Unit 4 AP Biology Cell Cycle and communication

Adenylyl cyclase

An enzyme that converts ATP to cyclic AMP in response to an external signal.

Anaphase

The stage of mitosis in which chromosomes separate and move to opposite poles of the cell.

Apoptosis

Programmed cell death that occurs in multicellular organisms.

Cancer

A disease characterized by uncontrolled cell division and growth.

Cell differentiation

The process by which a less specialized cell becomes a more specialized cell type.

Cell plate

A structure that forms during cytokinesis in plant cells and develops into the cell wall.

Centromere

The region of a chromosome where the two sister chromatids are joined.

Centrosomes

A structure that serves as the main microtubule organizing center of the cell.

Checkpoints in cell cycle

Regulatory points in the cell cycle that assess the readiness of the cell to proceed with division.

Chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus.

Chromosomes

Thread-like structures made of DNA and proteins that contain genetic information.

Contractile rings

Structure that aids in the separation of daughter cells during cytokinesis.

Cyclic AMP (cAMP)

A second messenger important in many biological processes.

Cyclin

A protein that regulates the cell cycle by activating cyclin-dependent kinases.

Cyclin-dependent kinases (CDKs)

Enzymes that, when activated by cyclins, regulate the cell cycle progression.

Cytokinesis

The process during cell division where the cytoplasm of a parental cell is divided into two daughter cells.

Direct contact (plasmodesmata and gap junctions)

Forms of intercellular communication allowing exchange of substances.

Endocrine signaling

The process by which hormones are secreted into the bloodstream and affect distant cells.

G proteins

Molecular switches that relay signals from receptors on the cell surface.

G0

A phase in the cell cycle where the cell is in a resting or non-dividing state.

G1

The first gap phase of the cell cycle, where the cell grows and prepares for DNA replication.

G2

The second gap phase of the cell cycle, where the cell prepares for mitosis.

GDP/GTP

Nucleotides that act as energy sources for cellular processes; GTP is often involved in protein synthesis.

Genome

The complete set of genes or genetic material present in a cell or organism.

G-protein-coupled receptors (GPCRs)

A large family of receptors that detect molecules outside the cell and activate internal signal transduction pathways.

Growth factors

Substances, often proteins, that stimulate cell growth, proliferation, and differentiation.

Hormones

Chemical messages produced by endocrine glands that regulate physiological processes.

Interphase

The phase of the cell cycle where the cell grows and prepares for division.

Kinases

Enzymes that add phosphate groups to other molecules, typically proteins.

Kinetochore

A protein structure on the chromosome where the spindle fibers attach during cell division.

Ligand

A molecule that binds to another (usually larger) molecule.

Ligand-gated channel

A type of ion channel that opens in response to the binding of a ligand.

M phase

The phase of the cell cycle that includes mitosis and cytokinesis.

Metaphase

Stage of mitosis where chromosomes align in the center of the cell.

Metaphase plate

The imaginary plane where chromosomes are aligned during metaphase.

Microtubules/Spindle

Cytoskeletal structures that help separate chromosomes during cell division.

Mitosis

The process of cell division that results in two genetically identical daughter cells.

MPF (maturation-promoting factor)

A protein complex that triggers the progression of the cell cycle from G2 to M phase.

Negative feedback mechanisms

Processes that respond to a change by initiating responses that counteract that change.

Neurotransmitters

Chemical messengers that transmit signals across a synapse between neurons.

Nucleolus

A dense structure within the nucleus where ribosomal RNA is synthesized.

Oncogenes

Genes that have the potential to cause cancer when mutated or expressed at high levels.

Paracrine signaling

Cell signaling in which the target cell is close to the signal-releasing cell.

Phosphatases

Enzymes that remove phosphate groups from molecules, often counteracting the actions of kinases.

Phosphorylation cascade

A series of chemical reactions during cell signaling in which one enzyme activates another.

Positive feedback mechanisms

Processes that amplify responses and processes in biological systems.

Prophase

The first stage of mitosis, when chromosomes become visible and the nuclear envelope starts to break down.

Receptor

A protein molecule that receives and transmits signals inside the cell.

S phase

The phase of the cell cycle in which DNA is replicated.

Second messengers

Intracellular signaling molecules that help transmit signals from receptors to target molecules inside the cell.

Signal amplification

The process by which a single signal can lead to a large number of cellular responses.

Sister chromatids

Identical copies of a chromosome connected by a centromere.

Stem cells

Undifferentiated cells with the potential to differentiate into various cell types.

Synaptic signaling

Cell signaling that occurs between neurons at the synapse.

Telophase

The final stage of mitosis, during which the chromosomes decondense and the nuclear envelope re-forms.