Osmoregulation and Ion regulation Lecture 1

Question 1

Physiology:

Answer 1

Study of an organisms vital functions

Question 2

Define osmolytes:

Answer 2

Any solution that affects osmotic properties.

Question 3

Three types of osmolytes:

Answer 3

1. ) Carbohydrates (sorbitol)
2. ) Amino acids and their derivatives (proline)
3. ) Methylamines (TMAO)

Question 4

Do most ions affect or not affect protein functions?

Answer 4

affect!

Question 5

Obligatory exchange of water happens how?

Answer 5

Through integument(skin), feeding, excretion and respiration.

Question 6

Some cells from the loop of Henle are exposed to environments with varying osmotic concentration over time that can range from 600-1200 mOsm. What physiological mechanism allows these to survive these changes in the osmotic environment?

Answer 6

Different concentration gradients!!!!

Question 7

Why does osmoregulation matter? 2 points.

Answer 7

1) Proteins structure and function is affected by the osmotic concentration of their environment (e.g. cytosol)
•Hofmeister series
2) The volume of cells is affected by changes in the osmotic concentration of their environment

Question 8

What is the fundamental and chemical reason why water loss is a problem?

Answer 8

Organic molecules function in that water! When the amount of water changes there is a change in ion concentrations across the environment. Protein function is affected by ion concentrations and functions within a narrow range of ion concentrations

Question 9

What is the Hoffmeister Series?

Answer 9

The Hofmeister series series is a classification of ions in order of their ability to salt out or salt in proteins. The effects of these changes were first worked out by Franz Hofmeister, who studied the effects of cations and anions on the solubility of proteins.

Question 10

What is the least affecting salt and proteins?

Answer 10

Pottasium, if you have a lot of it thought it will affect it!

Question 11

No one has ever discovered a water pump in cells, what implications does this have for the cell?

Answer 11

So most cells suffer when water is missing in the plasma. Cells are able to maintain ionic difference across the cell membrane but not osmotic difference.

Question 12

Osmolarity:

Answer 12

Is the measure of solute concentration

Question 13

What happens when there are changes in osmolarity?

Answer 13

causes a trans membrane osmotic gradient and therefore water moves across the membrane affecting cell volume.

Question 14

Isontonic:

Answer 14

Same concentrations in and outside of bag

Question 15

Hypertonic:

Answer 15

Water rushes out!

Question 16

Hypotonic:

Answer 16

Water rushes in!

Question 17

A 2M sucrose solotuion in a bag with a semi-permeable membrane is put into distilled water, what happens?

Answer 17

Water rushes in! Distilled water is hypotonic to the bag!

Question 18

A 2M sucrose solution in a bag with semi-permable membrane is put into 10 M solution water. What happens?

Answer 18

Water rushes out of the bag

Question 19

When cells have osmotic stress they start to have volume problems. That sucks! How have they evolved to fight back?

Answer 19

By transporting ions! In hypotonic situations they pump ions out! In hypertonic situations they pump ions in.

Question 20

What ions are lost in hypotonic situation?

Answer 20

K and Cl

Question 21

What ions are taken in during hypertonic situations

Answer 21

Na, K and Cl

Question 22

Perturbing osmolytes:

Answer 22

disrupt metabolism when they are in high concentration or when large shifts in their concentrations occur
–e.g. Urea

Question 23

Compatible osmolytes:

Answer 23

Do not affect protein function

–e.g. glycine, proline, inositol and sorbitol

Question 24

Osmoconformers:

Answer 24

Body fluids and cells are equal in osmotic pressure to the environment,
Mainly found in the oceans, where osmolarity averages 1000 mOsm

Question 25

Osmoregulators:

Answer 25

Osmotic pressure of body fluids is homeostatically regulated and usually different from the external environment