Practicals

Question 1

What does a spectrophotometer measure?

Answer 1

Absorbance of a probe solution at any wave length

Question 2

What does an Absorbance of A=1 mean?

Answer 2

A = log10(light transmitted through blank solution/light transmitted through test solution)

–> Only 10% of light is transmitted and 90% absorbed

Question 3

How does haemoglobin change colour at different oxygenation states?

Answer 3

Oxy= bright red

Desoxy= dark, purplish

Question 4

How can you use lambert-Beersch law to determine concentration?

Answer 4

A = E × c × ℓ

A is the absorbance of the solution
c is the concentration of the absorbing substance (typically in mol/liter)
ℓ is the path length (in cm)
E is the Extinction Coefficient, a constant for the substance being measured at that particular wavelength.

Question 5

What is Vmax ?

Answer 5

Vmax is the maximum enzyme velocity

Question 6

What is K_m ?

Answer 6

KM (known as the Michaelis constant) is the substrate concentration at which the rate of reaction is exactly half that of the Vmax.