Lecture 6: Plant Structure and Function

Question 1

what are the challenges faced by plants on land?

Answer 1

drying out, lack of support, gas exchange, uptake and transport of water and nutrients, reproduction

Question 2

primary cell wall?

Answer 2

primary cell wall: in all plant cells
- secreted by plasma membrane
- composed of cellulose
-provides support and protection to the cell

Question 3

secondary cell wall?

Answer 3

only in some cells
- secreted by plasma membrane after primary wall
- composed of cellulose and lignin
- adds strength and rigidity: wood

Question 4

whats a plasmodesmata?

Answer 4

small holes in a cell wall: water, solutes, and small molecules can pass freely between cells

Question 5

what is turgor pressure?

Answer 5

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

Question 6

Vascular plants have 3 main organs organized into 2 organ systems called?

Answer 6

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

Question 7

function and structures of roots?

Answer 7

functions are anchor the plant and absorb water and nutrients from the soil
structures: primary root, lateral root, root hairs, and tap root

Question 8

function and structures of stems?

Answer 8

function: to raise and seperate the photosynthetic structure of plant towards the sun
structures: nodes ad internodes, apical/terminal bud, axillary bud

Question 9

function and structure of leaves?

Answer 9

function: for photosynthesis and gas exchange
structures: flattened blade, petiole

Question 10

What are the 3 plant tissue systems?

Answer 10

dermal, vascular, and ground tissue systems

Question 11

dermal tissue system?

Answer 11

outer covering of the plant: first line of defense like our skin
it is composed of epidermal tissue and periderm

Question 12

what is the epidermal tissue responsible for?

Answer 12

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

Question 13

What specialized cells is the epidermal tissue composed of?

Answer 13

guard cells: flank stomata to control opening and closing for gas exchange
root hairs: increase surface area for absorption

Question 14

What is the vascular tissue system for and composed of?

Answer 14

it is the transport system of the plant and is composed of xylem and phloem

Question 15

what is the function of xylem?

Answer 15

moves water upwards from root to shoot

Question 16

what is the function of the phloem?

Answer 16

moves sugar from source to sink

Question 17

what are xylem composed of?

Answer 17

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

Question 18

What are phloem composed of?

Answer 18

specialized sugar conducting cells, seive tube elements that transport organic molecules, companioin cells which helo load sugar into sieve tube elements

Question 19

what is the function of ground tissue system and what are they composed of?

Answer 19

storage, photosynthesis, and support , composed of pith: tissue that are internal to vascular tissue and cortex: tissue external to vascular tissue

Question 20

What are the 3 specialized cells in the ground tissue system?

Answer 20

parenchyma cells, collenchyma cells, ad sclerenchyma cells

Question 21

parenchyma cells?

Answer 21

living cells that perform most metabolic functions of the cell including photosynthesis

Question 22

collenchyma cells?

Answer 22

living cells that provide flexible support

Question 23

sclerenchyma cells?

Answer 23

dead at maturity cells that provide structural support

Question 24

What is meristems?

Answer 24

areas of rapid cell division that facilitate growth in plants and there is 2 kinds including apical and lateral meristems

Question 25

apical meristems?

Answer 25

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

Question 26

lateral meristems?

Answer 26

in stems and roots of woody plants:
vascular cambium: produces secondary xylem and phloem
cork cambium: replaces epidermis with thicker periderm