Lecture 6: Plant Structure and Function Flashcards
what are the challenges faced by plants on land?
drying out, lack of support, gas exchange, uptake and transport of water and nutrients, reproduction
primary cell wall?
primary cell wall: in all plant cells
- secreted by plasma membrane
- composed of cellulose
-provides support and protection to the cell
secondary cell wall?
only in some cells
- secreted by plasma membrane after primary wall
- composed of cellulose and lignin
- adds strength and rigidity: wood
whats a plasmodesmata?
small holes in a cell wall: water, solutes, and small molecules can pass freely between cells
what is turgor pressure?
outward force exerted by water inside the cell against the primary cell wall
ANIMAL CELL without no cell wall will burst PLANT CELL cell wall prevents from bursting
Vascular plants have 3 main organs organized into 2 organ systems called?
root system and shoot system
root system: absorb water and nutrients from soil and the organs involved are roots
shoot system: responsible for photosynthesis and the organs involved are stems and leaves
function and structures of roots?
functions are anchor the plant and absorb water and nutrients from the soil
structures: primary root, lateral root, root hairs, and tap root
function and structures of stems?
function: to raise and seperate the photosynthetic structure of plant towards the sun
structures: nodes ad internodes, apical/terminal bud, axillary bud
function and structure of leaves?
function: for photosynthesis and gas exchange
structures: flattened blade, petiole
What are the 3 plant tissue systems?
dermal, vascular, and ground tissue systems
dermal tissue system?
outer covering of the plant: first line of defense like our skin
it is composed of epidermal tissue and periderm
what is the epidermal tissue responsible for?
the epidermis: is in non woody and young woody plants
- secretes a waxy coating to prevent water loss
- the root epidermis absorbs water and minerals
periderm: in woody plants instead if epidermis
What specialized cells is the epidermal tissue composed of?
guard cells: flank stomata to control opening and closing for gas exchange
root hairs: increase surface area for absorption
What is the vascular tissue system for and composed of?
it is the transport system of the plant and is composed of xylem and phloem
what is the function of xylem?
moves water upwards from root to shoot
what is the function of the phloem?
moves sugar from source to sink
what are xylem composed of?
specialized water/nutrient conducting cells
-tracheids: long thin cells, thick secondary cell walls
- vessel elements: wider and shorter than tracheids: connected end to end lengthwise and more efficient at water transport than tracheids
What are phloem composed of?
specialized sugar conducting cells, seive tube elements that transport organic molecules, companioin cells which helo load sugar into sieve tube elements
what is the function of ground tissue system and what are they composed of?
storage, photosynthesis, and support , composed of pith: tissue that are internal to vascular tissue and cortex: tissue external to vascular tissue
What are the 3 specialized cells in the ground tissue system?
parenchyma cells, collenchyma cells, ad sclerenchyma cells
parenchyma cells?
living cells that perform most metabolic functions of the cell including photosynthesis
collenchyma cells?
living cells that provide flexible support
sclerenchyma cells?
dead at maturity cells that provide structural support
What is meristems?
areas of rapid cell division that facilitate growth in plants and there is 2 kinds including apical and lateral meristems
apical meristems?
at tips of roots and shoots: make xylem and phloem
- root: as new cells grow they push end of root further into soil
-shoot: as cells in the apical meristem divide, plant grows upwards and creates new leaves
lateral meristems?
in stems and roots of woody plants:
vascular cambium: produces secondary xylem and phloem
cork cambium: replaces epidermis with thicker periderm
