Question

1) Which is true concerning bacteriorhodopsin-based phototrophy?

1. Retinal is the light absorbing molecule in the protein (T)

2. It optimally absorbs light in the green wavelength, giving the bacteriorhodopsin in a purple color (T)

3. Light induced conformational changes of retinal cause the protein to extrude one proton (T)

4. All are true

2) Which statement is false regarding a bacteriophage in the lysogenic cycle?

1. The bacteriophage will permanently remain in the lysogenic state

2. While in this cycle it would cause no harm to the host cell

3. As the host cell divides, the bacteriophage genome will be present in all of the host cell's progeny

4. It would become a prophage

5. No false statements, All are true

3) Which among A-D is false concerning reassortment of the influenza virus genome?

1. It results in antigenic drift (both are reassortment)

2. It can occur if two different influenza strains infect the same cell

3. It can lead to changes in the virus that allow it to avoid our immune system

4. It has led to prior virus forms like H3N2 and H2N2

5. None of A-D is false, all are true statements

Answer 1

1) Answer is All are true

Retinal is the light absorbing molcule in the bacteriorhodopsin protein, it absorbs a photon from light. It absorbs light in the green wavelength, absorption maxima is at 560nm and the bacteriorhodopsin is in purple colour and the retinal after absorbing a photon from light undergoes conformational changes and extrudes a proton from the holding place to the extracellular region of the membrane.Hence all the statements are true

2) Answer - none of the statements are false, All of the statements are true

The lysogenic cycle does not cause the death of the host cells hence ipermenantly remains in the lysogeny state, and as the host cells divide the bacteriophage integrates into the host genome and is passed onto its progeny and becomes prophage also while in this cycle unlike the lytic cycle it does not cause harm to the host cells. hence all of these statements are true and none of it is false.

3) Answer is - IT can occur if two different influenza strains infect the same cell - this statement is false.

Reassortment of the influenza virus genome occurs only between influenza viruses of the same type. All the rest of the staements pertaining to the reassortment of influenza virus genome is true.