Topic 6a - Plant structure & nutrient support

Question 1

Non-vascular plants include…

Answer 1

liverworts

mosses

Question 2

Vascular plants include…

Answer 2

Ferns

gymnosperms & angiosperms (seed plants)

Question 3

Monocot characterisation…?

Answer 3

flowers in threes
leaves - smooth parallel veins
stems - scattered vascular bundles
roots - fibrous
seeds - 1 cotyledon (seed leaf)

Question 4

Dicot characteristics…?

Answer 4

flowers - 4's or 5's
leaves - net-like veins
stems - vascular bundles form ring around stem
roots - taproot system
seeds - 2 cotyledons (seed leaves)

Question 5

Characteristics of Meristem cells…

Answer 5

undifferentiated

divide mitotically -> meristem cells and/or differentiated cells

Question 6

Characteristics of differentiated cells…

Answer 6

mature

specialised for specific functions

Question 7

Apical meristems are located where? Resultant growth termed…?

Answer 7

located at tips of roots & shoots

…termed primary growth -> develops into leaves & buds

Question 8

Lateral meristems located… Resultant growth termed…?

Answer 8

around perimeter of stems, roots & branches

…termed secondary growth

Question 9

3 main plant tissue systems?

Answer 9

• dermal (outer)
• ground (mid)
• vascular (inner) typically

Question 10

A bit more on dermal tissue… (location, function, types)

Answer 10

outermost layer
primarily protective
2 main types - epidermis (young), periderm (older)

Question 11

A bit about ground tissue…

Answer 11

The “meat” of the plant. (middle)

3 types

Question 12

What are the 3 types of ground tissue? Function? Eg’s?

Answer 12

parenchyma - photosynthesis, nutrient storage, hormone secretion (eg potato)
collenchyma - mainly support (e.g. celery stalk)
sclerenchyma - mainly support & protection (e.g. pear)

Question 13

Vascular tissue… function? types?

Answer 13

vessels transporting water & nutrients thru plant

2 types - xylem & phloem

Question 14

Functions of xylem… types?

Answer 14

transport of water & minerals from roots to shoots via pores

2 types of vessels - tracheids & vessel elements

Question 15

Function of phloem? types?

Answer 15

transport dissolved nutrients & hormones (in any direction)

2 types - sieve tube elements & companion cells

Question 16

A bit about stems… functions

Answer 16

support for leaves (major function)

Also transport water, nutrients & photosynthate

Question 17

Dicot stem - primary growth functions…

Answer 17

support
storage (starch)
photosynthesis

Question 18

Difference between primary & secondary growth of dicot stems?

Answer 18

primary has: primary phloem & xylem & vascular cambium

secondary has: primary AND secondary phloem & xylem AND DIVIDING vascular cambium

Question 19

Roots functions?

Answer 19

anchor the plant

uptake & storage of water & minerals

Question 20

Nutrients in roots taken up by … transport?

Answer 20

active

Question 21

Define rhizosymbionts…

Answer 21

assist roots in nutrient uptake

2 kinds - mycorrhizae & nitrogen-fixing bacteria

Question 22

Water enters … via …?

Answer 22

root xylem via osmosis

Question 23

What is transpiration? What ‘theory’ is involved?

Answer 23

mechanism allowing transport of water many meters to leaves

“cohesion-tension” theory involved

Question 24

Describe “cohesion-tension” theory. Out loud!

Answer 24

Water enters vascular cylinder of root -> cohesion of water molecules via H-bonds creates water chain -> evaporates thru stomata

Question 25

What is stomatal control of transpiration? Involves a balance between …?

Answer 25

allowing entry to CO2 & allowing loss of water

Question 26

Explain water transpiration via stomatal opening (looks like green anus)…

Answer 26

K+ enters guard cells -> water follows -> guard cells lengthen & bend outward -> pore (green anus) opens

Question 27

What stimulates movement of K+ (re. stomatal opening)?

Answer 27

light (movement inward)
low CO2 (inward)
absidic acid (outward)

Question 28

Describe pressure-flow theory…

Answer 28

sugars move to sites of high [ ] (sources) -> sites of low [ ] (sinks) how??
high [ ] of sugar at source draws water in by osmosis -> increase pressure
[ ] of sugar decreased at sinks
thus pressure differential causes net movement from source to sink