Carbohydrates Flashcards
What is a carbohydrate
A molecule containing elements carbon, hydrogen and oxygen
What is a monosaccharide and examples
- a single sugar/ carb unit
- e.g. glucose, ribose
What is a disaccharide and examples
- 2 monosaccharides joined
- e.g. lactose, sucrose
What is a polysaccharide and examples
- 3 or more monosaccharides
- e.g. glycogen, starch
Where is fructose found
- it is naturally occurring in fruits
Where is lactose found
- in milk products
Where is sucrose found
- a naturally occurring sugar
What is the sweet-ness relationship between fructose, glucose and galactose
fructose is sweeter that glucose, which is sweeter than galactose
What is the chemical formula of glucose
- C6H12O6
- hexose monosaccharide
What is the difference in structure of alpha and beta glucose
- alpha right side= H
OH - beta right side= OH
H
Why is glucose polar and soluble in water
-due to the bonds between the hydroxyl groups and water molecules
- the solubility allows glucose to be dissolved in the cell cytosol
What is a glycosidic bond
- a covalent bond formed between 2 glucose molecules
- condensation reaction ( a water molecule is formed)
- the number represent the carbons it is between e.g. 1-4
alpha glucose + alpha glucose=
Maltose (a disaccharide)
alpha glucose + fructose=
Sucrose
Galactose + glucose=
Lactose
Chemical formula of ribose
- C5H10O5
- pentose monosaccharide
What is the function of starch, what is it made up of, key properties
- excess store of glucose in plants
- many alpha glucose molecules joined together by glycosidic bonds
- insoluble in water
what 2 polysaccharides make up starch
- amylose
- amylopectin
Structure and function of amylose
- 1-4 glycosidic bonds give a coiled and twisted structure
- unbranched
- long
- compact, so good for storage
Structure and function of amylopectin
- 1-4 and 1-6 glycosidic bonds
- branched structure
Make up and function of cellulose
- many beta glucose molecules joined together
- component of plant cell walls
Structural functions of cellulose
- Hydroxyl groups on C1 and C4 to far apart, every alternate beta molecule flipped upside down so shorter distance
- unable to coil and bend
Cellulose and fibres
- when cellulose molecules make bonds with each other, it forms MICROFIBRILS
- microfibrils join together to make MACROFIBRILS
- microfibrils combine to make fibres that are insoluble and strong so make cell walls
Function and basic structure of glycogen
- store of excess glucose in animals and fungi
- alpha glucose molecules joined together
Structural features of glycogen
- very branched structure
- compact, so less space needed for storage
- many free ends- glucose can be added/removed easily and quickly
Glycogen and starch hydrolysis reactions
- when glucose is required for e.g. respiration, hydrolysis reactions occur, which require the addition of a water molecule
- reaction catalysed by enzymes, the enzymes that are the reverse of the ones in condensation reactions
