Studied by 28 peopleSecondary use for vascular bundle in stem and why
Stability against wind, because it’s a cylinder
In a plant stem, the ** is on the inside and the ** is on the outside
xylem, phloem
functions of plant roots
Anchoring plant in soil, absorption of water & minerals, food storage
pathway of water through plant
Root hair cell, Root cortex cell, xylem vessel, mesophyll cell in leaf
Function of xylem?
Transports water and mineral ions UP the stem
Function of phloem?
Transports nutrients UP AND DOWN the stem, from source to sink
What’s the function of the lignin?
Makes the cell wall impermeable and very strong
Why are the cells of the xylem vessel dead?
No cell wall, continuous, doesn’t absorb water
Where is the cortex and what dose it contain?
It’s between the vascular bundle and epidermis, it contains starch, and sometimes chloroplasts
What uses does the epidermis have, and where is it?
It helps maintain the shape of the stem and reduce loss of water vapor, and it’s on the outside of the stem
What’s the use of the pith, and where is it?
It supports the stem, and it’s on the center
Where are the vascular bundles on the root?
In the center
How do root hair cells absorb water?
Via osmosis
How do root hair cells absorb Mineral salts?
Via active transport
What dose active transport use?
Energy from cellular respiration
Define Transpiration
Loss of water vapor through plant leaves by evaporation of the water at the surface of mesophyll cells, followed by diffusion of water vapor through stomata
Transpiration is a ___ process
Passive
What’s adhesion force?
Force between water molecule and inside of xylem vessel
What’s cohesion force?
Force that attracts water molecules to each other
Main function of Transpiration?
Creates suction force that sucks up water from roots up to leafs
What’s wilting?
Loss of plant rigidity because of turgor pressure decrease in plant’s vacuole
Why does wilting occur?
Plant doesn’t get enough water (higher transpiration rate than absorption by roots)
How does ambient humidity affect the transpiration rate?
Higher humidity, Lower transpiration rate as high water potential outside leaf
How does ambient temperature affect the transpiration rate?
High Temperature, High transpiration
How does light intensity affect the transpiration rate?
High light intensity, high transpiration rate, as the stomata open
How dose air movement affect the transpiration rate?
High air movement, high transpiration rate, as humidity around the plant decreases as wind moves it away
Define translocation
The movement of sucrose and amino acids in the phloem, from regions of production (Source), to regions of storage or regions where they are used in respiration or growth (sink)
What would be the source and sink in summer?
Source: Leaf
Sink: Bud, Roots, Fruit, Tubers
What would be the source and sink in winter?
Source: Roots, Tubers
Sink: Every cell of the plant (cellular respiration)
Define diffusion
Movement of a substance from a high concentration to a low concentration
Define osmosis
Movement of water from high to low concentration through a partially permeable membrane
Define active transport
The movement of a substance from a low concentration to a high concentration
Note
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