Chapter 39.1- Water and electrolyte balance

Question 1

What is osmosis?

Answer 1

the movement of water from a place of low solute to higher solute

Question 2

Is water a solute or a solvent?

Answer 2

Water is a solvent

Question 3

What is the difference between a semipermeable membrane and a selectively permeable membrane?

Answer 3

Semipermeable: allows water the pass through but not other solutes

Selectively permeable membrane: cell membranes allows certain molecules to pass through but not all

Question 4

How does water pass through cell membranes?

Answer 4

Through channels where water can flow called aquaporins

Question 5

What is osmatic pressure?

Answer 5

it is the pressure needed to prevent water from moving by osmosis across a selectively permeable membrane.

Question 6

What is the relationship between solute concentration and osmatic pressure?

Answer 6

the higher the concentration of solute the higher the osmatic pressure of water

Question 7

What are the two ways that water movement can be prevented in a cell?

Answer 7

Osmatic pressure : pressure

Hydrostastic pressure: gravity + stiffness of container walls

Question 8

When is equilibrium reached during osmosis?

Answer 8

Equilibrim is reached during osmosis when the osmatic pressure equals the amount of hydrostatic pressure

Question 9

What is osmoregulation?

Answer 9

Osmoregulation is the regulation of water in order to keep internal fluids from being too diluted or too concentrated.

Question 10

Osmoregulation is achieved by the control of

Answer 10

solutes especially electrolytes

Question 11

How does freshwater fish and terrestrial animals gain water vs lose water?

Answer 11

Gain: by drinking water with low solute concentration
(hypotonic solutions) food, cellular respiration,
freshwater fishes through their gills

Lose: Animal through urine and feces. Sweating and lung evaporation. Salt water fishes through their gills.

Question 12

How do animals, marine animals and freshwater fishes gain vs electrolytes?

Answer 12

Gain: Animals gain electrolytes through their food and marine animals through salt water

Lost: in urine and feces. Or in gills

Question 13

What are osomoconformers?

Answer 13

They keep their cells internal fluids as the same concentration of the enviorment. They go with the flow.

Question 14

What are osmoregulators ?

Answer 14

osmoregulators are animals that maintain the cell at a lower/higher concentration than the surrounding environment.

Question 15

What are the characteristics of osmoregulators? and what organisms are osomegulators?

Answer 15

• they use alot of energy in order to maintain homeostasis
• Because of homeostasis they can live in diverse environments
• most vertebrates
• freshwater fishes and terrestrial

Question 16

What are some characteristics of osomoconformers ? What organisms are osomoconformers?

Answer 16

• most invertebrates (sea stars, lobsters, mussels)
• they tend to live in enviorments where the concentration of water is stable such as sea water.
• cells are actively pumping sodium out and potassium in

Question 17

How does marine fishes osmoregulate?

Answer 17

Marine fishes osmoregulate through actively secreting salt through gills, feces, and energy pumping ions

Question 18

What are the challenges marine fishes face as osmoregulators?

Answer 18

The fish is hypertonic compared to the salt water in the environment and therefore loses a lot of water. And needs to pump out salt content.

Salt water ions move into the fish and water moves out.

Question 19

How does freshwater fishes osmoregulate?

Answer 19

• they do not drink water bc they have so much water
• they produced diluted urine
• they maintain high concentrations of electrolytes
  -they use their gills to pump chloride and sodium into the cells

Question 20

What are some challenges that freshwater fishes that osomoregulate face?

Answer 20

they are hypertonic to the enviorment so the water enters their cell and their salt ions get secreted

Question 21

How does amphibians deal with excess salt? how do land animals intake water

Answer 21

sea turtles iguanas ands sea birds have salt glands

• land animals produce concentrated urine and drink water

Question 22

How does a salt gland work?

Answer 22

• it actively pumps ions from the blood into cells that make up the glands.
• excrets salt through the gland and naval cavity
• it allows birds and reptiles to gain netw water by drinking sea water