ap bio -- unit 5: cell communication

crashing out

Prophase

nucleus begins to break down. spindle fibers begin to form. DNA is condenses around histones into visible chromosomes. this is the first phase of mitosis.

Metaphase

the duplicated chromosomes line up in the middle of the cell. the spindle fibers attach to the chromosomes. a check point takes place.

Anaphase

the sister chromatids are pulled apart from one another. the are pulled to opposite poles of the cell by spindle fibers

Telophase

This stage is the opposite of prophase. two nuclei are rebuilt, spindle fibers are broken down and the chromosomes decondenses. This is the end of mitosis

Mitosis

A type of cell division in which each daughter cell is genetically identical to the parent cell. makes body cells.

Interphase

Includes G1, Synthesis, and G2. The cell grows and DNA is replicated. Cells spend most the time in this phase.

Cytokinesis

cell pinches in on itself to split the cytoplasm in two.

G1

The cell grows, duplicates organelles, make DNA rep proteins

G2

Cell grows, makes proteins for mitosis

S Phase

The cell replicates all DNA.

sister chromatids

identical copies of a chromosome. made during S phase. they are joined together at the center and are eventually separated during mitosis.

Prophase drawing

Metaphase drawing

Anaphase drawing

Telophase drawing

Interphase drawing

Histones

DNA is wrapped up around these protein molecules so they are condensed and organized.

G1 checkpoint

checks for cell size, nutrients, and DNA damage

G2 checkpoint

checks for cell size; checks that all DNA has been replicated correctly.

G0

The nondividing, resting state of cells. Cell carries out its typical functions in this state. differentiated cells remain in this phase.

M Checkpoint

the cell ensures all sister chromatids are attached to a spindle fiber.

Apoptosis

programmed cell death, initiated if there are mutations or infection

spindle fibers

Protein structures which move the chromosomes during cell division. made of microtubules.

ligase

An enzyme that connects two fragments of DNA to make a single fragment, joins okazaki fragments

Okazaki fragments

Small fragments of DNA produced on the lagging strand during DNA replication

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

primase

An enzyme that adds RNA nucleotides to indicate the starting region for replication

Topoisomerase

corrects "overwinding" ahead of replication forks by unraveling the DNA double helix

antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. they run in opposite directions

ligand

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

Recpetor

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

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.

Responses to cell signaling

turn a gene on or off, apoptosis, undergo mitosis

Plasmadesmata

an open channel in a plant cell wall that connects the cytoplasm of adjacent cells

gap junctions

provides cytoplasmic channels between adjacent animal cells

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

positive feedback loop

feedback loop that causes a system to change further in the same direction; the response amplifies the signal

negative feedback loop

A feedback loop that causes a system to change in the opposite direction from which it is moving; WEAKENS THE STIMULUS

signal amplification

turns one signal molecule into multiple second messenger molecules; happens during transduction

Second messenger

A small, nonprotein, 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.

G protein

a protein coupled to a receptor; conveys messages to other molecules when a ligand binds with and activates the receptor

adenylyl cyclase

Converts ATP to cyclic AMP in response to an extracellular signal.

Kinase

an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule.

Cyclin

one of a family of closely related proteins that regulate the cell cycle in eukaryotic cells by binding to CDKs

CDK

Cyclin-dependent kinases. A protein kinase that is active only when attached to a particular cyclin. Activity rises and falls depending on the concentration of the cyclin partner.