1) Chemiosmosis VS Photophosphorylation
The meaning of the two terms can be derived from the words themselves.
Chemiosmosis refers simply to the movement of H+ ions i.e. pump across the membrane when electrons move along the ETC to release energy for activity. The electrons then diffuse back across the membrane through the hydrophilic pore of the ATPase with a release of energy that is coupled to the synthesis of ATP.
(where H+ moves from and to depends on the topic)
Photophosphorylation: how light energy is used to phosphorylate ADP to make ATP or how light energy is converted to chemical energy.
This would cover the many events from PSII to PS I and how ATP is eventually synthesized. Thus, chemiosmosis plays a part in photophorylation but here we are concerned with the process of synthesis of ATP. Chemiosmosis is just about H+ movement -reference to ATP is minor but usually we include it in brief.
2) ATPase? ATP synthetase? ATP synthase?
It is ATPase or ATP synthase.
In DNA genomics we have aminoacyl-tRNA synthetase!
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M & M
3. In tutorial, there was a given answer (by me) comparing anaI and anaII: each chromosome in anaI is bound by spindle fibers from one pole while in anaII, each chromosomes is bound by spindle fibers from both poles
Amendment: This should be a difference in Metaphase not Anaphase. In anaphaseII, the 2 sister chromatids would have been separated so each chromosome is actually attached to spindle fibers from each poles...
2nd mark is: whether centromere has divided or not
3rd mark is: the sister chromatids are pulled together towards each pole in anaI but the sister chromatids are separated and pulled towards opp poles in anaII
4. Crossing over = physical exchange of equivalent portions of genetic material. It is NOT when one non-sister chromatid is on top of the other/overlap.
5. Chiasma must form first before crossing over can take place. (amendment to notes)
6.What is the middle lamella (cytokinesis/Plant)
Cell walls consist of 3 types of layers:
Middle lamella:This is the first layer formed during cell division. The middle part of cell wall that is made up of pectic compounds and protein and cements the cell walls of two adjoining cells together. Plants need this to give them stability and so that they can form plasmodesmata between the cells. It is the first layer which is deposited at the time of cytokinesis.
Primary wall: This is formed after the middle lamella and consists of a rigid skeleton of cellulose microfibrils embedded in a gel-like matrix composed of pectic compounds, hemicellulose, and glycoproteins.
Secondary wall: formed after cell enlargement is completed. The secondary wall is extremely rigid and provides compression strength. It is made of cellulose, hemicellulose and lignin. The secondary wall is often layered.
6a. Mitosis, mitotic cycle, cytokinesis? (Inspiration from Qn 25 of mcQs.)
1) the cell cycle is also known as the mitotic cycle. Thus it will include the Interphase as well as the M phase (M for mitotic/mitosis PHASE).
2) the mitosis PHASE, comprises of Mitosis (pro-meta-ana-telo-phase)+ Cytokinesis
so mitotic cycle, mitotic/mitosis phase and mitosis are different ideas.
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VIRUS
7. Can many prophages exist in a bacteria? (I forgot whether I have addressed this) - (ADDITIONAL)
Depends on the context.
Once a lambda phage enter a lysogenic cycle as prophage, there is superinfection http://en.wikipedia.org/wiki/Superinfection where the DNA of other lambda phages is rendered useless
However, if the bacteria get infected by another type of virus, it is possible to have different type of prophages in the cell because the immune mechanism/inihibitory mechanism of lambda phage may not work on other types of virus. =)
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Bacteria
MCQ test
Lecture Notes
8. what is an effector molecule?
(note that we are talking about effector MOLECULE. Effector in physio is different)
An effector is a molecule (originally referring to small molecules but now encompassing any regulatory molecule, includes proteins) that binds to a protein and thereby alters the activity of that protein. A modulator molecule binds to a regulatory site during allosteric modulation and allosterically modulates the shape of the protein.
(http://en.wikipedia.org/wiki/Effector_(biology))
Thus tryptophan and lactose are effectors because they binds to repressors(a protein) to alter its function/activity - Trp activates it while Lac inhibit it. cAMP is also an effector molecule.
(it is just that effectors may have specific names or reference like co-repressor. 'Effector molecule' is an umbrella term.)
9. What is a metabolite?
Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules.
(http://en.wikipedia.org/wiki/Metabolite)
Very general. Not to worry over.
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