Plants - Structure and Function

Question 1

Natural selection has molded plant structure to support function at the

Answer 1

organ, tissue, and cellular levels

Question 2

Organs adapted to

Answer 2

• take up water and minerals from below ground
• take up CO2 and light from above ground

Question 3

They are organized into two systems

Answer 3

1. Root system
2. Shoot system

Question 4

Roots rely on ….. produced by ….. in the ….. system

Answer 4

sugar / photosynthesis / shoot

Question 5

Shoots rely on …… and …… absorbed by the ….. system

Answer 5

water / minerals / root

Question 6

Roots important functions:

Answer 6

• Anchoring the plant
• Absorbing minerals and water
• Storing carbohydrates

Question 7

Lateral roots

Answer 7

branch off from the primary root improving anchorage and water absorption

Question 8

Taproot

Answer 8

usually develops from the primary root and functions in anchoring the plant in the soil

Question 9

Root hairs

Answer 9

finger-like extensions of epidermal cells, increase the absorptive surface of the root

Question 10

Mycorrhizal associations, symbiotic interactions with soil fungi, increase

Answer 10

mineral absorption in most plants

Question 11

Stem

Answer 11

a plant organ bearing leaves and bu

Question 12

Stems consist of an alternating system of

Answer 12

nodes and internodes

Question 13

Nodes

Answer 13

the points at which leaves are attached

Question 14

Internodes

Answer 14

the stem segments between nodes

Question 15

Apical bud

Answer 15

Also known as the growing shoot tip causes elongation of a young shoot

Question 16

Axillary bud

Answer 16

A structure that has the potential to form a lateral branch, thorn, or flower

Question 17

The primary function of the stem is to

Answer 17

elongate and orient the shoot to maximize photosynthesis

Question 18

Many plants have modified stems that perform

Answer 18

alternate functions

Question 19

Leaves

Answer 19

• main photosynthetic organ of most vascular plants
• intercept light, exchange gases, dissipate heat, and defend against herbivores and pathogens

Question 20

What does a leaf consist?

Answer 20

generally consists of a flattened blade and a stalk, the petiole, which joins the leaf to the stem

Question 21

Veins

Answer 21

The vascular tissue of leaves, monocots and eudicots differ in their arrangement

Question 22

Most monocots have

Answer 22

parallel veins

Question 23

Most eudicots have

Answer 23

branching veins

Question 24

What helps with plant identification

Answer 24

Leaf shape, arrangement of veins, and spatial pattern of leaves

Question 25

Leaf shape may be

Answer 25

simple or compound

Question 26

Tissue systems

Answer 26

Dermal Vascular Ground

Question 27

Dermal tissue

Answer 27

protective outer coating

Question 28

A waxy cuticle covers the

Answer 28

epidermis (non-woody) and protects leaves and most stems from water loss

Question 29

A protective layer called the periderm replaces the

Answer 29

epidermis in older regions of woody stems and roots

Question 30

Guard cells

Answer 30

specialized dermal cells that facilitate gas exchange in shoots

Question 31

Vascular tissue

Answer 31

helps transport materials through the plant and provides mechanical support

Question 32

Xylem

Answer 32

conducts water and dissolved minerals upward from roots into the shoots (dead at maturity)

Question 33

Phloem

Answer 33

transports sugars from where they are made (primarily leaves) to actively growing parts of the plant or storage structures (alive at maturity, but lack a nucleus, ribosomes, vacuole, and elements of the cytoskeleton)

Question 34

Ground tissue

Answer 34

includes cells specialized for storage, photosynthesis, support, and short-distance transport

Question 35

Indeterminate growth

Answer 35

A plant can grow throughout its life

Question 36

Meristems

Answer 36

undifferentiated tissues composed of dividing cells that allow continuous growth

Question 37

determinate growth

Answer 37

Most animals and some plant organs cease to grow at a certain size

Question 38

2 main types of meristems

Answer 38

apical meristems and lateral meristems

Question 39

Apical meristems

Answer 39

located at the tips of roots and shoots

Question 40

Primary growth

Answer 40

Cells of the apical meristems allow for elongation of shoots and roots

Question 41

Secondary growth

Answer 41

Allow the stems and roots of woody plants to grow in circumference

Question 42

In most eudicots, the vascular tissue consists of

Answer 42

vascular bundles arranged in a ring

Question 43

In most monocot stems, the vascular bundles are

Answer 43

scattered throughout the ground tissue

Question 44

The waxy cuticle coating the leaf epidermis reduces water loss except where interrupted by

Answer 44

stomata

Question 45

Stomata

Answer 45

pores in the epidermis, allow exchange of CO2 and O2 between the surrounding air and photosynthetic cells inside the leaf

Question 46

Each stoma is flanked by two guard cells, which

Answer 46

regulate its opening and closing to reduce water loss

Question 47

Mesophyll

Answer 47

(ground tissue) of eudicots has two layers

Question 48

Cells of the palisade mesophyll (upper layer) are

Answer 48

rich in chloroplasts to maximize light capture

Question 49

Cells of the spongy mesophyll (lower layer) are

Answer 49

loosely packed to create air spaces for gas exchange

Question 50

What causes the movement of water and minerals in most vascular plants?

Answer 50

Water and minerals are pulled up from the roots by negative pressure generated by evaporation from leaves

Question 51

What causes the movement of sugars in most vascular plants?

Answer 51

Sugars are pushed by positive pressure from where they are produced or stored to where they are needed

Question 52

Early nonvascular land plants lived in shallow water and had

Answer 52

aerial shoots

Question 53

Natural selection favored

Answer 53

taller plants with flat appendages, multicellular branching roots, and efficient transport

Question 54

Long distance transport of water, minerals and sugar was possible after the evolution of

Answer 54

xylem and phloem

Question 55

the more energy invested into branching

Answer 55

the less energy available for growth in height

Question 56

Why do plants need so much water?

Answer 56

90% is lost through stomata

Question 57

Why waste so much water through the stomata?

Answer 57

Keeps plant rigid, transportation as well.

Question 58

If a plant grows in a hot, wet place, would you expect it to have more or fewer stomata?

Answer 58

More! It needs to remove water quickly to maintain pressure.

Question 59

Shady environment?

Answer 59

Fewer

Question 60

Shoot adaptations represent compromises between

Answer 60

enhancing photosynthesis and minimizing water loss

Question 61

When turgid (full of water)

Answer 61

guard cells bow outward and the pore between them opens

Question 62

When flaccid (not full)

Answer 62

guard cells become less bowed and the pore closes

Question 63

Stomatal opening at dawn is triggered by

Answer 63

Light CO2 depletion An internal “clock” in guard cells

Question 64

Freely available water is required to

Answer 64

keep stomata open for uptake of CO2

Question 65

Xerophytes

Answer 65

plants adapted to arid climates

Question 66

Some xerophytes avoid drying out by

Answer 66

completing their entire life cycle during the rainy season