Signal Transduction Pathway

A series of steps linking a mechanical, chemical, or electrical stimulus to a specific cellular response

Local Regulators

A secreted molecule that influences cells near where it is secreted

Hormones

In multi-cellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body, changing the target cells' functioning. Hormones are thus important in long-distance signaling

1.) Reception

2.) Transduction

3.) Response

Ligand

A molecule that binds specifically to another molecule, usually a large one

G protein-coupled receptor (GPCR)

G Protein

Receptor tyrosine kinases (RTKs)

A receptor protein spanning the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tryosine on another protein. RTKs often respond to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins within the cell.

Ligand-gated ion channel (receptor)

A transmembrane protein containing a pore that opens or closes as it changes shape in response to signaling

Protein kinase

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein

Protein phosphatases

An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase

Second messengers

Cyclic AMP or cAMP

Adenylyl Cyclase

Inositol trisphosphate (IP₃)

Diacylglycerol (DAG)

Scaffolding proteins

Apoptosis

Cell division

Cell cycle

Genome

Chromosomes

Chromatin

Somatic cells

Gametes

Sister Chromatids

Centromere

Mitosis

Cytokinesis

Mitotic (M) phase

Interphase

G₁ phase

S phase

G₂ phase

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

Mitotic Spindle

Centrosome

Aster

Kinetochore

Metaphase plate

Cleavage

Cleavage furrow

Cell plate

Binary fission

Origin of replication

Cell Cycle Control System

Checkpoint

G₀ phase

Cyclin

Cyclin-dependent kinases or Cdks

Growth factor

Density-dependent inhibition

Anchorage dependence

Transformation

Benign tumor

Malignant tumor

Metastasis

Life Cycle

Karyotype

Homologous chromosomes

Sex chromosomes

Autosomes

Diploid cell

Haploid cells

Zygote

Fertilization

Meiosis

Alternation of generations