FINAL EXAM BIO 116 RUTGERS
(LECTURES 19-28) 2026/2027 ACTUAL
QUESTIONS WITH VERIFIED ANSWERS.
Lecture 19 - Action Potentials
What are neurons?
➡Functions?
Neuron
➡Basic functional unit/cell of nervous system
➡"One way street"
FUNCTION
➡Conduct electrical signals, integrate info
Describe the components of a neuron.
➡Where are APs generated?
Cell Body
➡contains organelles
1. Dendrites
➡Receive info
➡Usually many short dendrites
2. Axon
➡Passes signal
➡Usually one long axon per neuron
➡Axon hillock (base) generates APs/signals
➡Often branched at end (synaptic terminals)
,What is a nerve?
Nerve: Axons of many neurons held together w/ connective
tissue
What are the different types of neurons?
➡Which is most abundant?
Sensory
➡Afferent neurons
➡Sensory receptor ➡ nervous system
Interneurons
➡only interact w/ other neurons (90% of neurons)
Motor
➡efferent neurons
➡Nervous system ➡ effector (muscle etc)
What type of membrane do neurons have?
➡What is special about it regarding charge?
Neurons have a selectively permeable, polarized membrane
➡has different charges on each side:
➡OUTSIDE = more positive (+)
➡INSIDE = more negative (-)
What is Membrane Potential (MP)?
https://www.youtube.com/watch?v=tIzF2tWy6KI
Membrane Potential
➡potential E to do work
➡Uneven charge on inside & outside of cell (Inside = -, Outside
= +)
,What are Excitable Cells?
➡Give some examples?
Excitable Cells
➡Cells that can rapidly change membrane potential
➡Ex: Neurons, muscle cells
How is membrane potential measured?
➡What unit?
MP is measured using Voltage, specifically by a voltmeter
(millivolt = mV)
What is Resting Potential?
➡In mV?
Resting Potential
➡Membrane potential of a neuron at rest (not excited)
➡≈-70mV
Due to:
➡Na/K pump
➡Ion channels
What is the Sodium Potassium Pump?
➡What type of transport?
Sodium Potassium Pump
➡Transmembrane transport protein found throughout neuron
➡Uses active transport (requires E to go against cnctr.
gradient)
1 Cycle
➡3 Na+ out
➡2 K+ in (salty banana)
, How does the Na/K pump maintain a negative membrane
potential?
➡Because there are more positive (Na+) ions being pumped
out than positive (K+) in, the MP remains (-)
What are Leaky K+ Ion channels?
Leaky Ion Channels
➡Membrane proteins that are always open
➡Use facilitated diffusion
➡Leaky K+ Channels: Potassium diffuses out, sodium can't
diffuse in
(NOT voltage gated)
More + outside cell, maintain (-) internal MP
What are some types of changes to membrane potential?
Hyperpolarization
➡MP becomes more negative than resting potential (away
from 0)
Depolarization
➡Becomes more positive (closer to 0)
What is the Threshold?
➡In mV?
Threshold
➡The minimum membrane potential required to trigger action
potential
➡-55mV for most neurons
(LECTURES 19-28) 2026/2027 ACTUAL
QUESTIONS WITH VERIFIED ANSWERS.
Lecture 19 - Action Potentials
What are neurons?
➡Functions?
Neuron
➡Basic functional unit/cell of nervous system
➡"One way street"
FUNCTION
➡Conduct electrical signals, integrate info
Describe the components of a neuron.
➡Where are APs generated?
Cell Body
➡contains organelles
1. Dendrites
➡Receive info
➡Usually many short dendrites
2. Axon
➡Passes signal
➡Usually one long axon per neuron
➡Axon hillock (base) generates APs/signals
➡Often branched at end (synaptic terminals)
,What is a nerve?
Nerve: Axons of many neurons held together w/ connective
tissue
What are the different types of neurons?
➡Which is most abundant?
Sensory
➡Afferent neurons
➡Sensory receptor ➡ nervous system
Interneurons
➡only interact w/ other neurons (90% of neurons)
Motor
➡efferent neurons
➡Nervous system ➡ effector (muscle etc)
What type of membrane do neurons have?
➡What is special about it regarding charge?
Neurons have a selectively permeable, polarized membrane
➡has different charges on each side:
➡OUTSIDE = more positive (+)
➡INSIDE = more negative (-)
What is Membrane Potential (MP)?
https://www.youtube.com/watch?v=tIzF2tWy6KI
Membrane Potential
➡potential E to do work
➡Uneven charge on inside & outside of cell (Inside = -, Outside
= +)
,What are Excitable Cells?
➡Give some examples?
Excitable Cells
➡Cells that can rapidly change membrane potential
➡Ex: Neurons, muscle cells
How is membrane potential measured?
➡What unit?
MP is measured using Voltage, specifically by a voltmeter
(millivolt = mV)
What is Resting Potential?
➡In mV?
Resting Potential
➡Membrane potential of a neuron at rest (not excited)
➡≈-70mV
Due to:
➡Na/K pump
➡Ion channels
What is the Sodium Potassium Pump?
➡What type of transport?
Sodium Potassium Pump
➡Transmembrane transport protein found throughout neuron
➡Uses active transport (requires E to go against cnctr.
gradient)
1 Cycle
➡3 Na+ out
➡2 K+ in (salty banana)
, How does the Na/K pump maintain a negative membrane
potential?
➡Because there are more positive (Na+) ions being pumped
out than positive (K+) in, the MP remains (-)
What are Leaky K+ Ion channels?
Leaky Ion Channels
➡Membrane proteins that are always open
➡Use facilitated diffusion
➡Leaky K+ Channels: Potassium diffuses out, sodium can't
diffuse in
(NOT voltage gated)
More + outside cell, maintain (-) internal MP
What are some types of changes to membrane potential?
Hyperpolarization
➡MP becomes more negative than resting potential (away
from 0)
Depolarization
➡Becomes more positive (closer to 0)
What is the Threshold?
➡In mV?
Threshold
➡The minimum membrane potential required to trigger action
potential
➡-55mV for most neurons
