Chapter 11-12 AP Biology

apoptosis

programmed cell death; infected, damaged cells, end of functionally life span

cyclic AMP

second messenger; activates phosphorylation of protein kinase A; intracellular signaling molecule; cyclic adenosine monophosphate (ex - epinephrine binds to liver/muscle cell plasma membrane elevating the cytosolic conc. of cyclic AMP)

G protein

activates G protein-coupled receptors that bind GTP (replacing GDP) --> activates enzyme to become GDP

ligand

molecule that binds specifically to a receptor site of another (larger) molecule; receptor protein changes shape --> activates receptor

protein kinase

enzyme that transfers phosphate groups from ATP to a protein; phosphorylates protein; relay molecules in signal transduction pathways

anchorage dependence

cell must be attached to a substratum to divide/initiate cell division.

signal transduction pathway

sequence of changes/process where a signal on cell's surface is converted into cellular response.

benign tumor

mass of abnormal cells that remain at the original site (too few genetic and cellular changes to survive at a new site)

binary fission

asexual reproduction - single-celled prokaryote; cell grows roughly x2, then divides into two cells of the same size

cell cycle

life of a cell from when it's formed (during division of a parent cell) til it divides into 2 daughter cells

cell plate

vesicles from Golgi move across microtubules to middle of cell forming double membrane in dividing plant cell (then cell wall forms; cytokinesis)

centromere

region of chromosomal dna holds two sister chromatids together; narrow "waist"

checkpoint

control point in cell cycle; stop and go-ahead signals regulate cycle

chromatin

complex of dna + proteins that makes up chromosomes

chromosome

contains one long dna + threadlike proteins + genes; replication/distribution of dna; dna carries genes/traits, protein maintain structure/activity

cleavage furrow

shallow groove in cell surface near old metaphase plate.

cyclin-dependent kinase

kinase that drives cell cycle; depends on changes in conc. of cyclin

cyclin

a protein (cyclically fluctuates in cell) attached to kinase --> makes it active

cytokinesis

division of cytoplasm at the end of mitosis (cleavage furrow in animal cell)

density dependent inhibition

external physical factor affects cell division; ex phenomenon where crowded cells stop dividing (animal cells)

G0 phase

nondividing state; cell exits cell cycle (sometimes reversibly); no go-ahead signal at G1

G1 phase

first gap (growth phase) of interphase in cell cycle; before DNA synthesis

G2 phase

second gap (growth phase) = cell cycle interphase; after DNA synthesis

genome

dna + genetic info in chromosomes in a cell; instruction for making organisms,

growth factor

regulatory protein released to stimulate division (+growth) of cells

interphase

metabolic activity + growth (produces proteins + cytoplasmic organelles - mitch./ER); prepares for division; G1 + S + G2 phases

kinetochore

protein structure on centromere - links sis chromatid to mitotic spindle

malignant tumor

genetic/cellular changes allow cells to spread to new tissues (cell surface changes --> cancer cells detach from neighboring surfaces/ECM) + impair organ functions; excessive multiplication

metaphase plate

imaginary plane between two spindle poles where the centromeres (of duplicated chromosomes) line up

metastasis

spread of cancer cells to locations (besides original site)

hybridization

mating of two true-breeding (produces same variety plant over generations) varieties

mitotic (M) phase

mitosis + cytokinesis; shortest part of cell cycle

mitotic spindle

fibers (of protein + microtubule) controls chromosome movement during mitosis; forms in cytoplasm - prophase

MPF

trigger's cell passage into m phase (past g2); cyclin-cdk complex; relies on cyclin conc.); initiates mitosis

S phase

synthesis (cell cycle); dna replicated (in interphase).

sister chromatids

identical joined copies of a chromosome; contains dna molecules; bound by centromere

transformation

cells that acquire ability to divide indefinitely (cancer cells)