Carbohydrates Flashcards
monosaccharides, disaccharides and polysaccharides
what is the general formula for a monosaccharide
(CH20)n
what is the formula for a hexose sugar
C6H1206
when do the carbon atoms of carbs form a ring
when the sugar is dissolved in water
state the 4 functions of monosaccharides
- energy in respiration- C-H and H-H bonds broken to release energy, which is transferred to make ATP
- building blocks for larger molecules- glucose used to make starch, glycogen, cellulose and chitin
- intermediates in reactions e.g triose in respiration and photosynthesis
- constituents of nucleotides e.g deoxyribose in DNA, ribose in RNA, ATP and ADP
how are two monosaccharides bonded together
formation of a 1-4 glycosidic bond and elimination of water (condensation reaction)
what is maltose made of and what is its function
glucose+glucose
germination seeds
what is sucrose made of and what is its function
glucose+fructose
transport in phloem of flowering plants
what is lactose made of and what is its function
glucose+galactose
milk
what is a reducing sugar
a sugar that can donate an electron
-with benedicts, the sugar donates an electron to reduce copper ions, and they change colour
how to test for a non reducing sugar
a non reducing sugar like sucrose must be broken down first by heating with HCl, and alkali must be added to the benedicts
what is glucose converted to in plant cells and animal cells and why
starch (plant) and glycogen (animal).
{storage polysaccharides}
This is because glucose is soluble so it would increase the conc of the cell contents and draw in water by osmosis
why must glucose be converted into storage polysaccharides
-they are insoluble so have no osmotic effect
-they cannot diffuse out of the cell
-compact molecules so can be stored in a small space
-carry lots of energy in C-H and C-C bonds
what polymers does starch consist of
amylopectin and amylose
describe the structure of amylose
linear molecule with 1-4 glycosidic bonds that repeat to form a chain which coils into a helix
describe the structure of amylopectin
chains of glucose monomers joined with 1-4 glycosidic bonds. They are cross linked with 1-6 glycosidic bonds (side branches) and fit inside amylose
describe the structure of glycogen
similar to amylopectin, it has 1-4 and 1-6 glycosidic bonds, except it contains more branches than amylopectin
what is cellulose
structural polysaccharide found in cell walls
describe the structure of an individual cellulose molecule
long chain of beta glucose units joined by 1-4 glycosidic bonds. The beta-link rotates adjacent glucose molecules by 180
describe the structure of cellulose
hydrogen bonds between OH groups of adjacent chains. Many of these bond chains together to form microfibrils.
The microfibrils are all held together and called fibres
what is chitin
a structural polysaccharide found in the exoskeleton of insects and fungal cell walls
describe the structure of chitin
similar to cellulose with 1-4 beta glucose molecules, but has amino acid groups added to make a heteropolysaccharide. It also forms microfibrils.
what are the properties of chitin
strong, waterproof and lightweight
