Cell Communication & Cell Cycle Vocabulary

Flashcards of vocabulary terms related to cell communication and the cell cycle.

Ligand

Molecule that binds specifically to other molecules (such as receptors)

Paracrine signaling

Cells communicate over relatively short distances

Synapse

Junction between nerve cells where signal transmission occurs

Autocrine signaling

Cell signals to itself, ligand binds to receptors on its own surface

Endocrine signaling

Long distance signaling, uses the circulatory system as a distribution network, signals known as hormones

Intracellular mediators

Small signaling molecules that can diffuse between two cells

Quorum sensing

Bacteria monitor the density of the population based on chemical signals

Autoinducers

Signaling molecules continually secreted by bacteria to announce their presence to their neighbors

Biofilm

Surface-attached communities of bacterial cells that stick to one another and to their substrate

Plasmodesmata

Places where a hole is punched in the cell wall to allow direct cytoplasmic exchange between two cells

Gap junctions

Channels between neighboring cells that allow transport of ions, H2O, etc. (like plasmodesmata in animal cells)

Tight junctions

Create a watertight seal between two adjacent animal cells

Desmosomes

In animal cells, act like spot welds between adjacent epithelial cells; involves a complex of proteins

Cadherins

Adhesion proteins found on the membranes of both cells & interact in space between, holding them together

Intracellular receptors

Receptor proteins on the inside of cell, ligands are usually small & hydrophobic

Cell-surface receptors

Bind to ligands on outside surface of cells

Ligand-gated ion channel

Ion channels that can open in response to the binding of a ligand

G-protein coupled receptors

Large family of receptors that share structure & method of signaling; all bind GTP to hydrolyze GDP

Enzyme-linked receptors

Cell-surface receptors with intracellular domains associated with enzymes

Upstream

Describes molecules & events that came earlier in the relay chain

Downstream

Describes molecules & events that come later in the relay chain

Phosphorylation

Alters protein activity with addition of a phosphate group; transfer of phosphate group is catalyzed by kinase

Phosphatases

Flip proteins back to the non-phosphorylated state

Second messengers

Small, non-protein molecules that pass along a signal initiated by the binding of a ligand to its receptor

Transcription

Makes RNA copy of DNA

Translation

Reads info from RNA to make a protein

Apoptosis

Programmed cell death

Homeostasis

Tendency to resist change in order to maintain a stable, relatively constant internal environment

Negative feedback loops

Act to oppose the stimulus that triggers them back toward a set point

Positive feedback loops

Amplify the starting signal

Interphase

Cell grows & makes a copy of its DNA

Mitotic phase

Cell separates its DNA into two sets & divides its cytoplasm, forming two new cells

G1 phase

Cell grows larger, copies organelles, & makes molecular building blocks for later steps

S phase

Cell synthesizes a complete copy of DNA in its nucleus & duplicates centrosome

G2 phase

Cell grows more, makes proteins & organelles, begins to reorganize contents in prep for mitosis

Mitosis

DNA condenses into chromosomes & is pulled apart by mitotic spindle

Cytokinesis

Cytoplasm of cell is split in two

Cleavage furrow

Indentation produced as the ring contracts inward during cytokinesis in animal cells

G0 phase

Cell not preparing to divide - its doing its job

Kinetochore microtubules

Microtubules that bind a chromosome

Centromeres

Regions of DNA where sister chromatids are most tightly connected

Checkpoint

Stage in eukaryotic cell cycle at which the cell examines internal & external cues & decides whether or not to move forward w/ division

Cyclins

Group of related proteins that drive the events of a phase

Cyclin-dependent kinases (Cdks)

Enzymes that phosphorylate target proteins

Anaphase-promoting complex/cyclosome (APC/C)

Causes destruction of proteins holding sister chromatids together

p53

Ensures that cells do not pass on damaged DNA

Cancer

Disease of uncontrolled cell division

Replicative immortality

Cancer cells divide many more times than a normal body cell

Metastasis

Cancer cells gain the ability to migrate to other parts of the body

Angiogenesis

Cancer cells promote the growth of new blood vessels which gives tumor cells a source of oxygen & nutrients

Benign tumor

Mass of cells that divide too much but do not have the potential to invade other tissues

Malignant tumor

Group of cells that divide excessively & can invade other tissues

Oncogenes

Overactive, cancer-promoting forms of genes

Tumor suppressors

Genes that normally block cell cycle progression