unit 4 ap bio Flashcards
signal transduction pathway
Convert signals on a cell’s surface into cellular responses
local regulators
messenger molecules that travel short distances
horomones
chemicals that plants and animals use in long distance signaling
3 processes that cells who receive signals go through
1) reception
2) transduction
3) response
reception
A cell detects a signaling molecule from the outside of the cell
transduction
signal sensed by the receptor protein is transmitted to the inside of the cell
response
A response is a change in cellular behavior due to the signal
ligand
signal molecule
G protein-coupled receptor
plasma membrane receptor that works with help of G protein
G protein
acts as on/off switch, if GDP is bound to G protein then G protein is inactive
receptor tyrosine kinase
membrane receptors that attach phosphates to tyrosines, trigger multiple signal transduction pathways at once
ligand gated ion channel
receptor acts as a gate when the receptor changes shape
when signal molecule binds as a ligand to receptor, gate allows specific ions (Na+, Ca2+) through a channel in the receptor
protein kinase
transfer phosphates from ATP to protein in a process called phosphorylation
protein phosphates
remove phosphates from proteins in a process called dephosphorylation
second messengers
small, nonprotein, water soluble molecules or ions that spread throughout a cell by diffusion
cyclic AMP or cAMP
most widely used second messenger, activates protein kinase A
adenylyl cyclase
enzyme in plasma membrane, converts ATP to cAMP in response to extracellular signal
phases of the cell cycle
G1 or G0, S, G2, M
what is the purpose of cell cycle
development from fertilized egg
growth
repair
produce two identical daughter cells
how does cell cycle contribute to growth and repair
the cycle allows for our body to repair damaged cells and produce new stronger ones so we can stay healthy
difference between chromatid and chromatin
Chromatin is the DNA and proteins that make up a chromosome.
Chromatids are identical pieces of DNA held together by a centromere
difference between mitosis and cytokinesis in plant and animal cells
mitosis in animals- mitotic spindle is formed w the help of two centrioles
mitosis in plants- mitotic spindle is formed without any help
plant cytokinesis- cytoplasmic division starts at center and moves towards cell wall
animal cytokinesis- cytoplasmic division starts at edges of cell at plasma membrane and moves towards center
somatic cell
nonreproductive cell, two sets of chromosomes
gametes
reproductive cells; sperm and egg, half as many chromosomes as somatic
centromere
narrow waist of duplicated chromosome, where the two chromatids are most closely attached
what does meiosis yield
nonidentical daughter cells that have only one set of chromosomes, half as many parent cell
centrosome
where the assembly of spindle microtubules begin, “microtubule organizing center”
mitotic spindle
apparatus of microtubules that control chromosome movement during mitosis
compare mitosis and meiosis
mitosis is division of nucleus and meisosis produces gametes (sex cells)
paracrine signaling
allows cells to communicate with each other by releasing signaling molecules that bind to and activate surrounding cells
scafolding protein
large relay proteins to which other relay proteins are attached
can increase signal transduction efficiency by grouping together different proteins involved in same pathway
apoptosis
programmed or controlled cell suicide
chopped and packed into vesicles that are digested by scavenger cells
prevents enzymes from leaking out of dying cell and damaging neighbor cells
phosphorylation cascade
sequence of signaling pathway events where one enzyme phosphorylates another , causing a chain reaction leading to the phosphorylation of thousands of proteins
what triggers apoptosis
extracellular death signaling ligand
DNA damage in nucleus
protein misfolding in endoplasmic reticulum
