nigger

positive feedback

A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organism away from a steady state.

negative feedback

A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state.

feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

paracrine signaling

Signal released from a cell has an effect on neighboring cells.

synaptic signaling

a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell

synapse

Gap between neurons

cell surface receptors

receptors found in the plasma membrane

hydrophobic

Having an aversion to water

hydrophilic

Attracted to water

ligand

A molecule that binds specifically to a receptor site of another molecule.

ion channel receptors

Channel proteins that allow ions to enter or leave a cell

G-protein-linked receptor

A signal receptor protein in the plasma membrane that responds to the binding signal molecule by activating a G protein.

signal transduction pathway

The process by which a signal on a cell's surface is converted into a specific cellular response.

cascade effect

with each step, the hormone's effects are amplified

homeostasis

A tendency to maintain a balanced or constant internal state

interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

centrioles

Located near the nucleus and help to organize cell division

prophase

Chromosomes become visible, nuclear envelop dissolves, spindle forms

metaphase

Chromosomes line up in the middle of the cell

anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

sister chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.

telophase

phase of mitosis in which the distinct individual chromosomes begin to spread out into a tangle of chromatin

cell plate

the precursor of a new plant cell wall that forms during cell division and divides a cell into two

cleavage furrow

The area of the cell membrane that pinches in and eventually separates the dividing cell

cancer

disorder in which some of the body's cells lose the ability to control growth

metastasize

the process by which cancer spreads from one place to another

apoptosis

programmed cell death

cyclin dependent kinase

a protein that binds with a cyclin to activate it, which regulates a step in the cell cycle

cyclic AMP (cAMP)

A compound formed from ATP that acts as a second messenger.

hormone

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

phosphorylation cascade

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

protein kinase

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

receptor

protein that detects a signal molecule and performs an action in response

second messenger

A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signal received by a signal receptor protein.

signal cascade

An entire series of reactions which occurs as a result of a single trigger reaction or compound.

stages of cell signaling

reception, transduction, response

G1

cell grows

G0

resting phase

G2

Final preparation phase. Cell checks for DNA errors and begins to form centrosomes. (Prepares for Mitosis)

S phase

DNA is replicated

cyclins

A group of proteins whose function is to regulate the progression of a cell through the cell cycle and whose concentrations rise and fall throughout the cell cycle