Exam 2 Flashcards
Xylem
- transports water and minerals from roots to shoots
- Content: Waters and minerals
- Speed: faster
- Direction: up
- Purpose: Deliver water for turgid pressure, maintain photosynthesis
Phloem
- Transports photosynthates from their sources (leaves, shoots, etc.) to the roots
- Content: Photosynthates/sugar
- Speed: slow
- Direction: Multidirectional
- Purpose: sugar used in energy and ATP production, fuels respiration
Apoplast
-extracellular space, outside of cell membrane
Symplast
-all cytoplasm in the plant (including plasmodesmata)
Water Potential
- The pressure on water to move
- The sum of the solute potential and the pressure potential
- Water moves from areas with high water potential to areas with low water potential
Solute Potential
- Directly proportional to the molarity of a solution (is always negative)
- Increased absolute solute potential has a negative effect on water potential
Pressure Potential
-Physical pressure on a solution (can be positive or negative)
Bulk Flow
-Movement of water throughout a plant in response to negative pressure
Epidermal Cells
- The first barrier for water intake in roots
- Sometimes involving aquaporins
Mycorrhizae
- Mutual relationship between plant roots and fungi
- Fungi help roots gather more water and minerals by increasing surface area
Endoderm Cells
-Serve as a final checkpoint for the selective passage of minerals from the cortex into the vascular cylinder
Casparian Strip
-Waxy barrier that determines what enters the Xylem, in the Steele
Root Pressure in Transpiration
- Pushing
- Depends on pumping ions into Xylem
- Caused by increased pressure and water potential in the roots
- Aids in transport of Xylem Sap
Cohesion-Tension in Transpiration
- Pulling
- Depends on transpiration and hydrogen bonding
- Transpiration in plant leaves creates negative water potential in the shoots
- **use its cohesive properties to be pulled up
Explain how cohesion-tension arises in leaves, including the role of guard cells and negative pressure at the intra-leaf air-water interface
- Cohesion-tension occurs in leaves due to transpiration and its negating effect on water potential in the leaves
- Guard cells= responsible for opening/closing the stomata, release water, leading to transpiration
Given information about solute and pressure potential, predict whether water will move into or out of a plant cell
- Increased solute potential lessens water potential
- Positive pressure potential increases water potential
- Negative pressure potential decreases water potential.
Gastrovascular Cavity
- Coelom-like
- Involves no tissue
- Lets what freely enter/exit
Open Circulatory System
- Uses hemolymph
- Continuous w/ interstitial fluid
- Hemolymph can be used for movement
- Not efficient for maintaining high Oxygen levels
- Unable to support big animals w/ high metabolism or warm-blooded animals
- Grasshoppers, and other insects
Closed Circulatory System
- Blood does not come into direct contact with interstitial fluids
- Exchange happens across plasma membrane
- Network must be very large to reach every cell
- Good for maintaining high Oxygen levels
- Good for animals with high metabolism and warm-blood
- Ex:Earthworms, humans, etc.
- Types: single, double 3 chamber, double 4 chamber
Single Circulation
- Atrium- pumps blood from body into heart
- Ventricle- pumps blood from heart to body
- Artery- carries blood away from the heart
- Vein- carries blood towards the heart
- Capillaries
- **Plasma membranes are smaller w/ thinner membranes
- **Where exchange happens
- Moving body helps move blood to heart
Double Circulation
-Heart pumps blood to lungs and body
• 3 chambers in ectotherms
• 4 chambers in endotherms
• Constant need for Oxygen
Capillary/ Capillary Bed
- Microscopic vessels with porous walls
- Network of capillaries where exchange happens across the membrane of vessels and cells
Pulmonary Artery
-Transports deoxygenated blood from right ventricle to lungs
Pulmonary Vein
-Transports oxygenated blood from lungs to left atrium