Biological Molecules Flashcards

Question

How do triglycerides form?

Answer 1

condensation reaction between 1 glycerol molecule (-OH) and 3 fatty acids (R-COOH) forms an ester bond releases 3 molecules of water

Answer 2

``` the r group has no double carbon bonds as much hydrogen bonding as possible no kink in chain high melting and boiling point found in animal fats ```

Answer 3

r group contains double carbon bonds kink in chain lower melting point found in plant oils

Answer 4

high energy:mass ratio- high calorific value from oxidation high proportion of carbon and hydrogen - high calorific value insoluble in water- no osmotic effect on cells low density- buoyancy of aquatic animals

Answer 5

similar to triglycerides but one of the fatty acids is replaced by a phosphate molecule fatty acids are hydrophobic phosphate is hydrophilic

Answer 6

forms phospholipid bilayer in aqueous environments hydrophilic heads are exposed amphipathic- one end of molecule will mix with water and other end won't

Answer 7

the organisation is spontaneous large molecules and small polar molecules cant pass through small non polar molecules, lipid soluble molecules can pass through

Answer 8

emulsion test- dissolve solid samples in ethanol add water and shake milky white emulsion forms if positive

Answer 9

formed of many amino acids joined together to form polypeptides proteins are made up of one or more polypeptide

Answer 10

amino acids have an amine group (NH2), carboxyl group (COOH) and an R group 20 amino acids

Answer 11

amino acids are joined by peptide bonds in condensation reactions where a molecule of water is released NH2 joins to COOH group can form dipeptides or polypeptides they are broken down by hydrolysis

Answer 12

sequence of amino acids in the polypeptide chain | determined by the sequence of codons on the mRNA

Answer 13

hydrogen bonds form between amino acids (NH and CO group) in chain can coil into alpha helix- all N-H bonds on same side of protein chain h bonds parallel to helical axis can fold into beta pleated sheet- two or more parts of the chain run parallel to each other- linked by h bonds

Answer 14

the 3D shape formed from the coiled or folded chain coiled further

Answer 15

hydrogen bonds- form between different parts of the polypeptide chain and are numerous and easily broken ionic bonds- form between carboxyl and amine groups that aren't involved in peptide bonds and easily broken by changes in pH disulphide bridges- covalent bonds in sulphur atoms between two cystine amino acids - strong

Answer 16

long, narrow strands used for structure and support that are insoluble in water

Answer 17

spherical and compact with a 3D molecular structure involved in metabolic processes

Answer 18

functional protein composed of more than one polypeptide chain 3D structure held together by same bonds as in tertiary structure

Answer 19

capillary tube to spot mixture onto pencil line place chromatography paper in solvent allow solvent to run use revealing agent to see spots calculate Rf values and match to database

Answer 20

the biuret tests for the presence of a peptide bond add a few drops of sodium hydroxide add copper sulfate solution blue to purple if protein is present

Answer 21

globular proteins + biological catalysts | speed up reactions by lowering activation energy and are not used up in reactions

Answer 22

substrate binds to active site of an enzyme enzyme substrate complex forms active site slightly changes shape so it is complementary to substrate reduces activation energy

Answer 23

active site is specific to certain substrates complementary and forms ES complex active site determined by primary structure/ amino acid sequence and tertiary structure changes in bonds in tertiary structure change shape of active site- no longer complementary to substrate

Answer 24

particles have more kinetic energy so more ESc form collide with more energy to overcome activation energy high temp causes denaturation as H bonds holding tertiary structure are disrupted which changes shape of active site- no longer complementary irreversible

Answer 25

once pH goes beyond optimum, enzymes denature ionic bonds in tertiary structure break/ disrupted charges on amino acids change so primary structure changes

Answer 26

rate increases with more substrate as more substrates can collide with enzymes to form ESC levels off as enzyme molecules become saturated with substrate so all active sites are used up adding more substrate has no effect

Answer 27

rate increases with more enzymes as more ESC form | at high enzyme conc substrates become limiting factor as there are no more substrates to bind with enzymes and form ESC

Answer 28

prevent the binding of substrates to active sites so fewer ESC are formed

Answer 29

inhibitor is similar shape to substrate fits/bind to active site (complementary) prevent enzyme substrate complexes forming chemically different so product is not formed reversible at high substrate conc, some enzyme is still available to bind so more enzyme substrate collisions + more ESC form

Answer 30

attaches to enzyme at site away from active site changes shape of active site by changing tertiary structure active site no longer complementary so less substrate can bind irreversible at high substrate conc, enzyme is no longer available so less chance of ESC forming

Answer 31

catabolic- large molecules are broken down into smaller subunits eg one substrate binds and is broken into two molecules anabolic- two molecules enter the enzymes active site and form into one molecule

Biological Molecules Flashcards

(55 cards)