b4 plant biology Flashcards
what is the role of leaves? what subcellular structure is required for this?
absorb light and carry out photosynthesis
chloraplasts
how are leaves adapted to their role of absorbing light and carrying out photosynthesis?
- broad: large surface area for light absorption
- thin: short diffusion distance for gases
- vascular bundles: to transport reactant and product
what is inside of vascular bundles?
xylem and phloem
what level of organisation is the palisade mesophyll, why?
- a tissue
- it’s a group of cells with a similar structure and function (photosynthesis)
give two adaptations of the upper epidermal tissue (of a leaf)?
-thin and transparent
-waxy cuticle
give two adaptations of the palisade mesophyll?
- regular-shaped cells, arranged end-on, near upper surface
- most chloroplasts at the top of the cells
give two adaptations of the spongy mesophyll?
- irregular-shaped cells
- many air spaces
give two adaptations of the lower epidermal tissue?
- many stomata
- pairs of guard cells
give two adaptations of vascular bundles?
- contains phloem
- contains xylem
what is the function of the adaptations of the upper epidermal tissue?
adaptations:
- thin and transparent : (function) allows light to pass to the mesophyll layers
- waxy cuticle: (function) protects the leaf and reduces water loss
what is the function of the adaptations of the palisade mesophyll tissue?
- regular-shaped cells arranged end-on, near upper surface: (function) absorbs the maximum amount of light possible
- most chloroplasts at the top of cells: (function) absorbs the maximum amount of light possible
what is the function of the adaptations of the spongy mesophyll tissue?
- irregular-shaped cells: (function) increases surface area for co2 absorption
- many air spaces: (function) allows gases to diffuse through layer
what is the function of the adaptations of the lower epidermal tissue?
- many stomata: (function) allows gases to enter and leave the leaf
- pairs of guard cells: (function) allows the stomata to open and close
what is the function of the adaptations of the vascular bundles?
- contains phloem: (function) transporting glucose away from the lead
- contains xylem: (function) transporting water and mineral ions to the leaf
suggest the advantage of the stomata being in the lower epidermis?
- reduces water loss, if it was on the upper epidermis then water would evaporate
suggest how plants that grow in hot and dry conditions may be adapted?
- fewer stomata
- smaller leaves/spines
(these both reduce water loss)
describe the location and role of the meristem tissue?
meristem tissue is found at the growing tips of shoots and roots. they contain plant stem cells to allow new cells to be produced for growth and differentiation to form new plant organs
explain how the structure of root hair cells are adapted to their function?
root hair cells have an extension providing a large surface area, to increase the rate of water absorption by osmosis; many mitochondria, to release energy for active transport of mineral ions, and a thin cell wall to reduce diffusion distance for absorption
