Purpose of the “Properties of Nerves and Neurons” lab?
Observe what would happen to a frog’s sciatic nerve if manipulated
Neuron
Individual neurological cell
Nerve
A bundle of neurons, some of which have different properties as far as speed and threshold
Oscilloscope tracing
Shows how long a signal takes to travel across a nerve
Conduction speed equation
distance/time
Relationship between temperature and conduction velocity
Directly related
Relationship between fiber diameter and conduction speed
Directly related
Relationship between fiber diameter and threshold
Inversely related
TTX
Flattened peaks in 5 minutes
Blocks sodium ion channels (first step of conduction)
Novocain
Blocks sodium ion channels
Ether
Flattened peaks in 60 minutes
Makes membranes swell so deep that channels are submerged and sodium/potassium ions cannot pass
Membrane swells entirely in 60 minutes
Ouabain
Immediately stops disequilibrium pumps, but effect is not noticed for 24 hours (takes that long for gradient to dissipate/leak down to equilibrium)
Purpose of the “Transport in Plants and Animals” lab?
Examine and label heart, learn mechanical work of heart, recognize heart noises in a stethoscope, determine blood pressure and heart rate, use an EKG, use a microscope to learn the appearance and locations of plant transport structures
Xylem
Transports water and dissolved substances upward from roots
Phloem
Transports organic compounds manufactured by the plant (like sugars and amino acids) up and down within the organism
What does the flow of fluids through xylem and phloem depend on?
Differences in water potential
Right atrium fills with blood from:
Body
Left atrium fills with blood from:
Lungs
Right ventricle takes blood to:
Lungs
Left ventricle takes blood to:
Body
Tricuspid valve
RA to RV
Chordae tendinae
Heart tissue attached to flaps that keep them from being pushed back into atrium
Bicuspid valve
LA to LV
“Lub”
Created by turbulence from bicuspid/tricuspid valve closure
Pulmonary valve
RV to pulmonary artery
Aortic valve
LV to aorta
“Dub”
Created by turbulence from pulmonary/ aortic valve closure
Systolic pressure
first and higher; measures force of blood against brachial artery wall when LV contracts
Diastolic pressure
second and lower; measures force of blood against brachial artery wall when LV relaxes
Korotkoff sounds
: noises produced by turbulence that are detectable by stethoscope
SA Node
(segment of heart muscle tissue in the right atrium) depolarizes initially, current spreads out from the SA node and stimulated muscles of atria to contract (atria are electrically insulated from ventricles)
AV Node
nest of tissues that allows for conduction down to the ventricles, delay happens, signal is passed on to Purkinje fibers which pass to ventricular muscle, then contraction
What happens simultaneously?
Ventricular depolariation and atria repolarization
P wave
Atrial depolarization
QRS complex
Ventricular depolarization (atrial repolarization cannot be seen)
T wave
Ventricular repolarization
Vascular plants
Have internal transport systems
Monocots
1 embryonic leaf, parallel leaf venation, multiples of 3 flowering parts
Eudicots
2 embryonic leaves, netted leaf venation, multiples of 4/5 flowering parts
Roots
Vascular transport tissue concentrated in center
Monocot xylem
Forms a circle
Eudicot xylem
Forms an X
Monocot stem
Vascular bundles throughout
Eudicot stem
Ring of vascular bundles
Purpose of “Plant Hormones” lab
Examine the effects of indoleacetic acid and kinetin on the growth of new shoots in Alaska peas
Which growth was manipulated?
Lateral growth
Indoleacetic acid (IAA)
Auxin hormone; auxins stimulate cell elongation
What was removed from each plant and why?
Apex of each pea plant; eliminated source of IAA
High ratio IAA/Kinetin
Suppressed growth
Low ratio IAA/Kinetin
Encourages growth
Which “colors” could be compared?
Those with only one variable manipulated
Value with no hormone added
1
Value with hormone added
10
Probability <0.05
Difference is likely due to treatment
Probability ≥ 0.05
Difference is likely due to chance
df equation
n_1+n_2 - 2
s_u equation
√((s_1^2)/n_1 +(s_2^2)/n_2 )
t equation
(x ̅_1-x ̅_2)/s_u
Purpose of “Water Potential and Osmosis” lab
Determine the Ψ of potato cells by immersing potato tissues into solutions with different molarities of sucrose (which doesn’t diffuse across cell membranes)
Independent variable in Water Potential lab
sucrose concentration
Dependent variable in Water Potential lab
Percent change in mass
Relationship between sucrose concentration and change in mass
Inversely related
Diffusion
Movement of molecules in solution from high to low concentration
Osmosis
Water diffuses through a semi-permeable membrane
At what temperatures are molecules constantly in motion?
Those above absolute zero
What happens with solutes are added to water?
Effective water concentration goes down because polar solutes tend to bind to water molecules and reduce their mobility, especially through a semi-permeable membrane
Water potential (Ψ)
takes into account the effects of solutes in water and pressure; measure of the chemical potential of water in terms of free energy per mole of water, but expressed in terms of pressure (force per unit area, usually in bars2)
Solute potential equation
Ψ_s=-iCRT
Relationship between solute potential and solute concentration
Inversely related
Equilibrium estimation
When C is about .2-.3M
Role of pressure
When diffusion of water into a cell is prevented by built-up turgor pressure as water enters; as pressure builds, the cell becomes turgid and water cannot enter the cell
Water potential equation
Ψ=Ψ_S+Ψ_P
What happens as pressure builds up over time?
Cell walls become distended by increased cytoplasmic volume, but can withstand it
Problem with animal cells
Will lyse in solutions with high Ψ due to a lack of cell walls (unable to resist stretching of cell membrane)
When the temperature of the nerve chamber is lowered, which of the following occurs?
Oscilloscope peaks shift right