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structure , growth and devolopment of plants Flashcards

unit 4

1
Q

define a tissue

A

a tissue is a group of one or more cell types that carry out a specilized function .

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2
Q

what is a meristem

A

a meristem is undifferenciated tissues that are constently dividing under suitable condions to produce other new cells or new meristems .

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3
Q

what are the characteristics of meristems (6)

A
  1. living cells
    2.isodiametric
    3.has a dense cytoplasm
    4.has a central nucleus
    5.structurally and functionally undifferenciated
    6.has the ability to multiply
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4
Q

what are the 3 overlapping zones of cells consisting of succesive stages

A

cell divison
cell elongation
cell differenciated

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5
Q

what are the 3 types of meristems and explain the functions of the 3

A

apical , lateral , intercalary

1.apical - located at the root and shoot tips and they add new cells that increase the length of the plant .

2.lateral - it is located in the vascular and cork cambium . it increases the circumfarence of the root .the vascular cambium produces the secondary xylem and phloem and the cork cambium produces a thick and tough periderm to replace the epidermis .

3.intercalary - it is located in the base of stems and roots of monocots (grass) and involves in the rapid regrowth of the damaged leaves .

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6
Q

define the primery growth of the root

A

elognation of the root due to the activity of the primery meristems located in the root apex is called primery growth of the root

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7
Q

what are the 3 process that take place during the primery growth of the root and where do they take place

A

cell division - zone of cell division
cell elongation - zone of elongation
cell diffrenciation - zone of maturation

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8
Q

what type of cells do the zone of cell divison contain , what is its function , what is the function of the structure made .

in the root

A

the zone of cell divison contains root apical meristems and it s derivatives
it cuts cells to both sides and the cells cut downwards differenciate to form the root cap
the root cap will protect the root from the damage from friction when travelling through the soil .
the cells cut inwards go through cell elongation to more than 10 times the original .

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9
Q

define the primery growth of the shoot

A

the elongation of the shoot due to the activity of primery meristems located on the shoot apex called the primery growth of the shoot

unlike the root apex this only produce cells inwards

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10
Q

from what part of the shoot does the leaves devolop

A

leaf primodia

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11
Q

what are the changes that take place during the process of differenciation

A

changes in cytoplasm , cell wall and orgenelles

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12
Q

: What is the outer protective covering of plants?

A

The outer protective covering of plants is the epidermis.

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13
Q

Where is the epidermis found in plants?

A

it is the outer most single cell layer of a plant primery root or stem
The epidermis is found in the stems and roots of the primary plant body and leaves.

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14
Q

Describe the structure of the epidermis.

A

The epidermis is a tightly packed single-cell layer, normally covered by a cuticle in aerial parts.

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15
Q

what is the the cuticle

A

The cuticle is a waxy epidermal coating found on the aerial parts of the plant.

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16
Q

Name the specialized cells found in the epidermis.
what is the specialty in the guard cell ?

A

Specialized cells in the epidermis include:
- Guard cells - the only dermal tissue to contain a chloroplast
- Trichomes - epidermal outgrowths such as hairs and glands
- Root hair

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17
Q

list the functions of the epidermis
cutical -
root hair -
guard cells -
trichomes

4

A

Defense against physical damage and pathogens
- Cuticle prevents water loss
- Root hairs absorb water and mineral ions
- Guard cells facilitate gaseous exchange
- hair like trichomes reduce water loss and reflect excess light

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18
Q

What role do trichomes play in plant defense?

A

Some trichomes secrete chemicals that defend against insects , pathogens, and herbivores

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19
Q

What replaces the epidermis in older stems and roots after secondary growth?

A

A protective layer called the periderm

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20
Q

what are 2 types of ground tissue

A

pith - inside the vascular bundle
cortex - outside the vascular bundle

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21
Q

what are the functions of ground tissue cells

A

storage , photosynthesis , support and short distence transport

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22
Q

true or false

1.parenchyma cells are living even at maturity
2.parenchyma cells have secondary cell walls most of the time
3.they have a large central nucleus

A

1.true
2.flase , they all have the primery cell wall which is thin flexible and most lack the secondary wall
3.false , they have a large central vacuole

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23
Q

explain the functions of the parenchyma cells

A

1.performs most of the metabolic activities in the plant - they synthesise various organic compounds

2.storage - some cells in the root and the stem contain plasmids(leucoplast ) which store more starch .

3.parenchyma cells often has the ability to divide and differenciate and has meristematic properties .this property helps it to restroe dammaged tissue and also helps in tissue culture practices .

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24
Q

compare the collenchyma cell with the parenchyma

A

the collenchyma is generally elongated and has a thicker primery cell wall than the parenchyma , the primery cell wall is unevenly thickened with cellulose .these cells are also flexible and they are living even in maturity

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25
where is collechyma situated and what is it 's function
the young stems and petioles have collenchyma cells just below the epidermis . function - the give mechanical support to leaves and stems without restraining growth .
26
how does the sclerenchyma tissue compare to other ground tissues
they are dead cells maturiy and the secondary cell wall is formed after cell elongation and i made up of lignin.
27
compare and contrast the sclereids and fibers
sclereids - shorter and wider than fibers and has lignified secondary wall fibers - grouped in strands , long slender and taperd
28
explain the location and the function of both types of sclerenchyma
slcereids - they are found in places where growth has already stopped . eg- nut shells , fleash of coarse fruits , seed coats fibers - used to commercially obtain fibers coconut husk fiber and hemp fiber ccommon function is to provide strenght and support without restriction growth
29
what are the 2 types of tissue in vascular tissue
xylem and phloem
30
what are the types of cells in xylem and which of them are living
xylem vessel element xylem parenchyma - living tracheids xylem fiber
31
the only gymnosperm to contain xylem vessel element is
Gentophyta phylum
32
what are the functions of all the cells in the xylem
xylem vessel element - water transport and provide support to prevent collapse under the tension of the water transport . tracheids - water transport fibers - give mechanical support xylem parenchyma - storage and radial transport
33
what are the features of the xylem vessel element
long , cylindical dead cells the secondary walls are thickend by lignin perforation plates are present at eh end walls of the vessel element . other walls are interupted by pits
34
what are the features of tracheids
long thin cells with tapering ends the secondary cell wall is thickend by lignin - this provide support not to collapse under the pressue . and is interupted by pits. and they are also found in all vascular plants unlike vessel element which is in all angiospersm and some gymnosperms .
35
what are the cell types in the pholem tissue and which of them are living
seive tube element - living pholem parenchyma - living companion cells - living phloem fibers
36
What type of phloem cells are present in seedless vascular plants and gymnosperms instead of sieve tube elements?
In seedless vascular plants and gymnosperms sieve tube elements and companion cells are absent. Instead of sieve tube elements, long narrow cells called sieve cells are present in these plants.
37
What cellular components are absent in sieve tube elements?
Sieve tube elements lack a nucleus, ribosomes, a distinct vacuole, and cytoskeletal elements.
38
What happens to the cytoplasm in sieve tube elements?
The cytoplasm in sieve tube elements is reduced to a thin peripheral layer.
39
Why do sieve tube elements lack certain cellular components?
The absence of components like a nucleus and ribosomes allows nutrients to pass more freely through the sieve tube elements.
40
How are sieve tube elements arranged in phloem?
Chains of sieve tube elements are aligned to form sieve tubes.
41
What is the function of the sieve plate in sieve tube elements?
The sieve plate, found on the end walls between sieve tube elements, allows fluid to move from one sieve element to the next.
42
What are non-conducting cells in the phloem, and where are they found?
Non-conducting cells are found alongside each sieve tube element and are connected to the sieve tube element by numerous plasmodesmata.
43
What is the role of the nucleus and ribosomes in non-conducting cells?
The nucleus and ribosomes of non-conducting cells also serve the adjacent sieve tube element, supporting its functions.
44
How do some companion cells aid in phloem transport?
in leaves help in phloem loading, while in other organs, they assist in phloem unloading.
45
what is defined as growth
the irreversible increase of dry mass of an organism
46
what are the diffrent types of parenchyma
pericycle and endodermis
47
what is the ground tissue between the vascular bundle and the epidermis called ? what is it made up of
cortex , parenchyma cells with intercellular spaces
48
what are the functions of the cortex
storing carbohydrates , and transports water and minerals towards the endodermis
49
what is the endodermis defined as and what is it made up of ?
the innermost single cell layer of the cortex , parenchyma
50
what blocks the vascular appoplast from the cortical appoplast
the belt called the casparian strip in the endodermis
51
what is the casparian strip made up of , what is it's bio molecule type
suberin , it is a lipid (Wax)
52
what is the exact location of the pericycle
the 2 or 3 cell layers of parenchyma which are interior to the endodermis
53
explain the pericycle in the dicto root | the location and the function (2)
the pericycle parenchyma cells have meristamatic abilities it involves in the growth of the lateral roots and the secondary root
54
explain the pericycle in the monocot root ?
they do not have meristamatic abilites
55
what is the arrangemnt of the vascular bundel in the monocot root
it is in a ring of alternating xylem and pholem
56
what is the function of the epidermis in the dicto stem
to prevent from dessication and infections
57
what interupts the epidermis in the dictot stem
pores called stomata
58
what is the function and the location of collencyma and sclerenchyma cells in the dicot root
near the vascular bundle and right below the epdermis
59
what is the arrangment of the vascular budle in the dicto stem
it is arranged as a ring and it grows the primery xylem towards the pith and the primery pholem towards the cortex
60
what is outside the dicto stem vascular bundle
cluster of sclerenchyma
61
what structure contains the large luman
dicot stem - has a large pith
62
from where are the lateral roots born
auxiliary bud
63
Is the ground tissue of a monocot shoot differentiated into cortex and pith?
no they are noT differencuate into cortex and pith
64
What surrounds each vascular bundle in a monocot stem?
A: Each vascular bundle is surrounded by sclerenchyma.
65
what is the speciality in the vascular bundle int he monocot stem
it does not have a cambium in the middle of the xyleme and the phloem
66
what is the arrangment of the vascular bundles in the monoco stem
it is scatterd thorougt the ground tissue
67
what is defined as secondary growth ?
the increase of the circumfarence of plant roots and stems due to the activity of lateral meristems is known as secondary growth
68
in what specific plants does secondary growth take place?
in woody perrenial plants
69
what are the tissues that produce cells for secondary growth ?
vascular cambium - secondary xylem and phloem cork cambium - cork cells and periderm
70
what are the functions of secondary growth ?
give more support and strength for the plants increase vascular flow
71
what are cork cells made out of ? and what are the functions of it ?
a wax called suberin impregnented cells , protect the stem from water loss , protect it from bacterial and fungi invasions
72
true or false primery growth and secondary growth happens simultaniously in a specific organ of a plant
false , primery growth and secondary growth occure simultaniously in the plant but secondary growth in a perticular organ happens after the primery growth ceased
73
in a typical woody stem what does the vascular combium consist of ? and name the exact location of it
a contineus cylinder of a single cell layer of undiffrenciated located exterior to the pimery xylem and pith and interior to the primery pholem and cortex
74
what is the location of the vascular cambium in a typical woody root ?
laterally extreior to the xylem and interior to the pholoem and the pericycle
75
what are the rings of inetials
the vascular cambium veiwed in a cross section is defined as vascular rays
76
what are the 2 types of vascular cambium orientations ?
one is elongated and its axis is parerel to the axis of the stem or the root . one is shorter and its axis is perpendicular to the axis of the stem or the root
77
what is the function of the elongated vascular cambium ?
it produces vascular cells such as the cells in the xylem and the pholem
78
what is the function of the vascular rays
connect the secondary xylem and phloem , store carbohydrates , wound healing
79
what gives the wood it 's hard nature and strength ?
the xylem vessel cells walls are highly lignified
80
what causes the epidermis to split , dry and fall off during secondary growth ?
the growth of the cells inside , the epidermis is pushed outward .
81
what forms the cork cambium in the stem ?
cylinder of cells arising from the outer layer of the cortex
82
what forms the cork cambium in the roots ?
the pericycle
83
true or false the cork cells formed to the exteroir becomes cork cells
true ,
84
as cork cells age what compound do they deposit
a waxy hydrophobic material named suberin
85
what are the functions of the cork tissue ?
support and strenght , prevent water loss , prevent entering of pathogens and physical damage prevenstion
86
how does gas exchange happen through the periderm ? how is the structure formed
through lenticels , it is formed by loosing arranged cork cells that can be seen as horizonatal slits
87
what happens to the cork cambium as the stems and the roots grow further ?
the cork cambium looses its meristamatic activity
88
how is the loss of the meristamatic activity in the cork cambium recoverd by the plant ?
a new layer from the interior starts production of cork cells
89
as new cells continue to add what will happen to the old outer regions of the cork cells ?
it will crack and peel off
90
define the term bark
bark is defined as the regions outer from the vascular cambium
91
what are heart wood?
it is the old secondary xylem which no longer function
92
what is known as sap wood ?
the newest layers of secondary xylem which still function
93
compare and contrast sap wood and heart wood colure
the heart wood is darker because of all the resins that is in the older xylem that would help protect the core of the tree from fungi and wood boring insects
94
what vascular tissue still , after secondary growth contineus it's function and what happens to the rest?
the young secondary phloem , the old secondary phloem will slough off
95
what is defined as hard wood?
hard wood is the xylem vessels of dicot angiosperms
96
what is defined as soft wood
the wood of gymnosperms
97
what makes soft wood softer than the hard wood
the gymnosperms which do not have xylem vessles are less hard and tough because than the lignified xylem in the hard wood
98
what are referd to as growth rings
the changes in the secondary xylem wall and luman is visible in the cross section of a tree trunk as light and dark rings
99
explain the xylem characteristics in spring wood ? what is the function of spring wood ?
large lumans , thin walls , is to transport more water for the new growing leaves
100
what is called summer wood ? what is the function of summer wood ?
xylem vessels that grow for the rest of the year other than the beginning of spring - summer wood it has smaller lumans and thicker walls its function - more support for the tree

Biology (11 decks)

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