Compare and contrast the structure and function of the osmoregulatory organs of flatworms, earthworms, and insects, detailing where and how the processes of filtration, reabsorption, secretion, and excretion occur.

●Flatworm

Protonephridia: this are tubes that branch all through the body into bulb-like flame cells; only open to exterior and not the interior of the body; cilia take in fluid from the body; it helps in preventing loss of ions

Reabsorption of water and metabolic waste product

Excretion is aided by excretory pores

●Earthworms

(Meta)nephridia: its tube system open to both inward and outside area of the body; it iundergies the closed circulatory system

Filtration: derive fluid in coelom via nephrostomes (bigger molecules are not included)

Reabsorption of salt takes place in nephrostomes

Nephrostomes is also involved in secretions.

Excretion: urine is excreted through the nephridiopores

●Insects

Malpighian tubules: it is a continuation of digestive tract that branch off; urine is not produced by filtration due to the fact that no pressure difference (open circulatory system) occurs admist the blood in body cavity and tubules; and can preserve water till a large degree.

Reabsorption: water and K+ is recollected into circulatory system through the tubules.

Secretion will result in water absorption through osmosis

Secretion: substances such as waste molecules, Na+, and K+ have an inflow into the tubules through active transport

Excretion of small molecules and waste products take the appearance of feces

answers are:

lysogenic     viral dna merges with host cell dna

lysogenic     no symptoms

lytic               viral dna takes over

lysogenic     virus does not destroy host cell

lytic               virus destroys host cell

lytic               induces symptoms of viral infection

lysogenic       cell reproduces and spreads provirus