Ecologist has proposed following explanation to lead biodiversity at tropic.

a) Higher productivity in the tropics allows for more species

b)  Environments are more stable and predictable in the tropics, with fairly constant temperatures and rainfall levels year-round

c) Predators and pathogens limit competition in the tropics, which allows more species to coexist

d) High evolutionary speed at tropic than temperate

TLS Online TPP Program

#Question id: 15340

#Unit 4. Cell Communication and Cell Signaling

Serrogate light chain formation takes place in 

TLS Online TPP Program

#Question id: 15341

#Unit 4. Cell Communication and Cell Signaling

Formation of pre B-cell  describing__

A. Surrogate light chain formation 

B. On these surface present IgM

C. Heavy chain had been formed

D. DJ H chain recombination

TLS Online TPP Program

#Question id: 15342

#Unit 4. Cell Communication and Cell Signaling

The heavy chain is then expressed on the cell surface in combination with the surrogate light chain, which is made up of_______________, together they form the pre-B-cell receptor,

TLS Online TPP Program

#Question id: 15360

#Unit 4. Cell Communication and Cell Signaling

The cytochrome P450 constitute a superfamily of heme-containing enzymes that occur in nearly all living organisms, from bacteria to mammals, These monooxygenases, which in animals are embedded in the endoplasmic reticulum membrane, catalyze reactions of the sort

                  RH + O₂ + 2 H⁺ + 2e⁻ → ROH + H₂O 

The electrons (e−) are supplied by NADPH, which passes them to cytochrome P450’s heme prosthetic group via the intermediacy of the enzyme NADPH P450 reductase. Here RH represents a wide variety of usually lipophilic compounds for which the different cytochromes P450 are specific. They include

a. polycyclic aromatic hydrocarbons 

b. polycyclic biphenyls

c. frequently carcinogenic compounds that are present in tobacco smoke, broiled meats, and other pyrolysis products

d. which were widely used in electrical insulators and as plasticizers and are also carcinogenic.

TLS Online TPP Program

#Question id: 15361

#Unit 4. Cell Communication and Cell Signaling

The chemical benzo(a)pyrene, found in cigarette smoke as well as in coal tar, undergoes metabolic activation in the lungs to form a potent mutagen that mainly, causes conversion of guanine (G) to thymine (T) bases, a transversion mutation, When applied to cultured bronchial epithelial cells, activated benzo(a)pyrene induces many mutations, including inactivating mutations of the p53 gene, at codon number______

TLS Online TPP Program

#Question id: 15362

#Unit 4. Cell Communication and Cell Signaling

Aflatoxin a fungal metabolite found in moldy grains, induces