TLS Online TPP Program

#Question id: 7110


What may be the molecular trigger that causes cells in the presomitic mesoderm to finally condense into somites?

#Unit 5. Developmental Biology
  1. A gradient of retinoic acid exists that emanates both anteriorly and posteriorly from the somites.

  2. The FGF gradient drops off in the region that is forming somites.

  3. Periodic waves of c-hairy1 are expressed in the presomitic mesoderm, such that cells in the more anterior somites will have been exposed to fewer waves of c-hairy1 than the cells in more posterior somites.

  4. Signaling from the receptor Notch is required for somite formation.
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TLS Online TPP Program

#Question id: 2193

#Unit 2. Cellular Organization

A membrane is examined using freeze-fracture and freeze-etch analysis. The surfaces are shown to have almost no pits or bumps. Which of the following is the most likely source of the membrane?

TLS Online TPP Program

#Question id: 28275

#Unit 5. Developmental Biology

 what will happened when sulfated polysaccharide binds to its receptor on the sperm____ 
a) activates CatSper calcium channel
b) activates sperm membrane calcium transport channel
c) activates sperm membrane sodium-hydrogen exchanger
d) activates sperm membrane phospholipase enzyme

TLS Online TPP Program

#Question id: 945

#Unit 1. Molecules and their Interaction Relevant to Biology

A key precursor in the synthesis of aromatic amino acids (tryptophan, tyrosine and phenylalanine) is ________.

TLS Online TPP Program

#Question id: 868

#Unit 1. Molecules and their Interaction Relevant to Biology

Which statements is incorrect about ‘The chaperonin-assisted catalysis of protein folding’

A. The non-cooperative nature of ATP binding establishes GroEL as an allosteric enzyme.

B. In GroEL with a total of 14 subunits in two heptameric rings are observed.

C. In vivo GroES is composed of seven identical subunits whilst GroEL is composed of 14 larger subunits.

D. Gro-EL being called chaperonin60 (cpn60) and Gro-ES chaperonin10 (cpn10).

TLS Online TPP Program

#Question id: 10263

#Unit 8. Inheritance Biology

During cell division, sometimes there will be failure of separation of sister chromatids. This event is called