Photosynthesis shoot 1 Flashcards
What are leaves attached to?
What does the terminal bud on a plant contain?
What is found close to the connection between leaves and stems?
Nodes on the stem, often through a petiole.
The apical meristem.
Axillary buds
What is photosynthetic Parenchyma
Photosynthetic parenchyma is called chlorenchyma (contains chloroplasts). thin primary cell walls
Leaf tissues
what is spongy mesophyll and palisade parenchyma?
Spongy mesophyll (where photosynthesis is happening) is made of irregular chlorenchyma cells, contains large intercellular spaces (for CO2 to move through easily) and makes up the bulk of the leaf.
Palisade parenchyma is below the upper epidermis and is made of regularly organised narrow chlorenchyma cells.
What is Collenchyma and where is it found?
Collenchyma is a supportive tissue for growing stems and leaves.
Cells in collenchyma have thick cellulose-rich primary cell wall.
Ribs of stems, petioles and leaves
Describe vascular tissue in the stem, leaves and at the nodes
Where are the bundles found?
Vessels for transport of water, nutrients and carbohydrates are organised in bundles. They are found in stems and leaves (and roots).
*In the stem the plant contains many bundles.
*In leaves, vascular bundles are called veins. Reach all parts of the leaf blade.
*At a node, one, three, five, or more vascular bundles branch from the stem and diverge toward the petiole.
Vascular bundle between cortex and pith (parenchyma) (The innermost region of the stem is the pith whereas the outer region is the cortex.)
*phloem on outside and xylem on the inside of the bundle
Sclerenchyma
Sclerenchyma tissue provides mechanical support, in particular as a sheath of fibre cells around vascular bundles Cells in mature sclerenchyma are dead and have a thick lignified wall. Forms a ring around the bundles
Pears contain sclereids (made of sclerenchyma)
What is secondary growth? perennial plants
Radial growth (thickening) of stems and roots. It exists in most perennial gymnosperms and eudicots but not in monocots.
radial meristems are called cambium
New cells are produced in the vascular cambium and the cork cambium.
What is bark made of?
Bark is made of the periderm and all phloem layers.
What is the main photosynthetic pigment.
What is the structure of chlorophyll?
Where does light reaction take place?
explain antenna complex?
Chlorophyll a
*hydrophobic tail likes to interact with lipids in the thylakoid membrane.
*Porphyrin ring with magnesium in the middle where light is captured and energy is harvested in the ring.
In the lumen of the thylakoids
thylakoids are sheets of inner membrane stacks of discs = grana
Chlorophyll a and accessory pigments (chlorophyll b and carotenoids), organized into an antenna complex, transmit energy from sunlight to chlorophyll a in the reaction center.
Channeling the energy from the photons into one single chlorophyll
Linear electron transport between PSII and PSI
Electrons are transferred via several carriers in the electron transport chain from photosystem II to photosystem I, losing reducing power on the way.
What happens to the electrons in photosynthesis
photons cause Chl* which loses an electron it becomes oxidized (Chl+)
Chl+ is reduced by getting an electron back from splitting water. As electrons are transported down the electron transport chain it loses energy
The excitation by light of PSI reaction center powers more electron movement across another electron transport chain, ending up in the reduction of NADP+ into NADPH.
P700 lost electron is replaced by the one carried by plastocyanin, originating from PSII.
What are the damaging effects of high light
Generation of reactive oxygen species under high light this causes excess energy/electrons that end up on oxygen.
Reactive oxygen species (ROS) then damage the cell.
