Neurobiology Study Guide Cards

Question 1

What are the three types of signaling in neurons?

Answer 1

Synaptic, paracrine, and endocrine signaling.

Question 2

What are the main components of signaling cascades?

Answer 2

Signaling molecules, receptors, second messengers, protein kinases, phosphatases.

Question 3

Name three types of signaling molecules.

Answer 3

Neurotransmitters, neuropeptides, hormones.

Question 4

What are the two main types of receptors?

Answer 4

Ionotropic and metabotropic receptors.

Question 5

What is the role of G proteins in signaling?

Answer 5

They can activate/inhibit enzymes and directly open/close ion channels

Question 6

What regulates G protein activity?

Answer 6

GTP binding activates; GDP binding inactivates; regulated by GAPs (GTPase-activating proteins).

Question 7

What is a kinase? What is a phosphatase?

Answer 7

A kinase adds phosphate groups; a phosphatase removes them.

Question 8

Give an example of a metabotropic receptor and its neurotransmitter.

Answer 8

Dopamine receptors (metabotropic, dopamine).

Question 9

What second messengers are derived from PIP2?

Answer 9

DAG and IP3.

Question 10

What are the roles of cAMP and cGMP?

Answer 10

Activate PKA and PKG; can also open cyclic nucleotide-gated channels.

Question 11

Which second messenger directly increases intracellular calcium?

Answer 11

IP3 (via IP3 receptors on ER).

Question 12

What enzyme produces DAG and IP3?

Answer 12

Phospholipase C

Question 13

What is CREB and why is it important?

Answer 13

A transcription factor activated during long-term plasticity and memory.

Question 14

What distinguishes short-term plasticity from long-term plasticity?

Answer 14

Short-term: lasts seconds to minutes, involves post-translational modifications. (Rearrangement of furniture)

Long-term: lasts hours to years, involves gene transcription and protein synthesis. (Remodeled house)

Question 15

What is synaptic facilitation?

Answer 15

A temporary increase in synaptic strength due to repeated stimulation.

due to accumulated presynaptic Ca²⁺, enhancing neurotransmitter release.

Question 16

What is synaptic depression?

Answer 16

A temporary decrease in synaptic strength due to neurotransmitter depletion.

Question 17

What type of plasticity occurs in Aplysia for habituation and sensitization?

Answer 17

Long-term plasticity involving serotonin and changes in transcription.

Question 18

What is required for hippocampal long-term potentiation (LTP)?

Answer 18

High-frequency tetanic stimulation.

Question 19

What are the properties of LTP?

Answer 19

Specificity and associativity.

Question 20

Which receptors are critical for LTP initiation?

Answer 20

NMDA receptors (for Ca²⁺ influx) and AMPA receptors (for depolarization).

Question 21

How can LTP be blocked?

Answer 21

By blocking transcription factors like CREB or NMDA receptor activation.

Question 22

How is transcriptional regulation involved in long-term memory?

Answer 22

Via factors like CREB in both Aplysia and hippocampus during memory formation.

Question 23

Can a neurotransmitter be both excitatory and inhibitory?

Answer 23

Yes. For example, GABA is excitatory in early development due to chloride ion gradient and inhibitory in adults.

Question 24

What is a channelopathy involving inactivation?

Answer 24

Certain epilepsy forms caused by Na⁺ channel inactivation defects.

Question 25

How can neurotransmitters modulate signal transduction?

Answer 25

Through G-protein coupled receptors that activate second messenger pathways.

Question 26

What are the four important ions in neuronal communication and their roles?

Answer 26

Na⁺ (depolarization), K⁺ (repolarization), Ca²⁺ (neurotransmitter release), Cl⁻ (inhibitory responses).

Question 27

What is HSAM?

Answer 27

Highly Superior Autobiographical Memory; ability to recall personal experiences in great detail.

Question 28

What is memory reconsolidation?

Answer 28

The process where recalled memories become labile and can be altered before being stored again.

Question 29

Synaptic signaling

Answer 29

- Local and fast, occurs at synapses between neurons.

Question 30

Paracrine signaling

Answer 30

- Signals diffuse to nearby target cells without synaptic junctions.

Question 31

Endocrine signaling

Answer 31

- Hormones released into the bloodstream act on distant cells.

Question 32

Extracellular signaling molecule

Answer 32

- Neurotransmitter or Hormone

Question 33

Receptor protein

Answer 33

- GPCR, ion channel

Question 34

Intracellular second messengers

Answer 34

- cAMP, cGMP, Calcium, and IP3

Question 35

Effector proteins

Answer 35

- kinases, phosphatases

Question 36

Cellular response

Answer 36

- gene expression, ion channel modulation

Question 37

Specificity

Answer 37

Only the actively stimulated synapse is strengthened during LTP, while inactive neighboring synapses remain unchanged. Example: If neuron A synapses onto neuron B at two different points (synapse 1 and synapse 2), and only synapse 1 receives strong stimulation, only synapse 1 will undergo LTP, not synapse 2.

Question 38

Associativity

Answer 38

A weakly stimulated synapse can also undergo LTP if it is active at the same time as a strongly stimulated synapse on the same postsynaptic neuron. Example: If a weak input (e.g., bell ringing) and a strong input (e.g., food presentation) are activated together on the same postsynaptic neuron, the weak synapse can be potentiated too—"cells that fire together, wire together."

Question 39

What kinases are classified as Ser/Thr kinases?

Answer 39

PKA (Protein Kinase A) PKC (Protein Kinase C) CaMKII (Calcium/calmodulin-dependent kinase II)

Question 40

What are the targets of DAG and IP3, and where do they come from?

Answer 40

DAG and IP3 are generated from PIP2 cleavage by phospholipase C DAG activates PKC IP3 triggers Ca²⁺ release from the ER

Question 41

How is calcium removed from the cell after signaling?

Answer 41

Pumped out via PMCA (plasma membrane Ca²⁺ ATPase) Sequestered into ER via SERCA pump Exchanged with Na⁺ via NCX (Na⁺/Ca²⁺ exchanger)

Question 42

What are the two main types of acetylcholine (ACh) receptors and their functions?

Answer 42

Nicotinic (ionotropic): Cause EPSPs via Na⁺ influx Muscarinic (metabotropic): In the heart, open K⁺ channels to slow heart rate

Question 43

Describe the difference between monomeric and trimeric G proteins.

Answer 43

Monomeric G proteins (e.g., Ras): Single subunit; important in growth pathways. Trimeric G proteins (α, β, γ): Activated by GPCRs; α binds GTP/GDP and regulates downstream effectors.

Question 44

What are second messengers and what are some examples?

Answer 44

Small intracellular molecules that amplify and relay signals from receptors. Examples: Calcium (Ca²⁺): Released from intracellular stores, activates kinases like CaMKII cAMP/cGMP: Activate PKA/PKG and open cyclic nucleotide-gated ion channels DAG: Activates PKC IP3: Binds to IP3 receptors on the ER to release calcium

Question 45

What are the structural differences between cAMP and cGMP, and how are they generated?

Answer 45

cAMP: made from ATP by adenylyl cyclase cGMP: made from GTP by guanylyl cyclase

Question 46

What enzymes degrade cAMP and cGMP to terminate their signals?

Answer 46

Phosphodiesterases (PDEs) hydrolyze cAMP and cGMP into AMP and GMP, respectively.

Question 47

What is the role of calcium-binding proteins like calmodulin?

Answer 47

Calmodulin binds Ca²⁺ and activates enzymes like CaMKII, which participate in memory and plasticity pathways.

Question 48

What does CaMKII do in neuronal signaling?

Answer 48

CaMKII is a serine/threonine kinase activated by Ca²⁺/calmodulin. It phosphorylates ion channels and receptors, and is critical for LTP and memory formation.