PSL 250 REVIEW FOR FINAL EXAM QUESTIONS WITH VERIFIED ANSWERS LATEST UPDATE 2026

PSL 250 REVIEW FOR FINAL EXAM QUESTIONS WITH VERIFIED ANSWERS LATEST UPDATE 2026 Molecules - Answers Assembly of atoms Carbs, Lipids, Proteins Cells - Answers Basic unit of life Use energy Tissues - Answers Collection of similar cells w same local function Negative Feedback and Positive Feedback - Answers When X event causes a change away from a set point and then response Y causes it to return to set point Event X causes change from one set point to another Metabolism - Answers Done by liver Thousands of reactions Rough ER - Answers Ribosomes link amino acids Newly formed proteins threaded into lumen New proteins move from rough to smooth ER Smooth ER - Answers produces vesiles that transport new proteins to golgi apparatus Lysosomes - Answers Contain digestive enzymes Digest molecules down to useable size Edocytosis - Answers Must occur to balance exocytosis Extra cellular molecules bind to receptors and trigger membrane infolding Glycolysis - Answers No oxygen Glucose + NAD + 2ATP = NADH + 2 Pyruvate + 2ATP Aerobic Energy Production - Answers KREBS Cytoskeleton - Answers Intercellular frameworks Protein polymer filaments Microtubules - Answers Polymer of tubin Help with cell stability, transport along neurons, transport of orgnaelles Protein Receptors - Answers on outside of cell activated by physical change or touch activates channel or enzymes Protein Channels - Answers only ions can pass span throughout membrane receptors open the channels Carb Protein Complexes - Answers Identify "self" to immune system Ficks Law of Diffusion - Answers Rate of diffusion Q = (P)(A) ( change C / change X) / MW larger weight means slower diffusion Carrier transport - Answers protein molecules change shape and let molecules move across the membrane energy from concentration gradient or ATP Resting Membrane Potential - Answers Voltage across cell membrane when cell is not activated K+ dominates at rest (most open channels) Equalibrium Potential - Answers Only open channels determine membrane potential If cell is negative enough K+ wont flow at -90 If cell is positive enough, NA+ wont flow at +60 Depolariization - Answers Membrane potential is less negative Caused by K+ channels closing and Na+ channels opening MP moves toward Na+ equalibrium Hyperpolarization - Answers More K+ channels open Graded Potentials - Answers Size of potential is proportional to size of stimulus Phases of AP - Answers Depolarization threshold-- Na+ enters the cell and all channels open AP Spike -- All Axons - Answers Carry AP away from cell body Faster w myelin Myelin - Answers Fatty surrounding of axon Insulated to prevent electrical loss Increases action potential speed Nodes of Ranvier - Answers Spaces between myelin completes AP circuit Presynaptic Neuron - Answers End of axon, terminal button Recieves AP down the axon AP opens Ca++ channels on nob EPSP - Answers Na+ channels open Need many to reach threshold IPSP - Answers K+ or Cl- channels open K+ leavse Membrane potential becomes more negative Temporal Summation - Answers EPSP ffrom same neuron close in time Sum to reach threshold Spatial Summation - Answers ESPS from different neuron add up Sum to reach threshold cAMP - Answers activate kinase, add phosphates to molecules Kinase transfers phosphate groups Interneurons - Answers In CNS -- 99% of all neurons Perform thinking and memory Makes connections cannot divide Plasticity - Answers No mitosis of neurons Instead learning involes making new synapses between existing neurons Language Control - Answers Left ide of brain Brocas area -- speech formation Wernickes Area-- comprehension of speech and visions Basal Nuclei - Answers collection of 5 structures on each side of brain all connected to each other