Transport In Plant Cells Flashcards
Why don’t plant cells need a transport system?
Plant cells have a large surface area in relation to volume so substances can easily get in and out of the cell and the rate of diffusion for substances is fast enough for its needs.
Transport in plants occurs through the vascular bundle which is made up of?
The xylem and the phloem
Describe the function of the xylem
The xylem is responsible for the upward movement of water and dissolved minerals from the roots, to the stem, to the leaves then to the rest of the plant.
Define the xylem.
Xylems are very long tube like structures made of individual structures that are stacked end to end. These structures are responsible for the upward movement of water and dissolved minerals from the roots to the stem to the leaves then to the rest of the plant.
Describe the function of the phloem
The phloem vessel is responsible for transporting sugar and other organic nutrients made from the leaves both up and downwards in the plant
Define the phloem vessel
The phloem is made of sieve cells which are entangled living cells. these tubes are connected to another by holes on the end walls between one cell and the next. The phloem is responsible for transporting sugar and other organic nutrients made from the leaves both up and downwards in the plant
Name the substances that are transported around the plant
Water, sugar, organic nutrients, minerals
Name the substances transported by the xylem and phloem
Xylem- water and dissolved minerals
Phloem- sugar and organic minerals
Describe the structure of the cross section of a plant root and stem.
In the root system the xylem forms a central column forming a solid support. The phloem is towards the center, outside the xylem. In the stem, the transport tissue of the xylem and the phloem are grouped into a vascular bundle.
How do elongated root hairs increase the TSA for water absorption in a plant?
They have thin walls to speed up the intake of water by osmosis and they have large vacuoles that absorb water quickly and transport it to the next cells .
In which part of the plant is the high concentration and low concentration?
High- the root
Low- the plant itself
Describe the five steps by which water moves through plants
1) root hairs take in water from the soil by osmosis
2) water moves through the root cortex to the xylem
3) water rises in the xylem vessel because of capillary action
4) water moves through the stem to the leaves
5) water is lost through the leaves , used by transpiration
Define the term transpiration
Transpiration is the movement of water through a plant. It is where water is absorbed by the root and passes through plant then is lost by evaporation through the leaves. ( this is sometimes called the transpiration stream)
What’re is the transpiration stream?
This is the constant flow of water through the plant.
What is evaporation
Evaporation is the conversion of liquid into water vapor as it leaves the cells and enters the air space. This is a process used to cool the plant.
Water moves up the the xylem because of three factors, what are they?
Capillarity, root pressure , and transpiration pull
Define the terms adhesion and cohesion
Adhesion is when molecules tend to stick to an object and cohesion is when molecules stick together.
Define capillarity
Capillarity is when water molecules stick together and to surfaces of narrow tubes and the water rises up the tube. (The narrower the tube, the higher the water will rise) ( xylem vessels are extremely narrow and the attraction between the water molecules and the xylem walls is great)
Define root pressure
Root pressure is the pressure created in the root xylem when water is absorbed into the plant from the soil. The pressure there is greater than in the leaf xylem because water is being pulled out of the leaf xylem by transpiration.
Define transpiration pull
The transpiration pull happens when cohesive forces hold water molecules together and the loss of water by evaporation in the upper areas of a plant creates a tension that ‘pulls’ water upwards and water is continually lost from the leaves. And so more water is drawn through the xylem.
What will happen if the stem and root of a plant are sealed in a poly theme bag for 24hrs
Condensation will form inside the bag . The water would be coming from the leaves instead of from soil.
Xylem and phloem are examples of _______ tissue.
Vascular
The plant tissue that Carrie’s food materials downward fro, the leaves to the rest of the plant is the _______
Phloem
The xylem transports substances in which direction?
Upward
Phloem tubes transports substances from where in the plant?
Leaves to the rest of the plant
Which vascular bundle transports sucrose and amino acids
Phloem
How does water enter the roots from the soil?
Osmosis
Plants absorb water through their ______
Roots