1 biological molecules Flashcards
what is the reaction that causes two monomers to be joined together and what happens to a water molecule?
condensation reaction
water molecule is formed
what is the reaction that breaks down polymers and what happens to a water molecule?
hydrolysis
water molecule is added
what is the formula for glucose?
C6H12O6
what is the name for a monomer of a sugar?
monosaccharide
give 3 examples of a monosaccharide
glucose
galactose
fructose
what is the name for a polymer of a sugar?
polysaccharide
give 3 examples of a polysaccharide
starch
glycogen
cellulose
give 3 examples of a disaccharide
maltose
sucrose
lactose
how do you make maltose?
glucose + glucose
how do you make sucrose?
glucose + fructose
how do you make lactose?
glucose + galactose
how do you test for reducing sugar?
benedict’s test
how do you carry out the test for reducing sugars?
- add 2cm3 of benedict’s reagent to 2cm3 of sample
- heat in 95 degrees water bath for 5 mins
- positive result = blue to brick red precipitate
negative result = no colour change
what is the bond called that is formed between two monosaccarides?
glycosidic
describe a test for a non-reducing sugar
- if benedict’s test for reducing sugar has a negative result,
- add equal amount of dilute HCl to sample and heat in 95 water bath for 5 min
- add sodium hydrogencarbonate to neutralise
- add equal amount of benedict’s solution and heat to 95 for 5 min
- positive = blue to brick red precipitate
negative = no colour change
describe the structure of starch (amylose)
unbranched coiled chain of alpha glucose
1-4 glycosidic bonds
give the functions of amylose
insoluble so doesn’t affect water potential
insoluble so doesn’t diffuse out of cells
compact so a lot can be stored in small spaces
describe the structure of amylopectin
branched chain of alpha glucose
1-4, 1-6 glycosidic bonds
give a function of amylopectin
branches mean monosaccharides can be released rapidly
what is the test for starch?
iodine
describe the iodine test for starch
- place 2cm3 of sample in test tube
- add iodine solution and shake
- positive result = blue black colour
what is the structure of glycogen?
branched chain of alpha glucose
1-4 and 1-6 glycosidic bonds
what are functions for glycogen?
insoluble so doesn’t diffuse out of cells
compact so a lot can be stored in small spaces
highly branched so can be readily hydrolysed
what is the structure of cellulose?
straight unbranched chains of beta glucose (each molecule rotated 180)
1-4 glycosidic bonds
cellulose molecules run parallel to eachother and cross linked by H bonds to form microfibrils which form fibrils
where is cellulose found?
component of plant cell walls -prevents cell from bursting
where is glycogen found?
animal muscles
where is starch found?
plants
what is the bond for lipids called?
ester bond
what is a triglyceride?
three fatty acids and a glycerol