Unit 4 Flashcards
Chapters 11 + 12
Quorum Sensing
The ability of bacteria to sense local population densities if they have a concentration of signaling molecules
Cell Junctions
Sections that can directly connect the cytoplasm of adjacent cells in plants and animals
Paracrine Signaling
Type of local signaling in animals that relies on growth factors to stimulate nearby cells to grow and divide; occurs when signal molecules bind to receptors
Synaptic Signaling
Local signaling in animals that occurs when a neurotransmitter is released in response to an electric signal
Hormones
Type of long distance signaling chemical; endocrine signaling
Ligand
The specific signal molecule that attaches to its receptor on or in the target cell
G Protein-Coupled Receptors (GPCRs)
Lie on the cells’ surface and work with G Proteins to transduce signals across the plasma membrane
GTP
Type of cellular energy that plays a role in signaling pathways
Receptor Tyrosine Kinases (RTKs)
Membrane receptors that attach phosphates to tyrosines; can trigger multiple pathways at once
Ligand-Gated Ion Channels
Act as a gate that opens/closes when receptor changes shape due to binding
Transcription Factor
Certain complexes that can turn specific genes on/off
Phosphorylation
Process by which phosphates are transferred from ATP to protein which yields ADP
Phosphorylation Cascade
System of “passing down the phosphate” in which many relay molecules work together with one signal
Dephosphorylation
Process that removes phosphates from proteins
Second Messengers
Small, nonprotein, water-soluble molecules/ions that spread throughout cell by diffusion and participate in signaling pathways
Scaffolding Proteins
Large relay proteins to which other relay proteins are attached that increase signal transduction efficiency by grouping together related proteins within the same pathway
Apoptosis
Process of “programmed cell death” that is carried out by cells that have reached the end of their lifespan or have irreparable damage
Cell Cycle
Duration of a cell’s life from formation to division
Genome
All the DNA that can be found in each species
Somatic Cells
Nonreproductive cells that have 2 sets of chromosomes that exist as a pair
Gametes
Reproductive cells that have a single set of chromosomes
Centromere
Narrow junction point of duplicated chromosomes where chromatids attach
Sister Chromatids
The two identical copies of a chromosome resulting from DNA replication before mitosis
Cohesions
Areas where sister chromatids are attached
Mitosis
The division of genetic material in the nucleus which conserves the number of chromosomes in its daughter cells
Cytokinesis
The division of the cytoplasm
Mitotic Spindle
A structure made of microtubules that control chromosome movement during mitosis
Centrosome
Organelle in animal cells were the mitotic spindles are formed
Kinectochores
Protein complexes associated with centromeres where spindle microtubules attach to
Metaphase Plate
Horizontal plane between spindle poles where chromosomes align during Metaphase
Separase
Enzyme that cleaves cohesions between sister chromatids during anaphase
Cleavage Furrow
The splitting/formation of the new plasma membrane in animal cells undergoing cytokinesis
Cell Plate
The new cell wall formed in plant cells undergoing cytokinesis
Binary Fission
Method of prokaryotic reproduction in which the 2 daughter chromosomes actively move apart (requires no spindles, microtubules, or centromeres)
“Checkpoints”
Specific places in the cell cycle that require a signal for the cell to move into the next phase of division
Maturation-Promoting Factor (MPF)
A protein signal that triggers cell’s passage past G2 checkpoint; cell enters M phase
Growth Factors
External signals released by certain cells that stimulate cell division
Density-Dependent Inhibition
When a crowded cellular environment stops cells from dividing
Anchorage Dependence
Cells must be attached to a substratum (surface) in order to divide
