Review for Plant Test

What is the process by which water is absorbed by root hairs in plants?

Osmosis.

Through which pathways does water move through the cortex of a plant?

Apoplastic (cell wall) and symplastic (cytoplasm) pathways.

What structure in the endodermis forces water into the symplastic pathway?

The Casparian strip.

What are the three main forces that allow water to be transported upward in plants?

Transpiration pull, cohesion, and adhesion.

What theory explains how water is transported in the xylem?

Cohesion-tension theory.

Define cohesion in the context of water in plants.

Water molecules sticking to each other due to hydrogen bonding.

What is adhesion in relation to water transport in xylem?

Water sticking to xylem walls, preventing the column from breaking.

How does capillary action contribute to water transport in plants?

Helps water move up narrow xylem vessels.

What is the primary function of phloem in plants?

To transport sugars (sucrose) and other organic compounds via translocation.

What is the pressure-flow hypothesis in relation to phloem transport?

Sugar is actively loaded into phloem at the source, lowering water potential, leading to hydrostatic pressure which pushes sugar toward sinks.

What is the primary direction of xylem transport?

Upward only.

How are the structures of xylem and phloem different?

Xylem consists of dead cells with thick, lignified walls; phloem consists of living cells with sieve plates.

What role does the shoot apex play in a plant?

Contains apical meristem responsible for primary growth, producing new leaves and stems.

What effect does auxin have on plant cell elongation?

Promotes cell elongation in shoots.

What process results from auxin accumulating on the shaded side of a plant?

Asymmetric growth leading to phototropism.

What happens during pollination in flowering plants?

Transfer of pollen from anther to stigma.

What is the advantage of wind pollination?

No reliance on pollinators and large amounts of pollen increase fertilization chances.

What benefits does seed production in fruits provide?

Protects seeds, aids in dispersal, and provides nutrients to the developing embryo.