Excretory System - SS2 Biology Past Questions and Answers - page 2
Which process involves the elimination of metabolic waste products in urine for mammals?
Transpiration
Osmoregulation
Micturition
Which excretory organ in flowering plants allows for the removal of waste products from the plant cells?
Stomata
Xylem vessels
Phloem tubes
Discuss the process of excretion in living organisms. What are the main waste products generated and how are they eliminated?
Excretion is the process by which organisms eliminate waste products generated through metabolic processes. Common waste products include carbon dioxide, urea, uric acid, and excess water. In organisms such as humans and mammals, excretion primarily occurs through the urinary system, which filters blood and eliminates waste in the form of urine. In insects, malpighian tubules remove metabolic waste and maintain water balance, while earthworms use nephridia for excretion. Plants excrete waste products through various mechanisms, such as the stomata on leaves for the release of gases and the shedding of leaves for the disposal of waste substances.
Describe the excretory system of earthworms. How do earthworms remove waste products from their bodies?
Earthworms possess a network of excretory organs called nephridia. Nephridia filter waste materials, excess water, and metabolic by-products from the coelomic fluid. These waste products are then transported through tubules and excreted through pores located on the surface of the body. Nephridia also play a role in maintaining osmotic balance within the earthworm's body.
Explore the excretory system of flatworms. How do flatworms eliminate waste and maintain osmotic balance?
Flatworms, such as planarians, utilize specialized excretory structures called flame cells or protonephridia. Flame cells contain cilia that beat to create water currents within the worm's body. These cells filter waste materials and excess water from the interstitial fluid, and the waste products are eliminated through excretory pores. Flame cells also assist in osmoregulation, ensuring the proper balance of ions and water within the flatworm's body.
Discuss the excretory system of insects. How do insects eliminate waste products and regulate water balance?
Insects have a unique excretory system consisting of Malpighian tubules. Malpighian tubules remove nitrogenous waste, such as uric acid, from the hemolymph by actively transporting it into the tubules. These tubules also play a crucial role in regulating water balance. They actively transport potassium ions into the tubules, creating an osmotic gradient that drives the reabsorption of water from the hindgut back into the insect's body, effectively conserving water.
Describe the excretory system of mammals. How do mammals eliminate waste and maintain homeostasis through their kidneys?
Mammals possess a complex excretory system centered around the kidneys. The kidneys filter waste products, excess water, and ions from the blood to produce urine. The urine is then transported through the urinary tract and eliminated from the body. The kidneys also play a vital role in maintaining homeostasis by regulating the balance of electrolytes, pH levels, and water reabsorption.
Explore the mechanisms of excretion in flowering plants. How do plants eliminate waste products and maintain internal balance?
Flowering plants utilize various mechanisms for excretion. One significant process is transpiration, where excess water and certain waste substances are released as water vapor through the stomata on leaves. Plants also eliminate waste products through the shedding of leaves and bark. Additionally, some waste materials are stored in vacuoles within plant cells, isolated from the rest of the plant's tissues.