2-excretion Flashcards
Q: Why do plants need to excrete waste products?
A: Metabolic reactions in plant cells produce waste products like O₂, CO₂, water, and other chemicals that must be removed.
Q: What are the main excretory products in plants?
A: Oxygen, carbon dioxide, water vapour, and unwanted chemical substances.
: How does light intensity affect gas exchange in plants?
A:
Daytime: Photosynthesis > respiration → Oxygen is in excess (waste).
Nighttime: No photosynthesis → Carbon dioxide is in excess (waste).
Q: How are gases excreted from the plant?
A: Through the stomata by diffusion.
Q: Is excretion in plants an active or passive process?
A: Passive; gases diffuse out without using energy.
Q: What happens to unwanted chemicals in plants?
A: Stored in dying tissues (like autumn leaves) and removed when these fall off.
Q: What is excretion?
A: The removal of waste products of metabolism, toxic materials, and substances in excess from the body.
Q: What are the main metabolic waste products in humans?
A:
Carbon dioxide & water from respiration
Urea from excess amino acids (in the liver)
Excess substances like drugs and salts
Q: Why must waste products be excreted?
A:
Toxicity: They can harm the body.
pH Imbalance: CO₂ lowers pH, reducing enzyme activity.
Osmotic problems: Can cause dehydration by drawing water out of cells.
Storage issues: Waste takes up space needed for essential molecules.
Q: What’s the difference between excretion and egestion?
A:
Excretion: Removal of metabolic waste from cells.
Egestion: Removal of undigested food through the anus.
Q: What organs are involved in human excretion?
A:
Kidneys: Excrete urea, water, and excess salts in urine.
Lungs: Excrete carbon dioxide and water vapour.
Skin: Excretes urea, mineral ions, and water via sweat.
Q: Where is urea produced?
A: In the liver, from the breakdown of excess amino acids.
Q: How does the skin act as an excretory organ?
A: Sweat glands remove urea, salts, and water.
