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Mind Map
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Julia Romanów
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AQA AS Biology Unit 1 Molecule Structures (2015)
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biology
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molecule structures
carbohydrates
sugars
2015
a2
a level
sugar
as bio
a levels
Created by
Julia Romanów
over 9 years ago
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3446079
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2019-01-13T03:30:21Z
Carbohydrates
Meaning ' hydrated carbon'
Made up of carbon, oxygen and
hydrogen atoms.
Mono-saccharides
Mono- means 'one'
Glucose
Fructose
Galactose
General formula =
(CH^2O)n
Simplest of carbohydrates
Sweet tasting,
soluble
substances.
n = 3-7
Disaccharides
Di- means 'two'
Sucrose
Maltose
Lactose
Polysaccharides
Poly- means 'many'
Cellulose
Starch
Glycogen
Greek prefixes =
Mono/Di/Tri/Tetra/Penta/Hexa/Poly
Triose= carb with 3 carbons
Tetrose = carb with 4 carbons
Pentose = 5 carbons
Hexose = 6 carbons
E.g. Glucose
E.g. Ribose
E.g. Glyceraldehyde
C3H6O3
C5H11O5
C6H12O6
Ketose group (molecule with C=O
bond in the middle of chain)
Aldose= C=O bond at the
beggining
Hexoses and pentoses are long
enough to form ring structures
Glucose: 1) C=O bond breaks 2) C5
loses H and bonds with O instead
3) Broken H bonds with C1
Non-reducing sugars
Reducing sugars
Using water we can 'undo' the glycosidic
bond and separate the sugar into 2
monosaccharides (hydrolisis)
There are 2 types of Glucose - Alpha and Beta
They are isomers / the same composition but different arrangement of
structure (properties & functions may differ)
The difference is that once it form a
ring in the A the C1 OH will point down in
the B in will be up.
Formed when 2 monosaccharides react e.g A Glucose + A
Glucose = Maltose
The C1 OH & C4 HO react to form
H20 and a C-0-C bond (glycosidic
bond)
Sucrose = glucose & fructose (
1,4 glycosidic bond)
Called 'condensation reaction'
Lactose = Glucose & Galactose / 1,4 glycosidic bond
Polymers formed from repeated condensation reactions
of monosaccharides
Starch 2 forms : Amylose / amylopectin
Compact/ insoluble/ Has no osmotic effect / easily broken down
by enzymes when required.
1)Can be stored in smaller spaces
2)Can be stored in water cells without being used up
3)No net movement of water as a cause of starch
storage - no cells bursting
4)So plant can quickly respond to changes in glucose
levels
Amylose - Simplest form of starch (30%)
1000's of A-glucose in a straight chain (very tight
coils) / insoluble- enzymes only 'nibble' at its ends
Amylopectin (70%)
Every 20 or so = branch of a glucose molecule bonded
by a condensation reaction.
More ends to 'nibble' from = quicker reaction than amylose
when there's a glucose deficit
Glycogen: Animal version of Amylopectin
Difference: branch every 6/7 glucose molecule
(instead of 20) very compact
Energy store in animal livers
Animals more active - need more energy in shorter amount
of time
Cellulose: B-glucose molecules
linked by 1,4 glycosidic bonds
Every other glucose is upside down (alternating
pattern)
Rigid, straight and compact structure
many of These end up forming microfibrils
of cellulose
bonded together by hydrogen
bonds of adjacent cellulose
chains
H-H bonds are weak but in the masses are
quite strong
Starch test : Iodine test
Add iodine dissolved in potassium iodide to sample.
If it turns black-blue there's starch in it.
If it stays orange there is no starch.
Benedict's Test
Heat sample with benedict's reagent
stays blue
goes green, yellow, orange, red or brown
No reducing sugars present
Reducing sugars present
Heat new sample with HCL then neutralise with NaHCO3
Heat with Benedict's reagent
Goes green , yellow, orange, red or brown
Stays blue
No non-reducing sugars present
Non-reducing sugars present
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3446079
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2019-01-13T03:30:21Z
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