17707380
Description
Flashcards by Sam Gunnell, updated more than 1 year ago
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Created by Sam Gunnell
over 5 years ago
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| Question | Answer |
| Explain how water enters the plant and spreads throughout the roots | Water enters the roots via osmosis as the soil has a higher water potential. As water moves into the root hair cells, the cell becomes turgid and water moves to cells with less water potential via osmosis again |
| Does soil have a high or low water potential? Why? | High as there is a low concentration of mineral ions (solute) |
| What are the three pathways in which water moves across the roots? | Apoplast pathway Symplast pathway Vacuolar pathway |
| Does the apoplast pathway pass though the: Cytoplasm, cytoplasm and vacuoles, or the cell wall? | Cell wall |
| Does the symplast pathway pass though the: Cytoplasm, cytoplasm and vacuoles, or the cell wall? | Cytoplasm |
| Does the vacuolar pathway pass though the: Cytoplasm, cytoplasm and vacuoles, or the cell wall? | Cytoplasm and vacuoles |
| The cell wall must be _______ to allow for movement along the apoplast pathway | Fully permeable |
| Is there a lot or little resistance in the apoplast pathway? | Little resistance as the cellulose cell wall has a very open structure |
| Where does the apoplast pathway stop? | At the casperian strip in the endodermis cell |
| What connects cells? | Plasmodesmata |
| With the symplast pathway, water flows through the ___________ | Cytoplasm |
| What process allows water to move along the symplast pathway? | Osmosis |
| What is the casperian strip? | A band of waterproof cells in the endodermis |
| What is the waxy substance that makes up the casperian strip? | Suberin |
| What is the function of the casperian strip? | To stop water flowing through the apoplast pathway at the endodermis so that the water can move into the xylem |
| How and why does water move into the xylem? | Mineral ions move into the xylem via active transport (through transport proteins). As a result, the water potential inside the cytoplasm increases and water potential inside the xylem decreases, causing water to move into the xylem |
| Explain how sucrose is loaded into the phloem and how this forces movement of substances down the phloem? (**) | Sucrose is actively loaded from the companion cell to the sieve tube via active transport along with H+ ions through co-transporter proteins. This reduces the water potential inside the sieve tube, resulting in water moving from the xylem and companion cell to enter the sieve tube, increasing the pressure and forcing sap down the plant and through pores in the sieve plate |
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