1.1 Carbohydrates Flashcards
name 2 uses of carbohydrates
as energy sources
for structure
what elements are found in carbohydrates?
carbon, hydrogen, and oxygen
what is the general formula for carbohydrates?
Cx(H20)y
what is a structural isomer?
same molecular formula, different structure
give one similarity and one difference between an alpha and beta glucose
similarity- both are hexose sugars
difference- alpha has hydroxyl group at bottom whereas beta has hydroxyl group at top
name the type of reaction when two monosaccharides join
condensation
what two monosaccharides is maltose made from?
2 alpha glucoses
what two monosaccharides is lactose made from?
glucose + galactose
what two monosaccharides is sucrose made from?
glucose + fructose
how do you break a disaccharide?
use water in a hydrolysis reaction
what is a long chain of monosaccharides joined by?
glycosidic bonds
name three types of polysaccharides, what they are used for and where they are found?
starch- storage in plants
cellulose- structure in plants
glycogen - storage in animals
describe the structure of cellulose
- polymer of beta glucose
- has beta-1,4-glycosidic bonds
- forms straight chains called cellulose molecules
- hydrogen bonds link cellulose molecules to form a microfibril
- 3D lattic shape
- gives it a high tensile strength
describe the structure of starch
- polymer of alpha glucose
- large molecule found in anything that photosynthesises
- insoluble (no osmotic effect)
- compact (large amount stored in a small space)
- usually stored as intracellular starch grains in plastids (amyloplasts and chloroplasts)
- made up of amylose and amylopectin
describe the structure of amylose
straight chain molecule
alpha 1,4 glycosidic bonds
forms a coil
describe the structure of amylopectin and how this relates to its function
branches
alpha 1,4 and 1,6 glycosidic bonds
side branches that make it readily hydrolyseable- it allows enzymes that break down molecules to easily access glycosidic bonds so glucose can be released quickly
describe the structure of glycogen and where it can be found
polymer of alpha glucose alpha 1,4 and 1,6 glycosidic bonds branched - readily hydrolyseable insoluble - no osmotic effect compact- large amount in small space found mostly in liver and muscle cells
give the equation for photosynthesis
6CO2 + 6H2O –> C6H12O6 + 6O2
describe the test for starch
add iodine
if starch is present, colour changes to blue/black
if there is no starch, colour remains brown
describe the test for reducing sugars
add Benedict’s reagent
if reducing sugars are present, it turns red, yellow or green
if no reducing sugars are present, remains blue
give three examples of reducing sugars
monosaccharides
maltose
lactose
