Lab 5 - osmoregulation

Question 1

Define: osmosis

Answer 1

The movement of water molecules across a semipermeable membrane from an area of low to high solute concentration.

Question 2

Define: osmoregulation

Answer 2

The regulation of water and ion concentrations in the body.

Question 3

Osmoregulators:

Answer 3

Animals that maintain body solute concentrations different from the environment. All freshwater animals are osmoregulators and are generally hyperosmotic.

Question 4

Osmoconformers:

Answer 4

Animals that do not maintain osmotic concentrations different from the environment. Generally, the large volume of water in the ocean ensures a relatively stable environment.

Question 5

Annelids and osmoregulation:

Answer 5

Take in water through skin, produce hyposmotic urine to get rid of excess water. Metanephridia - a highly developed organ system for excretion and osmoregulation.

Question 6

Experiment 1: worm

Answer 6

Worm in different seawater concentrations. Record weight change.

Question 7

Units:

Answer 7

Convert mV to grams

Question 8

Phys sig, experiment 1:

Answer 8

Worms in low % seawater (hyposmotic) should have gotten fat.

Question 9

How to talk about osmolarity:

Answer 9

Osmolarity of SOLUTION, not of the thing in the solution.

Question 10

Experiment 2: sheep erythrocytes

Answer 10

Put sheep blood in seawater concentrations. Observe shrinking or swelling.

Question 11

Calculating cell size:

Answer 11

40 dashes = 0.1mm

Size (um) = # of dashes * 100/40

Question 12

SEM equation:

Answer 12

STDEV / √n