Transport Flashcards
How is TF formed and how is it returned to the circulatory system
Formation
1. High blood / hydrostatic pressure / pressure filtration;
Forces water / fluid out;
2. Reject plasma, ignore tissue
3. Large proteins remain in capillary;
Return
4. Low water potential in capillary / blood;
5. Due to (plasma) proteins;
6. Water enters capillary / blood;
7. (By) osmosis;
7. Osmosis must be in correct context
Describe how haemoglobin loads and unloads oxygen in the blood. (4)
- Oxygen loads onto haemoglobin at high partial pressure.
- In the lungs haemoglobin has a high affinity for oxygen.
- Tissues have a low partial pressure of oxygen as it has been used in respiration.
- In tissues haemoglobin has a lower affinity for oxygen.
- Haemoglobin unloads oxygen at low partial pressure.
Co transport
- Na+ and K+ pumps use energy from atp pump out Na+ from cells into blood
Decreasing conc of Na+ in cells so higher conc in the lumen of ileum
-Na+ moves down CG from ileum lumen by facilitated diffusion
-as Na+ diffuses it brings glucose and amino acids through co-transporter proteins
-the glucose and AA move down cg from cells into blood by facilitated diffusion using carrier proteins
Describe the processes involved in the absorption and transport of
digested lipid molecules from the ileum into lymph vessels. (5)
-Micelles contain bile salts and fatty acids/monoglycerides;
-Make fatty acids/monoglycerides (more) soluble (in water)
-Fatty acids/monoglycerides absorbed by diffusion;
-Triglycerides (re)formed (in cells);
-Vesicles move to cell membrane;
Xylem
-upward transport of water and minerals from roots to leaves (transpiration)
-dead
Continuous columns
Phloem
Used for bidirectional transport of organic molecules from leaves to other plant tissues
Using ATP
translocation
-sieve tube cells living cells that join end to end to form tubes
-companion cells lots of mitochondria to provide ATP
Cohesion tension theory
How water is moved up a plant
-water evaporates through stomata form leaf
-reduces water po of leaf creating a water potential gradient from roots to leaf
-water drawn up into leaf from the xylem creating tension
-water molecules cohesive
-so whole water column is pulled upwards
-more water enters xylem through roots by osmosis
Where does gas exchange take place in a plant
Leaf spongy mesophyll
How has exchange occurs in a plant
Simple diffusion through open stomata pores
Guard cells
-Open and close the stomata to control water loss
-swell as they fill with water to open stomata pore
-shrink as they lose water to close the stomata pore
Adaptation of leaf
-waxy cuticle to stop water loss
-palisade cells at top of leaf full of chloroplast for photosynthesis
-spongy mesophyll with air spaces to allow gas exchange
-lower epidermis has lots of stomata for gas exchange
Translocation
-cells in leaf make glucose by photosynthesis
-sucrose actively loaded in sieve tube element from source cells using atp
-decreasing WP in sieve tube elements at the source
-water moves down WPG from xylem vessels into STE By osmosis
-creating high Hydrostatic pressure at source end
-sucrose forced down the STE from source towards the sink down hydrostatic pressure gradient
-sucrose actively transported down and out of STE into sink cells using ATP
-increased WP in STE at sink
-water moves back into xylem down WP via osmosis
-Hpp decreases at sink maintain hydrostatic pressure gradient
-sink cells use sucrose in respiration to make ATP or sink cells convert sucrose into glucose
