Second Exam: Plants Flashcards
(134 cards)
1
Q
How do plants obtain most of their water and minerals?
A
From their roots via the upper soil layers
2
Q
What are the basic physical properties of soil!
A
Texture and composition
3
Q
What does soil texture describe?
A
The inorganic solid phase of soil
4
Q
What is soil texture determined by?
A
The ratio of clay, silt, and sand
5
Q
What does soil composition describe?
A
Both the inorganic and organic chemical components of soil
6
Q
What are the organic components of soil also called?
A
Humus
7
Q
What are the inorganic components of soil also called?
A
Mineral
8
Q
What are the organic components of soil formed by?
A
The decomposition of living things
9
Q
What do the organic components of soil do to the soil?
A
Organic components increase the soil’s capacity to exchange cations
10
Q
Where are the inorganic components of soil typically more abundant?
A
Near bedrock
11
Q
What do cations do in the soil?
A
They adhere soil particles which prevents leaching
12
Q
What does cation exchange in soil do?
A
It enables plant uptake of cations by roots
13
Q
What are 3 examples of sustainable agricultural practices?
A
Drip-irrigation, terraced agriculture, and crop rotation
14
Q
What are the two categories of essential elements for plants?
A
Macro and micronutrients
15
Q
What are macronutrients?
A
Nutrients needed in large quantities
16
Q
How many essential elements are there?
A
17
17
Q
How many essential elements are macronutrients?
A
9
18
Q
Plants and soil microbes have a _______ relationship
A
Mutualistic
19
Q
What do nitrifying bacteria do?
A
They convert stuff into NO3-
20
Q
What converts stuff into NO3-?
A
Nitrifying bacteria
21
Q
What do ammonifying bacteria and nitrogen fixation do?
A
They convert stuff into NH4+
22
Q
What converts stuff into NH4+?
A
Ammonifying bacteria and nitrogen fixation
23
Q
What are mycorrhizae?
A
Mutualistic associations of fungi and roots
24
Q
What are the two types of mycorrhizae?
A
Ectomycorrhizae, and Arbuscular Mycorrhizae
25
Which type of mycorrhizae is more common?
Arbuscular mycorrhizae
26
What is ectomycorrhizae?
When the fungi go in between the cell walls of the root cells
27
What is arbuscular mycorrhizae?
When the fungi actually go inside the root cells
28
Describe why mycorrhizae is mutualistic
The fungi benefit because they get sugar from the roots, and the plant benefits because the fungi help it grow more roots
29
What are three types of plants that have nutritional adaptations that use organisms in a non-mutualistic way?
Epiphytes, parasitic plants, and carnivorous plants
30
What are epihphytes?
Plants that use other plants as structure
31
What are parasitic plants?
Plants that live on other plants and their nutrients (they steal their sugars and structure)
32
What are carnivorous plants?
Plants that eat bugs or rodents
33
Why are carnivorous plants carnivorous?
Because they adapted to live in nutrient-poor soil by getting their nutrients from animals instead of the soil
34
What does the root system of a plant do?
It supports the plant, and absorbs water and minerals
35
What is the shoot system of a plant comprised of?
Vegetative/ non-reproductive portions of the plant, such as the leaves and stems
36
What is the reproductive system of a plant comprised of?
Flowers and fruits
37
What three tissues make up the ground tissue system?
Parenchyma, collenchyma, and sclerenchyma
38
What do ground tissues do?
They do metabolism, storage, and support activities
39
Where are the ground tissues located?
In the stem
40
What are parenchyma cells?
They're an undifferentiated cell that contains organelles and a primary cell well
41
What are collenchyma cells?
They're similar to parenchyma cells, however, they're differentiated and have thickened cell walls to provide support
42
What are sclerenchyma cells?
They have a continuous secondary cell wall and a primary cell wall, and they provide more support and strength to cells (along with xylem and phloem)
43
What are the two types of sclerenchyma cells?
Fibers and sclerids
44
What are fibers (in the stem)?
A type of sclerenchyma cell that is long and slender
45
What are sclerids?
A type of sclerenchyma tissue that is often spherical shaped and branched
46
Where is the xylem located?
At the very center of the stele, and often has two or more extensions
47
Which is bigger in diameter: xylem or phloem?
Xylem
48
What does the Xylem do, and where is this conducted?
It carries water and minerals upwards, which is conducted in tracheids and vessel elements
49
Describe tracheids
A part of the xylem that is long and narrow, with end walls that are perforated with pits to allow water to move from cell to cell
50
Where is the phloem located?
Between xylem arms
51
What does the phloem do, and what specifically does this?
The phloem's sieve tube elements move dissolved sucrose down from the leaves and to the rest of the plant
52
Where is the vascular cambium located?
Inbetween the xylem and phloem
53
What is the vascular cambium designed to do?
It makes roots wider
54
What does the epidermis do in above ground plant organs?
It's involved with gas exchange
55
What does the epidermis do in below ground plant organs?
It's involved with water and ion uptake
56
What does the epidermis do in all parts of the plant?
It protects soft tissues and controls interactions with the plant's surroundings
57
What does primary growth increase?
The length of the plant
58
What does secondary growth increase?
The width of the plant
59
Where does primary growth occur?
At the apical meristems, which are at the root's tips, as well as the shoots and within the buds of stems
60
What types of plants does secondary growth occur in?
Woody plants
61
What type of plants does primary growth occur in?
All plants
62
What does secondary growth do?
It adds wood and bark
63
Where does secondary growth occur?
At the lateral meristems at the vascular cambium and cork cambium
64
What's the difference between apical and lateral meristems?
The apical meristem is involved with primary growth, and the lateral meristem is involved with secondary growth
65
What are taproot systems?
Root systems with one main root formed from the radicle, with many lateral roots branching out from the taproot
66
What type of root system gives access to deeper resources faster?
Taproot system
67
What type of plants is the taproot system characteristic of?
Dicots, eudicots, and gymnosperms
68
What are fibrous root systems?
Root systems that consist of many main roots of similar size arising from the stem, with lateral roots branching off of these roots
69
What type of plants is the fibrous root system characteristic of?
Oak trees and monocots
70
Monocots are most likely to have ________ root systems
Fibrous
71
What is a radicle?
A seedling's embryonic root
72
What is the difference between a primary eudicot root and a monocot root?
Monocots have a central pith, and eudicots have an x shaped center
73
What is the pith of a root?
Nonliving old tissue that makes up the "meat"
74
What is the difference between apoplastic and symplastic movement?
Apoplastic movement is movement through interconnected cell wall spaces in the cortex, and symplastic movement is through cells' and their cytoplasm
75
What is the structure of roots with secondary growth?
Woody eudicots lay down concentric rings as they get wider because of dead tissues like phloem getting pushed out, old xylem gets pushed into the dense center, and bark doesn't exist on roots because they need to absorb nutrients
76
What are two examples of mutualistic relationships between roots and other organisms?
Roots and nitrogen fixing bacteria, and roots and mycorrhizae (fungi)
77
What are three types of roots that are modified to perform uncommon functions?
Modified starch-storing roots, aerial roots, and humadiphor roots
78
What is an example of a modified starch-storing root?
Potatoes
79
What do aerial roots do?
They absorb gas water in humid areas above ground
80
What are humadiphor roots? What are 2 examples?
Roots that grow out of the ground and up. Examples include mangroves and possibly cyprus trees
81
What's the difference between simple and compound leaves?
Simple leaves only have one leaf, compound leaves have multiple
82
What are the three types of leaf arrangements?
Alternating, opposite, or whorled
83
What are the two types of leaf veins structures?
Parallel and netted
84
What are the types of netted veins?
Palmately, denate, or pinnately netted
85
What are the types of parallel veins?
Longitudinally and pinnately
86
What's the difference between leaf anatomy of eudicots and monocots?
Eudicots have more stomata on the lower surface, monocots have evenly distributed stomata
87
How does blue light relate to stomata?
Blue light can cause stomata to open
88
What are the reasons why guard cells would close the stomata?
It's night, there's a high concentration of CO2 in the guard cells, or the guard cells are dehydrated
89
When the guard cell holds the stomata open, what are its conditions?
It's turgid and has a low concentration of CO2
90
Define turgid
Having lots of water
91
What does transpiration do to plants?
It dehydrates them and causes them to need more water and close their stomata at night
92
What's the difference between transpiration and guttation?
Transpiration is with water and usually happens because of open stomata in the leaves, guttation is the exhumation of xylem sap on leaves
93
What is guttation?
The exudation of xylem sap on leaves
94
What are four examples of modified leaves?
Lily pads have modified leaves to float in a watery environment, pine needles have a reduced surface area for cold temperatures, onions are leaves with storage for starches due to lack of nutrients in soil, and cacti have needle leaves so they don't get eaten by dehydrated animals
95
What are trichomes?
Leaves with stingy hairs so people don't eat them (ex: stinging nettle)
96
Soil particles are _____ charged
Negatively
97
80-90% of a plant's fresh mass is _____
water
98
4% of a plant's dry mass is __________
inorganic substances from soil
99
96% of a plant's dry mass is _____
from CO2 assimilated during photosynthesis
100
What three factors contribute to plant growth?
Soil, air, and water
101
What are the most common plant nutrient deficiencies?
Nitrogen, potassium, and phosphorus
102
What is nitrogen fixation?
The conversion from N2 to NH3, which is then converted to NH4+
103
Describe the conversion to NO3
Nitrifying bacteria oxidize NH3 to nitrite (NO2–) then nitrite to nitrate (NO3–), but some nitrogen is lost to the atmosphere when denitrifying bacteria convert NO3– to N2
104
What are nodules?
Bumps in a plant's roots where it's "infected" with rhizobium bacteria
105
What are rhizobium bacteria?
Nitrogen-fixing bacteria that provide plants (legumes) with a source of fixed nitrogen
106
What are bacteroids? Where are they?
A form of rhizobium bacteria which is contained within vesicles formed by the root cell
107
What makes the relationship between rhizobium and plant roots mutualistic?
The plant obtains fixed nitrogen from Rhizobium, and Rhizobium obtains sugar and an anaerobic environment
108
What does crop rotation take advantage of?
The symbiotic relationship between legumes and nitrogen-fixing bacteria
109
What do root cap cells secrete and why?
They secrete lubricating polysaccharides to reduce friction
110
Besides secreting, what else do root cap cells do?
Protect the apical meristem
111
What are root hairs?
Short-lived tubular extensions located just behind the growing root tip
112
What is development of roots and root hairs controlled by?
Two regulatory genes that code for transcription factors
113
What's the order of the sections present in the cross-section of roots from outside to inside?
Root hairs, epidermis, exodermis, cortex, endodermis, pericycle, phloem, xylum
114
What is the cortex of a root made of?
Parenchyma cells
115
What type of cells are in the exodermis of a root?
Sclerenchyma cells
116
Where is the Casperian Strip located?
In the endodermis of roots
117
What is the endodermis?
The innermost layer of the cortex
118
What is the Casperian Strip?
A water-impermeable strip of waxy material that forces water and solutes to cross the plasma membranes of endodermal cells instead of slipping between the cells.
119
Why does the Casperian Strip have to do the job it does?
To ensure that only materials required by the root pass through the endodermis, while toxic substances and pathogens are generally exclude
120
What is the pericycle in roots?
Nonvascular tissue separating the endodermis from the phloem
121
What do root hairs do?
Increase the surface area of the root, which helps with absorption
122
What comprises the majority of the root?
The cortex
123
How many layers of epidermal cells cover roots?
One
124
What does most water that enters the root do?
It moves along the cell walls made of cellulose
125
What is the primary function of the root cortex?
Starch storage
126
What does the endodermis do?
It regulates the movement of water and minerals that enter the xylem
127
Each endodermal cell has what?
A casperian strip on its radial and transverse walls
128
What is the waterproof material in casparian strips made out of?
Suberin
129
What two pathways does water follow in the root?
Symplast pathways and apoplast pathways
130
The symplast pathway consists of what?
Living cells interconnected by plasmodesmada
131
To reach the vascular tissues of the xylem, water must pass through what?
The plasma membranes of endodermal cells
132
What is the stele?
The center of a eudicot's primary root
133
What does vascular cambium produce?
Xylum
134
Where does photosynthesis take place in leaves?
Palisade mesophyll
