osmoregulation 1

Question 1

three homeostatic processes

Answer 1

osmotic regulation
ionic regulation
nitrogen excretion

Question 2

osmotic regulation

Answer 2

osmotic pressure of body fluids

Question 3

ionic regulation

Answer 3

concentration of specific ions

Question 4

nitrogen excretion

Answer 4

excretion of end-products of protein metabolism

Question 5

osmotic pressure is created by…

Answer 5

solutes

Question 6

osmosis

Answer 6

diffusion of water

Question 7

osmotic pressure

Answer 7

force associated with diffusion of water

Question 8

osmolarity

Answer 8

ability of solution to induce water to diffuse across a membrane
-determined by total concentration of dissolved particles
(see pg 29-30)
-most cells are perfect osmometers

Question 9

sea water’s % salinity

Answer 9

3.5% salinity/sea salts

Question 10

hyperosmotic solution

Answer 10

loss/outflow of water to equalize osmotic pressure

-occurs in marine environment

Question 11

hyposmotic solution

Answer 11

inflow of water to equalize osmotic pressure

-occurs more in freshwater environment

Question 12

tonicity

Answer 12

-measure of osmotic pressure gradient of two solutions separated by a semipermeable membrane
(often used when describing the response of cells immersed in an external solution, ie. hyper/hypotonic)

Question 13

osmoregulation overview

Answer 13

• animals must control extracellular environment
• individual cell control is expensive
• mostly rely on epithelial tissues to isolate cells from the external environment
• kidney is central to ion and water balance
• also rely on gills and digestive mucosa

Question 14

useful terms: apical

Answer 14

side facing external environment/lumen

Question 15

useful terms: basolateral

Answer 15

-side facing internally

Question 16

interstitial (fluids)

Answer 16

small area between cells

Question 17

solutions vs solutes vs solvents

Answer 17

solutions=solute+solvent
solutes=thing being dissolved
solvents=thing solute being dissolved into

Question 18

ionic and osmotic challenges for marine environments

Answer 18

animals tend to gain salts and lose water

Question 19

freshwater ionic and osmotic challenges

Answer 19

-animals tend to lose salts and gain water

Question 20

terrestrial ionic and osmotic challenges

Answer 20

animals tend to lose water

Question 21

importance of ionic and osmotic regulation

Answer 21

ion concentration can affect structure and function of macromolecules
-disrupts proper cellular function
cells exposed to osmotic gradients can shrink of swell
-can damage or destroy cell, cause disruptions in cell-cell communication

Question 22

regulators vs conformers

Answer 22

reg=internal environment different from external and/or internal stays stable while external changes
conformers=internal conditions similar to external conditions even when external conditions change

Question 23

ionoconformer

Answer 23

exert little control over ion profile within extracellular space
-exclusively found in marine animals, ie. many invertebrates

Question 24

ionoregulator

Answer 24

• control ion profile of extracellular space

- ie. most vertebrates

Question 25

osmoconformer

Answer 25

• internal and external osmolarity similar

- ie. marine invertebrates

Question 26

osmoregulator

Answer 26

• osmolarity constant regardless of external environment

- ie. most vertebrates

Question 27

regulation

Answer 27

• ability to cope with range of external salinities
• doesn’t tell you optimal level
• applies to both osmoconformers and regulators

Question 28

stenohaline

Answer 28

tolerate only narrow ranges

Question 29

euryhaline

Answer 29

tolerate wide ranges

Question 30

eury/stenohaline osmoregulator vs conformer graph

Answer 30

• osmoconformer on a slope, while regulator close to parallel line
• eury wider range than steno in both cases

Question 31

problems related to osmotic regulation

Answer 31

• all organisms require water
• freshwater regulators=excess water intake
• marine regulators=excess ion load
• terrestrial osmoregulators=dessication

Question 32

sources of water

Answer 32

• drinking
• dietary water (not 100% efficient, must go through digestion and hydrolysis
• metabolic water (generated from oxidative phosphorylation)

Question 33

classifying solutes by their effects on macromolecules

Answer 33

perturbing
compatible
counteracting

Question 34

perturbing colutes

Answer 34

• disrupt macromolecular function

- Na+, K+, Cl-, SO4+, charged amino acids

Question 35

compatible solutes

Answer 35

• little affect on macromolecular function

- polyols (glycerol, glucose) and uncharged amino acids

Question 36

counteracting

Answer 36

• disruption function on their own, but counteract disruptive effects of other solutes when in combination
• ie. urea and TMAO

Question 37

2 most common osmo/ionocomformers and regulators

Answer 37

Na+ and Cl-

Question 38

cell volume

Answer 38

-solutes are moved in and out of extracellular fluid (ECF) to control cell volume, with water following solutes by osmosis

Question 39

regulatory volume increase (RVI)

Answer 39

import of ions causing influx of water

-sodium, chlorine, and potassium diffusion channels

Question 40

regulatory volume decrease (RVD)

Answer 40

expulsion of ions causing efflux of water

• potassium and chlorine diffusion channels
• calcium or sodium via atp pumps

Question 41

facilitated diffusion protein types

Answer 41

channels (free diffusion) and permease (selective)