Cell Cycle and Communication (Unit 4)

ligand

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

receptor

Protein that detects a signal molecule and performs an action in response. Could be located on the membrane surface, cytoplasm, or nucleus of a cell

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

plasmodesmada

openings in cell walls that allow cells to exchange materials; unique to plants

quorum sensing

The ability of bacteria to sense the presence of other bacteria via secreted chemical signals.

morphogens

Signaling molecules that stimulate cell differentiation and development.

signal transduction

A series of molecular changes that converts a signal on a target cell's surface to a specific response inside the cell.

phosphorylation

the addition of a phosphate group to a molecule

G-protein coupled receptors

A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. Also called a G protein-linked receptor.

Cyclic AMP (cAMP)

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

phosphorylation cascade

A series of different molecules in a pathway are phosphorylated in turn, each molecule adding a phosphate group to the next one in line

location of receptors

surface of the target cell, cytoplasm or the nucleus of the target cell

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

ligand gated channels

open in the presence of a specific binding substance, usually a hormone or neurotransmitter

phenotype

An organism's physical appearance, or visible traits.

genotype

genetic makeup of an organism

apoptosis

programmed cell death

negative feedback

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

positive feedback

Feedback that tends to magnify a process or increase its output.

homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry

mitosis

part of eukaryotic cell division during which the cell nucleus divides

interphase

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

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

G0 Phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

G2 phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs. Protein synthesis occurs and a large amount of ATP is made.

chromosome

A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins.

chromatid

one of two identical "sister" parts of a duplicated chromosome

prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

anaphase

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

telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.

cytokinesis

division of the cytoplasm to form two separate daughter cells

cyclin

one of a family of proteins that regulates the cell cycle in eukaryotic cells

Cancer

any malignant growth or tumor caused by abnormal and uncontrolled cell division