1.2-1.4 Monosaccharides + Polysaccharides Flashcards
Define monosaccharide
The monomers from which larger carbohydrates are made
Single sugar unit
Give 3 examples of monosaccharides
Glucose, fructose and galactose
What does a condensation reaction between two monosaccharides form? Draw it
A glycosidic bond between carbon 1 and carbon 4
How does maltose form? Draw it
Condensation of two alpha glucose molecules
How does sucrose form? Draw it
Condensation of a glucose molecule and a fructose molecule
How does lactose form? Draw it
Formed by the condensation of a glucose molecule and a galactose molecule
Define disaccharides
Pair of monosaccharides
Define polysaccharide
Formed by the condensation of many glucose units/ monosaccharide molecules
Give 3 examples of disaccharides
Maltose, sucrose and lactose
How is the glycosidic bond broken?
Hydrolysis
Where is starch found and what does it do?
Found in many parts of a plant in the form of small grains
Important component of food and major energy source in most diets
Never found in animal cells
Made of two different polysaccharides, amylose and amylopectin
What are some characteristics of polyaccharides?
Large molecules so are insoluble so can be stored
When hydrolysed break down into disaccharides/monosaccharide
How are glycogen and starch formed?
The condensation of alpha glucose
How is cellulose formed?
Condensation of beta glucose
How is amylose (sub-unit of starch) formed? Define amylose
- Each glycosidic bond forms a small bond in the polymer
- Collectively, these give a spiral/helix shape
- Amylose is a long unbranched chain of glucose units
Alpha 1-4 glycosidic bond
Define amylopectin
Highly branched polymer of glucose units
Alpha 1-6 glycosidic bond
What is the role of starch?
- Found in plants as small grains
- Seeds and storage organs
- Important components of good and major energy source in most diets
- Never found in animal cells
- Made of two different polysaccharides, amylose and amylopectin
What are the 5 main structures and functions of starch and how does it help with energy storage?
- Helices are compact so lots can be stored in a small space
- (Can be branched or unbranched) Branching chains have many ends so lots of ends for enzymes to hydrolyse starch quickly and release glucose which is easily transported and used in respiration
- Relatively long chains with few branches so is compact
- Insoluble so doesn’t affect water potential of cell
- Too big to pass through membranes so does not diffuse out of cells
What is different about glycogen’s structure?
Same overall structure as amylopectin but significantly more branching (more 1-6 glycosidic bonds)
Made of alpha glucose only
In what organisms and where is glycogen found?
Stored in liver and muscles of animals as small granules
Fungi cells also stores their carbohydrates as glycogen
Animals have a higher metabolic rate than plants
Found in animals and bacteria but never in plant cells
Compare starch structure to glycogen
- Glycogen has shorter chains and is more highly branched
- Glycogen has more ends for the enzymes to hydrolyse to release glucose molecules at a faster rate
What are the 3 main structure features of glycogen and their functions?
- Insoluble so does not tend to draw water into the cells by osmosis and does not diffuse out of cells
- Compact so lots stored in a small space
- More highly branched than starch so more ends that can be more rapidly broken down to form glucose (respiration)
- Important to animals –> higher metabolic and therefore respiratory rate than plants because they are more active
How is cellulose formed?
Beta glucose where each glucose molecule is inverted with respect to its neighbour
What is it called when lots of beta glucoses bond together?
Produces a long, straight, unbranching chain
This places many hydroxyl (OH)
