Week 8 - Plant Structure

Question 1

What are the three basic plant organs?

Answer 1

Roots
Stems
Leaves

Question 2

What are the functions of roots?

Answer 2

Anchoring the plant
Storing carbs
Absorbing water and nutrients

Question 3

Describe the taproot system

Answer 3

One main root (taproot), with lateral roots branching out of it

Question 4

What root system do eudicots have?

Answer 4

Taproot

Question 5

What root system do monocots have?

Answer 5

Fibrous root system

Question 6

Describe the fibrous root system

Answer 6

Adventitious root emerge from the base of the stem. No main root. Lateral roots come out of the many adventitious roots

Question 7

What are root hairs?

Answer 7

Hair-like extensions that cove the outside surface of young roots. Increases absorptive surface area

Question 8

Name and explain the modified roots

Answer 8

Prop roots: extra roots for structure. Type of adventitious root

Storage roots: Stockpile carbs

Green roots: can photosynthesize

Pneumatophores: Get atmospheric oxygen. MANGROVE TREES- the other roots can’t get much from the water (waterlogged)

Question 9

What are the functions of stems

Answer 9

Support

Distribute water and minerals, and sugar

Question 10

Name and explain the modified stems

Answer 10

Rhizomes: stem that grows horizontally underground to store carbs and take up more room

Stolons: Above ground. Grow horizontally to propagate (ex: strawberry plants)

Tubers: Store carbs

Question 11

Explain apical dominance

Answer 11

As long as apical buds stay intact, axillary buds stay dormant

Question 12

Explain the function of leaves

Answer 12

Photosynthesis

Question 13

What is the difference between simple and compound leaves?

Answer 13

Simple: flattened blade

Compound leaf: many leaflets

Question 14

Name and explain the different modified leaves

Answer 14

Tendrils: spiral to climb

Spines: deter herbivory

Storage: store water

Plantlets: asexual reproduction

Question 15

Explain dermal tissue

Answer 15

Dermal tissue
Covers outside surface.
Defense against physical damage. EPIDERMIS, guard cells and stomates (guard cells open and close stomata)

Includes periderm in woody plants

Question 16

Explain the vascular tissue (general)

Answer 16

Vascular tissue
Continuous vascular conduits.

Xylem- water from roots to shoots
Phloem- hormones, sugars, amino acids from where they are made to where they are needed

Question 17

Explain the ground tissue

Answer 17

Ground tissue.
The rest. Whatever is not occupied by vascular or dermal

Structural support and storage.

EUDICOTS
Ground tissue closest to the edge = cortex
Ground tissue closest to the center= pith

MONOCOTS
No difference in ground tissue

Question 18

What type of cell makes up the ground tissue?

Answer 18

Mesophyll
Upper layer if palisade mesophyll and loser layer of spongy mesophyll (less dense)

Question 19

Name the major plant cell types

Answer 19

Parenchyma
Collenchyma
Sclerenchyma

Question 20

Describe parenchyma cells

Answer 20

Thin, flexible primary cell walls. NO SECONDARY CELL WALLS

Metabolic functions of the plant (ex: photosynthesis and storage of photosynthates)

Can still divide and differentiate

Question 21

Describe collenchyma cells

Answer 21

Thickened, uneven cell walls
Lack secondary cell walls

Structural support

Found on the underside of the epidermal layer

VERY THICK FIRST CELL WALL

Question 22

Describe scherenchyma cells

Answer 22

Protection, support, long distance transport

LIGNIN IN SECODNARY CELL WALL

primary source of dietary fibre

1. SCLEREID CELLS
   found in nut shells. Short, regularly shaped
2. FIBRE CELLS
   long and slender.

Question 23

Describe the specialized xylem cells

Answer 23

1. Tracheids. Long, tapered end.
2. Vessel elements (angiosperms only) Wider.

Question 24

Describe the specialized phloem system cells

Answer 24

Move the products of photo where it iss needed or stored

1. Sieve tube elements. Like a straw. It’s emptied.
2. Companion cells. Serves the sieve tube elements

Question 25

What is the junction where two sieve tube elements meet called? What does it do?

Answer 25

Sieve plates

Enables the flow of phloem sap

Question 26

What is the root collar?

Answer 26

Where the stem transition into the root

Question 27

What is the difference between determinate and indeterminate growth?

Answer 27

Determinate: ex: leaves. Stop growing at maturity

Indeterminate (2 KINDS): primary and secondary

Question 28

What are the three zones if primary growth

Answer 28

Dufferentiation

Elongation

Division (nearest to root cap)

Question 29

What does secondary growth do?

Answer 29

Increases diameter of stems and roots

Question 30

What is the rule about differenciation and the vascular cambium?

Answer 30

If cells differenciate on the inside, it’s a xylem cell

outside = pholem

Question 31

Which cells accumulates?

Answer 31

XYLEM ACCUMULATES

PHLOEM DOES NOT

Question 32

What is the star pattern on a cut tree?

Answer 32

Vascular rays

provide substances from secondary xylem to secondary phloem

Question 33

Explain growth rings on trees

Answer 33

Xylem cells with different diameters

In spring xylem is thicker bc of water need to make new leaves

In summer structure is more important so it’s more densely packed.

Rings are alternating between esrly and late wood

Question 34

Is heartwood vascular? What is it?

Answer 34

Old xylem. not vascular anymore just for support

Question 35

What do cork cells have?

Answer 35

Pseuborin