1a (bio mols) Flashcards
what is a monomer?
examples
A small, basic unit from which larger molecules are made
monosaccharides, amino acids, nucleotides
What is a polymer?
A large, complex molecule composed of long chains of monomers joined together
What is a condensation reaction?
Joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water
What is hydrolysis?
Breaking a chemical bond between two molecules with the use of a water molecule
What is a monosaccharide? Examples?
Monomers that all carbohydrates are made of. Glucose, fructose, galactose
What is an isomer? What are the isomers of glucose?
A molecule with the same molecular formula but with atoms in a different way.
Alpha and beta glucose
What is a disaccharide? Examples?
Two monosaccharides joined by a reaction which forms a glycosidic bond.
Sucrose,lactose, maltose
Fructose+ glucose->
Sucrose
Glucose+ galactose->
Lactose
Glucose+ glucose->
Maltose
(2 alpha glucose)
All monosaccharides and some disaccharides are reducing sugars. True /False
True
What is a reducing sugar?
Sugars that can donate electrons to other chemicals
What is the test for reducing sugars?
HEAT reducing sugar with Benedict’s reagent ( copper 2 sulphate). it reduces benedict’s reagent forming INSOLUBLE RED PRETICIPATE of copper 1 oxide.
What is the test for non-reducing sugars?
Add 2cm3 ground sample to benedict’s and filter. place in boiling water for 5 mins- should remain blue (proves its not reducing). Add another 2cm3 sample to 2cm3 dilute HCL and gently boil for 5 mins (hydrolyses disaccharide into monosaccharide). Add sodium hydrogen carbonate to neutralise hcl so benedicts works. After this, test is same as for reducing sugars.
What are polysaccharides?
3 examples?
they are carbohydrates- multiple monosaccharides joined by condensation reactions.
starch, glycogen, cellulose.
Which polysaccharides are made of a-glucose?
starch and glycogen
Which carbohydrates are made of b-glucose?
cellulose
What is the structure of starch?
Mixture of 2 polysaccharides of a-glucose:
amylose- long, unbranched chain. angles of bonds cause it to coil so compact.
amylopectin- long branched chain
What is the function of starch?
How does its dtructure help its function?
plants store excess glucose as starch which can be broken down when needed.
amylose- coiled so compact and can store lots in small space
amylopectin- side branches allow enzymes to break down molecule and get to bonds easily so glucose quickly released.
starch is insoluble in water and doesnt affect water potential so water doesnt enter by osmosis which would make it swell.
What is the structure of glycogen?
polymer of a-glucose monosaccharides joined by glycosidic bonds. Highly branched and very compact.
What is the function of glycogen?
Highly branched so can be acted on by enzymes and be more quickly broken down into glucose for respiration. very compact so good for storage.
What is the structure of cellulose?
long, unbranched chains of b-glucose. alternate molecules are flipped so bonds can form. straight chain held by hydrogen bonds forming strong fibres (microfibrils)
What is the function of cellulose?
hydrogen bonds forming strong microfibrils mean it is good for structural support.
What is the test for starch?
Place 2cm3 sample into test tube add 2 drops potassium iodide and shake. starch changes colour of the iodine in the compound so turns BLUE/BLACK if not present, remains yellow.
What are lipids?
2 examples?
Fats and oils. Variety off diff components but all are hydrocarbons. components determine function.
triglycerides and phospholipids
What is the structure of a triglyceride?
One molecule of glycerol with 3 fatty acids attached. Fatty acids have hydrophobic tails.
all fatty acids have same basic structure but tail varies. 2 types: saturated, unsaturated (causes kinks)