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TLS Online TPP Program

#Question id: 15652

You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. You have isolated a mutation that causes constitutive melibiase activity, which you designate MelA–. P1 phage mapping experiments using a Tn5 insertion linked to Mel1 show that MelA– is not linked to Mel1. Moreover you find that when an amber suppressor is introduced into a MelA– mutant, normal melibiase regulation is restored. Classify the MelA– mutation in terms of its basic genetic properties, 

#Unit 13. Methods in Biology
  1.  MelA- as a recessive, loss of function mutation, whose wild-type allele codes for a cis-acting factor.
  2. MelA- as a recessive, loss of function mutation, whose wild-type allele codes for a trans-acting factor.
  3. MelA- as a dominant, gain of function mutation, whose wild-type allele codes for a trans-acting factor.
  4. MelA- as a dominant, gain of function mutation, whose wild-type allele codes for a cis-acting factor.
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TLS Online TPP Program

#Question id: 10211

#Unit 6. System Physiology – Plant

Which of the following mechanism is not involve in phtoprotection to plants?
TLS Online TPP Program

#Question id: 10212

#Unit 6. System Physiology – Plant

Which of the following mechanism is not involve in phtoprotection to plants?
TLS Online TPP Program

#Question id: 10213

#Unit 6. System Physiology – Plant

What is the reason behind that an organism cannot live or die in the presence of both light and molecular oxygen?
TLS Online TPP Program

#Question id: 10214

#Unit 6. System Physiology – Plant

LHCII, one of the membrane-bound antenna pigment proteins, which can be phosphorylated and non-phosphorylated by a specific kinase present in thylakoid membrane. Which of the following statements are NOT TRUE ?
TLS Online TPP Program

#Question id: 10215

#Unit 6. System Physiology – Plant

Chloroplast movement is widespread among algae, mosses, and leaves of higher plants, what will be the orientation of chloroplast in dark as well as in light?

a.) In dark, chloroplasts gather at the cell surfaces parallel to the plane of the leaf so that they are aligned perpendicularly to the incident light

b.) Under high light, , the chloroplasts move to the cell surfaces that are parallel to the incident light, thus avoiding excess absorption of light

c.) the orientation of the chloroplasts in the dark is such that maximizes absorption of light

d.) the orientation of the chloroplasts in the high light is such that maximizes absorption of light

Which of the following statements is correct?
TLS Online TPP Program

#Question id: 10216

#Unit 6. System Physiology – Plant

One of the mechanism that is thought to be involved in protecting the photosynthetic machinery against overexcitation and subsequent damage such mechanism is known as