TLS Online TPP Program

#Question id: 28983


Which of the following is the rate limiting step in synthesis of catecholamines?

#Unit 7. System Physiology – Animal
  1. conversion of dihydroxyphenylalanine to Dopamine by Dopa decarboxylase 
  2. conversion of phenylalanine to tyrosine by  phenylalanine hydroxylase
  3. Conversion of tyrosine to dihydroxyphenylalanine (DOPA) by tyrosine hydroxylase
  4. Conversion of tyrosine to dopamine by Dopa decarboxylase 
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TLS Online TPP Program

#Question id: 12140

#Unit 10. Ecological Principles

In some animal species, social organization involves the establishment of a system of ordered social rank instead of the occupancy of territories. Such a system of ordered social rank is referred to as a __________. 

TLS Online TPP Program

#Question id: 11096

#Unit 7. System Physiology – Animal

In which structure does diffusion of oxygen to capillaries not play a major role?

TLS Online TPP Program

#Question id: 10280

#Unit 6. System Physiology – Plant

The enzyme of glycolytic pathway that forms fructose 1,6-bisphosphate is called phosphofructokinase-1 (PFK-1), which statements can’t distinguish it from a second enzyme (PFK-2) Phosphofructokinase-2.

TLS Online TPP Program

#Question id: 1374

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to gap junctions.

i. Vertebrate gap junctions are composed of connexins, a family of structurally related transmembrane proteins with molecular weights between 26,000 and 60,000.

ii. Each vertebrate hexagonal particle consists of six noncovalently associated connexin molecules. Each individual connexin molecule has two membrane-spanning α helices with a topology similar to that of claudin.

iii. The permeability of gap junctions is regulated by posttranslational modification of connexins (e.g., phosphorylation) and is sensitive to changes in environmental conditions

such as intracellular pH and Ca2+ concentration, membrane potential, and the intercellular potential between adjacent interconnected cells (“voltage gating”).

iv. The assembly of connexins, their trafficking within cells, and the formation of functional gap junctions apparently depend on N-cadherin and its associated adapter proteins as well as desmosomal proteins.

Which of the following statements are correct?

TLS Online TPP Program

#Question id: 7199

#Unit 5. Developmental Biology

Following statements are regarding to the establishment of ventral axis in Drosophila.

A. Ventral follicle cells synthesize Pipe. Pipe signal sulfates ventral vitelline proteins.

B. GD cleaves Snake to its active form and forms a complex with Snake and uncleaved Easter proteins.

C. Sulfated vitelline membrane proteins bind Gastrulation-defective (GD).

D. Easter protein is cleaved into its active form. Cleaved Easter binds to and cleaves Spätzle; activated Spätzle binds to Toll receptor protein.

E. Dorsal protein enters the nucleus and ventralizes the cell.

F. Toll activation activates Tube and Pelle, which phosphorylate the Cactus protein. Cactus is degraded, releasing it from Dorsal.

Which of the following is the correct sequence?