What is tonicity? Correct Answer the ability of a solution to change shape or tone of cells by altering the cells internal water volume. A solution's tonicity depends on the solution's concentration of nonpenetrating solutes (e.g., NaCl) relative to that in the cell, not on the total osmolarity of...
Bio 342 Dr. Manuela Gardner - Exam 4 Study
Guide
What is tonicity? Correct Answer ✓✓ the ability of a solution to change
shape or tone of cells by altering the cells internal water volume. A
solution's tonicity depends on the solution's concentration of
nonpenetrating solutes (e.g., NaCl) relative to that in the cell, not on the
total osmolarity of the solution. Tonicity provides the information on
how the solution affects the cell's volume
- Why does it matter if a cell is hypertonic or hypotonic?
- Water movement depends on what type of solute? Correct Answer ✓✓
- A hypertonic solution has increased solute, and a net movement of
water outside causing the cell to shrink. A hypotonic solution has
decreased solute concentration, and a net movement of water inside the
cell, causing swelling or breakage.
- Osmolarity of extracellular and intracellular fluids
What is the difference between diffusion, facilitated diffusion and active
transport? When are they used? For which substances? Correct Answer
✓✓ - Diffusion: movement of solute from an area of high concentration
to an area of low concentration across a plasma membrane, Lipid-
soluble molecules (alcohol, CO2 ) → all, hydrophobic stuff, No specific
transporters are needed, No ATP needed
- Facilitated Diffusion: Ions and small polar molecules are assisted
across the plasma membrane by a transport protein channel/ carrier.
Limited by concentration gradient and number of protein channels →
affects permeability.
No ATP needed
,Channel Mediated: ion movement is facilitated by channels
Carrier Mediated: polar molecule movement is facilitated by protein
carriers
- Active transport: movement of a substance against its concentration
gradient via a protein pump
Na+/K+ ATPase/pump moves 3 Na+ out of the cell and 2 K+ into the
cell. An enzyme that moves ions via hydrolysis of ATP
What is hydrolysis? Correct Answer ✓✓ A chemical reaction in which a
compound is broken down into smaller molecules by reacting with
water.
why do we need O2? and how is it transported in the Blood? Correct
Answer ✓✓ We inhale due to Cellular Respiration and oxidative
phosphorylation needing Oxygen.
Solubility of O2 in aqueous solutions is low
Respiratory Pigments help to increase the amount of O2 in the blood
By binding oxygen to carriers, PO2 in the blood remains low →
improved O2 Extraction
Contains metal ions
Gives them a strong color
Oxygen binds reversibly to the metal ion
Bind to pigment at the lungs
Releases from the pigment at the tissues
, Why do we need to get rid of CO2? What happens to pH if we have too
much CO2? Correct Answer ✓✓ Because it's toxic and it takes up the
carrying capacity of the blood and O2 wouldn't be able to travel through
the body.
Increase in CO2, increases Hydrogen concentration → lowering the pH
How is pH measured? Which organs help you to maintain pH
homeostasis? Correct Answer ✓✓ measured by Hydrogen Atoms →
more H+, more acidic.
- The lungs help maintain pH homeostasis by inhaling and exhaling
- The kidneys, pee out or keep hydrogen atoms and bicarbonate, the
cardiac system, transports carbon dioxide and hydrogen ions as HCO3-
- The digestive system absorbs hydrogen ions
- Skeletal, buffers blood against excess pH.
How is the resting potential determined? Which ions are involved?
Which transporters? Correct Answer ✓✓ difference an ion
concentration of intracellular and extracellular fluid and permeability of
plasma membrane to different ions. Cl-, K+, and Na+ are the ions
involved, and the Na+/K+ ATPase pump is the transporter.
What does the Na+, K+ ATPase do? Why is it important? Correct
Answer ✓✓ Transports 3 Na+ out of the cell, and 2 K+ into the cell
against the gradient secondary active transport, also helps maintain
electrical charge and resting potential within the cell.
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