Biology 2601A/B Lecture Notes - Lecture 20: Boundary Layer, Root Pressure, Wind Speed

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greenwallaby395

18 Nov 2011

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Plants need water: for biochemical reactions, to maintain structure (turgor pressure, for photosynthesis. Due to this, less water is lost from the leaf tissues when the stomata is open. Roots: the root cap is not very permeable; therefore water will not be exchanged at the top, the root hair zone is where water and nutrients will be transported into the plant. Root hairs: root hairs enhance water uptake by their ability to penetrate water-containing capillary spaces between soil particles. Increase several fold the volume of water extracted from the soil: extend between the film grains into films of water. 2: apoplastic: around the outside of the cells, transmembrane: across cell"s membranes into different cells. Symplastic: water moves through the cell wall without any cell membranes. Aquaporins allow h o to move passively along a concentration gradient leave salt behind: the problem with saline/salty environments is that h o will evaporate and.

Related Questions

Carbon dioxide is a limiting resource for most aquatic plants,even though it can reach quite high concentrations in surfacewaters. How is that possible?

Plants deplete the water immediately surrounding their leaves,creating a low-CO2 boundary layer.

It's bound up in bicarbonate, which plants cannot use.

Lakes and oceans are too acidic for most aquatic plants tofunction.

Plants prefer to use bicarbonate for photosynthesis, so CO2 isnot used.

viridianjellyfish540

Why are stomata a necessary feature of plants? [2 pt; L1; II.A] Stomata are necessary because they are the only plant cells that actively undergo photosynthesis. The cuticle prevents gasses from entering cells. Without stomata, there would be no route for gas exchange. The water inside plants has to go somewhere. If it were not for stomata, the water vapor would build up inside the leaf, and the leaf would lyse. Stomata are required because they store the carbohydrates produced during photosynthesis and empty their contents directly into the vascular system.

1. As water cools below 4Â°C, it expands and becomes less dense. Why is this beneficial to organisms living in a lake during a cold winter?

2. Given that heat readily transfers between an organismâs body and water, what would you predict about the temperature of the boundary layer around an animalâs body compared to the temperature of the surrounding water in cold weather?

3. Based on the properties of water, why do non-polar compounds such as fats and oils not dissolve well in water?

4. In lakes around the world, some have thick deposits of limestone, which is made up of calcium carbonate, and are resistant to the effects of acid rain. What parallels can you draw between these lakes and the smokestack scrubbers being used in coal-powered factories?

5. Both saltwater and freshwater fish have adaptations to control the movement of water and salts across their external surfaces. Describe what would happen without these adaptations.

6. How would the process of natural selection favor the evolution of increased salt tolerance during the decades that cold regions of the world have increased the use of road salt, which ultimately finds its way into streams and lakes?

7. Using your knowledge of how CO₂ dissolves and reacts in water, explain why global increases in atmospheric CO₂ should cause a decrease in the pH of ocean water.

8. How would counter-current selection in fish gills be beneficial for an animal trying to get rid of CO₂?

9. How might the use of isozymes permit an aquatic organism to persist with a gradual increase in thermal pollution but not a rapid increase in thermal pollution?

10. If the algae that live in corals need CO₂ as a carbon source for photosynthesis, why do scientists argue that global increases in CO₂ are playing a role in the decline in coral reefs around the world?

Biology 2601A/B Lecture Notes - Lecture 20: Boundary Layer, Root Pressure, Wind Speed

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