Organs and Tissues Flashcards

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1
Q

What does a plants structure reflect?

A

Its interactions with the environment of two time scales (over the long term and short term).

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2
Q

How do plant structures reflect interactions with the environment over long term?

A

Natural selection causes species to accumulate morphological adaptations that enhance survival and reproductive success.

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3
Q

How do plant structures reflect interactions with the environment over short term?

A

Over short term, plants exhibit structural responses to their specific environments.
(eg. feathery leaves to enhance uptake of CO2)

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4
Q

What type of response is even faster than the short term response?

A

A physiological (functional) response/adjustment.
- eg. releasing a hormone which causes the stomata to close

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5
Q

What are the three basic organs of plants?

A

1) roots
2) stems
3) leaves

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6
Q

What is an angiosperm?

A

a flowering plant

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7
Q

What are the principal division of angiosperms?

A

1) monocots
2) dicots

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8
Q

What is special to monocots?

A

EMBRYOS: one cotyledon
LEAF VENATION: parallel venation
STEMS: vascular bundles randomly allocated
ROOTS: fibrous root system
FLOWERS: multiples of 3

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9
Q

What is special to dicots?

A

EMBRYOS: two cotyledons
LEAF VENATION: netlike venation
STEMS: vascular bundles arranged in a ring
ROOTS: taproot is present
FLOWERS: multiples of 4 and 5

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10
Q

What are the two places where plants inhabit their resources? What comes from each specific resource?

A

1) SOIL: water and minerals
2) AIR: CO2 and light

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11
Q

What two systems have plants evolved?

A

1) a subterranean (underground) root system
2) aerial shoot system

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12
Q

Are the two systems (root and shoot) independent of each other? Why?

A

No, both systems depend on each other.
- roots (lacking chloroplasts, living in the dark, not obtaining sugars from photosynthesis) would starve,
- shoot systems (reproductive tissue, flowers, etc.) depend on water and minerals absorbed from the soil.

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13
Q

What are the primary roles of the root system?

A
  • anchor the plant in the soil
  • absorb minerals and water
  • store food
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14
Q

What does a fibrous root system allow monocots to do?

A

extend its (the plants) exposure to soil water and minerals, as well as anchor it to the ground.

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15
Q

What does a taproot root system allow dicots to do?

A
  • anchor the plant
  • store food
  • support flowering
  • support fruit production
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16
Q

Where does most water and mineral absorption take place?

A

in the root tips

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17
Q

What increases the roots surface area?

A

root hairs

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18
Q

What are root hairs?

A

Root hairs are extensions of individual epidermal cells on the root surface.

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19
Q

What are “adventitious” roots?

A

roots which arise above ground from stems or leaves.

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20
Q

What are roots called which arise above ground from stems or leaves?

A

adventitious roots

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21
Q

What is the purpose of an adventitious root?

A

props which help support tall stems.

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22
Q

What does a shoot consist of?

A

stems and leaves

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23
Q

What are the two types of stems?

A

1) vegetative (leaf bearing)
2) reproductive (flower-bearing)

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24
Q

What is a stem?

A
  • a system of nodes (the points at which leaves are attached),
  • a system of internodes (stem segments between nodes)
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25
Q

What is an axillary bud?

A

the part of the plant located at the angle by each leaf and stem, with the potential to form a vegetative branch.

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26
Q

What has the potential to form a vegetative branch?

A

an axillary bud.

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27
Q

Where is the growth of a young shoot usually located?

A

at its apex (where there is a terminal bud with a developing leaves, and developing nodes and internodes)

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28
Q

What is a terminal bud?

A

a part of the plant with developing leaves and a compact series of nodes and internodes.
- special tissue called meristems (undifferentiated cells which produce vegetative and reproductive organs).

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29
Q

What are meristems?

A

undifferentiated cells ( can divide indefinitely and produce all differentiated tissues) which produce vegetative and reproductive organs.

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30
Q

What are the undifferentiated cells called in plants?

A

meristems

31
Q

What is apical dominance?

A

the presence of a terminal bud is partly responsible for inhibiting the growth of axillary buds.

32
Q

What does a plant manage to do by concentrating resources and growing taller?

A

apical dominance increases the plants exposure to light.

33
Q

What happens when a plant lacks a terminal bud?

A

the axillary bud break dominance and gives rise to a vegetative branch complete with its sown terminal bud, leaves and auxiliary buds.

34
Q

What are some examples of modified shoots? What are modified shoots?

A
  • modified roots are not roots, they are shoots
    eg.
  • stolons,
  • rhizomes,
  • tubers,
  • bulbs
35
Q

What do stolons allow for? Example of plant.

A

stolons, “runners”, grow on the surface and allow plants, such as strawberries to colonize large areas asexually, when a parent plant fragment is greater than the offspring.

36
Q

What are rhizomes?

A

horizontal stems that grow underground (ie. ginger).

37
Q

What are tubers?

A

swollen ends of rhizomes specialized for food storage (eg. potatoes).

38
Q

What are bulbs?

A

vertical, underground shoots consisting mostly of swollen bases of leaves that store food (eg. onions).

39
Q

What is the function of leaves?

A

Leaves are the main photosynthetic organs of most plants.

40
Q

What can photosynthesise in plants?

A

leaves and green stems

41
Q

What do leaves consist of?

A

1) flattened blades
2) a stalk (the PETRIOLE) (joining the leaf to a stem node)

42
Q

What do plants develop in the absense of petrioles? Where does this occur?

A

the base of the leaf forms a SHEATH that envelops the stem.
this occurs mainly in monocots.

43
Q

How to taxonomists classify plants?

A

besed on:
- leaf shape
- spacial arrangement of leaves
- pattern of veins

44
Q

What are the different types of leafs?

A

1) SIMPLE leaf: single, undivided blade
2) COMPOUND leaf: several leaflets attached to the petiole.

45
Q

What are examples of modifications of plant leaves?

A
  • cactus spines
  • tendrils for support
  • leaves modified for water storage
  • brightly coloured leaves attract pollinators
46
Q

What is a tissue?

A

a group of cells that preform a similar function

47
Q

What are the three tissue systems which plants are composed of?

A

1) dermal tissue
2) vascular tissue
3) ground tissue

48
Q

What is dermal tissue? What is the primary dermal tissue called?

A

primary dermal tissue = EPIDERMIS
- single layer of tightly packed cells
- covers and protects the younger parts of the plant
- can form extentions of epidermal cells near the root tips
- can secrete a waxy coat (CUTICLE), helping the aerial parts of a plant to retain water.

49
Q

What is the waxy cuticle of plants called?

A

the cuticle

50
Q

What is dermal tissue? What is the secondary dermal tissue called?

A

secondary dermal tissue=PERIDERM
- multilayer that replaces the epidermis during growth in the thickness of stems and roots.
- after accumulation the periderm forms the outer bark in trees

51
Q

What are the differences and similarities between the epidermis and periderm?

A

epidermis:
- flat cells
- thick cell walls
- waxy cuticle
- function: protect young plants

periderm:
- waterproof cells
- thick cell walls
- dead at maturity
- function: forms outer barks in trees

52
Q

What is vascular tissue in plants? What is it composed of? What does each section do?

A

Vascular tissue is involved in the transport of materials between roots and shoots.
1) XYLEM: transports water and dissolved materials upwards from the root to the shoot.
2) PHLOEM: transports food made in mature leaves through photosynthesis to the roots and non-photosynthetic parts of the shoot system.

53
Q

What does the xylem consist of?

A

1) TRACHEIDS: long, thin cells with narrow ends. moves water through pits.
function: transport and support.

2) VESSEL ELEMENTS: wider, shorter, thinner-walled, less narrow ends. aligned end to end.
function: allow for water flow due to perforated ends

  • elongated cells
  • dead at functional maturity
  • both have interrupted pits
  • fully specialised for their function
54
Q

Label a transection of a vascular bundle.

A
  • cork
  • xylem tissue
  • cambium
  • phylum tissue
  • pith
55
Q

How are the secondary walls of xylem hardened?

A

with lignin

56
Q

What occurs in the phloem? What cells is it composed of?

A
  • sucrose, organic compounds, and mineral ions move throughout tubes formed by sieve tube members
  • composed of:
    1) SIEVE TUBES:
  • lack nucleus, ribosomes and vacuoles. facilitate fluid flow.
    2) COMPANION CELLS: assist the sieve tube cells.
57
Q

What is the function of the pith?

A

store sugars and proteins

58
Q

What is the function of the cortex and epidermis?

A

protect the stem

59
Q

What is ground tissue?

A

tissue that is neither dermal or vascular tissue.

60
Q

What is the ground tissue in dicot stems? What is it divided into?

A

1) PITH: internal to vascular tissue
2) CORTEX: external to vascular tissue

61
Q

What is the function of the ground tissue?

A
  • photosynthesis
  • storage
  • support
62
Q

What are the three basic types of cells in plants?

A

1) PARENCHYMA CELLS
2) COLLENCHYMA CELLS
3) SCLERENCHYMA CELLS

63
Q

What are protoplasts?

A
  • plant cells that have had their cell walls removed by treatment with cellulolytic enzymes
  • the cell contents exclusive of the cell wall.
64
Q

What are parenchyma cells?

A
  • primary flexible walls
  • thin and flexible
  • lack secondary walls
  • preform most metabolic functions (synthesize and store organic products)
  • “typical” plant cell because it is LESS SPECIALIZED

EXCEPTION:
- highly specialised sieve-tube members (of the phloem) are parenchyma cells

NOTES:
- fleshy part of fruit=parenchyma cells
- colourless plastids store starch
- can contain chloroplasts
- it is possible to regenerate an entire plant from a single parenchyma cell

65
Q

What are developing plant cells before specializing?

A

parenchyma cells

66
Q

What happens to unspecialized adult parenchyma cells?

A
  • they do not undergo cell division,
  • retain their ability to divide and differenciate into other cell types
67
Q

What are collenchyma cells? What are their major characteristics?

A
  • thicker primary walls (UNEVENly thick)
  • grouped into strands or cylinders

FUNCTION:
- help support young parts of the plant

68
Q

What are sclerenchyma cells? What are their major characteristics?

A
  • thick secondary wall (strengthened by LIGNIN)
  • more rigid
  • cannot elongate
  • occur in plant regions that have stopped growing (lengthening)
  • dead at functional maturity

FUNCTION:
- support elements of the plant
- produce rigid secondary walls before the protoplast dies

69
Q

How can sclerenchyma cells enable cell wall stretching?

A

they create a spiral or ring pattern in growing plants

70
Q

What are vessel elements and tracheids in the xylem?

A

sclerenchyma cells

71
Q

What are the two other types of sclerenchyma cells?

A

1) FIBERS:
- long, slender, tapered
- occur in groups

2) SCLEREIDS:
- shorter
- irregular
- harden nutshells, seed coats and the gritty texture to pear fruits.

72
Q

What is a major difference between plants and animals?

A

growth and development in plants is not just limited to the embryonic and juvenile period but occurs throughout the whole life of the plant.

73
Q

What does a typical plant consist of?

A

embryonic organs, developing organs, and mature organs.

74
Q

State the functions of parenchyma cells, collenchyma cells and sclerenchyma cells.

A

PARENCHYMA CELLS:
- photosynthesis
- secretion
- storage

COLLENCHYMA CELLS:
- support leaves and stems

SCLERENCHYMA CELLS:
- support