Biology
Arrangement of Vascular Tissues in Flowering Plants
• Xylem and phloem often are grouped together -> vascular bundle • Cambium -> lies in between xylem and phloem -> divide and differentiate -> form new xylem and phloem tissues -> thickening of stem
Movement of Substances Into and Within Flowering Plants
Entry of Water and Nutrients into Plants • Absorption of water -> root hairs -> grow into close contact with liquid around them • Thin film of liquid surrounding soil particle -> dilute solution of mineral salts • Cell sap in root hair -> lower water potential than surrounding soil solution -> separated by partially permeable membrane • Water enter root hair cell by osmosis/active transport • Mineral salts -> diffusion and active transport
[pic]
How is the structure of root hair cell adapted to its function of absorption? • Elongated protrusion that increases surface area to volume ratio -> increase efficiency of absorption of water and mineral salts • Root hair grow between soil particles -> close contact with surrounding water
Active transport: when concentration of ions in soil solution is lower than that in root hair cell sap
Diffusion: when the concentration of ions in soil solution is higher than that in root cell
Movement of Water in Root • Entry of water dilutes cell sap of root hair cell, such that is of a higher water potential than that of the next inner cell in cortex or cortical cell • Water passes by osmosis from root hair cell into inner cortical cell • Continues until water enters xylem vessels -> moves up plant by transpiration pull
Movement of Water Against Gravity Up a Plant
1. Transpiration pull • Provides a suction force -> main factor that cause movement of water up xylem 2. Capillary action • Water tends to move up inside very narrow tubes ( capillary tube due to cohesion between water molecules) , as well as adhesion of water molecules on
• Xylem and phloem often are grouped together -> vascular bundle • Cambium -> lies in between xylem and phloem -> divide and differentiate -> form new xylem and phloem tissues -> thickening of stem
Movement of Substances Into and Within Flowering Plants
Entry of Water and Nutrients into Plants • Absorption of water -> root hairs -> grow into close contact with liquid around them • Thin film of liquid surrounding soil particle -> dilute solution of mineral salts • Cell sap in root hair -> lower water potential than surrounding soil solution -> separated by partially permeable membrane • Water enter root hair cell by osmosis/active transport • Mineral salts -> diffusion and active transport
[pic]
How is the structure of root hair cell adapted to its function of absorption? • Elongated protrusion that increases surface area to volume ratio -> increase efficiency of absorption of water and mineral salts • Root hair grow between soil particles -> close contact with surrounding water
Active transport: when concentration of ions in soil solution is lower than that in root hair cell sap
Diffusion: when the concentration of ions in soil solution is higher than that in root cell
Movement of Water in Root • Entry of water dilutes cell sap of root hair cell, such that is of a higher water potential than that of the next inner cell in cortex or cortical cell • Water passes by osmosis from root hair cell into inner cortical cell • Continues until water enters xylem vessels -> moves up plant by transpiration pull
Movement of Water Against Gravity Up a Plant
1. Transpiration pull • Provides a suction force -> main factor that cause movement of water up xylem 2. Capillary action • Water tends to move up inside very narrow tubes ( capillary tube due to cohesion between water molecules) , as well as adhesion of water molecules on