A2E Agenda:A2E Agenda:• Enzyme Function Worksheet/Activity (In IB 3406)• Brief Aquaporin Structure and Function Overview• Lab Presentations• Group Discussion of Aquaporin Readings• Aquaporin Revisited

Reminder: Bring a food sample tomorrow (soy, papaya, or corn are best) if you’d like

to test it tomorrow!

Comparing Your ModelsComparing Your Models

Comparing Comparing Your ModelsYour Models

Biological Functions of Biological Functions of Aquaporins:Aquaporins:

What do your

kidneys do?!?

Some Biological Functions Some Biological Functions of Aquaporinsof Aquaporins

Mammals have two Mammals have two kidneys, each supplied kidneys, each supplied

with LOTS of blood with LOTS of blood flow; as a result, all flow; as a result, all

blood is filtered blood is filtered ~every 30 minutes~every 30 minutes

Our kidneys can excrete Our kidneys can excrete urine 4X as urine 4X as

concentrated (1,200 concentrated (1,200 mosm/L) as our blood!mosm/L) as our blood! Image: The Biology Project

Functional Unit = the Functional Unit = the Nephron (single Nephron (single

long tubule with a long tubule with a ball of capillariesball of capillaries

Kidneys are Kidneys are compacted bundles compacted bundles of nephrons (~1.3 of nephrons (~1.3

million) all draining, million) all draining, eventually, into the eventually, into the

ureterureterImage: The Biology Project

Some Biological Functions Some Biological Functions of Aquaporinsof Aquaporins

What does Antidiuretic What does Antidiuretic Hormone (ADH) do?Hormone (ADH) do?

Note that Antidiuretic Hormone (ADH) is also known as vasopressin.

So should the cells lining the collecting ducts in your kidneys become more or less

permeable to water in response to ADH? How might they control this

permeability?

Revisiting Revisiting Aquaporin:Aquaporin: Use your understanding of protein Use your understanding of protein structure to construct a model structure to construct a model (drawing) of what a water channel in a (drawing) of what a water channel in a cell membrane would look like, and cell membrane would look like, and how it would orient itself in a plasma how it would orient itself in a plasma membrane. membrane.

Structure Structure of of

PhenylalaPhenylalanine and nine and

TryptophaTryptophann

GlycerolGlycerol