A level Biology: Post your doubts here!

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Mohammed salik

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kitkat <3 :p said:
can anyone explain the primary secondary tertiary and quaternary strutures of proteins please :(?
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Primary : Individual arrangements of Amino Acids with peptide Bond.
Secondary: Formations of Beta-Pleated sheets or Alpha helixic Due to Hydrogen Bonding between amino and carboxyl groups! (or R Groups)
Teritiary: This refers To Specific 3D-shape Of One polypeptide chain Due to Four different type of Bonding (Hydrogen, Disulphide, Hydrophobic/Hydrophilic Interactions and Ionic if R group is Charged)
Quaternary: This Is interaction Between More than One Polypeptide chains To Give More Complex 3D-Shape..!
:)
 
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kitkat <3 :P

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Mohammed salik said:
Primary : Individual arrangements of Amino Acids with peptide Bond.
Secondary: Formations of Beta-Pleated sheets or Alpha helixic Due to Hydrogen Bonding between amino and carboxyl groups! (or R Groups)
Teritiary: This refers To Specific 3D-shape Of One polypeptide chain Due to Four different type of Bonding (Hydrogen, Disulphide, Hydrophobic/Hydrophilic Interactions and Ionic if R group is Charged)
Quaternary: This Is interaction Between More than One Polypeptide chains To Give More Complex 3D-Shape..!
:)
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THANK YOU SO MUCH :D :) GOT IT :)
 
BeBeskii108

BeBeskii108

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Can somebody please describe how palisade layer cells are adapted for photosynthesis ?. I remember only few things and can not express clearly enough. 90degree to the horizontal, packed closely and I dont how how it really helps, light has to go through through only 3 layer of cell walls but I forget how it is happening.
 
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Mohammed salik

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BeBeskii108 said:
Can somebody please describe how palisade layer cells are adapted for photosynthesis ?. I remember only few things and can not express clearly enough. 90degree to the horizontal, packed closely and I dont how how it really helps, light has to go through through only 3 layer of cell walls but I forget how it is happening.
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This is what i could think of....
The palisade mesophyll cells are adapted for photosynthesis. They have a thin cytoplasm densely packed
with chloroplasts, which can move around the cell on the cytoskeleton to regions of greatest light intensity.
The palisade cells are closely packed together in rows to maximise light collection, and in plants adapted
to low light intensity there may be two rows of palisade cells. :)
 
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Snowysangel

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Mohammed salik said:
Primary : Individual arrangements of Amino Acids with peptide Bond.
Secondary: Formations of Beta-Pleated sheets or Alpha helixic Due to Hydrogen Bonding between amino and carboxyl groups! (or R Groups)
Teritiary: This refers To Specific 3D-shape Of One polypeptide chain Due to Four different type of Bonding (Hydrogen, Disulphide, Hydrophobic/Hydrophilic Interactions and Ionic if R group is Charged)
Quaternary: This Is interaction Between More than One Polypeptide chains To Give More Complex 3D-Shape..!
:)
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Isn't the Bond between the amine and carboxylic group, the peptide bond? So isn't that the primary structure
 
princeali97

princeali97

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VelaneDeBeaute said:
Channel proteins. ION CHANNELS. (What more does it require to make a connection?)
Also, per se I checked the book. There's no lingo there labeling channel proteins to exclusively facilitated diffusion. There is however only a statement that says active transport happens through carrier proteins but as I wrote already, active transport occurs through both types of proteins.
Here's more of an 'intellectual' answer for what you're asking.

I could go into discussion for this but exams are closing up so I'd say bring out some other important questions rather than wasting time with this debate which might carry a mark or two in the actual paper.
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Yes this was the type of answer i wanted. Thank you so much Mr.Genius!
 
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princeali97

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Wolfgangs said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s13_qp_13.pdf

I honestly didn't understand question 24. How to find the minimum or sometimes the maximum number of hydrogen bonds in a DNA?
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Min. no. of hydrogen bonds are present between adenine and thymine nitrogen bases i.e 2 (check pg#67 of coursebook)
Total no. of nitrogen bases=700 cuz each nucleotide contains 1 nitrogen base
Considering the whole molecule made up of Adenine and Thymine nitrogen bases only.For min:
number of hydrogen bonds= 2 x 700/2 =700
Hope u understood :)
 
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