Basic Molecules

Question 1

Estrogen receptor

Answer 1

Protein that bind estrogen to activate female trait genes

Question 2

Testosterone receptor

Answer 2

Protein that bind testosterone to activate make trait genes

Question 3

Glucocorticoid receptor

Answer 3

Protein that bind cortisol to regulate metabolism and immunity

Question 4

Hsp90

Answer 4

Protein that help fold and stabilize other proteins under stress

Question 5

G protein

Answer 5

heterotrimeric protein with α, β, and γ subunits;

Question 6

GPCR

Answer 6

membrane receptor that activates G proteins in response to extracellular signals like hormones or neurotransmitters.

Question 7

Receptor tyrosine kinase

Answer 7

-A transmembrane receptor. when a ligand binds to it , it autophorylates and activates intracellular signaling pathways

Question 8

cAMP

Answer 8

Cyclic adenosine monophosphate; a second messenger generated from ATP by adenylate cyclase.

Question 9

ATP

Answer 9

Adenosine triphosphate; high-energy molecule used as the cell’s energy currency.

Question 10

ADP

Answer 10

Adenosine diphosphate; ATP minus one phosphate, formed after energy release.

Question 11

Adenylate cyclase

Answer 11

Enzyme activated by Gs protein that converts ATP into cAMP

Question 12

Protein kinase A (PKA)

Answer 12

A cAMP-dependent serine/threonine kinase that phosphorylates target proteins (like ion channels causing them to open or close)

Question 13

Phospholipase C (PLC)

Answer 13

Enzyme that hydrolyzes PIP₂ into IP₃ and DAG, initiating intracellular signaling.

Question 14

DAG (diacylglycerol)

Answer 14

Lipid-derived second messenger that activates protein kinase C (PKC) at the membrane.

Question 15

IP₃ (inositol 1,4,5-trisphosphate)

Answer 15

Second messenger that binds IP₃ receptors on the ER to release Ca²⁺ into the cytosol.
its cleaved from PIP2

Question 16

Calcium ion (Ca²⁺)

Answer 16

Versatile second messenger involved in signaling pathways regulating secretion, contraction, and gene expression.

Question 17

Calmodulin

Answer 17

Calcium-binding protein that undergoes conformational change to activate Ca²⁺-dependent enzymes.

Question 18

CaMKII (Calcium/calmodulin-dependent protein kinase II)

Answer 18

Kinase activated by Ca²⁺-calmodulin complex, involved in synaptic plasticity and gene regulation.

Question 19

Calcium-dependent ion channel

Answer 19

Ion channel gated by intracellular Ca²⁺ levels, allowing selective ion movement across membranes.

Question 20

Ca²⁺ pump (e.g., SERCA or PMCA)

Answer 20

ATP-dependent transporter that actively exports Ca²⁺ from the cytosol to maintain low intracellular calcium.

Question 21

Ras

Answer 21

Small GTPase that switches between active (GTP-bound) and inactive (GDP-bound) forms to regulate cell proliferation.

Question 22

Ras activating/inhibiting proteins

Answer 22

GEFs (guanine nucleotide exchange factors) activate Ras by promoting GTP binding; GAPs (GTPase-activating proteins) inactivate Ras by accelerating GTP hydrolysis.

Question 23

MAPK, MAPKK, MAPKKK

Answer 23

Sequential kinases (MAPK cascade) that amplify and transmit growth signals from Ras to the nucleus.

Question 24

Growth factors

Answer 24

Extracellular signaling proteins that bind specific receptors to promote cell growth, division, and survival.

Question 25

Adaptors

Answer 25

Non-enzymatic proteins that connect receptors to downstream signaling proteins (e.g., Grb2).

Question 26

JAK

Answer 26

Janus kinase; tyrosine kinase that phosphorylates STAT proteins after cytokine receptor activation.

Question 27

STAT

Answer 27

Signal transducer and activator of transcription; phosphorylated by JAKs and translocates to the nucleus to regulate gene expression.

Question 28

Interferon

Answer 28

Cytokine that activates antiviral and immune responses via the JAK-STAT pathway.

Question 29

TNF-α (tumor necrosis factor-α)

Answer 29

Cytokine that induces inflammation, apoptosis, and immune activation.

Question 30

TNF-α receptor

Answer 30

Membrane receptor that binds TNF-α and initiates downstream inflammatory and apoptotic pathways.

Question 31

Iκ-B

Answer 31

Inhibitor of NF-κB; sequesters NF-κB in the cytoplasm under resting conditions.

Question 32

Iκ-B kinase (IKK)

Answer 32

Enzyme complex that phosphorylates Iκ-B, targeting it for degradation and releasing NF-κB.

Question 33

NF-κB

Answer 33

Transcription factor that enters the nucleus to activate genes involved in inflammation, survival, and immune responses.

Question 34

CRE (cAMP-response element)

Answer 34

Specific DNA sequence in gene promoters where phosphorylated CREB binds to activate transcription.

Question 35

CREB (cAMP response element-binding protein)

Answer 35

CREB (cAMP response element-binding protein):

Question 36

CBP (CREB-binding protein)

Answer 36

Coactivator that interacts with CREB to enhance transcription via chromatin remodeling.

Question 37

Ca²⁺ importer

Answer 37

Membrane protein that facilitates Ca²⁺ entry into the cytoplasm (e.g., voltage-gated calcium channels).

Question 38

Ca²⁺ exchanger

Answer 38

Antiporter that removes Ca²⁺ from the cytosol by exchanging it with Na⁺ (e.g., NCX: sodium-calcium exchanger).

Question 39

Transducin

Answer 39

G protein in photoreceptor cells that activates cGMP phosphodiesterase in response to light.

Question 40

Rhodopsin

Answer 40

Light-sensitive GPCR in photoreceptors that activates transducin upon absorbing photons.

Question 41

cGMP phosphodiesterase (PDE)

Answer 41

Enzyme that hydrolyzes cGMP to GMP, leading to the closure of ion channels in phototransduction.

Question 42

Retinal (cis/trans)

Answer 42

Light-sensitive molecule bound to rhodopsin; changes from 11-cis to all-trans form upon photon absorption.

Question 43

Guanylyl cyclase

Answer 43

Enzyme that converts GTP to cGMP, restoring resting state in photoreceptor cells.

Question 44

PI3 kinase (phosphoinositide 3-kinase)

Answer 44

Enzyme that phosphorylates PIP₂ to generate PIP₃, activating survival pathways.

Question 45

Akt (Protein kinase B)

Answer 45

Serine/threonine kinase activated by PIP₃ that promotes cell survival, growth, and metabolism.

Question 46

Death-inhibitory protein (e.g., Bcl-2)

Answer 46

Protein that inhibits apoptosis by blocking mitochondrial cytochrome c release.

Question 47

BAD

Answer 47

Pro-apoptotic Bcl-2 family protein inhibited by Akt-mediated phosphorylation.

Question 48

TGF-β (transforming growth factor-β)

Answer 48

Cytokine that regulates cell growth, differentiation, and immune responses.

Question 49

TGF-β receptor

Answer 49

Serine/threonine kinase receptor that activates Smad proteins upon ligand binding.

Question 50

Smad

Answer 50

Intracellular proteins phosphorylated by TGF-β receptors; translocate to the nucleus to regulate gene transcription

Question 51

Notch

Answer 51

Membrane receptor that, when cleaved upon ligand (Delta) binding, translocates to the nucleus to regulate gene expression.

Question 52

Delta

Answer 52

Membrane-bound ligand that activates Notch signaling during cell fate determination.