Unit 1: Biological Molecules

what is a monomer?

a single repeating unit of a polymer

what is a polymer?

a chain of monomers/repeating units

what is a condensation reaction?

joins two monomers together and has water as a product

what is a hydrolysis reaction?

breaks down polymers using water

what is a carbohydrate broken down into?

saccharides/sugars

what is protein broken down into?

amino acids

name 3 carbohydrates

cellulose, starch, glycogen

what are carbohydrates made of?

carbon, hydrogen, oxygen

what is the disaccharide and polysaccharide of glucose?

maltose and starch

name 4 characteristics of sugars

small, sweet, soluble, crystalline structure

name 4 characteristics of polysaccharides

macro, not sweet, insoluble, non-crystalline structure

name 3 monosaccharides

glucose, fructose, galactose

name 3 disaccharides

maltose, sucrose, lactose

what does alpha glucose look like?

alpha glucose

what does beta glucose look like?

beta glucose

how is maltose formed?

glucose + glucose in a condensation reaction

how is sucrose formed?

glucose + fructose in a condensation reaction

how is lactose formed?

glucose + galactose in a condensation reaction

what bonds are formed in a condensation reaction with glucose?

glycosidic bonds

which sugars are reducing sugars?

glucose, fructose, galactose, maltose, lactose

which sugar is a non-reducing sugar?

sucrose

is cellulose made of alpha or beta glucose?

beta glucose

is starch made of alpha or beta glucose?

alpha glucose

is glycogen made of alpha or beta glucose?

alpha glucose

what bonds hold two cellulose chains together?

hydrogen bonds

what bonds hold lipids together?

ester bonds

what is the symbol of water potential?

water potential

what is the structure of a glycerol molecule?

glycerol

what is the structure of a fatty acid?

fatty acid

how many double bonds do saturated fats have in the chain?

no double bonds in the chain

how many double bonds do monounsaturated fats have in the chain?

one double bond in the chain

how many double bonds do polyunsaturated fats have in the chain?

many double bonds in the chain

what is the simplified diagram for triglycerides?

triglyceride

how is a triglyceride different from a phospholipid?

- triglycerides have 3 fatty acids, phospholipids have 2 fatty acids

- triglycerides have no phosphate, phospholipids have 1 phosphate molecule

how is the head and tail on a lipid described?

head = hydrophilic

tail = hydrophobic

how are triglycerides formed?

triglyceride formation

what type of reaction forms triglycerides?

condensation reaction

what are the reactants and products in the formation of trigylcerides?

reactants = glycerol + 3 fatty acids

products = triglyceride + 3 water molecules

what are the 3 main types of bonding?

- covalent bonding

- ionic bonding

- hydrogen bonding

explain covalent bonding

atoms share electrons, so both outer shells are completely full

explain ionic bonding

electrostatic attraction due to opposite charges

explain hydrogen bonding

negative region of a polarised molecule and positive region of another attract each other and form a weak electrostatic attraction

what is the general formula for a monosaccharide?

(CH2O)n where n can be any number from 3 to 7

describe the test for a reducing sugar

1) 2cm of liquid sample in a test tube

2) equal volume of benedict's reagent

3) heat in water bath for 5 minutes

4) red colour change indicates high amounts of reducing sugar

describe the test for non-reducing sugar

1) 2cm of liquid sample and 2cm of benedict's reagent in a test tube

2) heat in water bath for 5 minutes

3) no colour change indicates that it is not a reducing sugar

4) hydrolyse another 2cm of sample using dilute hydrochloric acid and a water bath

5) neutralise solution using sodium hydrogencarbonate

6) retest using benedict's reagent

7) red colour change indicates there was a non-reducing sugar

describe the test for starch

1) 2cm of sample in a test tube

2) 2 drops of iodine solution

3) blue-black colour indicates starch

how is the structure of starch suited for its function?

- insoluble

- large

- compact

- branched

where is glycogen mainly stored?

liver and muscle cells

how is glycogen's structure suited for its function?

- insoluble

- compact

- branched

how does cellulose differ from starch and glycogen?

- made of beta glucose

- straight, unbranched chains

- hydrogen bonds

- microfibrils

what are the 4 roles of lipids?

- insulation

- source of energy

- waterproofing

- protection

describe the test for lipids

1) 2cm of sample and 5cm of ethanol

2) stir/shake

3) 5cm of water

4) shake

5) white precipitate indicates lipid

what are the 4 groups in an amino acid?

- amine group (NH2)

- carboxyl group (COOH)

- hydrogen atom (H)

- R group

what is the primary structure of a protein?

sequence of amino acids in a polypeptide chain

what does the primary structure of a protein determine?

shape and function

what is the secondary structure of a protein?

form weak hydrogen bonds in an alpha helix or a beta pleated sheet

what is the tertiary structure of a protein?

folds into a 3D structure and contains disulfide bridges, hydrogen bonds and ionic bonds

what is the quaternary structure of a protein?

links to another protein or non-protein (prosthesis group)

describe the test for proteins

1) equal volumes of sample and biuret solution

2) violet colour indicates protein

what do enzymes do?

lower the activation energy

describe the induced fit model

- enzyme and substrate collide

- form an enzyme-substrate complex

- active site changes shape

- puts a strain on substrate, distorting the bonds

- lowers activation energy