Sort the following events to reflect the order in which they occur for formation of new blood capillaries in conditions of insufficient oxygen supply. Your answer would be a four-letter string composed of letters A to D only, e.g. DACB.
(A) New tip cells are formed on the sides of nearby capillaries.
(B) Stalk cells divide and hollow out to form tubes.
(C) VEGF is secreted by the cell.
(D) The level of intracellular HIF1? increases.

Question

Sort the following events to reflect the order in which they occur for formation of new blood capillaries in conditions of insufficient oxygen supply. Your answer would be a four-letter string composed of letters A to D only, e.g. DACB.
(A)	New tip cells are formed on the sides of nearby capillaries.
(B)	Stalk cells divide and hollow out to form tubes.
(C)	VEGF is secreted by the cell.
(D)	The level of intracellular HIF1? increases.

Quizplus · Accepted Answer

Tissues requiring a blood supply can trigger branching of nearby blood vessels toward themselves by releasing vascular endothelial growth factor (VEGF). Under hypoxic conditions, hypoxia-inducible factor 1? (HIF1?) levels increase inside the cell. This transcription regulatory protein then induces the expression of VEGF, which is secreted. Endothelial cells respond to VEGF by invading in the direction set by the VEGF gradient.

Sort the Following Events to Reflect the Order in Which