Exchange in Plants and Animals Flashcards
How do root hair cells exchange things?
- They use active transport to actively transport nutrients from the soil into the root hair cell
- The concentration of minerals is higher in the root hair cell than the soil so respiration and active transport need to be used
How do humans use exchange in the gut?
- Nutrients in the gut are actively transported into the blood
How does gas exchange happen in the lungs?
Alveoli have:
- Large surface area
- Moist
- Thin walls
- Rich blood supply
How does exchange happen in fish?
- Water (containing oxygen) enters the fish through the mouth and passes through the gills. As this happens, oxygen diffuses from the water into the blood in the gills and carbon dioxide diffuses from the blood into the water.
- The blood flows through the lamellae in one direction and water flows in the opposite direction. This helps maintain a large concentration gradient.
Which structure in fish gills increases surface area?
Lamellae
What are the characteristics of lamellae?
Same as villi
What is phloem and describe what it transports and what is it called?
Elongated living cells joined end to end with perforated end walls to allow the movement of cell sap (dissolved sugars). The cell sap is transported from the leaves to other growing parts of the leaves for immediate use or for storage. The transport is in both directions. The movement of food substances in phloem is called translocation.
What is xylem and what is the movement of it called?
Made from dead cells strengthened by lignin. Carry water and mineral ions from the roots to stems and leaves. The movement of water from the roots through the xylem and out of the leaves is called the transpiration stream.
What is transpiration?
The loss of water from the leaves. This happens because the leaves are adapted to gas exchange so they have stomata for ease of gas exchange. The leaves have a higher concentration of water than the air outside so the water diffuses from the leaves into the air. This causes a slight loss of water. So water is sent to the leaves from the roots and through the xylem to the leaves.
What is the structure of the leaf and what does each structure do?
Waxy cuticle - Decreases amount of diffusion of water
Upper epidermal tissue - most of the plant is covered in this, the upper epidermis is transparent so light can get to the palisade mesophyll
Palisade mesophyll - Most of photosynthesis happens, has lots of chloroplasts
Spongy mesophyll - Airy part of leaf. Increases the rate of diffusion of gases
Meristem tissue - differentiates into other types of cells
Lower epidermal tissue - full of stomata which let CO2 diffuse into the leaf. The opening and closing of stomata is controlled by guard cells depending on the environment.
What goes in and out of the stomata?
Water, oxygen and carbon dioxide
How do the stomata open and close?
If the plants have lots of water the guard cells absorb the water and become big and open the stomata. When there isn’t much water the guard cells become flaccid and the stomata close. This is to stop too much water from being lost. There is more stomata on the underside of the leaf. The guard cells have a thinner outer wall and a thicker inner wall to make the opening and closing work. They’re also affected by light and close at night to save on water.
What does the small intestine do?
Absorbs minerals and water
What does the large intestine do?
Absorb excess water
