1
Biology 112
Please pick up a half sheet of paper
Ready your clickers
P t
l
t
h
t
t
t
Put away laptops, phones, etc etc etc.
(thanks)
Questions from last time?
Replicating thing criteria as applied to cells:
Have a container
Membranes (wall)
Gather raw material
Gather or make parts
Gather and transform energy
All done by proteins
Have a set of instructions
DNA
Pass instructions to replicas
Proteins and DNA
Mechanism to read the instructions
RNA and proteins
Let’s Talk Diffusion
Diagram shows computer
Simulation of diffusion
(random motion) of 400 black
dots.
Assume that the dots
represent molecules dropped
represent molecules dropped
into a liquid.
What causes diffusion?
Let’s Talk Diffusion
Expected answer:
“Two properties are at
work:
1.
The molecules are
moving (kinetic
energy)
2
The system will
2.
The system will
spontaneously tend
towards more
randomness, as
described by the
Second Law of
Thermodynamics. “
1.
The mass of the diffusing particle.
2.
The size of the space the particle is diffusing through.
3.
The number of molecules that are in the middle initially.
4.
The temperature of the system.
Consider a repeat of the diffusion
experiment. Which of the following will
affect
the rate each particle diffuses
?
AA
5.
The characteristics of the space the particle is diffusing through.
A.
All 5 characteristics
B.
Only 2 and 4
C.
Only 1, 3 and 5
D.
Only 1, 4 and 5
E.
Only 2, 3 and 4
Add a drop of
water soluble
dye to the water layer
water
Non-aqueous
oil
What’s the barrier?

This preview has intentionally blurred sections.
Sign up to view the full version.

This is the end of the preview.
Sign up
to
access the rest of the document.
- Winter '04
- BENBASAT
- Biology, Membranes, Chemical polarity
-
Click to edit the document details