Exam 1 Flashcards
1
Q
When did life appear?
A
3.8 to 3.5 billion years ago
2
Q
When did photosynthetic organisms appear?
A
3.8-3.5 bil
3
Q
What are some of the evidence proving when cyanobacteria appeared?
A
- The ratio of 12C/13C in organic material is higher than in inorganic rocks
- Fossils dating to that time resemble structures formed by cyanobacteria
4
Q
What of photosynthesis did ancestral cyanobacteria produce?
A
Water was not the electron donor and oxygen was not produced
5
Q
When did oxygen-producing (oxygenic) photosynthesis appear?
A
3.5 bil years ago
6
Q
What are the evidence of when oxygenic photosynthesis appeared?
A
Increase of the iron in soils due to the oxidation of Fe2+ t Fe3+ and the insolubility of this iron forming
7
Q
What effect did oxygenic photosynthesis have on life?
A
- Increased oxygen concentration changed Earth’s atmosphere, enabling other living organisms via aerobic respiration
- Led to the formation of the ozone layer to protect from high wavelength UV/UV-C rays
- Fixed CO2 –> organic matter available to food for heterotrophs
8
Q
When did eukaryotic organisms appear?
A
2.7 billion years ago
9
Q
What led to the evolution of eukaryotes and photosynthetic bacterium?
A
Primary endosymbiosis event where a host cell mitochondrion engulfed a non-photosynthetic bacterium.
Later endosymbiosis with a host cell contained a mitochondrion engulfing another bacterium for it to turn into a chloroplast
10
Q
What did the ancestral photosynthetic eukaryotes evolve into?
A
Glaucophytes (unicellular algae)
Rhodophytes (red algae)
Chlorophytes (green algae)
11
Q
What did land plants evolve from and when?
A
Land plants evolved from green algae around 475-450 million years ago. Adapted to living on land not surrounded by water anymore
12
Q
What do Charales and land plants have in common?
A
- Cellulose in the cell wall
- Formation of a phragmoplast during cell division
- Plasmodesmata
13
Q
What are the major unifying traits of plants?
A
- primary producers converting solar to chemical energy, stored as carbohydrate bonds
- Sessile, growing towards resources as an adaptation
- structurally reinforced to compensate growth mass
- nutrients from soil and photosynthesis are transported using nonphotosynthetic movement mechanisms
- lose water continually via evaporation and have evolved to avoid dessication.
- embryos derive nutrients from mother plant, which facilitate self-supporting land structures.
14
Q
What are the 5 key traits of land plants?
A
- apical meristems
- alternation of generations
- walled spores produced In sporangia
- multicellular gametangia
- Multicellular-dependant embryos
15
Q
What characterizes a bryophyte?
A
These plants are nonvascular. In reproduction, the gametophytes are not dependent on the sporophytes. The gametophyte is dominant where the sporophyte is small and grows off the gametophyte as an extension.
16
Q
What characterizes a tracheophyte?
A
These plants are vascular. The sporophyte is the dominant generation, where it grows off the tiny gametophyte.
17
Q
What characterizes a seed plant such as a gymnosperm? What makes gymnosperms special?
A
Gametophytes are non-autotrophic. It contains male and female gametophytes where the sporophyte encloses the female gametophyte, and the male gametophyte is dispersed, such as in gymnosperms.
In gymnosperms, there are male and female cones which have a microspore and megaspore, respectively. The male cone produces pollen, containing the microspore which go to the female cone where the megaspore is. The megaspore acts as a womb where the seed is formed with the embyro
18
Q
What characterizes angiosperms?
A
Angiosperms or flowering plants have flowers which attract pollinators.
The seed is enclosed in the fruit and gets dispersed by animals. A double fertilization even produces a diploid zygote as well as an 3n endospore, which provides nutrients to the embro/young plant.
19
Q
What are the differences between monocots and dicots?
A
Monocots have parts and multiples in 3.
Dicots have flowers in parts of 4s or 5s, or multiples of those numbers.
20
Q
When did angiosperms occur?
A
135-145 million years ago
21
Q
Which plant types correspond to non-autotrophic gametophytes?
A
Gymnosperms and angiosperms
22
Q
What plant structures derive from apical meristems?
A
leaves, flowers, roots, cambium…
23
Q
In dicots, where is the secondary xylem produced, where does it grow towards? Is the secondary xylem closer or farther away from the cambium compared to the primary?
A
it is produced from the cambium and grows towards the pith. The secondary xylem is closer to the cambium than compared to the primary.
24
Q
Vessel elements in the xylem are…
A
Specialized cells that are dead
25
What are the advantages of angiosperms?
1. Animals help plants reproduce by bringing the pollen to the stigma
2. Animals help disperse seeds via fruit-enclosed seeds
3. Endosperm production gives nutrients for embryo until leaves grow
26
What is a diecious flower? Are all flowers diecious?
Diecious flowers mean male and female flowers are not on the same plant. Some plants, such as cucumber and maize corn, have male and female flowers on the same plant.
27
What are meristems?
Areas where plant growth is localized in areas where nuclear and cell division occurs. Undifferentiated cells divide via cell division and differentiation giving rise to the whole plant body.
28
What are the two primary meristem styles?
R.A.M (roots) give rise to the root cap and the rest of the root
S.A.M (shoots) give rise to all aerial parts of the plant (stem, branches, leaves, and flowers)
29
What does the primary meristem give rise to?
The primary meristem grows the plant in length through auxiliary buds, SAM, RAM, and lateral roots.
30
What is the secondary meristem and what does it grow?
found along the length of the root&shoot and grows the plant horizontally. Secondary growth continues on primary growth & makes plant thickers.
Contains the vascular cambium, cork cambium, intercalary cambium
31
What is the vascular cambium?
Produces wood.
Arises in the vascular system between the xylem and phloem of the primary plant body. Cells divide longitudinally producing derivatives toward inside and outside of the vasc. cambium of roots and shoots.
Cells inside also differentiate into secondary xylem and phloem.
32
What are the secondary xylem and phloem?
The secondary xylem is a product of the vascular cambium, which conducts water and nutrients to organs and is characterized by thick secondary walls. Becomes annual rings. Xylem divides towards the inside.
The secondary phloem conducts photosynthesis products to the reproductive organs or downwards to other organs. Divides towards outside
33
What is the cork cambium?
Produces the protective periderm consisting of waterproof cells.
The cork plus cork cambium plus the secondary phloem consists of bark.
34
What are intercalary meristems?
Primary meristems located at the nodes allow grasses to grow even after it is cut.
35
What is the epidermis?
The epidermis is the outermost layer of cells in plant organs. It includes specialized cell types such as root hairs, guard cells, trichomes, and secretory cells
In older cells, it is sloughed off and replaced by periderm.
36
What are guard cells?
Guard cells open/close the stomata area and must be monitored so evaporation and co2 movement can be regulated
37
What are ground tissues>
Ground tissues contains pith, cortex, mesophyll and leaf cells. It is the bulk of the plant. It also includes
Parenchyma, collenchyma and sclerenchyma cells
38
What are parenchyma cells?
Parenchyma cells are the most abundant type of specialized ground tissue cells. They are present in all parts of the plant. They are spherical and can differentiate into various other ground and vascular tissues after production. They function primarily for food, water storage or photosynthesis.
39
What are collenchyma?
Collenchyma are thick primary walls that continually elongate. They lie right beneath the epidermis and function as flexible support for organelles.
40
What are sclerenchyma?
Sclerenchyma have thick cell walls of lignin, they are mostly dead and function as rigid support
41
what are parenchyma fibers?
These fibers connect living fiber cells and align them. The pit pairs form plasmodesmata, and it function as support.
42
What are vascular tissue?
Vascular tissue is composed of parenchyma and sclerenchyma cells as xylem and phloem.
43
What is xylem?
Xylem is composed of tracheids and vessel elements that are dead at maturity. these cells fuse together to form tubes that are hollow inside to transport water and minerals from the roots to all other organs in the plant.
Angiosperms have vessel elements with end wall preforations.
44
What is phloem?
Phloem contains sieve elements (sieve cells in gymno), which lack nuclei, most cytoplasmic organelles at maturity, and parenchyma. Phloem cells are NOT dead. they require companion cells to function.
The phloem functions to transport photosynthetic products and other elements throughout the plant.
45
What are the characteristics of a plant cell?
1. plant cells contain a cell wall
2. plant cells are autotrophic with chloroplasts and plastids
3. plant cells contain vacuoles.
46
What is the function of the stem?
the stem consists of the epidermis, ground tissue, vascular bundles, and cortex. It supports and transports the xylem, phloem and sap.
47
What are the function of the roots
It comprises epidermis, cortex, endodermis, pericycle, and vascular bundles. functions to anchor the plant into the soil and absorb water and necessary elements
48
What are the functions of leaves?
It contains the epidermis, ground tissues, and vascular tissue. Functions to provide transpiration and photosynthesis.
49
What is the Fluid mosaic model?
The fluid mosaic model are cell wall membranes made of phospholipid bilayers
The side exposed to cytoplasm outside and inside the cell is hydrophilic, while the inner layer is hydrophobic.
50
What is the composition of plant cell membranes in relation to cholesterol
Very little steroids/cholesterol
51
How do cell membranes regulate fluidity?
To increase fluidity, they…
1. Shorten the fatty acids
2. Increase unsaturated fat double bonds to reduce H
3. Increase the steroid concentration.
Gradual cold acclimation allows for cold tolerance in some plants
52
What is produced by rough ER and why. Where does it go?
ER synthesizes proteins and lipids on ribosomes attaches to ER. Specifically, ER produces OLEOSOMES and PROTEIN BODIES. OLEOSOMES are oil made for endosperm and consist of triglycerides and a lipid mono layer
The seed storage proteins are classified based on solubility and go to different areas
53
What’s special about the Golgi?
The golgi synthesizes polysaccharides for the cell wall EXCEPT CELLULOSE
The golgi GLYCOSILATES proteins received from the ER, meaning it adds sugar
Plant golgi is different from animal due to sugar branching
54
What’s up with the mitochondria?
Used for respiration. Fusions and fission form the mitochondrial networks. Always have smooth cellular membranes and convoluted inner membranes for ATP. In folding are called cristae and the inner area called matrix
55
What are protoplastids?
Located inside meristem cells and contain few or no inner membranes. In gymnos, they develop into chloroplasts if they are exposed to light in young plants. OR will turn to amyloplasts if exposed in darkness
56
What are etioplasts?
Like protoplastids, but develop protomellar bodies in the dark. They also contain protochlorophyll that will convert the plastid into chloroplasts when left in light but can revert if left in darkness again
57
What are chloroplasts
Divide by fission and are independient of nuclear fission because they are regulated environmentally. Chloroplasts are either anchored or mobile in plants. They are composed of inner and outer membranes. Stroma used for the carbon cycle and thylakoids. Accumulate chlorophyll and are found in mesophyll cells
58
What are chromoplasts?
Chromoplasts are chloroplasts that accumulate carotenoids as the chlorophyll degrades.
59
What are leucoplasts
Leucoplasts are colorless plastids that have a storage function that store and synthesizes starch and sugars
60
What are amyloplasts?
They are plastics that accumulate lots of starch, lipids and proteins. Can also turn into chloroplasts when exposed to light
61
What are vacuoles?
Vacuoles can compose 95% cell volume and are involved in storage, digestion, defense against pathogens, sequestration of toxins, pigmentation and PH active transport
62
What is vacuolar pH transport?
Inside of the vacuole has lower pH than the cytoplasm which allows for ion gradient where H ions actively transport inside of the vacuole. The acidity of the plant comes through the vacuole and this gradient is used to import other acids into the vac. Once of which is maleate which is used for resections
63
What’s with vacuolar storage?
Vacuoles have a higher concentration of H and Ca which is used in active transport. This storage function is also used in cell expansion and the membrane, tonoplasts, contains proteins and lipids
64
What is vacuolar sequesterization?
The vac isolates toxins such as tabaco and oxalate from the rest of the cell
65
How does the vacuole contribute to plant pigmentation?
The vacuole can store anthocyanins
66
What are some plant micro bodies?
Peroxisomes are involved in thee recovery of C after photorespiration in photosynthetic cells. It also generates H2O2 to be broken down
Glyoxisomes convert fatty acids into sugar in oil-storing seeds via oxidation
67
What's cool abt the nucleus
responsible for metabolism, regulation, growth and differentiation
68
What are the two examples of microtubule functions relating to cell division and growth?
1. Microfibril orientation around the cell dictates the direction of cell expansion. Wherever direction the microfibrils grow around will restrict the cell growth to go in the opposite direction. So a horizontal microfibril band will result in vertical growth.
2. Pre-prophase microfibril band determines the direction of cell division as it lines up the cell wall division point which causes the plant to grow in a direction.
69
What is the function of microtubules?
Dynamic structures
Prophase band determined cell division orientation
Pragmoplasts in the formation of cell plates
Cortical microtubules guide the deposition of cellulose fibers in the cell wall and determine the direction of cell expansion.
70
What are the function of microfilaments?
Cytoplasmic streaming
Pollen tube growth
Chloroplast orientation in response to light
71
Where are the proteins synthesized on free cytoplasmic ribosomes targeted to?
In chloroplasts:
Stroma-transit peptides and chaperones involved
Thylakoids: proteins have both a stromal transit peptide and as lumenal transit peptide
Mitochondria: different transit peptides, chaperones
Nucleus: Nuclear localization signals remain on protein
Peroxisomes
72
Where are proteins synthesized on ER ribosomes targeted?
Er
Golgi
Nuclear Env.
Vacuoles
Plasma membrane
Extracellular space (secreted out or on the cell wall)
73
What are the transit peptides on the stroma and thylakoid?
The transit peptides are located on the amino-terminal end according to chloroplast receptor proteins, and then it get processed and thrown away.
Thylakoid proteins have lumenal transit peptides where the protein will be bound, processed, and removed
74
Where can mitochondrial proteins go?
the membrane or the matrix
75
What's up with nuclear proteins?
Nuclear proteins must know to return to the right nucleus after mitosis, so it needs NLS that does NOT get removed.
76
What's the story for proteins synthesized on the ER surface?
Ribosomal protein RNA bind to floating ribosomes and then ends up on the ER surface as a peptide sequence. This causes a signal peptide to synthesize and bind to the receptor on the ER surface. Synthesize continues on ER surface and then travels in vesicles to wherever it needs to go to be finished.
77
What is the function of the cell wall?
Controls cell shape and volume to prevent cells from bursting
Increases mechanical strength of plant structure so the plant can stay upright
Glues cell together
Works as a barrier for molecules as well as for pathogens
78
What is the middle lamella?
The middle lamella is a thin layer of pectin-rich material located at the junction where the primary walls of neighbors come into contact
it is deposited first during cytokenesis, and remains the furthest away from the cytoplasm while the secondary cell wall is the closest to the cytoplasm
79
What are pectin polysaccharides?
they are hydrophilic polysaccharides that form a gel and make up the matrix
80
What about primary cell wall pectin composition?
They are branched polysaccharides containing galacturonic acid
with an amorphous network that regulates the cell wall
81
What does galacturonic acid do in pectin?
Primary cell wall pectin has a high proportion of galacturonic acid because it contains COOH which becomes negatively charged and causes water retention.
Negatively charged chains cross-link through Ca+ ion interactions which regulate the porosity. This crosslinking increases after the cell STOPS growing.
Methyl groups link to prevent gal. acid crosslinking
82
Where is hemicellulose located?
Both in the primary and secondary wall
83
What are the properties of hemicellulose?
branched B(1,4) polysaccharides consisting of different monosaccharides. units.
Cross-linking cellulose fibers and add strength to the cell wall
84
What are the monosaccharides of hemicellulose?
glucuronoarabinoxylans, glucomannans, xyloglucans
85
Where is cellulose synthesized?
On the cell membrane/surface by enzyme complexes (present on the plasma membrane
86
What are the properties of cellulose?
Extremely long, linear glucose/B-glucan polysaccharides that can crosslink to add strength to the cell wall. Digestable by specific organisms.
87
What are some of the protein types found in cells?
HRGP: hydroxyproline-rich glycoproteins found in extensin and expansion
PRP: proline-rich protein
GRP: glycine-rich proteins
AGP: arabinogalactan proteins are glycoproteins with sugars attached.
88
What is an example of a cell wall enzyme?
Expansin loosens the bonds in the cell wall
Extensin is used for structure(?)
89
The assembly process of cells?
REDO CARD
The ribosomal ER sends proteins to the Golgi in a vesicle to add sugars and then to the plasma membrane where it gets secreted from the cell wall to become cell wall, NOT CELLULOSE.
Involvement of the phragmoplast?
Secretion of materials in vesicles and polymerization with the middle lamella.
90
What are some defining characteristics of the secondary cell wall?
The secondary cell wall is more rigid as it contains lignin, very little pectin, and still has hemicellulose and proteins. Layers in the secondary cell wall get deposited in different directions, so they alternate.... for reasons..
91
What is the difference between primary and secondary wall cellulose?
Secondary cell wall cellulose contains a lower concentration/absence of pectin, resulting in the cellulose being less extensible than the primary cell wall.
92
What is the composition of the branched polysacch. in the secondary cell wall?
Mostly hemicellulose
93
What's up with lignin synthesis? (not the process, just the summary"
Lignin is a polymer of phenolic acids where polymerization takes place on cell walls by alcohol (writing this makes me want some) oxidation. This causes phenolic compounds to by synthesized by phenylalanine
94
What is important about lignin?
Lignin is important. it makes plants strong. I'm so sick of writing flashcards. I miss my wife and kids, I want to go home.
Lignin adds strength to vascular bundle dead cells and makes intercellular spaces impermeable to water in the Casparian strip of the endodermis
95
ok now tell me the synthesis of lignin and those chemicals that she emphasized.
Lignin is made from the polymerization and oxidation of monoligin synthesized from COUMARIC ACID --> monolignes. COUMARIC ACID is made from phenylanine which is synthesized by the PHEYLPROPANOID PATHWAY. that's the pathway I'm going to take when i go home
96
What's a cuticle?
The cuticle lies on the top of the cell wall and limits expansion inside the cell, making cells IMPERMIABLE FORTRESSES!!!!1!
It is composed of CUTIN - crosslinked fatty acids
and WAXIN - esters of fatty acids
97
What are cell wall materials used for
Textiles, paper (cellulose),
diet roughage (cellulose) (polysaccharides in brans)
charcoal <--- gonna be me
lumber
98
