Unit 5: Plants and Photosynthesis Flashcards
autotroph
makes its own food/energy
heterotroph
has to consume other organisms for food/energy
roots
anchor plants in ground, help hold soil in place, absorb water and nutrients to transport to the rest of the plant
leaves
where photosynthesis happens, broad surface absorbs more sunlight, have adapted to environment to prevent water loss
stem
support system, transports nutrients, defense against predators and disease, produce leaves and reproductive organs (flowers)
xylem
carry water (and water soluble substances) throughout the plant, many cells arranged end to end with openings in cells wall, cells are dead, (tracheids and vessel elements)
phloem
carry sugars (and other organic molecules) throughout the plant, cells arranged end to end with many small holes like a sieve, cells are alive (neighboring cells called companion cells support sieve tube elements
cuticle
thick waxy outer layer of tissue, protects against water loss
epidermis
single layer of cells on the outside of plants that help protect the plant
stoma
an opening in the epidermis of a leaf that allows gases to move into and out of the leaf
guard cells
Cells that control the opening and closing of the stomata
transpiration
the process by which plants release water into the atmosphere through their leaves
wilting
when plants leaves droop due to water loss, may mean over transpiration, blockage of xylem, disease, etc.
capillary action
the tendency of water to rise in a thin tube (cohesion, adhesion), how water moves up the xylem
photosynthesis
a process of chemical reactions in plants that turns light energy into chemical energy
chloroplast
The organelle in plant cells in which photosynthesis takes place
chlorophyll
pigments found in plants that absorb sunlight, give plants their green color (reflect green light)
pigments
organic molecules that absorb some wavelengths of light while reflecting others giving them their color
thylakoid
membrane bound organelle inside of a chloroplast where the light-dependent reactions occur
stroma
the “empty” fluid space in a chloroplast where the Calvin Cycle (light-independent reactions) take place
photosystem II
The first step of the light reactions, sunlight is absorbed and excites an electron, electron is passed onto electron transport chain, electron replaced by one produced water turning into oxygen
photosystem I
electron is re-excited when sunlight is absorbed, passed onto electron transport chain again
light-dependent reactions
occur in thylakoid, take in sunlight and water and produce oxygen gas, also convert NADP+ and ADP into NADPH and ATP (energized molecules)
light-independent reactions
occur in stroma, take in carbon dioxide and produce glucose, converts ATP and NADPH into ADP and NADP+ (uses their energy)
NADP+
an electron acceptor molecule, accepts electron in light reactions to become NADPH (energized form)
ATP
adenosine triphosphate, source of chemical energy for cells, produced in light reactions, used in Calvin Cycle and MANY other reactions
electron transport chain
the chain of molecules that allows the movement of electrons across the thylakoid membrane (from photosystems to proteins) required for light reactions
ATP synthase
enzyme in thylakoid membrane that facilitates the diffusion of H+ (protons) across the membrane, H+ atoms spin a turbine like structure in the enzyme as they pass through creating the energy to turn ADP into ATP
mesophyll
The inside of a leaf where photosynthesis occurs,
Palisade-on top of leaf to maximize photosynthesis
Spongy-has air space for gases to enter into
