LECTURE OUTCOMES 3
1. Reasons why photosystems have antenna proteins while the eye doesn’t.
It is because photosystems need antenna to gather as much light as
possible to harvest energy (photosynthetic do not care about image) while
photoreceptors do not need antenna because they need light to create an
2. Points of control for regulation of protein abundance.
(ie. why some cell needs more of certain enzyme but some don't!)
Protein abundance: point of control is influenced by:
- Transcription (rate of transcript is high)
converting DNA to mRNA
translating mRNa to protein. This is a major mechanism that dictates how
much protein is
- mRNA decay ***
when mRNA is made, some break down/decay (20 min or hours – this is
3. factors affecting mRNA transcript abundance.
When mRNa is made, some decay in min or hours. There is a competing
process during transcript. This is controlled by transcription.
4. steps in making a Northern Blot for measuring mRNA transcript abundance.
how do we measure transcript abundance for Northern blot (the single
: isolate RNA from cell and use gel electrophoresis to quantify how much
total RNA and micro RNA do I have. They are separated by size.
But I cannot see mRNA in the gel? It is because the abundance is lower 97%
of RNA is ribosomol RNA, that's why you cannot see mRNA (3%) - low
The radioactive gene specific probe detects the gene (ex. Hexokinase).
Single stranded DNA would hybridize with the same sequence gene on the
mRNA and it sticks on the membrane.
5. relative abundance of various types of RNA in typical cells.
97% RNA, 3% mRNA
6. steps in making a Western Blot for measuring protein abundance.
SDA page pigment protein stained with blue dye. There are so many
thousands protein in here but we measure by looking for protein abundance
of one protein equal amount of protein in there 5 blots, then transfer this gel
to the membrane and probe these blots and use antibody for
hixokinase(protein im looking for) because antibody will bind to the protein. So it is easier to detect the presence of antibody in the lab.
7. characteristics of constitutive vs. induced vs. repressed gene expression
a. Northern blots – transcript abundance (INDUCED EXPRESSION)
- isolate RNA from control at 40 C and wait 1 or 2 hr then run it on the
gel. This is controlled growth cell equal amount of RNA (single s