Biology MCQ

[canopied_cadenza]

A triglyceride consists of glycerol and three different fatty acids, linoleic acid (L), oleic acid (O) and palmitic acid (P)
The diagram shows one possible arrangement often fatty acids L, O and P in the molecule
what is the total number of different arrangements of the fatty acids in this triglyceride?
A: 3
B: 4
C: 5
C: 9

Correct answer is A, but I chose C (Thinking along the lines of 3 fatty acids and 3 positions therefore 3^3). I tried to write out all the possibilities and I couldn’t get to 9, but I got way past three... there must be something I am missing. (Diagram is attached)

 

[cool.fireboy24]

Good question LOL

Okay so lets look at all the possibilities


LOP - same as POL (cuz number 1 can be counted from any end)
OLP - same as PLO
LPO - same as OPL


So 3 arrangements only. IDK if this is right, has been a whole year since I gave AL Biology but I think this is how it comes to 3 arrangements

 

[canopied_cadenza]

Good question LOL

Okay so lets look at all the possibilities


LOP - same as POL (cuz number 1 can be counted from any end)
OLP - same as PLO
LPO - same as OPL


So 3 arrangements only. IDK if this is right, has been a whole year since I gave AL Biology but I think this is how it comes to 3 arrangements

Thanks for your answer. I didn’t realise that the opposites counted as 1 option, but looking back, that does make sense.

 

[Rain0.0]

hi i have a question regarding O/N 2015 p11
in question 39, why is the answer A?
and in question 17,why is the answer b?

 

[cool.fireboy24]

hi i have a question regarding O/N 2015 p11
in question 39, why is the answer A?
and in question 17,why is the answer b?

O/N 2015 P11,

Question 17: Glucose solution is more concentrated than water which means water molecules will move inside the visking tubing. Similarly, there is no presence of glucose inside the water so the solute (glucose) will move from the visking tubing into this surrounding water. Since this solute concentration will increase steadily, the colours will also change accordingly and show this increase.
Benedict colours (Increasing glucose conc.) = Blue -> Green -> Yellow -> Orange-red -> Dark/Brick Red

Question 39: Seems fairly simple, no? Do lemme know what you were thinking of.
1200/100000 * 100 = 0.12%
The diagram illustrates that total light energy available in a year to the particular producer is 1,000,000 and 1200 of this is available to the herbivore we are concerned with (Remember: they didn't say ALL herbivores). Rest is just math I guess

Good Luck!

 

[cool.fireboy24]

Also I just remembered, didn't the syllabus change in 2016 cuz I gave my paper last year in M/J 2019 and there was nothing to do with food chains/webs etc. in the syllabus. Don't concern yourself with Q39 (or the last 2-3 questions in most past papers before 2016)

 

[Rain0.0]

omg thank you so much !!!! youre a saviour ! and i shall check out the thing abt the syllabus changing thing. didnt think about that ! thank you !