All Class I enzymes aminoacylate their bound tRNA’s 3′-terminal 2′-OH group, whereas Class II enzymes charge the 3′-OH group.

TLS Online TPP Program

#Id: 7679

#Unit 1. Molecules and their Interaction Relevant to Biology

Because they cannot rotate, each peptide bond holds 6 atoms in a plane.

However, most possible angles of Phi (φ) and Psi (ψ) are impossible due to clashes

between atoms. These balls are much smaller than the atoms they represent.

TLS Online TPP Program

#Id: 7203

#Unit 5. Developmental Biology

Codominant Expression 

TLS Online TPP Program

#Id: 9095

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 8581

#Unit 2. Cellular Organization

B-type lamins - expressed in essentially all cells (primordial lamin proteins)

lamins A and C - developmentally regulated

TLS Online TPP Program

#Id: 10282

#Unit 6. System Physiology – Plant

ABA causes stomata to close by reversing the accumulation of potassium salts in guard cells and inducing the conversion of sugars into starch. 

The resulting fall in solute concentration leads to loss of water from the guard cell into the apoplast by osmosis, a fall in guard cell turgor, and closing of the stomatal pore.