lecture 13, Vasculature Flashcards

1
Q

what two things make up the vascular system?

A

xylem and phloem

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2
Q

the body plan is composed of….(example from a generic angiosperm)

A

an apical-basal pattern, a radial pattern, and three tissue systems (epidermis, ground tissue, and vascular tissue)

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3
Q

what is the meristem?

A

a section of the plant where constant cell division occurs - a continuing source of new cells

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4
Q

what does the apical meristem give rise to?

A

protoderm, ground meristem, and procambium (the primary meristems)

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5
Q

what do the primary meristems give rise to?

A

primary tissues:
protoderm –> epidermis
ground meristem –> ground tissue
procambium –> primary xylem and primary phloem (vascular tissue system)

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6
Q

what is xylem and what is it responsible for?

A

water conducting cells, responsible for conduction of minerals and water, support, and food storage

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7
Q

primary xylem comes from…

A

procambium

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8
Q

secondary xylem comes from…

A

vascular cambium

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9
Q

what kind of growth do most plants exhibit?

A

primary growth

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10
Q

what plants exhibit secondary growth

A

gymnosperms and other woody plants
eg) conifers

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11
Q

what two lateral meristems are responsible for secondary growth

A

vascular cambium and cork cambium

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12
Q

what are the cell types in secondary xylem?

A

tracheids and vessel elements - both have secondary cell walls and lack protoplasts at maturity

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13
Q

what are the supporting tissues in secondary xylem?

A

fibers and parenchyma

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14
Q

how are tracheids made up?

A

made up into structures called pits. pits are thin modified primary cell walls. prevents air bubbles from forming

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15
Q

how are vessel elements made up?

A

made up of perforation plates, areas lacking primary and secondary cell wall. they are ladder-like scalariform or a single large opening

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16
Q

how does differentiation of a vessel element occur?

A

secondary cell wall thickens, primary cell wall at ends and disintegrates, cell undergoes apoptosis or programmed cell death

17
Q

why are there both tracheids and vessel elements?

A

vessel elements are more vulnerable to air embolisms, a gas that has entered the vasculature and is obstructing water movement

18
Q

what are fiber cells?

A

sclerenchyma cells which line the tracheary elements. contain no protoplast and are dead at maturity

19
Q

how does water flow up the xylem?

A

via the cohesion/adhesion theory, water potential, and transpiration which is the driver of water flow

20
Q

what is phloem necessary for?

A

sugars, amino acids, lipids, micronutrients, hormones, proteins, RNA, and signaling molecules

21
Q

what are the 2 kinds of phloem?

A

protophloem and metaphloem

22
Q

what are the 2 components of the phloem?

A

sieve elements (sieve cells and sieve tube-elements) and companion cells (assoicated with fibers and parenchyma)

23
Q

what are sieve elements? what are the two types?

A

the principal conducting cells of phloem. they are a cluster of pores that join to adjacent cells.

sieve cells and
sieve tube elements (only in angiosperms)

24
Q

what is the structure of sieve tube elements?

A

long vessels, sieve plates conspicuous at ends.
Contain a P-protein that forms a plug by the sieve plate. The “plug” is created to modulate traffic.

25
Q

what is the P-protein?

A

known as Forisome, occur in some legumes and undergo rapid, reversible, calcium-controlled changes from condensed resting stage. in the dispersed state, they plug the sieve-plate pore, act as gate-keepers

26
Q

what are companion cells?

A

specialized parenchyma cells, living i.e. has a nucleus.
Tightly associated with sieve-tube elements and deliver materials (molecules, proteins, ATP, etc.)

27
Q

what does the mother of sieve-tube elements do?

A

forms sieve-tube element and companion cells. After division, P-protein bodies arise in cytoplasm

28
Q

recap: xylem contains …. and phloem contains …. (what do they do?)

A

xylem contains:
tracheary elements (tracheids and vessele elements), fibers, and parenchyma

-tracheary elements: conduction of water and minerals
-fibers: support; sometimes storage
-parenchyma: storage

phloem contains:
sieve elements, sclerenchyma (fibers and sclereids), and parenchyma

-sieve elements: long-distance transport of food
-sclerenchyma: support; sometimes storage
-parenchyma: storage