Lab Exam 1 Flashcards
What is the most common microscope in a classroom?
Compound or light microscope
What is the magnification range of a compound/ light microscope? What are the specimens required?
40x-1000x magnification. Thin, 2D specimens required.
What is the magnification of a scanning electron microscope? What kind of images does it produce?
Up to 10,000,000x magnification! Provides surface image of 3D specimens.
What is the magnification of a transmission electron microscope? What images does it provide?
Up to 10,000,000x magnification. 2D image of intracellular structures
What are osmotically active solutes? What is tonicity?
Solutes that cannot pass through the membrane (are “stuck”) will therefore influence the movement of water. These solutes exert an osmotic pressure on water, which pulls water toward them.
What is the difference between molarity and osmolarity?
Molarity is the number of moles of solutes per liter of liquid, whereas osmolarity is the number of osmotically active particles per liter of liquid.
How is molarity calculated, and how do we use dimensional analysis to convert units?
Molarity is moles per liter (mol/L), so we calculate the number of moles with the given gram divided by the substance’s molar mass and then divide it by how many liters of the substance we have. Always cancel units.
•Where are some key ions more concentrated? Inside or outside the cell?
Cl- is more concentrated outside the cell
Ca2+ is more concentrated outside the cell
Na+ is more concentrated outside the cell
K+ is more concentrated inside the cell
What is osmotic equilibrium? What does this movement affect?
Equal solution concentration on either side of the membrane. This movement affects the structure and function of cells.
Define diffusion
The movement of solute from a place of higher to lower concentration. If the solute can move through the membrane (perhaps it is a nonpolar steroid hormone, fatty acid, O2gas, or CO2gas), it will do so by the process of diffusion.
What is osmosis?
The movement of water across a membrane to maintain equal concentration of solutions on either side (osmotic equilibrium). If the solute CANNOT pass through the membrane (perhaps it is a polar carbohydrate or an ion like Na+), but water can, WATER will move by the process of osmosis to establish equal solution concentration of either side of the membrane.
What is the molarity of a solution that contains 10 grams of glucose (C6H12O6) in 1 dL of water?
10g / 1dL x 1 mol/180.00g x 1dL/10^-1L = 0.056M
Canceled units can’t be shown when typed, but always cancel units.
What is molarity?
The measure of concentration that indicates the number of moles of solute added to a solvent (always water for us) to end up with 1 liter of solution (Units: M = moles/L). Molarity is like a recipe for how to mix up a given solution
TRUE OR FALSE: Molarity does not tell you ANYTHING about how many osmotically-active solutes are actually in a solution, BECAUSE sometimes molecules break apart when added to water and sometimes they don’t
True
What is osmolarity?
Osmolarity measures the number of osmotically-active solutes in a solution. It measures solution concentration in terms of the number of osmotically-active solutes in solution. Osmolarity = osmoles of solute/1L of water. Not all solutes are equal when it comes to osmolarity - it depends on whether they dissociate in water or not.
If you put 1 mole of CaCl2 (an ionic molecule) into water, how many osmoles of solutes would you have?
Three osmoles of solutes
What are the common units of osmolarity?
OsM= osmoles/L
mOsM= milliosmoles/L
What is the cell membrane lipid bilayer permeable to?
•Nonpolar (hydrophobic) solutes
•Steroid hormones (testosterone, estrogens, etc.)
•Other lipid molecules (fatty acids, eicosanoids, etc.)
•Non-polar molecules, like gases (O2, CO2, NO, etc.)
•Small polar molecules with no net charge
•Water
What is the cell membrane lipid bilayer impermeable to?
•Polar (hydrophilic) or charged solutes
•Large polar molecules (proteins, carbohydrates, etc.)
•Ions (e.g., Na+, Cl-, K+, Ca2+, H+, HCO3-, etc.)
What is crenation?
When water is pulled out of a cell by osmosis, the cell become shriveled.
What is hemolysis?
When water rushes into an RBC by osmosis.
Describe each level of protein structure.
•Primary - 20 amino acids joined by peptide bonds create a “Beads on a string” look, called a peptide chain.
•Secondary - Formed by hydrogen bonds between adjacent chains or loops. Most commonly alpha-helices or beta pleated sheets.
•Tertiary - The protein’s three-dimensional shape. Determined by many different types of bonds, including disulfide bonds.
•Quaternary - made up of more than one polypeptide chain aka subunits.
What are ligands?
Proteins bind to some sort of “stuff” (i.e., molecules or ions) to do their work. Those molecules or ions are technically called ligands. Proteins have specific binding sites (also called active sites) on their surface to physically interact with their
ligand(s).
What are substrates?
Ligands that bind to and are acted upon by enzymes or membrane transporters are more specifically called SUBSTRATES. The protein-substrate complex will have a different chemical structure (e.g., areas indicated by white dashed circles) than when the two components were separate. Therefore, the complex will have a new and exciting function!
What are factors that alter the activity of a protein are called?
MODULATORS –> Can be either ACTIVATORSor INHIBITORS
What are two examples of environmental modulators
Temperature and pH.
Name the “fun facts” about enzymes.
- Most names end in “-ase”
- Speed up chemical reactions by lowering activation energy
- Are proteins
- Can be modulated
- Can be re-used.
- Act on specific substrates.
- Names often reflect what they do and what they act on
- Not changed by the chemical reaction
How do enzymes speed up chemical reactions?
By lowering activation energy
What type of biomolecule is starch?
carbohydrate
This type of protein is required to move certain substances from one side of a cell membrane to another.
Membrane transporters
Genes are turned on or off by these proteins.
Regulatory proteins.
Some immune system cells produce these proteins that bind to pathogens and mark them for destruction.
Immunoglobulins.
This type of protein, secreted by one cell and binding to another, serves an important role in cell-to-cell communication.
Signal molecules.
These proteins bind signal molecules and begin the process that leads to a cellular response.
Receptors.
This type of protein specifcally attaches a ligand and moves it from one location in the body to another.
Binding proteins
This type of protein speeds up the rate of chemical reactions / lowers the activation energy.
Enzymes
This step in a feedback loop is a messaging system (neuron and/or signal molecule) between the structure that detects the charge and the location where the information is processed.
Afferent pathway
This step ins a feedback loop is a messaging system (neuron and/or signal molecule) between the structure that processes information about a specific change in the internal or external environment of the body and the structure that can act to adjust the situation.
Efferent pathway
This step in a feedback loop is a strcture that can act to adjust or compensate for a change in the internal or external environment.
Effector
This step in a feedback loop is a structure that detects changes in the body’s internal or external envirornment.
Sensor
This step in a feedback loop is thestructure that detects changes in the body’s internal or external environment
Sensor
This step in a feedback loop is the actual change away from a set point in the body’s internal or external environment
Stimulus
This step in a feedback loop is the outcome of the processes that the body used to adjust to the original change.
Response
This step in a feedback loop is typically a mini-process map outlining exactly what will happen when the structure can act to adjust the situation does so
Effectors action
This step of a feedback loop is a structure that will process information about a specific change in the body’s internal or external environment
Integrating center
What is the normal osmolarity range of human blood in mOsM units?
290 - 300 mOsM
When looking at a specimen, one should always start with the ___ power objective.
lowest
Which knobs are used to move the slide and stage
forward, backwards, right and left so the specimen is in the middle of the light?
X/Y stage adjustment knobs
This focus knob is always used first, and only with the lowest objective.
Coarse focus knob
The only focus knob used with higher objectives is:
Fine focus knob
