biological molecules Flashcards
Three monosaccharides
-Glucose (C6H12O6)
-Galactose
-Fructose
Three disaccharides
Maltose
Lactose
Fructose
Three polysaccharides
Starch
Glycogen
Cellulose
Monosaccharides
-Simple sugars
Names end in ose
General formula =Cn (H2O ) n
Monosaccharides together form a disaccharide
-Condensation reaction form timers called disaccharides
_Disaccharides link together to form polysaccharides
- bonds formed between two monosaccharides to form a disaccharide is a1,4 glycosidic bond
Linked polymers
-polymers are made by linking many monomers together
-2 monomers link to form a dimer
-3 monomers link to form a trimer
Condensation reaction
-when two biological monomers join together water is produced
( think about how when two stones join together they push the water in between them out)
- water is produced
Hydrolysis reaction
Biological molecules can be separated into monomers by adding water to break the bond
Requires a catalyst, within the lab we can use acid or alkali as a catalyst (normally an enzyme)
What do we need to do when bonding monosaccharides
Need to take out water H2O due to a condensation reaction
Bond together after water has been taken out with an O
What makes maltose
Glucose + glucose
What makes sucrose
Glucose + fructose
What makes lactose
Glucose + galactose
Reducing sugars
Classed as simple sugars
They include all monosaccharides and most disaccharides
(Lactose and maltose)
Non reducing sugar
In sucrose the ring form of glucose and fructose cannot become linear so there is no free aldehyde group to react
Therefore cannot be oxidised and sucrose is described as a non reducing sugar
Carbohydrates , starch
-Polysaccharide
-Plant storage in the from
-seeds and storage organs (potatoes)
- component of food
- major source of energy
-energy store
What is starch made from
-chains of alpha glucose
- monomers are linked with glycosidic bonds during condensation reaction
-chains can be branched or unbranched
Starch
Structure relating to function
Insoluble =doesn’t draw water into cells by osmosis
Therefore the water potential of the cell is not effected
Large and insoluble so can’t diffuse out of the cell
Compact=large amount stored in a small space
Easily hydrolysed =glucose readily transported and available for use in respiration
Branching gives many ends = more sights for enzyme action
Never found in animal cells.
Glycogen
Found in animals and bacteria, never plants
Called animal starch =carbohydrate storage
-small granules in liver and muscles
-stored in small amounts - fat main storage molecule
-similar to Starch - shorter chains but more branched
Readily hydrolysed to alpha glucose
Glycogen- structure related to function
Insoluble =doesnt draw water into the cells by osmosis
Therefore the water potential of the cell is not effected
-large and insoluble so can’t diffuse out of cell
-compact large amounts stored in small spaces
-More branches than starch so has more ends
This speeds up enzyme action so is more rapidly hydrolysed to glucose monomers which are used in respiration
Animals therefore have a higher metabolic rate than plants
Cellulose
Structural polysaccharide in plants
-beta glucose monomers held together by 1,4 glycosidic bonds
Huge difference in structure compared to starch and glycogen
-forms straight and unbranched chains
Cellulose
Structure related to function
-straight chains run parallel with hydrogen bonds forming cross linkages between them
-each hydrogen is weak but the huge number of them strengthens the molecule
-this makes cellulose a valuable structural material
-every second glucose molecule is rotated through 180 degrees
-this produces a linear chain
-the cellulose molecules group to form microfibrils
-microfibrilis arrange in parallel groups to form fibres
- major component of cell walls
-stops cell lysis due to osmosis
-exerts inward pressure that stops water influx
-allows stem to be semi-rigid
-allows maximum area for photosynthesis.
4 main lipids
-triglycerides
-phospholipids
-cholesterol
-steroids
function of lipids
- substrate for respiration
- source of energy
- insulation ( slow conductors of heat and electrical insulators in the myelin sheath)
- protection of organs
- buoyancy and streamlining in aquatic animals
6.cell membranes ( waxy cuticle in plants and insects) - hormones ( steroids e.g oestrogen , testosterone)
- waterproofing ( waxy cuticle in plants and insects oil secretion from bebaceous glands)
hydrophilic
molecules/ groups are polar or charged and can mix/ dissolve in water
hydrophobic
molecules/groups are not polar or charged and so not dissolved in or mix with water
saturated
means a hydrocarbon chain with no c=c double bonds