Instrumentations for biotechnologists

Question 1

Electromagnetic radiation?

Answer 1

Can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light.

Question 3

Collimator function?

Answer 3

The primary role of a collimator is to convert diverging light from a source into aparallel beam.

Question 4

Monochromator function?

Answer 4

is to select a narrow band of wavelengths from the light source.
By adjusting the monochromator, the user can choose the exact wavelength needed for analysis

Question 5

The Beer-Lambert law

Answer 5

law describes the dependence of the absorbance on:
the concentration of the sample (C)
the optical path length (L)
the dependence on a sample-specific extinction coefficient (Ɛ),

Question 6

Transmittance (T)

Answer 6

is defined as the ratio of the intensity of light that passes through a sample (I) to the intensity of the incident light (I0).
(T) = I/I0

Question 7

1-Single beam spectrophotometer

Answer 7

All the light from the Monochromators goes to the sample, and then to the detector.
-Advantages: Relatively inexpensive and simple.
-Disadvantage: The reference point (blank) has to be reset frequently when measuring a series of samples over a period of time.

Question 8

2-Double beam spectrophotometer

Answer 8

A beam splitter splits the light into two streams of equal intensity. One path leads through the reference compartment (standard), the other through the sample

Question 9

Real-time PCR instruments consist of THREE main components:

Answer 9

1-Thermal Cycler (PCR machine)
2-Optical Module (to detect fluorescence in the tubes during the run)
3-Computer (to translate the fluorescence data into meaningful results)

Question 10

Threshold cycle

Answer 10

in real-time PCR is the cycle at which the system begins to detect the increase in the signal associated with exponential growth of PCR product during the log-linear phase