ap bio unit 4

paracrine

signals diffuse to and affect nearby cells

autocrine

signals affect the cells that made them

juxtacrine

signals act through direct stimulation of the adjacent cells

endocrine

signals to distant cells through bloodstream

quorum sensing

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

ligand

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

extracellular reception

large polar ligands bind on the cell membrane to be transported inside the cell

g protein

an intermediary between the receptor and an effector protein

G-protein Activation

receptor binding to a G protein and the G protein causing a GTP to displace the GDP (when the receptor is appropriately activated) leading to downstairs signal amplification

Receptor Proteins

when a ligand hits _________ it causes a shape change, activating the reaction

Role of Kinases

phosphorylate enzymes, activating or deactivating them (amplify a reaction)

Second Messengers

a small molecule that amplifies lager steps in a signal transduction pathway by binding to target enzymes noncovalently

Physical Change in Activation

a previously inaccessible active site is exposed, and the target protein goes on to preform a new cellular role

Insulin Signaling

in pancreas (-an endocrine hormone) and stimulates glycogenesis in liver and cells to lower blood glucose levels

GLUT4 Response to Insulin

glucose transporters are needed to get glucose from the blood to the cells, insulin is a signaling molecule and glucose transportation is a response

Type 2 Diabetes

cells stop responding to insulin, so glucose cannot be stored in the cells as glycogen

Mutation of Receptor

overgrowth of cancer cells

Loss of Secondary Molecule

alters protein shape

Negative Feedback

a primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation

Positive Feedback

a type of regulation that responds to a change in conditions by initiating responses that will amplify the change

Interphase

period of the cell cycle between cell divisions

G1

Stage of interphase where cells grow in size

S

stage of interphase where DNA is replicated

G2

stage of interphase where cells prepare for division

Mitosis

cell division

Prophase

prepare the nuclear envelope breaks down and the compacted chromosomes, each with 2 chromatids, attach to kinetochore microtubes

Metaphase

middle
the chromosomes line up at the middle of the cell (equatorial position)

Anaphase

apart
the chromatids separate and the daughter chromosomes move apart from each other toward the poles

Telophase

a nuclear envelope forms around each set of new chromosomes, nucleoli appear, and the chromosomes become less compact

Cytokinesis

final stage of cell reproduction where the cells cytoplasm gets divided

G1 Checkpoint

checks for cell size, nutrients and growth factors

G2 Checkpoint

checks for DNA damage

M Checkpoint

checks that the metaphase spindles are attached right and are centered
benefit of attaching on the middle of the spindle is the correct splitting of the chromosomes

G0

determines which processes of cell division are turned on and off

CDK

cyclin dependent kinase, turns cell processes on and off

MPF

causes the cell to move from interphase into mitosis

Porto-oncogenes

the corresponding normal cellular genes that are responsible for normal cell growth and division

Tumor Supressor Genes

genes that normally produce proteins that inhibit cell division

Mutated Proto-oncogenes

oncogenes move the cell through the cell cycle even when it shouldn't divide, causing cancer to spread

Mutated Tumor Suppressor Genes

are unable to respond to cell-cycle checkpoints or undergo apoptosis, this leads to more mutations and development of cancer

Apoptosis

programmed cell death when a cell is no longer needed by an organism or has damage/cancer

Intercellular Reception

small nonpolar ligands bind inside the cell

Tyrosine Kinase Phosphorylation

a receptor enzyme where insulin is activated by phosphorylation (add a phosphate group)