TLS Online TPP Program

#Question id: 565


A transition-state analog:

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. is less stable when binding to an enzyme than the normal substrate.

  2. resembles the active site of general acid-base enzymes.

  3. resembles the transition-state structure of the normal enzyme-substrate complex.

  4. stabilizes the transition state for the normal enzyme-substrate complex.

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TLS Online TPP Program

#Question id: 5679

#Unit 5. Developmental Biology

Following statements regarding to the molecular processes of capacitation.

A. The sperm cell membrane is altered by the removal of albumin by cholesterol in the female reproductive tract.

B. Particular proteins or carbohydrates on the sperm surface are lost during decapacitation.

C. The membrane potential of the sperm cell becomes more positive as potassium ions leave the sperm. This change in membrane potential may allow calcium channels to be opened and permit calcium to enter the sperm.

D. Calcium and bicarbonate ions are critical in activating cAMP production and in facilitating the membrane fusion events of the acrosome reaction.

E. As a result of cAMP formation, protein phosphorylation occurs. Once they are phosphorylated, some proteins migrate to the surface of the sperm head. One of these proteins is izumo, which is critical in sperm-egg fusion.

which one of the following combinations is correct?

TLS Online TPP Program

#Question id: 18079

#Unit 9. Diversity of Life Forms

Within a gymnosperm megasporangium, what is the correct sequence in which the following should appear during development, assuming that fertilization occurs? 
1. Sporophyte embryo 2. female gametophyte 
3. egg cell                 4. megaspore 

TLS Online TPP Program

#Question id: 13147

#Unit 8. Inheritance Biology

A cross was made between pure Blue and long pollen length with white and short pollen length. The F1 were test crossed. The F2 progeny obtained was as follows:
The genetic distance (cM) between flower colour and pollen length is;

TLS Online TPP Program

#Question id: 863

#Unit 1. Molecules and their Interaction Relevant to Biology

Ubiquitinated proteins are proteolytically degraded in an ATP-dependent process mediated by a large (∼2500 kD, 26S) multiprotein complex named the 26S proteasome;

TLS Online TPP Program

#Question id: 15989

#Unit 12. Applied Biology

Genetically modified plants have also been used for___