Which of the Following Statements Best Summarizes the Acid Growth

question 45

Multiple Choice

Which of the following statements best summarizes the acid growth hypothesis in an actively growing shoot?

• A) Auxin stimulates proton pumps in the plasma membrane and tonoplast.
• B) Auxin-activated proton pumps lower the pH of the cell wall, which breaks bonds and makes the walls more flexible.
• C) Auxins and gibberellins together act as a lubricant to help stretch cellulose microfibrils.
• D) Auxins activate aquaporins that increase turgor pressure in the cells.

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Definitions:

Capillary Permeability

The ability of substances to pass through the tiny blood vessels known as capillaries, either entering or exiting the bloodstream.

Chemotaxis

Attraction of living protoplasm (cells) to chemical stimuli.

Vasodilation

Increased diameter of blood vessels.

Histamine

A compound released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries.