Week 2: APs & Intro Cell-to-Cell Signalling

Question 1

Period during which no stimulus can initiate another action potential due to inactivated sodium channels

Answer 1

ABSOLUTE REFRACTORY PERIOD

Question 2

Period when a stronger-than-normal stimulus is required to initiate an action potential

Answer 2

RELATIVE REFRACTORY PERIOD

Question 3

Fast but inefficient current spread that decays as it travels along the membrane

Answer 3

ELECTROTONIC FLOW

Question 4

Method of action potential propagation where each segment of axon regenerates the signal

Answer 4

ACTIVE PROPAGATION

Question 5

Increase in axon size that reduces resistance and speeds up impulse transmission

Answer 5

INCREASED AXON DIAMETER

Question 6

Insulating layer that enables saltatory conduction and speeds up signal transmission

Answer 6

MYELINATION

Question 7

Type of conduction where the action potential jumps between nodes of Ranvier

Answer 7

SALTATORY CONDUCTION

Question 8

Classification system for neurons based on their conduction velocity, axon diameter, and myelination

Answer 8

NEURON CLASSES BY CONDUCTION VELOCITY

Question 9

Direct cell-to-cell communication via gap junctions allowing rapid ion flow

Answer 9

ELECTRICAL SYNAPTIC SIGNALLING

Question 10

Most common form of communication between neurons using neurotransmitters

Answer 10

CHEMICAL SYNAPTIC SIGNALLING

Question 11

Communication using chemicals between nearby non-neuronal cells

Answer 11

PARACRINE SIGNALLING

Question 12

Communication where a cell targets itself with signaling molecules

Answer 12

AUTOCRINE SIGNALLING

Question 13

Hormone-based long-distance signalling involving bloodstream transport

Answer 13

ENDOCRINE SIGNALLING

Question 14

Membrane-bound proteins that recognize and respond to specific chemical signals

Answer 14

RECEPTORS

Question 15

Property that allows a receptor to bind only to a specific type or class of ligand

Answer 15

RECEPTOR SPECIFICITY

Question 16

Degree to which a receptor binds a ligand easily and tightly

Answer 16

RECEPTOR AFFINITY

Question 17

Molecules that activate a receptor by mimicking the natural ligand

Answer 17

AGONISTS

Question 18

Molecules that bind to a receptor and block its activation

Answer 18

ANTAGONISTS

Question 19

Ligands that bind a site other than the active site to modulate receptor function

Answer 19

ALLOSTERIC MODULATORS

Question 20

Intracellular response triggered by external chemical signal binding a receptor

Answer 20

SIGNAL TRANSDUCTION

Question 21

Receptor that opens ion channels directly when activated by a ligand

Answer 21

IONOTROPIC RECEPTOR

Question 22

Receptor that activates intracellular signaling cascades via G-proteins

Answer 22

METABOTROPIC RECEPTOR

Question 23

Enzyme-linked receptor type that phosphorylates tyrosine residues on target proteins

Answer 23

TYROSINE KINASE RECEPTOR

Question 24

Receptor type that binds lipid-soluble hormones and acts on DNA

Answer 24

INTRACELLULAR RECEPTOR

Question 25

Molecules like cAMP or IP3 that relay signals inside the cell after receptor activation

Answer 25

SECOND MESSENGERS

Question 26

Inactive state of a G protein before ligand binding and GDP exchange

Answer 26

GDP-BOUND G PROTEIN

Question 27

Active state of a G protein after ligand-induced conformational change and GTP binding

Answer 27

GTP-BOUND G PROTEIN

Question 28

Proteins made of three subunits (α, β, γ) involved in signal transmission from GPCRs

Answer 28

HETEROTRIMERIC G PROTEINS

Question 29

Process of reducing receptor number on the membrane to modulate response strength

Answer 29

DOWN-REGULATION

Question 30

Process where receptors are internalized but not destroyed, temporarily reducing sensitivity

Answer 30

SEQUESTRATION

Question 31

Systems that rapidly alter membrane potential through ion channels

Answer 31

FAST RESPONSE SYSTEMS

Question 32

Slower, longer-lasting systems involving intracellular cascades and gene expression

Answer 32

SLOW RESPONSE SYSTEMS

Question 33

Ability of a signaling system to generate multiple effects from a single receptor-ligand interaction

Answer 33

DIVERSITY OF RESPONSE

Question 34

Amplifying effect where one ligand-receptor interaction leads to many downstream responses

Answer 34

AMPLIFICATION

Question 35

Ability of cells to modify their response quickly to adapt to immediate demands

Answer 35

RAPID PLASTICITY

Question 36

Ability to regulate a signal at multiple stages of the signaling cascade

Answer 36

MULTIPLE CONTROL SITES