Midterm 3- Split pea Flashcards
Sensory response pathway of plants
1)Sensory cells perceive a stimulus and transduces the information to an internal signal
2)Cell-Cell Signal released by the sensory cells travels throughout the body
3)Target cells receive the signal and change activity in a way that produces an appropriate response.
Receptor proteins
Detect environmental signals and change shape transferring the signal into an internal signal usually with a hormone
Signal Molecules
Located within the cell and elicit a response when bound to a matching receptor
Two methods of signal transduction
1)Phosphorlaytion, change of ADP into ATP on an associated protein
2)Secondary messengers: Trigger production of release of inter cellular signals that amplify a signal
Different type of response to signals
1)Activate membrane transport
2)Change in electrical potential or Ph
3)Change in gene expression
Phototropisim
Directed movement of plants in response to blue light
Why do plants bend towards blue light?
Blue light triggers the opening of stoma allowing for photosynthesis to occur
Photoreceptors
Receptors that detect blue light and intitate the phototropic response
Coleoptile
Protective sheath that is found on the tip of the plant that promotes the movement of plants towards light
Fritz Went experiment
Use of Mica (horomone blocking) and Agar(Hormone tranducting) in between coleptile and plant, the agar would allow movement to occur where as the mica did not
Auxin
Hormone that signals for plant elongation on the side opposite to detected light, promotes fruit development, leaf and fruit falling, differentiate xylem and phloem as well as vascular cambium, and simulates root growth
Auxin receptors
1)ABP1=Extracellular response
2)T1R1=Intracellular response
Acid growth hypothesis
1)Auxin triggers H+ pumps lowering the Ph to 4.5
2)Lowered Ph triggers expanisins to cut H bonds between cellulose and other cell wall polymers loosening the cell wall
3)K+ wants to restore chemical gradient so moves into the cell and brings water with it, expanding the cell
Role of Red light and Far red light in plants
Red light acts as an on switch for germination and far red light acts as an off switch for germination
Phytochrome and their conformations
Absorbs both red and far red light
Pr: Has absorbed FR light and needs red light, no germination occurs
PFR: Has absored Red light and needs FR light to change back, germination occurs
Etiolation
When no blue light is present then the plant grows extremly long, narrow, thin, and pale to try and break to the light
De-etoliation
Once light levels are sufficient stem growth slows and now energy is invested in chloroplast and leaves
Photoperiodism
Plants internal clock that is controlled by the CO gene, in short day plants they only flower during short days and long day plants only flower in long days
Effect of red and far red on photoperiodism
Red light triggers a daylight response and far red light triggers a night response
Florigen
Flowering horomone
Flowering Locus
Gene that promotes flowering when activated, it triggers the apical meristem to activate and form a flower.
Heliotropism
Tendency for certain plants to track the movement of the sun throughout the day and then reset over the course of the night
Heliotropisim and plant development
1)Tethered stems that cannot response to light photosynthesis less
2)As plant growth slows so did sunlight tracking
3)Auxin is expressed alternating amounts due to gene expression
Gravitropisim
Movement of roots downward in response to gravity