ALEVEL BIOLOGY - biological molecules

Polymers

large, complex, monomers joined together

what is the reaction to making polymers

condensation

what is the reaction to breaking polymer

hydrolysis

what is a hydrolysis reaction

reaction breaking the chemical bond between two monosaccharides using a water molecule

what is condensation

chemical bond between two molecules joining together with the elimination of a water molecule

Most carbohydrates are polymers including

proteins and nucleic acids

Examples of monomers

monosaccharides, amino acids and nuceotides and fatty acids and glycerol

Monomers

small, basic molecuar units. which builds to make larger molecules such as polymer

Monomers that make carbohydrates

monosaccharides

Examples of monosaccharides

glucose, fructose, galactose

All carbohydrates contain the elements

carbon, oxygen and hydrogen

Glucose is a

hexose sugar

what is a monsaccharide

a monomers that contains one sugar unit.
They are the monomers which larger carbohydrates are made

Hexose sugar

a monosaccharide that contains 6 carbon atoms in every molecule

2 types of glucose

alpha glucose and beta glucose

Alpha and Beta glucose are both

isomers

Alpha glucose

hydrogen at top, OH at bottom

Beta glucose

OH at top, hydrogen at bottom

Reaction that joins monosaccharides together

condensation reaction

Condensation reaction

when 2 monosaccharide are joined together with the formation of a new chemical bond and a water molecule is released

Bond formed in condensation reaction

glycosidic bond

Glycosidic bond formed when

water molecule is released

Disaccharide

when 2 monosaccharides join together

Glucose + glucose

maltose

Glucose + fructose

sucrose

Glucose + galactose

lactose

Amino acids make

proteins

Monosaccharies make

carbohydrates

Nucleotides make

nucleic acids

Fatty acids and glycerol make

lipids

Lots of amino acids make

polypeptides

Lots of monosaccharides make

polysaccharides

Lots of nucleotides make

polynucleotides

Lots of fatty acids and glycerol make

triglycerides

Lots of monomers make

polymers

Hydrolysis

addition of a water molecule to break glycosidic bond

Sugars

monosaccharides, glucose, fructose, galactose, sucrose and lactose

Example of a hydrolysis reaction

carbohydrates can be broken down into constituent monosaccharides

Test for reducing and non reducing sugars

benedict's test

Reducing sugars

donate electrons to other chemicals

Benedicts test for reducing sugars includes

all monosaccharides, glucose and some disaccharides, maltose and lactose

Process of Benedicts test for reducing sugars

benedicts reagent is added to sample, heated in water bath which has been brought to the boil

Positive result for Benedicts test

coloured precipitate, brick red

Coloured precipitate in Benedicts solution

solid particles suspended in solution

Colours will change from for Benedicts test

blue, green, yellow, orange, brick red

Higher concentration of reducing sugar

the further the colour will change

Colour change can be used for

comparing amount of reducing sugars in different solutions

Benedicts test for non-reducing sugars

broken down into monosaccharides first by using a hydrolysis reaction, sample is taken, dilute hydrochloric acid is added, heated in boiling water bath, soultion is neutralised with sodium hydrogencarbonate, benedicts reagent is added

what is a colorimeter

to mesure the abundance of remaining benedict reagent

Mor accurate way for Benedicts result

filter solution and weigh precipitate
or
Removing the precipitate and using a COLORIMITER to mesure the abundance of remaining benedict reagent

Negative result for benedicts test for non-reducing sugar

solution will stay blue, no sugars present, neither reducing or non-reducing

Disaccharide involved in non-reducing Benedicts test

sucrose

Lots of alpha glucoses form

amylose

2 alpha glucoses form

maltose

what are polysaccharides

when two or more monosaccharides join together by condensation reaction. they form long chains of monomers

examples of polysaccharides

starch , cellulose, glycogen

Cells get energy from

glucose

what is Starch used for

main energy storage material in plants, it is insoluable . it is a mixture of amylose and amylopectin

way in which starch molecules are adapted for their function in plant cells.

1. Insoluble;
2. Don't affect water potential;
OR
3. Helical;
Accept form spirals
4. Compact;
OR
5. starch is a Large molecule;
6. so it Cannot leave cell.

Explain how cellulose molecules are adapted for their function in plant cells.

Long and straight chains;
2. Become linked together by many hydrogen bonds to form fibrils;
3. Provide strength (to cell wall).

what happened when starch is broken down

they break down and release glucose which provides energy to the plant

plants store excess glucose as

starch

When a plant needs more glucose for energy

they break down the starch to release the glucose

2 polysaccharides that make up starch

amylose and amylopectin

Coiled structure of amylose

makes it compact so good for storage as more can fit into a smaller area

bond between amylose

1-4 gylcosidic bond

Amylopectin

long, branched chain of alpha glucose and has 1-4 and 1-6 glycosidic bonds

Amylose

long, unbranched chain of alpha glucose, angles of glycosidic bonds give it a coiled structure making it compact and good for storage. it has has 1-4 glycosidic bonds

Side branches of amylopectin allow

enzymes that break down the molecule to get at the glycosidic bonds easier so glucose can be released quickly

bonds in amylopectin

1-4 and 1-6 gylcosidic

Starch is

insoluble and has a helical shape

Insoluble

does not affect water potential which does not cause water to enter cells through osmosis which would make them swell

Test for starch

iodine test

Process of iodine test

iodine is dissolved in potassium iodide solution and is added to test sample

Positive result for iodine test

solution will turn from a browny/orangey colour to a dark blue/black

Glycogen

main energy storage material in animals

Glyogen is a

compact molecule

Structure of glycogen

is similar to amylopectin except that it has more branches, very compact

Animals store excess glucose as

glycogen

Glycogen is good for

storage animals

Glycogen is a polysaccharide of

alpha glucose

Cellulose

is major component of cell walls in plants

Cellulose is made of

long, unbranched chains of beta glucose and alternate beta glucose molecules are inverted

Lots of branches on glycogen is good because

glucose can be released quickly

When Beta glucose molecules bond they form

straight cellulose chains

Cellulose chains are linked together by

hydrogen bonds to form strong fibres

Microfibrils

strong fibres mean that cellulose provides structural support for cells in plant cell walls

test for lipids

emulsion test

how do you test for lipids

sake the test substance with wthanol for a minite and pour solutioninto water
any lipid produces will show a milky emulsion
- the more lipids the more notisable milky colour

what are lipids

lipids are made from a mixture of componats which are all hydrocarbons

what are the two types of lipids

Trigylcerides
Phospholipids

what is the structure of trigylceride

one molecule of glycerol and 3 molecule of fatty acids

what is the structure of fatty acid

what is the structure of glycreol

what are fatty acids made from

hydrocarbons

fatty acids in lipids are hy...

hydrophopic- they repel water . the tail is insoluable so it doent affect the water potential so osmosis can't occur

what are the two types of fatty acids

saturated and unstaurated hydrocarbons

what is a saturated fatty acid

it doesnt contain any double bond

what is saturated fatty acids

it has double bonds

how to test for saturated and unsaturated fats

bromein test if unsaturated it would go colourledd
if saturated it would remain orange