Labs Flashcards
Effect of heat on quarternary proteins
Disrupts hydrophobic interactions and dipole-dipole interactions
Thiol reducing agent on proteins
Disrupts disuphide bonds
SDS on proteins
Is an anionic detergent.
It solubilises, denatures + coats proteins w/ -ve charge
What property allows SDS to dissolve hypdrophobic molecules?
Lipophillic tail
Conjugate
Combine with another molecule or join together
Pattern of absorbance measure
the particular wavelengths of light absorbed by conjugated bonds in a molecule
Deuterium lamps in spectrophotometry
Emit UV light so are suitable for measuring the absorbance of DNA, RNA and proteins.
Absorbance of UV light in proteins
Peptide bonds and aromatic rings in amino acids absorb UV light
Scanning spectroscopy
Uses a range of wavelengths when measuring absorbance.
When using a micropipette
1) Have appropriate tip on when touching liquid
2) Hold pipette up straight with liquid in
3) Take liquid in slowly so it doesnt ‘jump’ in the mechanism
Wavelength absorbed by DNA
~260nm
WAvelength absorbed by protein
~280nm
Absorbance measure at 280nm generally has absorbance equivalent to :
1mg of protein per imL of solution
Measuring protein quantification
A280 of 1 ~ 1g/L = 1mg/mL of protein
What causes bands to be fainter in electrophoresis?
Sample more diluted
Cell volume equals
(Pi x 6) x width^(2) x length
What causes lipid accumulation to increase with cell biovolume in algae?
As the cells generate and accumulate oil bodies within the cytosol in response to nitrogen starvation this causes and increase in cell volume, hence an increase in cell biovolume positively correlates with increased lipid content.
Why is oil immersion used in microscopy?
to increase the resolution of the image of the small cell.
When making a blood film, which cell type is most abundant?
Erythrocytes
Microcytic means someones red cells are…
Low mean corpuscular (cell) volume (MCV)
When identifying ABO blood groups, an individual showing agglutination w/ anti-B antisera only will have the following blood group
B
1fl equals
10^(-15) L
1pg equals
10^(-12) g
Blood pressure equals
BP = CO x TPR
An old man was found to have a BP of 160/100 on four occasions. What is this condition? What happens to BP w/ age? Why?
Patient is Hypertensive. Systolic BP increases because blood vessels become hardened (arteriosclerosis) and lose elasticity
What does resolved mean?
Separated
Bands on a gel that are well resolved are well separated from each other, and each band is distinct
What gel concentration is better for larger DNA fragments? AND why
Lower concentrations
Larger pore size, so DNA fragments can better resolve, and their bands more defined.
Why is a control used when studying enzyme substrate reactions?
To prove changes in enzyme activity are due to substrate. Without control, you couldn’t conclude substrate addition had any effect.
If you repeated the ‘Switching on Genes’ experiment, but grew the E. coli cells in glucose-containing growth medium, rather than glycerol medium, how would you expect the result to differ and why?
Inducible lac operon will show a basal level of B-gal production even in absence of inducer; operon is repressed by presence of glucose. Thus if the medium was glucose-based, there would be no increase in basal level of B-gal production
In the experiment ‘Switching on Genes’, you adjust you readings for any base level of β-galactosidase present at time T=0. Why is this important?
Aim of experiment is to see what happens to β-galactosidase activity upon addition of inducer. Even without inducer there is low level transcription of lac operon, giving low but detectable β-galactosidase activity. By subtracting this uninduced β-galactosidase activity from each sample the graph will show the induced level of β-galactosidase activity at each time point
