Molecular techniques

Question 1

Why is Biotin good for labelling DNA?

Answer 1

Is SUPER high affinity for streptavidin

Question 2

What is northern blotting used for?

Answer 2

RNA
Can tell you how much of a given RNA is being made, what its size is, and if more that one mRNA is transcribed from a gene

Question 3

What is a micro-array used for and how does it work?

Answer 3

• For RNA as well
• Label all the transcription INSTEAD of sequence specific probes
• Attach flouresence group for each cDNA

Question 4

How do researchers detect a specific protein?

Answer 4

Antibodies

Question 5

Why is washing with SDS an important step in SDS-PAGE?

Answer 5

Because proteins have different charges (ie lys is pos, arg is neg) AND they have different shapes so need to standardize them via SDS which denatures them and makes them negative

Question 6

What is western blotting used for?

Answer 6

Proteins
Proteins imobilized on nylon membrane, antibodies bind them, then 2nd detectable reagent binds the antibodies

Question 7

How does mass spectrometry detect proteins?

Answer 7

Have to digest proteins with trypsin first, then mass-spec can accurately measure the mass and charge
Can predict every single protein that might be made from that genome

Proteins can be broken up into fragments depending on their primary structure. So, every protein will produce a unique pattern of fragments. Computation using genome data can predicted all possible fragments from all proteins. Mass Spectrometry can identify many fragments produce from a sample and thereby identify the primary constituents of the same.