BL1001 particle skills Flashcards
You have calibrated the eyepiece graticule for a low powered objective lens. On moving up to the medium powered objective
How will the distance in space between each graticule etched line will contain how many micrometer lines?
Fewer than before
What is TLC used for
Thin layer chromatography is used to identify, access purity of a substance or follow a reaction
How can TLC be used to access the purity of a compound
If the sample is pure, it will not separate into its components during chromatography, so will appear as a single spot. An impure sample will separate during chromatography sow will appear as one or more spots.
How can TLC be used to identify a substance?
The Rf value can be calculated and compared to known samples.
Rf=distance traveled by the sample / distance traveled by solvent front
Sometime known samples are run alongside unknown fro direct comparison
How can colourless spots on a TLC plate be developed?
Either by using UV florescent TLC plated (sample will appear as a dark spot under UV light)
OR
Spray with developping agent (e.g. ninhydrin for amino acids)
Describe the amino-acid composition of Collagen
triple repeat (X-Y-Z)n
this causes collagen sequence to form a triple helical protein which further assemble into fibrils which themselves assemble into tough collagen samples.
What is Osteogenesis Imperfecta?
A disease cause as a consequence of a mutation which causes a single change in type 1 collagen in the amino acid position X of the repeat (X-Y-Z)n. This cause there to be a weak point in the triple helix structure which results in defective mineralisation of collagen fibres in bone.
What is the maximum absorbance of UV used for UV absorbance spectroscopy of most DNA
260nm
What is the maximum absorbance of UV used for UV absorbance spectroscopy of most proteins
280nm
What is the mitotic spindle mainly made of?
Microtubules
What drives cytoplasmic streaming? The interaction of myosin with…?
Microfilaments
Mendel’s second law of inheritance
states that the alleles of one gene sort into the gametes independently of the alleles of another gene
What factor separates DNA molecules during electrophoresis using agarose gel?
. Agarose gels contain a small but uniform pore size. The smaller DNA molecules move through the small pores more easily than the larger DNA molecules, therefore during electrophoresis the smaller DNA molecules move further through the gel over time compared to the larger molecules. Therefore DNA molecules are separated into populations of molecules of similar size by electrophoresis solely based on the length of the DNA molecule.
How many amino acids have nitrogen in their side-chains?
6
