A countercurrent system is a system in which the inflow runs parallel to, counter to, and in close proximity to the outflow for some distance. This occurs for both the loops of Henle and the vasa recta in the renal medulla

TLS Online TPP Program

#Id: 10019

#Unit 4. Cell Communication and Cell Signaling

Hh binds to Ptc, causing Ptc to be endocytosed from the cell surface and degraded, relieving the inhibition of Smo.

TLS Online TPP Program

#Id: 7011

#Unit 5. Developmental Biology

Regulation is highly influenced by the microenvironment that surrounds a stem cell and is known as the stem cell niche.

TLS Online TPP Program

#Id: 918

#Unit 13. Methods in Biology

Propidium iodide-labeled cells in order as

1. Apoptotic cells

2. G1/G0

3. S

4. G2/M  

TLS Online TPP Program

#Id: 2167

#Unit 11. Evolution and Behavior

Natural selection is any consistent difference in fitness among different classes of biological entities.

TLS Online TPP Program

#Id: 8041

#Unit 1. Molecules and their Interaction Relevant to Biology

There are two type representation of amino acid structure

1. By Fischer’s convention L and D

2. By absolute configuration RS System