Notes 4

Question 1

The 5 major types of plant cells are what?

Answer 1

-Parenchyma
-Collenchyma
-Sclerenchyma
-Water conducting cells of xylem (tracheids and vessel elements)
-Sugar conducting cells of the phloem (sieve tube elements and companion cells)

Question 2

What are parenchyma cells?

Answer 2

Mature parenchyma cells have thin flexible primary walls, lack secondary walls, have large central vacuole when mature, perform most metabolic functions, undergo photosynthesis in the leafs, store starch in stems and roots, and retain the ability to divide and differentiate.

Question 3

What are collenchyma cells?

Answer 3

Collenchyma cells are grouped in strands and help support young parts of the plant shoot,elongate cells with thicker and uneven cell walls, and provide flexible support without restraining growth

Question 4

What are sclerenchyma cells?

Answer 4

Sclerenchyma cells are rigid due to thick secondary walls strengthened with lignin and are dead at functional maturity. There are 2 types specialized for support and strengthening.
-Sclereids are short and irregular in shape with lignified secondary walls.
-Fibers are long slender tapered and grouped in strands, there are hemp fibers for rope and flax fibres for linen.

Question 5

What are the 2 types of water conducting cells?

Answer 5

There are 2 types of water conducting cells, tracheids and vessel elements, tubular, elongated and both are dead and maturity.

Question 6

What are tracheids?

Answer 6

Tracheids are found in the xylem of nearly all vascular plants. Water moves between cells through pits.

Question 7

What are vessel elements?

Answer 7

Vessel elements found in most angiosperms, a few gymnosperms, and a few seedless vascular plants. They align end to end to form long micropipes called vessels.

Question 8

Water flows through ___ in end walls.

Answer 8

Perforation plates

Question 9

T or F: Sieve tube elements are dead at fucntional maturity.

Answer 9

false. Sieve tube elements are alive at functional maturity but lack organelles.

Question 10

What are sieve tube plates?

Answer 10

Sieve plates are porous end walls that allow fluid to flow between cells along the sieve tube. Each sieve tube element has a companion cell whose nucleus and ribosomes serve both cells (connected by plasmodesmata)

Question 11

Primary growth arises from where?

Answer 11

Primary growth arises directly from cells produced by apical meristems

Question 12

The root tip is covered by what?

Answer 12

The root tip is covered by a root cap which protects the apical meristem as the root pushes through soil.
The root cap also secretes a polysaccharide slime that lubricates the soil around the tip of the root.

Question 13

Growth occurs just behind the root tip is what 3 zones of cells?

Answer 13

The zone of cell division (includes apical meristem), the zone of elongation, and the zone of differentiation or maturation.

Question 14

T or F: The apical meristem produces all the cells of the root and root cap

Answer 14

True.

Question 15

Lengthening occurs in what zone?

Answer 15

The zone of elongation

Question 16

What is the most important protein for cell division?

Answer 16

Cyclin

Question 17

The primary growth stage of roots produces what tissues?

Answer 17

The primary growth of roots produces the epidermis, ground tissue, and vascular tissue.

Question 18

Whats the make up of the stele in angiosperms?

Answer 18

In angiosperm roots, the stele is a vascular cylinder, solid core of xylem and phloem.

Question 19

What is the difference in xylem and phloem in monocots and eudicots?

Answer 19

In most eudicot the xylem is starlike in appearance with phloem between the arms.
In many monocots, a core of parenchyma cells is surrounded by rings of xylem and phloem.

Question 20

What type of tissue/cells fills the cortex of eudicots?

Answer 20

In eudicots The ground tissues, mostly parenchyma cells, fills the cortex

Question 21

The innermost layer of the cortex is called what?

Answer 21

The endodermis. The endodermis regulates passage of substances from soil into the vascular cylinder.

Question 22

Lateral root arise from where?

Answer 22

Within the pericycle, the outer most cell layer in the vasular cylinder.

Question 23

What is a shoot apical meristem?

Answer 23

A shoot apical meristem is a dome shaped mass of dividing cells at the shoot tip.

Question 24

How do leaves develop?

Answer 24

Leaves develop from leaf primordia, projections that emerge along the sides of the apical meristem.
Axillary bud meristem can later produce branches

Question 25

How do lateral shoots develop?

Answer 25

Lateral shoots develop from axillary bud meristems on the stem surface.

Question 26

How are vascular bundles arranged in monocots and eudicots?

Answer 26

In most eudicots, the vascular tissue consists of vascular bundles arranged in a ring.
In the most monocot stems, the vascular bundles are scattered throughout the ground tissue.

Question 27

Leaf epidermis is interrupted by what?

Answer 27

Leaf epidermis is interrupted by stomata (singular stoma) pores that allow CO2 and O2 exchange between the air and the photosynthetic cells. Stomata are also for evaporative water loss.
Each stomatal pore is flanked by 2 guard cells, which regulate opening and closing.

Question 28

The ground tissue in a leaf is called what?

Answer 28

The ground tissue in a leaf called mesophyll is sandwiched between the upper and lower epidermis. The mesophyll of eudicots has 2 layers, the palisade mesophyll in the upper part of the leaf, and the spongy mesophyll in the lower parts of the leaf.

Question 29

Whats the benefit of air space in mesophyll?

Answer 29

Allows for gas exchange

Question 30

T or F: The vascular tissue of each leaf is discontinuous with the vascular tissue of the stem.

Answer 30

False. The vascular tissue of each leaf is continuous with the vascular tissue of the stem. Veins are the leaf vascular bundles and function as the leafs skeleton and Each vein in a leaf is enclosed by a protective bundle sheath.

Question 31

Secondary growth is what?

Answer 31

A growth thickness produced the lateral meristems.

Question 32

T or F: Secondary growth is characteristic of monocots.

Answer 32

False. Secondary growth is characteristic of gymnosperm and many eudicots but not monocots.

Question 33

Secondary growth occurs where?

Answer 33

Secondary growth occurs in stems and roots of woody plants.

Question 34

Secondary growth consists of tissues produced by what?

Answer 34

Secondary growth consists of the tissues produce by the vascular cambium and cork cambium.

Question 35

What is vascular cambium?

Answer 35

Vascular cambium adds secondary xylem (wood) and secondary phloem increasing vascular flow and support for shoots.

Question 36

What is cork cambium?

Answer 36

Cork cambium produces a tough thick covering of waxy cells that protect from water loss and invasion by insects, bacteria and fungi. Cork cambium gives rise to cork cells that accumulate to the exterior of the cork cambium. Cork cells deposit waxy suberin in their walls then die. Waxy cork layer functions as barrier protects from water loss, damage, and pathogens. The cork cambium and the tissues it produces compose a layer of periderm

Question 37

T or F: In woody plants primary growth and secondary growth occur simultaneously

Answer 37

True. As primary growth adds leaves and lengthens and roots in younger regions, secondary growth thickens stems and roots in older regions where primary growth has stopped

Question 38

T or F: The vascular cambium is a cylinder of meristematic cells only 10 cells thick: wholly responsible for production of secondary vascular tissue.

Answer 38

False. The vascular cambium is a cylinder of meristematic cells only one cell thick and is wholly responsible for production of secondary vascular tissue.

Question 39

How does secondary growth work in the vasular cambium?

Answer 39

In a cross section, the vascular cambium appears as a ring of initial (stem cells) as these cells divide they increase the circumference of the vascular cambium and add secondary xylem (wood) to the inside of the cambium and the second phloem (inner layer of bark) to the outside.

Question 40

What the difference in early and late developed wood?

Answer 40

Early wood that develops in the spring has secondary xylem cells with large diameters and thin walls, this maximizes water delivery to leaves.
Late wood, formed in late summer, has thick walled cells that do not transport as much water, but provide more support.
Growth rings are visible where late and early wood meet, and can be used to estimate a tree’s age.

Question 41

Whats the science of analyzing tree growth ring patterns?

Answer 41

Dendrochronology. Thick ring=warm year thin rings=a cold or dry one

Question 42

Does the seconadry xylem in older trees still transport material?

Answer 42

As a tree or woody shrub ages, the older layers of secondary xylem, the heartwood, no longer transport water and minerals.
The outer layers known as sap wood still transport materials through the xylem. Older secondary phloem sloughs off and does not accumulate.

Question 43

What are lenticels and what are their purpose?

Answer 43

Lenticels (small raised areas) in the periderm allow for gas exchange between living stem or root cells and the outside air.

Question 44

What is tree bark?

Answer 44

Bark consists of all the tissues external to the vascular cambium including secondary phloem and layers of periderm.