymph

Thank you

 

[SohaibButt]

how 4 could be possible? It always 5

 

[SohaibButt]

I think alveoli 1, capillary 1, and red blood cell 2 (phospholipid BIlayer) so total is 1+1+2=4!
Why do you say 5?

How is it different from it?

 

[angryrider_56]

Oxygen goes from the alveolar's lumen to the cytoplasm of the erythrocyte, and that's 5 membranes:

• the "top" of the alveolar epithelial cell
• the "bottom" of such cell
• the "top" of the endothelial cell (capillary)
• the "bottom" of such cell
• the erythrocyte membrane

oxygen diffuses through the cell membrane entering the cell, moves through the cytoplasm, and diffuses through the membrane again exiting the cell. So, for each cell, you have to count 2 membranes. For the last one, the erythrocyte, you have only 1 membrane (because it is O2 final destination).

 

[angryrider_56]

How is it different from it? View attachment 63794

also the 1st question asked about PHOSPHLIPID layers but the second question asked about MEMBRANES (As a whole).
That's my clarification tbh

 

[SohaibButt]

also the 1st question asked about PHOSPHLIPID layers but the second question asked about MEMBRANES (As a whole).
That's my clarification tbh

I got it thanks!!

 

[angryrider_56]

View attachment 63793 how 4 could be possible? It always 5

Btw is the answer 4 or 10?
I believe it's 10 becuase 5 times two.....is 10

 

[SohaibButt]

Btw is the answer 4 or 10?
I believe it's 10 becuase 5 times two.....is 10

Yeah i was confused too!!!

 

[SohaibButt]

Btw is the answer 4 or 10?
I believe it's 10 becuase 5 times two.....is 10

But it's A

 

[angryrider_56]

"In this question, he said to hemoglobin .. So the minim no of cell surface membranes is 5 ..
But, if he says the minimum number to plasma .. then it’s 4 ..
Because I think there is 2% that travels in the blood plasma ..
You’ll pass along questions that the minimum no for both co2 and o2 is 4 ! This is because some travels in blood plasma not inside the rbc (hemoglobin)
But in this question he specified .. that the minimum no to hemoglobin molecule is what he wants ..
This message is to clarify any doubts you’ll pass along when solving such questions ..
One membrane has 2 phospholipids .. Sometimes he refers to cell surface membrane by saying phospholipid bilayer ..
Not just phospholipids .."
I received this answer from a teacher

 

[SohaibButt]

"In this question, he said to hemoglobin .. So the minim no of cell surface membranes is 5 ..
But, if he says the minimum number to plasma .. then it’s 4 ..
Because I think there is 2% that travels in the blood plasma ..
You’ll pass along questions that the minimum no for both co2 and o2 is 4 ! This is because some travels in blood plasma not inside the rbc (hemoglobin)
But in this question he specified .. that the minimum no to hemoglobin molecule is what he wants ..
This message is to clarify any doubts you’ll pass along when solving such questions ..
One membrane has 2 phospholipids .. Sometimes he refers to cell surface membrane by saying phospholipid bilayer ..
Not just phospholipids .."
I received this answer from a teacher

But phospholipid layers is different from cell membrane?