Text Book Flashcards
Ab intito
involves building a protein from ‘scratch’ using information about bonds and the standard geometry of how atoms work together – multiple solutions to the amino acid sequence
Comparative protein modelling
: looks for similar sequences of amino acids in other proteins and sue that to predict the protein shape
- Can help in biochemistry in identifying new medicines
What is a reducing sugar
can give electrons to other molecules
Why can sucrose be referred to as a non-reducing sugar
the groups which act as reducing agents on the components of monosaccharides are unavailable as they are involved in the glycosidic bond of sucrose so sucrose cannot act as a reducing agent and is referred to as a non- reducing sugar
Why do you have to check there is no reducing sugar in the solution before testing for the presence of a non-reducing sugar
Have to check the sugar can not first act as a reducing agent – you split monomers apart and see if groups exposed can be used as reducing agents
Precipitate vs emulsion
Precipitate is a solid substance commonly suspended in a liquid ; emulsion is droplets suspended in a solution
Why is there an emulsion
Because lipids are insoluble in water and can not be dissolved as there charges are distributed evenly – hydrophobic - cluster together in droplets rather than mixing with the polar water molecules
Reducing sugar conc test
1) Carry out the Bendedicts test using fixed volumes and concentrations of the juices and Bendedicts solution
2) Heat in a centrifuge
3) Filter the precipitates out of each solution
4) Place in a cuvette
5) Place a blank of distilled wtae rin the colorimeter to set it to zero
6) Place a red filter in and measure for each cuvette the % transmission of light through them
7) Compare with calibration graph to read off the concentrations of reducing sugar present
8) Repeat a number of times to obtain a mean
Colorimeter vs biosensor
1) Colorimeter vs Biosensor: both take a variable that cant be easily measured into an electrical signal
Biosensor: uses a biologically derived intermediate which then determines the strength of the electrical signal
Colorimeter: uses absorption of light to determine the strength of the electrical signal
If two liquids have different colours
Plot calibration curve for % transmission against concentrations for each sugar
If two travel at the same speed
use a diff solvent or change the Ph
How to measure colourless molecules
Ultraviolet light: Thin layer Chromatography has a chemical that fluoresces under UV light if you oook at the plate under UV light most of it will glow except those places where the spots have travelled too
Ninhydrin: amino acids – allow plate to dry and then spray – binds to amino acids which are visible as brown/ purple spots
Iodine: allow plate to dry and then place in an enclosed container with a few iodine crystals – iodine forms a gas which then binds to the molecules in each of the spots
Balanced diet
Contains proper proportions of carbohydrates; fats; proteins; vitamins; minerals and water necessary to maintain good health
Emulsion test
Take food and place in a test tube, add ethanol and mix thoroughly; add to water if a lipid is present an emulsion will appear
- turns cloudy/milky white
Properties of collagen
Collagen is a fibrous protein
- Triose helix
- Every third amino acid is glycine
- Primary structure is amino acids bonded together via a peptide bond
- Spirals into a left handed helix
- Few hydrophilic groups
- Insoluble
- Small R group of glycine enables twisting
- R groups on the outside
- Adjacent molecules joined by cross links – staggered: fibril formed
