Photosynthesis Flashcards
How do photosynthetic organisms or photoautotrophs get their nutrients?
absorb carbon dioxide, water and radiant energy from the environment through photosynthesis and transform these components into sugar and oxygen
how do heterotrophs get their nutrients?
they can not synthesize their own glucose and therefore must obtain their energy from other living things in their environment. they are completely dependent on photoautotrophs for food
what is the appearance of two different types of leaves?
- deciduous leaves are thin and broad
- Needle Leaves are thin and narrow
what is the purpose of a leaf?
to increase the surface area exposed to the sun and limit the distance important gases must travel to reach chloroplast
what is chlorophyll?
the only plant organelle containing chlorophyll, the photosynthetic active pigment
why are leafs coated with a waxy cuticle?
to prevent excess light absorptions and water evaporation
what is the appearance of the epidermis layers?
a transparent colourless layer of cells below to cuticle
what is the function of the epidermis layers?
Prevent water loss
allow light to pass through to the mesophyll cells
what is the mesophyll of the plant leaf?
the photosynthetic cells that form the bulk of the plant leaf.
what is an important note about chloroplast in the mesophyll?
chloroplast are most abundant in the spongy and palisade mesophyll
what is the difference between spongy and palisade cells?
SPongy cells are more spread out with air spaces between them. Palisade cells are more tightly packed together and possess more chloroplast because there are more cells present
what is the function of the vascular bundles?
they are needed to transport water and minerals to the leaves from the roots and carbohydrates produced from photosynthesis from the leaves to the roots.
where are the guard cells located?
on the lower epidermis
what is the function of stomata cells?
regulate the gas exchange with the environment and allow water to escape by transpiration (releasing water vapour from the air to the leaves)
what is transpiration?
the evaporation of water from the aerial parts of the plant ( parts of the plant that are above the soil including the stem, leaves, and petioles) with the help of the stomata
what are the two benefits of transpiration?
- helps pull more water vapour and other substances from the roots where they are absorbed into the leaves where they are used
- has an evaporative cooling effect. Prevents leaves from heating to temperatures that could inhibit or even denature enzymes catalysing photosynthetic reactions
what are the two benefits of transpiration?
- helps pull more water vapour and other substances from the roots where they are absorbed into the leaves where they are used
- has an evaporative cooling effect. Prevents leaves from heating to temperatures that could inhibit or even denature enzymes catalyzing photosynthetic reactions
how are stomata controlled by the guard cells?
stomata opens when the guard cells or swollen and closes when the guard cells are limp
what is the size of the guard cells determined by?
the direction of osmosis (water moving in and out of the cell)
what direction does osmosis flow?
the direction of osmosis flow in the same direction of potassium ions across the guard cell membrane
how does potassium concentration influence when the guard cells open?
when the concentration of potassium is high outside, the potassium ions flow in to balance of the concentration. water follows, and the cell swells. the swollen cells buckle outward, therefore, opening the stomata
how does pottaisum ion concentation influence when the guard cells close?
When the concentration of potassium is high inside the leaf the potassium ions move out the balance of the concentration. water follows, the guard cells sag and the stomata close
when does the stomata open and close and why?
stomata open during the day and close at night. The morning sun activates receptors on the guard cells membrane which activate the proton pumps. the proton pump drive protons out and the electrochemical gradient that results drives potassium ions in to balance gradient. water follows, the cells swell, stomata open.
when do the stomata open and close and why?
stomata open during the day and close at night. The morning sun activates receptors on the guard cells membrane which activate the proton pumps. the proton pump drive protons out and the electrochemical gradient that results drives potassium ions in to balance gradient. water follows, the cells swell, stomata open.
What do photosynthetic pigments do?
Absorb light energy and begin the process of photosynthesis
What is the structure of chlorophyll
Contains a porphyria ring attached to a long hydrocarbon tail
What is the structure of prophyrin?
Contains an Mg atom at its center surrounded by a hydrocarbon ring with alternating single and double bonds
where are delocalized electrons found?
in the alternating bonds of the porphyrin ring attached to a long hydrocarbon tail.
what does the porphyrin rind do
absorbs light energy and begins photosynthesis
what is the difference between chlorophyll a and chlorophyll b
Chlorophyll a contains a methyl group at the R position
-chlorophyll b contains an aldehyde at the ar position
what is the significance of the functional groups in chlorophyll
the functional groups affect the type of light energy the molecules can absorb
what does the phytol tail do?
anchors the molecules in a membrane associating with the hydrophobic region of the phospholipid bilayer
where does photosynthesis occur
partially within the stroma and partially within the thylakoid membrane
