BCH 261 Lecture Notes - Lecture 4: Reversible Reaction, Buffer Solution, Mols
7 Jun 2018
School
Department
Course
Professor
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BCH 261 – 121 – Biochemistry
Professor Gagan Gupta
January 18, 2018
Professor:
D2L: Lecture slides will be posted two hours before lecture.
Lecture: Stop Global Warming / End World Hunger
Slide:
RuBisCO is the enzyme that catalyzes an important stop in the plant life on earth that
photosynthesizes.
Slide: Is the Dream Real?
Letter, swapped rubisco to cyanobacteria which is much more processive. They swapped it to see
if it made plants more efficient. They were able to get cyanobacteria to express in tobacco plants.
On right, normal tobacco plant. B and C are the tobacco plants transfected with genes for
cyanobacterium rubisco, even though they were able to process CO2 better, the plants aren’t
growing. They don’t know why. They only seem to grow well when CO2 levels are really high.
The rubisco isn’t holding well. They need all kinds of other chaperones inside to help it achieve
its activity.
Slide: Diffusion
Talked about the special properties of water. One phenomena important to biologists is what
water does as a solvent and how solvents behave when in water.
Diffusion occurs when movement of molecules are present in higher concentration in a region of
lower concentration until both concentrations are equal. Classical definition. Mostly seen in
gases, but happens in liquids because molecules are always moving in liquids also.
Slide: Osmosis
Special case of diffusion, defined as dealing with water. The movement of water across a
semipermeable membrane. Usually happens across a concentration gradient.
Osmosis works because water molecules can transverse through the semi-permeable membrane.
Isotonic solution – have equal amounts of solute on both sides of the membrane. When one side
has an imbalance, the side is considered hypertonic (right) versus the other hypotonic. Will get
mobility of water across the semi...membrane to try to work out the imbalance
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Slide: Osmotic Pressure
Simple apparatus for measuring osmotic pressure when you have pure water in a cube, separated
by semi-permeable membrane. Get water flowing into the tube
The distance it rises can be measured and quantified. Can also use a calibrated force measurement
– water - pushes piston out, can be measured by a sensor.
Slide: The Plasma Membrane is semi-permeable to Water
Typically your cell is more concentrated, full of ions, proteins, sugars compared to the
extracellular medium. Cell is always fighting because water wants to rush into that cell. Most
cells are actively trying to balance out osmotic pressure.
Cells are full of ‘solutes’ = high osmolality. Therefore, mammalian cells pump Na and Cl- to the
extracellular fluid to balance osmolality.
Slide: Examples of Osmosis: Root Pressure
Soil outside the root is hypotonic to the root cell so water enters by osmosis.
The whole system is connected to the leaves. You have various other pressures that help water get
into the plants, not just for osmosis.
Slide: Example of Osmosis in Action (II): Water Desalination
Reverse osmosis – trying to instead of getting osmosis occurring in one direction, you’re going
against the concentration gradient. If you have salt water you want to purify to make it less salty.
You apply pressure at A and push water against a concentration gradient through a semi
permeable filter that won’t let salt through. So on one side you have lots of salt and water, on the
other side you will have pure water. This is an expensive process.
Slide: Example of Osmosis in Action (III): “Prune Hands”??
It’s controversial, we don’t know why we get pruny hands.
As far as research goes, this isn’t complete, this paper was done by the Centre of Behaviour and
Evolution. The science is not set in stone.
Why is it so special that only your fingertips get pruny and not your whole body?
Some theories if we were drowning, pruny hands would help us grip rocks. There’s also evidence
there is a nerve impulse. Certain diseases and people with nerve damage don’t get pruny hands.
Slide: Water Ionization
Theory is if you drink non alkaline water you will be healthy.
Document Summary
D2l: lecture slides will be posted two hours before lecture. Lecture: stop global warming / end world hunger. Rubisco is the enzyme that catalyzes an important stop in the plant life on earth that photosynthesizes. Letter, swapped rubisco to cyanobacteria which is much more processive. They swapped it to see if it made plants more efficient. They were able to get cyanobacteria to express in tobacco plants. B and c are the tobacco plants transfected with genes for cyanobacterium rubisco, even though they were able to process co2 better, the plants aren"t growing. They only seem to grow well when co2 levels are really high. They need all kinds of other chaperones inside to help it achieve its activity. One phenomena important to biologists is what water does as a solvent and how solvents behave when in water. Diffusion occurs when movement of molecules are present in higher concentration in a region of lower concentration until both concentrations are equal.
