AP BIO unit 4

quorum sensing

The ability of bacteria to sense the presence of other bacteria via secreted chemical signals. This allows bacteria to sense changed in thier environment.

Haploid cells

A cell containing only one set of chromosomes (n).

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

ligand

A molecule that binds specifically to another molecule, usually a larger one.

Shmoo

A projection from yeast in response to mating pheromones.

Cell signaling

The process of cell-to-cell communication mediated by signaling molecules and membrane receptors

Autocrine signaling

When the secreting cell targets itself

Endocrine

when the target cell is far from the signal cell in cell communication

Synaptic

chemical release and diffusion across a synapse; a type of paracrine cell signaling

Paracrine

Cell signaling when the target cell is nearby the secreting cell.

Juxtacrine

Cell communication where the 2 cells are touching.

reception stage of cell signaling

A stage in cell signaling where the ligand binds to a receptor. Receptor shape changes.

Transduction Stage

Relay molecules are activated due to reception, they are in a transduction pathway. Small molecules can also act as a messenger.

Response stage of cell signaling

The signal that was transducted results in a celluar response

Intracellular receptors

receptors located inside the cell rather than on its cell membrane. They turn on genes inside the cell that make mRNA that code to make a protien.

What happens when there is a G protein-coupled receptor in reception

The signal molecule activates the receptor. This with GTP (the G-protien) activate an enzyme. That enzyme will lead to a reaction that causes a celluar respose

What happens if there is a ligand gated ion channel in reception

The membrane receptor acts as a gate and that gate opens/closes when the ligand binds to the receptor. The ions moving into the cell cause a cellular response.

What happens if there are enzymatic receptors in reception?

Receptors act as enzymes that are activated by a ligand. They cause a series of reactions that cause a cellular response.

phosphorylation cascade

A series of enzyme-catalyzed phosphorylation reactions used in signal transduction pathways to amplify and convey a signal inward from the plasma membrane.

protien kinase (PK)

The enzyme that transfers a phosphate group from atp to another protien

Protein Phosphatase

An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase. This controls the strength/length of a cell response.

Apoptosis

programmed cell death. Parts of cells are put into vecicles that are digested by scavenger cells

What may cause Apoptosis

An extracellular death ligand, DNA damage in the nucleus, and protein misfolding in the ER

Feedback mechanisms

cycles in which the product of one reaction causes another to start or stop

Positive feedback

A response where a stimulus makes reactions happen that further increase the stimulus.

negative feedback

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus

unicellular organism

An organism made up of one cell.

Multicellular organism

Organism made up of many cells

Genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

somatic cells

non reproductive cells; have 2 sets of chromosomes

Gametes

reproductive cells; have half as much DNA

Chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Centromere

Area where the chromatids of a chromosome are attached

Cytokinesis

Division of the cytoplasm during cell division

Phases of cell cycle

Interphase (G1, S, G2), then Mitosis (Prophase, Metaphase, Anaphase , Telophase)

Mitotic Spindle

Apparatus of microtubules that control chromosome movement in mitosis

Aster

A radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosis.

cleavage furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

Cell plate

A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

binary fission

type of asexual reproduction in prokaryotes in which an organism replicates its DNA and divides in half, producing two identical daughter cells

Nuclear cellular response

after phosphorylation cascade, many signaling pathways regulate protein synthesis by turning specific genes ON or OFF in the nucleus

cytoplasmic cellular response

A change in the cytoplasm of the cell after a signal recieved, that doesent directly change gene transcription

Hydrophilic ligand

-cannot cross cell membrane on its own

-there has to have a receptor on the outside of the membrane

-it is polar; repels the lipid membrane

hydrophobic ligand

-can dissolve through plasma membrane and bind to receptor on the inside of the cell

-nonpolar--> dissolve

Prometaphase

The second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.