Photosynthesis & Cell communication (ch10&11) Flashcards
what are the light reactions of photosynthesis
- occurs in the thylakoid membranes
- converts solar energy to chemical energy
- transfers electrons & protons from water to NADP+, forming NADPH
- produces ATP from ADP through phosphorylation
properties of light
light is a form of electromagnetic energy
light has wavelike properties
purpose and products of the calvin cycle
uses ATP & NADPH produced during light reactions to generate G3P
quorum sensing
method of cell communication that allows bacteria to detect population density
local signalling
occurs between nearby cells
- direct contact via cell junctions & cell-cell recognition
- paracrine/synaptic signalling
long-distance signalling
communication throughout an organism
- based on secretion & detection of signalling molecules produced by plants & animals
what occurs in the reception stage of cell signalling
a cell detects a signalling molecule outside of the cell
- requires a receptor protein to recognize signalling molecules
- signalling molecule acts as ligands (binding impacts shape & function of receptor)
what occurs in transduction stage of cell signalling
series of steps (cascades) that converts a signal (with second messengers) to cause a specific cellular response
- multistep signal transduction pathway involving relay molecules
what occurs in the response stage of cell signalling
transduced signal finally triggers a specific cellular response, involving catalysts, activation of genes, etc.
what are receptor proteins
bind to signal molecules, and the resulting structural change temporarily modifies the function of the receptor
G protein-coupled receptors (GPCRs)
work with a G protein that binds GDP/GTP
Receptor tyrosine kinases (RTKs)
self-phosphorylates, dimerizes, & structurally modifies relay proteins
Ligand-gated ion channel receptors
a channel that opens in response to signal molecule binding
secondary messengers
small, nonprotein molecules involved in signal transduction
types of responses elicited by signal transduction pathways
- changes in gene expression via transcriptional regulation
- changes in rate of protein’s activity (cell function)
signal specificity
different cells have different responses to the same signal based on their collection of proteins (proteome)
signal termination
cellular response to a signal needs to stop once the signal is removed
