Introductory Biology Notes
1. Plant Nutrition
Nine macronutrients of plants: C, H, N, O, P, S, K, Ca, Mg
Components of soil:
Horizon a (topsoil): humus, leaf litter, decaying matter
Horizon b (middle): minerals but no humus
Horizon c (bottom): rock
Most common nutrient deficiencies: N, P, K
2. Transport of Water and Minerals in Xylem
Xylem transports water and minerals from the roots to the leaves
Plant cells include: cell wall, plasma membrane, nucleus, chloroplasts and central vacuole
Soil to root
Water is absorbed into root hairs
Ions weakly attracted to soil particles
Root epidermis to xylem
Water cannot be transported to rest of plant until it enters the xylem of the vascular cylinder or stele
Apoplastic route: everything external to the plasma membrane
Goes in between plant cells
Symplastic route: cytosol inside of the plant cell
Traveling through plasma membrane of endodermal cells and bypasses Caspian strip
Trans membrane route: crosses cell wall
Casparian strip
Endodermal tissue
“Checks” water and minerals that want to cross via the apoplastic route
Layer of waxy substance in the endodermal tissue
Active transport
Important because it keeps materials that aren’t necessary and toxins from getting to the xylem
Roots to leaves
Against gravity
Xylem sap: material contained within xylem tissue
Primarily water, but dissolved minerals as well
Transpiration: loss of water from the leaves of a plant by evaporation through stomata that tugs or pulls on water from the bottom
Requires no energy
Driven by concentration gradients and properties of water
Negative pressure
Stomata regulate rate of transpiration by opening and closing during certain times, but can result in dehydration if open too much and there is not enough water uptake from the soil
Openings flanked by guard cells
Actual opening is called stomata
Guard cells close the stomata when they lose water
Properties of water
Cohesion: how two water molecules are attracted to each other through
Nine macronutrients of plants: C, H, N, O, P, S, K, Ca, Mg
Components of soil:
Horizon a (topsoil): humus, leaf litter, decaying matter
Horizon b (middle): minerals but no humus
Horizon c (bottom): rock
Most common nutrient deficiencies: N, P, K
2. Transport of Water and Minerals in Xylem
Xylem transports water and minerals from the roots to the leaves
Plant cells include: cell wall, plasma membrane, nucleus, chloroplasts and central vacuole
Soil to root
Water is absorbed into root hairs
Ions weakly attracted to soil particles
Root epidermis to xylem
Water cannot be transported to rest of plant until it enters the xylem of the vascular cylinder or stele
Apoplastic route: everything external to the plasma membrane
Goes in between plant cells
Symplastic route: cytosol inside of the plant cell
Traveling through plasma membrane of endodermal cells and bypasses Caspian strip
Trans membrane route: crosses cell wall
Casparian strip
Endodermal tissue
“Checks” water and minerals that want to cross via the apoplastic route
Layer of waxy substance in the endodermal tissue
Active transport
Important because it keeps materials that aren’t necessary and toxins from getting to the xylem
Roots to leaves
Against gravity
Xylem sap: material contained within xylem tissue
Primarily water, but dissolved minerals as well
Transpiration: loss of water from the leaves of a plant by evaporation through stomata that tugs or pulls on water from the bottom
Requires no energy
Driven by concentration gradients and properties of water
Negative pressure
Stomata regulate rate of transpiration by opening and closing during certain times, but can result in dehydration if open too much and there is not enough water uptake from the soil
Openings flanked by guard cells
Actual opening is called stomata
Guard cells close the stomata when they lose water
Properties of water
Cohesion: how two water molecules are attracted to each other through