Which statements are true about group I and group II introns,

A. Group I (and II) introns are not enzymes because they have a turnover number of only 1.

B. A third transesterification reaction can occur to cyclize the intron.

C. They cannot be readily converted into ribozymes.

D. It is similar to the way that the self-cleaving Hammerhead could be converted to a ribozyme by separating the active site from the substrate

#Question id: 9580

#Unit 6. System Physiology – Plant

Many Antenna Complexes Have a common structural motif In all eukaryotic photosynthetic organisms that contain both chlorophyll a and chlorophyll b, the most abundant antenna proteins are members of a large family of structurally related proteins, some of these proteins are associated with PSI and PSII such as LHCI and LHCII , Select the incorrect one regarding LHC complexes;

#Question id: 9581

#Unit 6. System Physiology – Plant

These four Photosystem II, Cytochrome b6 f, Photosystem I and ATP synthase integral membrane complexes are vectorially oriented in the thylakoid membrane to function as follows, find out the incorrect statements;

#Question id: 9582

#Unit 6. System Physiology – Plant

Electrons ejected from chlorophyll travel through a series of electron carriers organized in the “Z Scheme” shows a current version of the Z scheme, in which all the electron carriers known to function in electron flow from H2O to NADP Presented in the following sequence;

a.) P680 reduce by Yz has received electrons from oxidation of water P680→P680*→pheophytin→ plastoquinones→ cytochrome b6 f complex→ plastocyanin→ in turn reduces (PSI) P700+

b.) P700+→ P700*→ membrane-bound iron–sulfur proteins → A0→ A1 → flavoprotein ferredoxin–NADP reductase (FNR) soluble → ferredoxin(Fd) → NADP+ to NADPH

c.) P700+→ P700*→ A0→ A1→ membrane-bound iron–sulfur proteins→ ferredoxin(Fd)→ soluble flavoprotein ferredoxin–NADP reductase (FNR)→ NADP+ to NADPH

d.) P680 reduce by Yz has received electrons from oxidation of water P680→P680*→ plastoquinones → pheophytin → cytochrome b6 f complex→ plastocyanin→ in turn reduces (PSI) P700+

Which one of the following combinations is correct?

#Question id: 9583

#Unit 6. System Physiology – Plant

 A mechanism known as the Q cycle accounts for most of the observations in which structure and reactions of plastoquinone that operate in,

#Question id: 9584

#Unit 6. System Physiology – Plant

In given Relationship of oxygen production to flash energy, the first evidence for the interaction between the antenna pigments and the reaction centre, What conclusion can be drawn about based on graph;

a.) several hundred pigments are associated with each reaction centre and that each reaction centre must operate four times to produce 1 molecule of oxygen—hence the value of 2500 chlorophylls per O2

b.) low light intensity of the curve, an increase in the number of photons stimulates a proportional increase in oxygen evolution. Thus, the slope of the curve measures the quantum yield for oxygen production

c.) The quantum yield for a particular process can range from 0 →if that process does not respond to light to 1.0→if every photon absorbed contributes to the process by forming a product

d.) O2 require more than a single photochemical event to be formed, and therefore have a lower quantum yield of formation than the photochemical quantum yield. It takes about ten photons to produce one molecule of O2, so the quantum yield of O2 production is about 0.1

Which of the following statements would be correct relates with graph?

#Question id: 9585

#Unit 6. System Physiology – Plant

In light reaction the reaction centre of PSII  receives electron from water molecules by splitting into oxygen, If 5 oxygen molecules evolved per 50 quanta was

absorbed then what is the quantum yield?