Control and coordination in
7 flashcards to master this topic
Describe the mechanism by which the Venus flytrap rapidly closes upon stimulation.
Stimulation of trigger hairs causes an action potential that propagates across the leaf lobes. This triggers rapid turgor pressure changes in cells at the hinge, causing the lobes to snap shut, trapping the insect.
Explain how auxin promotes cell elongation in plant shoots.
Auxin stimulates proton (H+) pumps in the plasma membrane, acidifying the cell wall. This activates expansins, enzymes that loosen cellulose microfibrils, allowing the cell to expand due to turgor pressure.
What is the role of gibberellin in barley seed germination?
Gibberellin stimulates the aleurone layer to produce amylase. Amylase hydrolyzes starch stored in the endosperm into glucose, providing energy for the growing embryo.
What is the function of 'expansins' during cell elongation?
Expansins are enzymes that loosen the bonds between cellulose microfibrils in the plant cell wall. This allows the cell wall to become more flexible and stretchable, facilitating cell expansion.
Describe the sequence of events that lead to the closure of the Venus flytrap leaf lobes when a fly lands on it.
Fly lands, stimulating trigger hairs --> Action potential generated --> Turgor pressure change in hinge cells --> Rapid closure of trap.
Explain the relationship between acidification of the cell wall and cell elongation.
Acidification of the cell wall by proton pumps activates expansins. Expansins loosen cellulose microfibrils. This makes the cell wall more flexible, allowing it to expand under turgor pressure, resulting in cell elongation.
What cells are involved in the gibberellin-mediated breakdown of starch in a barley seed?
Gibberellin produced by the embryo stimulates the aleurone layer to synthesize and secrete amylase. Amylase then hydrolyzes starch in the endosperm.
Ready to test yourself?
Practice with MCQ questions to check your understanding of Control and coordination in.
Take QuizStudy Mode
Rate each card Hard, Okay, or Easy after flipping.