Lect 1 biochemiical
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1) Biophysics is the science that explains biological systems and processes using the principles of physics. It spans scales from molecules to whole organisms. 2) Key biological processes like diffusion, osmosis, viscosity and surface tension are governed by fundamental physics laws and concepts. Diffusion is the net movement of particles from an area of higher concentration to lower concentration down a concentration gradient. Osmosis is the movement of water molecules through a partially permeable membrane from a solution of higher water potential to lower water potential. 3) Diffusion and osmosis play important roles like facilitating the movement of substances into and out of cells. The behavior of plant and animal cells differs when placed in solutions of varying water potentials due
![When the roots begin to sense a water shortage
in the soil, abscisic acid (ABA) is
released.[6] ABA binds to receptor proteins in
the guard cells' plasma membrane and cytosol,
which first raises the pH of the cytosol of the
cells and cause the concentration of free
Ca2+ to increase in the cytosol due to influx
from outside the cell and release of Ca2+ from
internal stores such as the endoplasmic
reticulum and vacuoles.[7] This causes the
chloride (Cl-) and inorganic ions to exit the
cells. Second, this stops the uptake of any
further K+ into the cells and, subsequently, the
loss of K+. The loss of these solutes causes an
increase in water potential, which results in the
diffusion of water back out of the cell
by osmosis. This makes the cel lplasmolysed,
which results in the closing of the stomatal
pores.
An open stoma (a) and a
closed stoma (b)
1 Epidermal cell
2 Guard cell
3 Stoma
4 K+ ions
5 Water
6 Vacuole](https://image.slidesharecdn.com/lect1biochemiical-141118114128-conversion-gate02/85/Lect-1-biochemiical-35-320.jpg)
Lect 1 biochemiical
- 1. BCH 504 Analytical and Biochemical Techniques (2+1)
- 2. What is “Biophysics” Biophysics is a specialized sub area of biology It is the science of physical principles of life itself and of biological systems. Biophysics is an interdisciplinary science that explains the laws and principles of physics which govern various biological processes. Biophysics spans all levels of biological organization from molecular scale to whole organism
- 3. Biological activities happening in different organs of living body like kidney, liver, heart, lungs as well as those in intracellular and extracellular biological fluid are governed by fundamental laws of physics namely Diffusion Osmosis Viscosity Surface Tension
- 4. Movement of Substances Diffusion Osmosis
- 5. Diffusion
- 6. Lets Recap from Chemistry… 3 particle states of matter Diffusion What is the particle arrangement and motion? Solid Liquid Gas
- 7. Diffusion Definition: The net movement of particles from a region of higher concentration to a region of lower concentration, down the concentration gradient. High concentration Low concentration
- 8. Diffusion in liquid state : Ink dye : Water molecules
- 9. Diffusion in liquid state : Ink dye : Water molecules
- 10. Diffusion in gaseous state : Perfume molecules : Air molecules
- 11. Diffusion in gaseous state : Perfume molecules : Air molecules
- 12. Net Movement Note: This barrier does not illustrate a partially permeable membrane.
- 13. Net Movement
- 14. Equilibrium When particles reaches an equilibrium, does the particles stop moving? Hint: Particles move in a random and dynamic motion.
- 15. Concentration Gradient The concentration difference between regions of high concentration and low concentration. High concentration gradient Down the concentration gradient Low concentration gradient
- 16. Concentration Gradient Which slide will allow you to go down faster? A B Answer: A
- 17. Concentration Gradient The steeper the concentration gradient, the faster diffusion takes place Steeper concentration gradient Fast rate of diffusion Less steep concentration gradient Slow rate of diffusion
- 18. Which graph will result in the fastest rate of diffusion? A B C D
- 19. Factors that affects the rate of substance movement… Cross-sectional area through which diffusion occurs Temperature Molecular weight of a substance Distance through with diffusion occurs Concentration gradient
- 20. Examples Movement of substances in and out of amoeba cells Movement of CO2 and O2 in and out of lung cells Movement of nitrates in and out of root hair cells
- 21. Movement of Substances Diffusion Osmosis Net movement of particles from a region of high concentration to a region of low concentration, down the concentration gradient. includes definition Key Ideas: 1) Liquid/ Gas particles move from region of high concentration to low concentration 2) Movement of particles is random and dynamic in equilibrium (net) 3) Concentration gradient 4) Examples of diffusion
- 22. Osmosis
- 23. Osmosis Definition: The movement of water molecules through a partially permeable membrane from a solution of high water potential, to a solution of lower water potential. Partially permeable membrane : sucrose :water molecules
- 24. Partially Permeable Membrane Permeable Membrane •Allows both the solvent (water) and the solutes ( dissolved substances to pass through) •Equal concentration of all ions in both sides of the membrane. •Eg: Cell Wall of plant cells •Allows some substances to pass through but not others. •Unequal concentration of ions in both sides of the membrane •Eg: Cell membrane in plant and animal cells.
- 25. The movement of water molecules through a Partially permeable membrane : sucrose :water molecules partially permeable membrane •Only water molecules passes through the partially permeable membrane (sucrose solution too big to pass through the partially permeable membrane).
- 26. Water Potential Water potential is the measure of the tendency of water to move from one place to another. Dilute Solution: High water potential Concentrated Solution: Low water potential Same concentration: Equal water potential Water potential Gradient: Water molecules move from a high water potential to a lower water potential.
- 27. From a solution of high water potential, to a solution of lower water potential. •Only water molecules passes through the partially permeable membrane (sucrose solution too big to pass through the partially permeable membrane). : sucrose :water molecules Partially permeable membrane High water potential Low water potential Movement of water molecules
- 28. From a solution of high water potential, to a solution •Only water molecules passes through the partially permeable membrane (sucrose solution too big to pass through the partially permeable membrane). : sucrose :water molecules of lower water potential. Partially permeable membrane Raised water level
- 29. Hypotonic Vs Hypertonic Higher water potential compared to _____/ Lower water potential compared to ____ : sucrose :water molecules Used to compare 2 solutions. Hypotonic to ____ / Hypertonic to _____. *Isotonic: Same water potential x y High concentration of sucrose : Low water potential X is Hypotonic compared to y Low concentration of sucrose : High water potential Y is Hypertonic compared to x
- 30. Osmosis in living organisms Plant Cells Animal Cells Plant cell behaves differently from animal cell when placed in solutions with differing water potentials. •Due to presence of cell wall in plants.
- 31. Osmosis in plant cell Fully permeable: allows most dissolved substances to pass through Cell surface membrane is a partially permeable membrane
- 32. Plant cell in High water potential 1. Cell vacuole has lower water potential compared to solutions outside cell 2. Water enters cell by osmosis. 3. Vacuole increases in size, pushes against cell wall 4. Cell wall exerts opposing pressure (against turgor pressure) 5. Plant cell expands and become turgid (cell does not bursts) Turgor
- 33. Why is turgor important? Maintain the shape of soft tissues in plants Able to remain firm and erect because of turgor pressure. High rate of evaporation of water from cells. Lose turgidity and will wilt. Movement of plant parts Flowers open during the day and close at night Changes in the turgidity of the plants on the opposite surfaces of the petals Mimosa plants Opening and closing of stomata due to changes in turgidity in guard cells.
- 34. When conditions are conducive to stomatal opening (e.g., high light intensity and high humidity), a proton pump drives protons (H+) from the guard cells. This means that the cells' electrical potential becomes increasingly negative. The negative potential opens potassium voltage-gated channels and so an uptake of potassium ions (K+) occurs. To maintain this internal negative voltage so that entry of potassium ions does not stop, negative ions balance the influx of potassium. In some cases, chloride ions enter, while in other plants the organic ion malate is produced in guard cells. This increase in solute concentration lowers the water potential inside the cell, which results in the diffusion of water into the cell through osmosis. This increases the cell's volume and turgor pressure. Then, because of rings of cellulose microfibrils that prevent the width of the guard cells from swelling, and thus only allow the extra turgor pressure to elongate the guard cells, whose ends are held firmly in place by surrounding epidermal cells, the two guard cells lengthen by bowing apart from one another, creating an open pore through which gas can move. An open stoma (a) and a closed stoma (b) 1 Epidermal cell 2 Guard cell 3 Stoma 4 K+ ions 5 Water 6 Vacuole
- 35. When the roots begin to sense a water shortage in the soil, abscisic acid (ABA) is released.[6] ABA binds to receptor proteins in the guard cells' plasma membrane and cytosol, which first raises the pH of the cytosol of the cells and cause the concentration of free Ca2+ to increase in the cytosol due to influx from outside the cell and release of Ca2+ from internal stores such as the endoplasmic reticulum and vacuoles.[7] This causes the chloride (Cl-) and inorganic ions to exit the cells. Second, this stops the uptake of any further K+ into the cells and, subsequently, the loss of K+. The loss of these solutes causes an increase in water potential, which results in the diffusion of water back out of the cell by osmosis. This makes the cel lplasmolysed, which results in the closing of the stomatal pores. An open stoma (a) and a closed stoma (b) 1 Epidermal cell 2 Guard cell 3 Stoma 4 K+ ions 5 Water 6 Vacuole
- 36. Plant cell in Low water potential 1. Vacuole has higher water potential compared to solution outside cell. 2. Water leave cells by osmosis 3. Vacuole decreases in size 4. Cytoplasm shrinks away from cell wall ( Plasmolysis.) Can be restored to original state. How?
- 37. Plasmolysis Causes tissue to be limp or flaccid Cells will be killed if remain plasmolysed too long Not advisable to add too much fertilisers. Why? How to reverse this?
- 38. Osmosis in living organisms Plant Cells Animal Cells Plant cell behaves differently from animal cell when placed in solutions with differing water potentials. •Due to presence of cell wall in plants.
- 39. Animal cell in High water potential 1. Cytoplasm has lower water potential compared to solution outside cell 2. Water enters by osmosis 3. Animal cell will swell and may bursts as it does not have a cell wall to protect it.
- 40. Animal cell in Low water potential 1. Cytoplasm has higher water potential compared to the solution outside the cell. 2. Water leaves by osmosis 3. Cell shrinks and little spikes appear on cell surface membrane. (Crenation)
- 41. What if cell placed in isotonic solution?
- 42. lol
- 43. Factors that affects the rate of diffusion… Concentration/Water potential Gradient Cross-sectional area through which diffusion occurs Temperature Molecular weight of a substance Distance through with diffusion occurs
- 44. Why do you think cells are so small??? Why most large organisms are multi-cellular and not unicellular?
- 45. Surface Area to Volume Ratio Affects rate of movement of substances across cell surface membranes. “The greater the surface area of cell surface membrane to per unit of volume, the faster the rate of diffusion of a substance for a given concentration gradient.” ???
- 46. Surface area to volume ratio Which one has a bigger surface area?
- 47. Surface area to volume ratio The larger the surface area to volume ratio, the faster the rate of substance movements. Cells adaptations for better absorption of materials. (increased surface area) Root hair cells Epithelial cells of small intestine Red blood cells
- 48. Movement of Substances Diffusion Osmosis Active Transport Net movement of particles from a region of high concentration to a region of low concentration, down the concentration gradient. includes definition Key Ideas: 1) Liquid/ Gas particles move from region of high concentration to low concentration 2) Movement of particles is random and dynamic in equilibrium (net) 3) Concentration gradient 4) Examples of diffusion definition The movement of water molecules through a partially permeable membrane from a solution of high water potential, to a solution of lower water potential. Key Ideas: Opposites! 1) Only water molecules 2) Partially permeable membrane 3) High water potential to low water potential 4) Hypertonic & hypotonic 5) Osmosis in living cells 6) SA to Vol ratio 7) Adaptations
- 49. Movement of Substances Diffusion Osmosis Active Transport Net movement of particles from a region of high concentration to a region of low concentration, down the concentration gradient. includes definition Key Ideas: 1) Liquid/ Gas particles move from region of high concentration to low concentration 2) Movement of particles is random and dynamic in equilibrium (net) 3) Concentration gradient 4) Examples of diffusion definition The movement of water molecules through a partially permeable membrane from a solution of high water potential, to a solution of lower water potential. Key Ideas: 1) Only water molecules 2) Partially permeable membrane 3) High water potential to low water potential 4) Hypertonic & hypotonic 5) Osmosis in living cells 6) SA to Vol ratio 7) Adaptations definition Energy is used to move particles against concentration gradient ( from a region of low concentration to a region of higher concentration) , up a concentration gradient. Key Ideas: 1) Requires energy 2) From low to high 3) Only in living cell 4) Active transport in living cells
Editor's Notes
- #20: *Temperature The higher the temperature the higher the rate of diffusion. *Presence of organic solvents They dissolve the phospholipid bi-layer allowing more substance out. A high amount of organic solvent will break the membrane down completely. *Concentration gradient The larger the difference in concentration of a substance in and out of a cell the higher the rate of diffusion. *Membrane thickness The thinner the membrane the higher the rate of diffusion because the molecules have less of a distance to travel. *pH The more extreme the pH the less the amount of large and polar molecules and ions pass the membrane as the pH denatures the specific shape of the carrier and channel proteins. *Surface area available The more surface area compared to volume the higher the rate of diffusion. *More ATP production More active transport so more molecules moved from lower concentration to higher concentration. *Respiratory inhibitor present like cyanide Less active transport.
- #34: The leaves also close under various other stimuli, such as touching, warming, blowing, or shaking. These types of movements have been termed seismonasticmovements. The movement occurs when specific regions of cells lose turgor pressure, which is the force that is applied onto the cell wall by water within the cell vacuoles and other cell contents. When the plant is disturbed, specific regions on the stems are stimulated to release chemicals including potassium ions which force water out of the cell vacuoles and the water diffuses out of the cells, producing a loss of cell pressure and cell collapse; this differential turgidity between different regions of cells results in the closing of the leaflets and the collapse of the leaf petiole.
- #47: Surface area =6a2