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
Aorta
-Pumps oxygenated blood from heart to body
Superior Vena Cava
-Pumps deoxygenated blood from head/arms to heart
Inferior Vena Cava
-Pumps deoxygenated blood from legs/torso to heart
Pathway of blood circulation in closed double circulation 4 chambers
- Starting from capillary beds, deoxygenated blood travels through the inferior vena cava (if coming from legs and torso) or the superior vena cava (if coming from the head and arms) to the right atrium.
- Blood moves from right atrium into right ventricle, where it is pumped through the pulmonary arteries, into the lungs.
- Pulmonary vein –>Newly oxygenated blood travels to the left atrium and then the left ventricle where it is pushed through the aorta into the capillary beds
- Repeat
Compare and Contrast Artery, Vein, Capillary
- Artery
- *S: 3 layers, relatively thick
- *F:No exchange, absorbs the most BP
- Vein
- *S: 3 layers, thinner than artery
- *F: No exchange, less BP than artery
- Capillary
- *S: 2 layers, thin basal lamina
- *F: Exchange w/ interstitial fluid
Partial Pressure
- Pressure exerted by a gas in a mix of gases
- proportional to ratio of gas composition