Plant tissue culture

1) Lecture overview on plant tissue culture:
http://www.youtube.com/watch?v=0lzOjd9Izn8


2) Video and picture of plant tissue culture technique:

http://www.youtube.com/watch?v=0Y4dCVrl37k&list=FL-cFTJ8NxBjonnjuwSQgSsw




3) Picture of callus:

Genetic engineering of pGLO plasmid

Bacterial cultures

http://www.cas.vanderbilt.edu/bsci111a/microbiology/supplemental.htm

DNA transformation

http://www.dnalc.org/view/15918-Transformation.html

Photosynthesis Tutorial Essay Q13 [8]

·         Light energy is converted to chemical energy in the form of ATP.

·         Consist of cyclic photophosphorylation involving only photosystem I and

non-cyclic photophosphorylation involving both photosystems II and I.

·         Light energy captured by pigments/light harvesting complexes passed to

special chlorophyll a, causing excitation of electrons to

higher energy level, which is subsequently captured by primary electron acceptor.

·         For cyclic photophosphorylation, excited electrons are returned back to

special chlorophyll a (final electron acceptor), after passing down chain of electron carriers and proton pumps.

·         For non-cyclic photophosphorylation, Photosystem I receives replacement of

electrons from photosystem II,

·         photosystem II receives replacement of electrons from photolysis of water with

production of oxygen as byproduct.

·         Excited electrons are passed along a chain of electron carriers of progressively

lower energy level/electron transport chain, energy released used by proton pumps to

pump H+ from stroma into thylakoid space.

·         Creating a proton gradient across thylakoid membrane.

·         ATP synthase harness proton gradient/proton motive force to generate ATP as

H⁺ diffuse back into stroma via ATP synthase.

·         Chemiosmosis couples energy released from passage of electrons down

electron transport chain to active transport of H⁺ from stroma into thylakoid space

via proton pumps.

·         For non-cyclic photophosphorylation, NADP reductase combines electrons with H⁺

and NADP⁺ (final electron acceptor) to form NADPH for use in Calvin cycle.

Absorption and action spectra

  

1) Comparison between prokaryotic mRNA (polycistronic) and eukaryotic mRNA (monocistronic) 

- note that 5' UTR and 3' UTR is present in both prokaryotes and eukaryotes. The 5' UTR in prokaryote is important as it contains the Shine-Dalgarno sequence, while the 5' UTR in eukaryotes is important as it can regulate translation as regulatory proteins can bind to it and prevent binding of ribosomes so as to carry out translation.

 

- note that unlike the prokaryotes, there is RNA processing in eukaryotes. Hence eukaryotic mRNA contain the 5' GTP cap (important for recognition/binding by eukaryotic ribosome and prevent mRNA degradation) and the 3' poly A tail (facilitate export of mRNA from nucleus and prevent mRNA degradation)  



2) Another picture showing that the prokaryotic mRNA is polycistronic.

- The Shine-Dalgarno sequences (impt for recognition and binding of prokaryotic ribosomes) are in between the multiple start and stop codons on the prokaryotic mRNA.

 3) Another diagram that shows the Shine-Dalgarno sequences on prokaryotic mRNA more clealy.

- Since the prokaryotic mRNA has multiple ribosome binding sites called Shine Dalgarno sequences, thus can lead to the synthesis of several different polypeptides. This is unlike the eukaryotic mRNA with only one ribosome binding site/ start site, so it can only lead to the synthesis of one polypeptide.