Biological Molexules

Monomer

Small units which join up to form polymers

Polymer

molecules made from a large number of monomers joined up

Example of monomer

Monosaccaride

Nucleotides

Amino Acid

Condensation Reaction

Joining 2 molecules together by forming a chemical bond and elimination of water

Hydrolysis

Breaks a chemical bond by using water

Example of Monosaccharides

Glucose

Fructose

Galactose

Disaccaride formation

Formation via the condensation reaction of 2 monosaccarides to form a glycosidic bond

Examples of dissacharide formation:

Glucose + Glucose = Maltose

Glucose + Fructose = Sucrose

Glucose + Galactose = Lactose

Example of Polysaccharides

Glycogen

Starch

Cellulose

Starch structure funcion

• alpha glucose

• unbranched and coiled which allows lots of glucose to be stored in a small space making it an efficient energy store (compact)

• long branched polymer of alpha glucose which increases the number of points an enzymes can attach (branced)

Insoluble - doesn't affect water potential

Amylose Structure

• unbranched coiled alpha glucose which allows lots of glucose to be stored in a small space making it an efficient energy store (compact)

• alpha glucose

• 1,4 Glycosidic bonds

Amylopectin structure

• long branched polymer of alpha glucose which increases the number of points an enzymes can attach

• alpha glucose

• 1,4 and 1,6 glycosidic bonds

Glycogen structure

• Alpha glucose

• 1,4 and 1,6 glycosidic bonds

• branched which increases the amount of points an enzyme can attach so many glucose monomer can be released rapidly

• Compact so lots of it can be stored in a small space for an efficient energy store

• insoluble in water so doesn’t affect water potential

Cellulose structure

• Beta glucose

• forms a straight chain which run parallel to each other

• linked by hydrogen bonding to form microfibrils

Example of non reducing sugar

Sucrose

Test for reducing sugars:

• Add benedict solution and heat in water bath

• brickred ppt positive result

blue → brickred depending on concentration

Non reducing sugar

• do benedict solution test again to confirm it’s non reducing (negative result : stays blue)

• Add dilute HCL and heat

• Brick red ppt forms

Test for starch

• Iodine dissolved in Potassium Iodine solution

• brown/orange → blue black (positive result)

Formation of triglyceride

Condensation reaction between glycerol and 3 fatty acids

Difference between saturated and unsaturated fatty acids

Saturated : contains no C=C bonds

Unsaturated: atleast one C=C bond

Phospolipids structure

glycerol 2 fattyacids and phosphate group

hydrophillic head, hydrophobic tail

How does triglycerides structure relate to function?

Insoluble - doesn’t affect water potential

Low mass to energy ratio so stores alot of energy in a small volume

How does Phospolipids structure relate to its function?

Polar molecule so forms a bilayer

Allows them to form glycopids by combining with carbohydrates.

Glycolipids function

Cell recognition

Test for lipids

• add ethanol and shake

• positve test: white emulsion

Formation of dipeptides and polypeptides

dipeptide - condensation reaction between 2 amino acids forming a peptide bond

polypeptide - condensation reaction between many amino acids forming a peptide bond

Primary structure of proteins

Sequences of amino acids

Secondary structure of proteins

Hydrogen bonds form between the amino acids in the chain and gets folded into a beta pleated sheet or coiled into an alpha helix

Tertiary structure of protiens

The 3d folding of a polypeptide chain which contains hydrogen bonding, ionic bonding and a disulfide bridge

Quartenary structure

A number of polypetide chains joined together to form a protein

Test for proteins

• add a few drops of biuret solution

• positve test: blue→ lilac purple

Explain the induced fit model

• Substrate binds to active site

• Active site changes shape to become complementary to the substrate

• forms enzyme - substrate complex

Hows temperature a limiting factor of ror

• increases ror at first

• after the optimum, hydrogen and ionic bonds break which changes the enzymes tertiary structure changing the shape of the active site

• the substrate is no longer complementary to the dentured enzyme

How is pH a limiting factor

• different enzymes have different optimum pH

• as you move away from the optimum, the ror decreases

• due to the change of the conc of H+ and OH- ions interferes with the hydrogen/ionic bonding changing the tertiary structure and active site

• the substrate is no longer complementary to the denatured enzyme

Effect of Enzyme concentration

• at first, enzyme concentration is proportional to rate of reaction

• After a certain time, the amount of substrate becomes a limiting factor meaning increasing enzyme concentration nolonger has an effect and ror levels out

Effect of Substrate concentration

• At first substrate concentration is proportional to ror

• After a certain time, the amount of enzymes becomes a limiting factor meaning substrate concentration no longer has an effect and ror levels out

Explain competitive inhibition

• competitive inhibitors have a similar shape to the enzymes active site

• they can fit into the active site forming an enzyme inhibitor complex

• this prevents substrates from binding to the active site

Explain non competitive inhibition

• binds to the allosteric site

• changes the tertiary structure

• alters the shape

• no longer complementary to substrate

RNA function

transfers genetic information from DNA to ribosomes

What does a nucleotide consist of

• phosphate group

• pentose sugar

• nitrogenous base

joined by condensation reactions

How do nucleotides join up

• nucleotides join together via a condensation reaction forming a phosphodiester bod

How does DNA structure relate to function

• weak H bonds between polynucleotides so can be easily separated in DNA replication

• very large molecule so carries lots of genetic informations

Difference between DNA and RNA

DNA:

• longer

• deoxyribose

• double stranded helix

• thymine

RNA:

• shorter

• ribose

• single stranded

• uracil

Semi conservative

Each new DNA molecule has a strand from the original

Explain DNA replication

• DNA helicase breaks H bonds between the strands and DNA unwinds

• One strand acts as a Template

• Free flowing nucleotides allign at complementary base pairings

• DNA Polymerase joins the nucleotides together in a condensation reaction forming a phosphodiester bond.

What does ATP consists of

• adenine

• ribose

• 3 phosphate groups

Why is ATP a good energy source

• lots of energy stored in phosphate bonds

• low activation energy of these bonds so broken easily

• Lots of energy released

Phosphorylation meanint

The inorganic phosphate group in ATP can be added to another compound to make it more reactive

What is ATP used for

• active transport

• muscle contractions

• phosphorylation

• initial respiration reactions

Use of water

• metabolite

• solvent (polar so can react with other polar molecules)

• high specific heat capacity (due to hydrogen bonding and therefore water doesn’t experience rapid change of temperature so can act as a buffer and enzymes can stay at optimum)

• latent heat of vapourisation (due to hydrogen so good cooling for organisms without loosing alot of water)

• cohesion and adhesion (allows water to flow becoming a good transport of substances, creates surface tension which can cool organisms down)

Cohesion and Adhesion meaning

Cohesion - forms hydrogen bonds with each other

Adhesion- forms hydrogen bonds with other molecules

Fe+2 use

• found in haemoglobin

• important for transporting oxygen around the body

Na+ use

• involved in co transport of substances across cell membranes

• Active transport

• Nerve impulses

Phosphate Ions use

• bonds between phosphate groups store energy in ATP

• phosphate groups allow DNA and RNA nucleotides to join up forming polynucleotides

• Phospolipids