Excretion Flashcards
1
Q
Define excretion:
A
- Removal of waste products by an organism
- regulates internal environment:
- controls cell/body water content
- maintenance of solute composition
- excretion of metabolic waste products
2
Q
Define secretion:
A
Movement of material that has specific task after leaving the cell or organism
3
Q
Define elimination:
A
removal of unabsorbed food that has never been a part of the body (usually as facaes)
4
Q
What would happen if excretion did not occur?
A
Disruption of cell membranes, inefficient metabolism, death.
5
Q
Define passive transport:
A
- where solutes cross the membrane w/o the involvement of a specific transport system.
- movement of solutes due to a chemical gradient of a solute through osmosis and diffusion
- bacteria, fungi, some aquatic plants.
6
Q
Define the role of active transport:
A
- Systems to gain substances ___ in the opposite direction.
- Most species have specialised cells or organs that evolved to assist w/ excretion and elimination
- active transport of waste products allows for organisms to be larger and more complex in size.
7
Q
What are guard cells? Explain there function.
A
- located on the outer surface of leaves and stems.
- produce in pairs w/ a gap between them (stomatal pore).
- Involved in gas exchange and assist w/ controlling water loss.
- Stomatal pores open most when the plant has lots of water and the guard cells are swollen.
- The stomatal pores close when water availability is low and the guard cells shrink.
8
Q
What are flame cells? Explain their function.
A
- specialised excretory cells found in freshwater invertebrates.
- FC = function like a mammalina kidney (removing wastes).
- Bunelle of flame cells = protonephrida
- early animals have pro…
- later animals have more complex nephrida along with associated glands.
- vertebrates have kidneys and a liver along w/ associated glands.
9
Q
What is the coelom:
A
- Fluid filled - internal support
- separates internal processes from gut
- allows transport of fluids
- provides space for internal development of internal organs
- enables increased body size.
10
Q
Detail the excretion of protists and early euks:
A
- simple celled orgs have just the one cell to play with and there are no specialised organs
- majority of waste and biproducts of metabolism are eliminated by passive diffusion and osmosis.
- active transport of waste (chemicals) occurs through specialised membrane channels and/or are expelled directly.
11
Q
How do amoeba excrete?
A
- phagocytose food particles in a vacuole, excrete enzymes to digest it, release waste in a reverse process (exocytosis)
12
Q
Explain the process in which fungi excretes waste:
A
- specialised organs
- some waste and biproducts of metabolism are eliminated by passive diffusion or osmosis.
- Active transport of wastes occurs through specialsed cell membrane channels and are expelled directly using a comparable method to bacteri (exocytosis w/ food vacuoles, contraticle vacuoles).
13
Q
What are the 3 key mechanisms of a plant?
A
- Transpiration: waste excreted through stomata as the stem and outer surface of the stem.
- Storing: storing in bark or leaves.
- Excreting metabolic wastes through diffusion.
14
Q
Explain the process of transpiration:
A
- transpiration = day
- Guttation = night
- drops of xylem spa gather on the tips pr edges pf plants (some fungi)
- water builds up at night due to root pressure.
15
Q
Explain how waste is stored in plants:
A
- plants produce waste materials that get accumlated in the vacuoles of opening cells.
- stems, leaves, or bark of trees
- cells eventually die and fall off the plant.
- excretion gets rid of potentially toxic substances.
- can be manipulated by humans (rubber or maple syrup).
