Unit 4 - Cell Communication and Cell Cycle

Generating

making a signal in the cell.

Transmitting

sending the signal to another cell.

Receiving

target cell detecting the signal.

Responding

cell reacting to the signal.

Direct cell-to-cell contact

communication through physical connection (e.g., immune system, plasmodesmata in plants, gap junctions in animals).

Short distance contact

communication over small gaps (e.g., nerve cells, skin cells, WBC).

Long distance contact

signals travel via blood (e.g., hormones in the endocrine system).

Autocrine signaling

a cell releases signals that act on itself.

Paracrine signaling

cells release signals affecting nearby cells.

Synaptic signaling

a neuron releases neurotransmitters into a synapse to stimulate a target cell.

Serotonin

neurotransmitter involved in mood, sleep, and appetite.

Dopamine

neurotransmitter linked to reward, pleasure, and motor control.

Acetylcholine

neurotransmitter aiding muscle contraction and nerve function.

Neurotransmitters

local regulators influencing neighboring cells in the nervous system.

Hormones

regulate growth, metabolism, and reproduction by binding to target cells.

Signal transduction

process where a signal activates a response in a target cell.

Receptor protein

surface protein that binds specific signals like ligands.

Ligand

a chemical signal that binds to a receptor protein.

Cellular response

the result of a signal transduction cascade in the cell.

Ion Channel Receptors

allow ions to pass through the membrane to regulate cell activity.

G-Protein-Coupled Receptors (GPCRs)

activate G proteins, triggering reactions and producing cAMP for a cellular response.

cAMP

secondary messenger activated by GPCRs to amplify the cell's response.

Cell cycle

life of a cell from its formation to its division.

Interphase

includes G1 (growth), S (DNA synthesis), and G2 (preparation for division).

G1 phase

first gap phase where the cell grows and carries out normal functions.

S phase

DNA synthesis where chromosomes are replicated.

G2 phase

second gap phase where the cell prepares for division.

Mitosis

nuclear division occurs.

Cytokinesis

cytoplasm divides, completing cell division.

External Signals

signals from outside the cell that help regulate division.

Epidermal Growth Factors (EGF)

local signals promoting cell growth and repair.

Platelet-Derived Growth Factors (PDGF)

local signals aiding wound healing and tissue repair.

Growth Hormones

long-distance signals stimulating growth and division in tissues.

Cyclins

proteins that are produced at specific stages of the cell cycle.

CDKs

enzymes that depend on cyclins for activation.

Tumor suppressor genes

genes that prevent uncontrolled cell growth.