2.3 Structure and function of plant parts

Question 1

The external structure of a typical angiosperm has two major systems:

Answer 1

Shoot and root system

Question 2

_ is the plant part usually found above the ground and includes the organs such as stem, branches, leaves, buds, flowers and fruits.

Answer 2

The shoot system

Question 3

T/F
Leaves and branches may be missing from an angiosperm depending on the reproductive stage of the plant.

Answer 3

False, it’s flowers and fruits

Question 4

_ is the part of the plant that usually grows downward into the ground.

Answer 4

The root system

Question 5

_ includes the primary or tap root, lateral or branch roots, root hairs and root cap.

Answer 5

The root system

Question 6

_ are distinguished from
an underground stem in that, it does not bear either leaves or buds.

Answer 6

Roots

Question 7

The external structure of a typical leaf consists of the _, _, _, _, _, _ and _.

Answer 7

petiole (leaf stalk), lamina (blade – broadest part), veins, midrib, margin, base and tips (apex)

Question 8

The _ is the broadest part, which is flat, wide and commonly thin.

Answer 8

lamina

Question 9

_ provides large surface area, which enables leaf to collect light.

Answer 9

Lamina

Question 10

The _ thinness creates short distance for gas exchange through the _.

Answer 10

lamina, stomata

Question 11

The _ is harder than the lamina and contains the vein (transporting vessels) of the leaf as well as supportive tissues with hard cell wall.

Answer 11

midrib

Question 12

With regard to root, there are basically two types of roots, namely _ and _.

Answer 12

tap-roots and fibrous roots

Question 13

A _ consists of one large, primary vertical root.

Answer 13

tap-root

Question 14

_ has very few lateral roots that develop and grow from this main root.

Answer 14

tap-root

Question 15

By penetrating deep into the soil, _ provide stability (anchorage) and absorb water located deep in the ground.

Answer 15

tap roots

Question 16

Tap root system is a feature of _ plants.

Answer 16

dicot

Question 17

A _ is usually formed by thin, moderately branching roots growing from stems.

Answer 17

fibrous root

Question 18

T/F
The lateral roots in fibrous roots are different in length.

Answer 18

False, they are more or less similar size and length.

Question 19

In grasses, _ develop as consists of fine hair – like root that spread out from the base of the stem.

Answer 19

fibrous roots

Question 20

_ is very efficient for absorbing water and minerals close to soil surface.

Answer 20

Fibrous root

Question 21

_ creates a thick network of roots that are good at holding soil together and protect soil from erosion.

Answer 21

Fibrous root

Question 22

Fibrous roots are features of _ plants .

Answer 22

monocot

Question 23

There are two internal layers of a leaf, namely; _ and _.

Answer 23

Outer layer and middle (inner) layer

Question 24

Outer layer is also known as the _, a single layer of tightly packed cells that covers the upper and lower surface of the leaf

Answer 24

epidermis

Question 25

The _ epidermis is usually covered by a waxy cuticle, which transmits sunlight for photosynthesis but restricts water loss by evaporation from the leaf tissue.

Answer 25

upper

Question 26

The _ epidermis usually contains bean-shaped guard cells that leave open spaces known as stomata (singular stoma).

Answer 26

lower

Question 27

_ are “little mouths” or “ little noses”, which regulate O2 release, CO2 intake and water loss.

Answer 27

Stomata

Question 28

In most leaves, stomata are more abundant in the _ epidermis, reducing water loss due to direct sunlight.

Answer 28

lower

Question 29

Middle layer is known as the _ (“middle leaf”) layer

Answer 29

mesophyll

Question 30

_ lies between the upper and lower epidermis.

Answer 30

Mesophyll layer

Question 31

_ includes tissues that are directly or indirectly involved in photosynthesis.

Answer 31

Mesophyll layer

Question 32

There are two regions in the mesophyll layer:

Answer 32

The palisade and spongy layer

Question 33

The _ layer is composed of regularly arranged and closely packed columnar (vertically elongated) cells.

Answer 33

palisade

Question 34

The cells in the _ contain the largest number of chloroplasts per cell.

Answer 34

palisade layer

Question 35

As the _ is immediately beneath the upper epidermis, it is in the best position to capture most of the sunlight and this enables it to carry out most of the photosynthesis.

Answer 35

palisade layer

Question 36

The slight but precise separation of the columnar cells in the _ maximizes the diffusion of CO2 and capillary movement of H20.

Answer 36

palisade layer

Question 37

_ lies below the palisade cells.

Answer 37

The spongy layer

Question 38

_ are irregularly shaped with fewer chloroplasts.

Answer 38

Spongy cells

Question 39

_ are very loosely arranged with numerous airspaces.

Answer 39

Spongy cells

Question 40

The air spaces in the _, which are very close to the stomata allow the diffusion of O2, water vapor and CO2.

Answer 40

spongy layer

Question 41

The _ is the outermost layer of the stem.

Answer 41

epidermis

Question 42

The _ walls are greatly thickened with cuticles, which minimizes the rate of transpiration.

Answer 42

outer

Question 43

In the _, the cells are compactly arranged, which in turn protect the underlying tissues from mechanical injury and prevent the entry of harmful organisms.

Answer 43

epidermis

Question 44

_ lies below the epidermis.

Answer 44

Hypodermis

Question 45

_ is mainly composed of collenchyma cells that are specially thickened at the corners due to the deposition of thick cellulose.

Answer 45

Hypodermis

Question 46

_ gives mechanical strength to the stem.

Answer 46

Hypodermis

Question 47

_ consists of few layers of thin-walled, large, round, or oval cells, having intercellular space and serving for storage of food.

Answer 47

Cortex

Question 48

_ is the innermost layer of the cortex that separates the cortex from the vascular bundles.

Answer 48

Endodermis

Question 49

T/F In endodermis, the cells are widely arranged and usually contain starch grains.

Answer 49

False, they are compactly arranged

Question 50

_ serves as a food reserve and may be termed as a starch sheath.

Answer 50

Endodermis

Question 51

_ are longitudinal strands of conducting tissues or transporting vessels, consisting essentially of xylem and phloem arranged in a ring around the central pith.

Answer 51

Vascular bundles

Question 52

Each vascular bundle has a patch of xylem towards the _ and a patch of phloem towards the _ and a strip of actively dividing young cells (cambium) in between them.

Answer 52

pith, endodermis

Question 53

_ transports water and dissolved minerals to the photosynthetic tissues, mainly to the leaf while _ transports synthesized food to different tissues, either for utilization or storage.

Answer 53

Xylem, phloem

Question 54

_ occupies the central portion of the stem, composed of thin-walled cells, which are rounded or polygonal, with or without intercellular space.

Answer 54

Pith

Question 55

_ stores food and helps in the internal translocation of water

Answer 55

Pith

Question 56

_ is the outermost layer made up of single-layer cells.

Answer 56

Peliferous layer

Question 57

In piliferous layer, the _ is absent.

Answer 57

cuticle

Question 58

_ consists the single-celled root hairs.

Answer 58

Piliferous layer

Question 59

_ is a multi-layered large zone made of thin-walled oval or rounded loosely arranged cells with intercellular spaces.

Answer 59

Cortex

Question 60

_ stores food and water.

Answer 60

Cortex

Question 61

_ is the innermost layer of the cortex, made of barrel-shaped closely packed cells.

Answer 61

Endodermis

Question 62

_ helps the movement of water and dissolved nutrients from the cortex into the xylem

Answer 62

Endodermis

Question 63

_ is a single layer inner to endodermis.

Answer 63

Pericycle

Question 64

_ is the site of origin of lateral roots.

Answer 64

Pericycle

Question 65

_ consist of xylem and phloem with meristematic (cambium) or actively dividing cells between them

Answer 65

Vascular bundles

Question 66

_ is present in young roots while absent in old roots.

Answer 66

Pith

Question 67

Pith is present in _ roots while absent in _ roots.

Answer 67

young, old