3.3 Carbohydrates Flashcards
What is a carbohydrate
General formula?
Compound with carbon hydrogen and oxygen atoms only
2) Cx(H2O)y
What is a monosaccharide, di and poly?
Monosaccharides are single units of carbohydrates, di are 2
Polysaccharides are multiple units of monomer monosaccharides
What are the properties of glucose in general
- six carbons = a hexose monosaccharide
- variations of it: alpha and beta
- polar due to hydroxyl groups
- soluble in water
Why is glucose soluble in water , why important ?
- soluble due to interaction of hydrogen bonds of both polar water and the glucose.
- this important as this means it can dissolve into the cytosol (aqueous part of cell)
Alpha glucose structure
Beta glucose structure
Remember alpha don’t follow rules, so don’t follow up down up down
Down up down up
2) beta follows so up down up down
What are the different disaccharides and how do you make them.
How many carbons do these have?
Order of sweetness?
1) Maltose = glucose + glucose
2) Sucrose= glucose + FRUCTOSE
3) Galactose = glucose + lactose
- 6, so hexose
3) =sucrose, fructose, glucose , galactose
Which are the pentose monosaccharides
Ribose and deoxyribose, used to make DNA
Starch amylose structure
What does this do
- Long chains of alpha glucose bonded , non branched
- forms helix held together by hydrogen bonds = more compact and better for storage
Starch properties in general
- compact , chemical energy store, insoluble and easily digestible
Amylose properties (3)
- helix = compact and ideal for storage
-insoluble means it does not create a WATER GRADIENT, so water csn’t enter by osmosis to cause swelling .
(Converted from soluble to insoluble for storage)
-metabolically inactive
Amylopectin structure
- Long chains of alpha glucose monomers bonded together, but WITH BRANCHES TOO
- branch = 1/25 units
- (More branches = more free ends )
- forms helixes too( thus compact)
Amylopectin bonding
1-4 glycosidic
+
1-6 glycosidic 1/25
Amylopectin properties
3
- Branching makes Amylopectin MORE COMPACT= ideal for storage
- multiple branches = MULTIPLE FREE ENDS, meaning more enzymes can act on amylopectin at once, so easy adding and removing of glucose
- INSOLUBLE STILL = doesn’t affect water potential
Glycogen structure
- short , but BRANCHED chains of alpha glucose monomers bonded together
- More branches than Amylopectin
(Free ends)
Glycogen bonding
1-4 + 1-6 too AS BRANCHES THERE
Properties of glycogen
- why is compact storage more important for glycogen ?
What name given to ability for free ends to allow for quick adding of glucose etc
- More branches in glycogen = even MORE compact and less space needed for it to be stored = perfect for storage
(Needed because animals are mobile) - free ends = EASILLY HYDROLISED
- insoluble
Cellulose structure
Micro etc
- Long, unbranched chains of beta glucose monomers
- straight chain that cannot coil
- chains are linked by HYDROGEN BONDS TOO, to from strong fibres called micro fibrils
- these join to make MACRO FIBRILIS
- which join to make cellulose fibres
Cellulose bonding
1- 4 beta glycosidic binds,
- each alternate beta monomer flipped so that condensation can take place
Cellulose properties
Why do the micro macro help for a cell wall?
- hydrogen bind linkage between chains making the micro macro fibrils means cellulose is STRONG AND INSOLUBLE , which is needed for cell walls
- compact and better for storage as closed
Function of starch / glycogen
Main Energy store in plants and animals
- stores soluble glucose as Insoluble polysaccharides that don’t affect water potential it’s, (meaning water can’t cause cells to burst) until needed for something !!
Function of cellulose however
- plants and humans?
- provides structural support for for cells in plants
- very hard to breakdown , forming FIBRE /ROUGHAGE necessary for healthy digestive system
Some other functions of glucose
- store energy
- structural
- soluble to insoluble
- deoxyribose ribose
- respiration
- SUCROSE FOR TRANSPORT IN PLANTS
- ANTIGENS (recognition molecules ) (made from glycolipids )
How are dissachrides broken down
- hydrolysis reaction
- water added
- reactions catalysed by enzymes
- glycosidic bond broken, now back to useable monomers
Why does polysaccharides branch in alpha glucose unit
- when you line them up they have to curve , meaning they branch
- beta glucose doesn’t as they flip meaning they form straight chains
