NOTES: Italics indicates NOT from the mark scheme (often means no
mark schemes relating to the spec point). These are taken instead
from the CIE A Level textbook, which occasionally includes extra
detail to help my own understanding. All others are directly copied
from CIE 9700 mark schemes.
Mark scheme abbreviations: I = ignore, A = accept, R = reject. A
semi-colon “;” separates marking points, which are sometimes
numbered. “AVP” = any valid point. See the start of any mark
scheme for full abbreviations.
Numbers before the heading of a note indicate the specification
reference.
For example: Topic 2, “7 – molecular structure of polysaccharides…”
refers to specification point 2.7)
2. Biological Molecules (including details of food tests required for
Paper 3)
Carbohydrates:
4 - glucose, fructose, maltose are reducing; sucrose is non-reducing
7 - molecular structure of polysaccharides and contributions to
functions:
Starch (amylose and amylopectin) :
amylose, spiral / spiralled / helix / helical ; only 1,4 α bonds
amylopectin branched ; 1,4 α and 1,6 α bonds
compact / AW ; qualified ;
e.g. for maximum storage (so) insoluble / osmotically inactive /
inert ;
amylopectin, many free ends (so easily supplies glucose) ;
(amylose / amylopectin / starch) contain glucose for immediate use
as respiratory substrate (on hydrolysis) ;
Glycogen : 1,4 α and 1,6 α bonds
many, terminals / ends, for, attachment of glucose and removal of
glucose ;
glucose can be stored quickly ;
mark schemes relating to the spec point). These are taken instead
from the CIE A Level textbook, which occasionally includes extra
detail to help my own understanding. All others are directly copied
from CIE 9700 mark schemes.
Mark scheme abbreviations: I = ignore, A = accept, R = reject. A
semi-colon “;” separates marking points, which are sometimes
numbered. “AVP” = any valid point. See the start of any mark
scheme for full abbreviations.
Numbers before the heading of a note indicate the specification
reference.
For example: Topic 2, “7 – molecular structure of polysaccharides…”
refers to specification point 2.7)
2. Biological Molecules (including details of food tests required for
Paper 3)
Carbohydrates:
4 - glucose, fructose, maltose are reducing; sucrose is non-reducing
7 - molecular structure of polysaccharides and contributions to
functions:
Starch (amylose and amylopectin) :
amylose, spiral / spiralled / helix / helical ; only 1,4 α bonds
amylopectin branched ; 1,4 α and 1,6 α bonds
compact / AW ; qualified ;
e.g. for maximum storage (so) insoluble / osmotically inactive /
inert ;
amylopectin, many free ends (so easily supplies glucose) ;
(amylose / amylopectin / starch) contain glucose for immediate use
as respiratory substrate (on hydrolysis) ;
Glycogen : 1,4 α and 1,6 α bonds
many, terminals / ends, for, attachment of glucose and removal of
glucose ;
glucose can be stored quickly ;
