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76 Cards in this Set
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Define: Hermaphrodite Provide specific plant examples. Why is being a hermaphrodite an issue with plants? |
producing male and female gametes Ex: Arabidopsis thaliana, weeds Issue: leads to inbreeding and decreased genetic variability. Increased risk of extinction. |
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Incomplete Flower |
lacks one or more of the normal flower organs (stamen, carpel, petals, sepal, pistils) |
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1.Pistillate Flower
2. Staminate Flower |
1. Female flower: only contains carpel reproductive structure. Lacks stamen. 2. Male Flower: only contains stamen reproductive structure. Lacks pistils. |
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Species that have unisexual (incomplete) flowers |
are called monoecious or dioecious Monoecious- hermaphrodite, but stamen and carpel regions are spatially separated (ears of corn are female region, flowers are male region) Dioecious- only produces ONE reproductive organ **either male or female |
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What is the benefit of monoecious and dioecious incomplete flowers? |
They discourage inbreeding by the way their structure is built. No inbreeding=more genetic diversity. Must obtain gametophyte from other plant in population |
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Self-Incompatibility |
rejection of genetically identical pollen by carpel |
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Ways to reduce self-fertilization (inbreeding) |
1. Timing pollen release 2. Timing carpel development Want to create pollen grains before carpels develop |
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Asexual Reproduction What is it and what are the benefits? |
a major mode of reproduction for plants creates genetically identical offspring rapid colonization no dependency on pollinators good for stable environments |
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What are the disadvantages of asexual reproduction? |
no genetic diversity susceptible to disease+changes in environment that could drive species to extinction |
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How does asexual reproduction occur in plants? |
modified stems & roots which create new plants Stolon- horizontal stem from the base of a plant that produces new plants (ex: strawberries) Rhizome- horizontal, below ground stem Roots |
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Fragmentation Provide example |
type of asexual reproduction detached organ develops into complete, new plant Ex: Kalanchoe buds will fall off to create new plants |
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Parenchyma Cell |
plant cell in the ground tissue that can differentiate into all cell types Can become shoot/root apical meristems and other structures in plant Can put foreign DNA into a parenchyma cell and it will grow a new plant |
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Root and shoot apical meristem are created by |
parenchyma cells. Once created, root and shoot development are due to root and shoot apical meristem. |
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Apomixis What are the three events that must occur for apomixis to be successful? |
asexual reproduction of a seed produces seeds that are genetically identical to parent 1. Apomeiosis- creation of female gametophyte without meiosis. Creates diploid gametes. 2. Parthenogenesis- fertilization:independent embryo development 3. Fertilization independent of endosperm formation |
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Asexual adaptation for reproduction without pollinator |
apomixis |
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What is the benefit of asexual reproduction in plants to humans? |
can create fruits+veggies more rapidly by creating clones (no seed needed) ex: bananas do not have any seeds, they are created by rhizomes (underground stem) that creates new shoots |
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Artificial Asexual Reproduction: Grafting Why is this done? |
Grafting- joining 2 different plants together. Phloem&Xylem must form together to live. Stock- plant that donates root system Scion- plant that is fused to stock root system Purpose: to get healthier plant, less susceptible to disease. |
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Artificial Asexual Reproduction: In Vitro Cloning |
create protoplasts by removing cell walls add a transgene treat with minerals and hormones and parenchyma cells callus will form new cell wall a single cell can create a new plant |
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Plants can regenerate from _______________ |
a single cell |
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Define Gall and what is it due to? |
A gall is a tumor like growth on the stem of a plant caused by Agrobacterium tumefacians. Infects cell wall. |
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Method of Creating GMO crops: Dealing with Bacteria |
Inserting desired DNA with the Agrobacterium tumefacians Ti plasmid. Will get into plant host's DNA and it will receive the desired traits such as increased nutrients. |
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Method of Creating GMO Crops: BT Toxin What are the benefits |
Bacillusthuringiensis : A soil bacterium that creates a protein that is toxic to bugs, thus, is used as an organic pesticide Purpose: can be added to plant's DNA so when bug bites the plant it will die Very specific to the bugs it will kill. Increases crop yields, decreases use of syn. pesticides |
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Organic Pesticide |
readily breaks down in the environment ex: BT Toxin |
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EPSP synthetase |
enzyme responsible for creating aromatic amino acids in plants. Round-up, glyphosate, inhibits EPSP synthetase, leading plant to die when sprayed Plants that have the EPSP synthetase transgene will not die when sprayed |
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Systemic Herbacide |
kills unwanted weeds by inhibiting EPSP synthetase |
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Glyphosate Resistance |
plants engineered to contain the transgene bacterial EPSP synthetase so when sprayed will not die |
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Golden Rice |
GMO rice. Endosperm produces vitamin A. Due to three genes, psy, crtl, and icy being added to endosperm. |
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Concerns over transgenic plants |
1. Transgene escapes into wild 2. Off- target effects of BT. Could kill bugs not targeted like the monarch butterfly 3. Ethics- not natural plants 4. Allergies to these transgenic plants |
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Define: Hormone How do they travel? |
a small molecule that acts over long-distance to change metabolism, physiology, and growth in mammals, the circulatory system in plants, some compounds can have a hormone-like effect only locally, while simple metabolites like surcrose can create hormone-like responses |
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Define: Phototropism How does this happen? What is this driven by? What hormone causes this? |
tendency for stems and leaves to grow toward regions of higher light Cells on the shaded side expand at a faster rate than the sunny side, making the plant bend towards the sun driven by cellular expansion&caused by auxin |
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How does a plant know to bend towards the light? |
Light is perceived only at the tip of the coleoptile. A water soluble messenger travels down shoot with asymmetric distribution of the auxin causing cellular expansion more on shaded side. |
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Hormone: Auxin
Source Tissue |
growth promoting hormone causing cellular expansion (responsible for phototrophism) causes auxiliary buds to stay inactive shoot apical meristem |
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How is the plant hormone auxin transported? |
It is transported by the trans-membrane route Pumped in one direction through parenchyma cells. On the basal (bottom) part of cell, auxin efflux proteins pump auxin out of the parenchyma cells. Then, auxin influx carriers are transmembrane proteins that allow auxin into parenchyma cell |
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Apical vs Basal |
top vs bottom |
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How is cellular expansion driven? |
Auxin acidfiying cell walls, loosens cell walls and turgor pressure expands cell. |
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How does auxin inhibit auxiliary bud growth? |
From the shoot apical meristem, auxin travels down the shoot, auxiliary buds sense hormone and stay inactive. This is apical dominance. |
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What is the most common form of Auxin? What is Auxin derived from? |
indole acetic acid (IAA) derived from amino acid tryptophan |
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Hormone: Cytokinins Source Tissue How is this hormone transported? |
stimulates cell division and expansion when working together with auxin stimulates growth of axillary buds Root Tissue Transported by xylem |
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What happens when plant hormones work solo? (for auxin, cytokinins) |
Auxin- cells expand, but do not divide Cytokinins- nothing Together- cellular expansion and division |
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What hormones contribute to apical dominance? |
auxin, cytokinins, and strigolactone |
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Hormone: Gibberelins Source Tissue Function |
initially hormone was found to be secreted by a - fungal pathogen of rice "foolish seedling disease" source tissue: apical buds, young leaves, roots promotes stem elongation
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"Dwarf" plants are deficient in what hormone? |
Gibberelins- hormone that promotes stem elongation |
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Define: Bolting What hormone is this due to? |
plants that produced flowering stems are said to have bolted Due to the hormone gibberelins |
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Gibberelins play a critical role in germination. What do they do? |
stimulate production of enzymes that digest complex carbs to simple sugars. This aids seedling growth. |
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Hormone: Abscisic Acid What is this hormone's function? Why is this important? |
slows plant growth Important for seed dormancy and drought tolerance Seed dormancy- Removal of ABA level stops dormancy |
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Abscisic Acid is responsible for.. |
regulating the opening and closing the stomata Increased ABA levels cause stomata to close, thus, limiting the amount of water loss and gas exchange |
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Hormone: Ethylene |
produced in response to stresses important for fruit ripening (put bananas in bag to ripen them quicker- they ripen faster because ethylene is produced inside the bag) bursts of ethylene control senescence (programmed cell death) |
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"Triple Response" |
triggered by a mechanical stress during seed germination, leading to ethylene production 1. Slows stem elongation 2. Thickens stem 3. Causes plant to grow horizontally ** a way to avoid rocks |
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What hormone is this due to? |
Ethylene it is the "triple response" |
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Two mutants are shown. Name each mutant. |
a) ethylene insensitive mutant- cannot sense ethylene b) constitutive triple response mutant- always thinks it is sensing ethylene |
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What are the hormones auxin and ethylene responsible for? |
controlling leaf abscission (leaf shedding) |
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What is senescence and what hormone is this controlled by? |
senescence is programmed cell death and it is controlled by ethylene |
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The effects of plant hormones are dependent on.. |
1. concentration of hormone 2. concentration of other hormones 3. Specific tissue |
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Hormone: Strigolactone |
produced in roots in repsonse to low phosphate conditions or in response to high auxin flow from shoot |
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Turgid Cell |
Turgid-meaning swollen or hard. Filled with water to the point where it cannot uptake any more due to the pressure being so high |
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Flaccid Cell |
Flaccid- when cell loses water due to being put in concentrated sugar solution. Causes cell to shrink. Cell is said to be plasmolysed. |
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What is the function of movement proteins? |
increasing pore size of plasmodesmata, thus, increasing the size and amount of material that can travel through the plasmodesmata |
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Why do plants without adequate water tend to wilt? |
pressure potential inside the cells decreases, thus, the plant will not stand up straight anymore |
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Activities of an active photosynthetic leaf |
1. Release water to air 2. Release oxygen to air 3. Absorb carbon dioxide from air |
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Diffusion of solutes in the Xylem occurs primarily via the _____________________ route, while diffusion of solutes in the Phloem occurs primarily via the _________________ route |
apoplastic; symplastic |
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Casparian Strip |
found in root endodermis, does not allow solutes to travel apoplastically to the vascular bundle |
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Conflict between photosynthesis and water loss |
Photosynthesis requires a large amount of gas exchange at leaves, but this leads to high rates of water evaporation |
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Leaves that sense drought stress respond by modifying the behavior of guard cells. Which of the following is LEAST likely in guard cells of a drought-stressed leaf? |
Guard cells will be turgid (LEAST LIKELY BECAUSE THAT MEANS THE STOMATA IS OPEN) |
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Which bulk flow requires active transport? |
phloem bulk flow |
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What type of cell is E most likely to be? |
A companion cell (specialized parenchyma cell). A helping agent in phloem |
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Gameteophyte |
multi-cellular haploid structure that produces gametes (egg or sperm) via mitosis (ex: mega and microsporophytes) |
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The cells that directly result from meiosis are called.. |
spores |
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Match the pre-fertilization structures with the structures they develop into in a mature seed 1. Ovary 2. Integument 3. Ovule |
1. Fruit 2. Seed Coat 3. Seed |
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Purpose of fruits is to.. |
disperse seeds |
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Function: Synergid Cells |
release chemicals to attract pollen tubes |
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The GFP is expressed in which structure of the globular stage embryo? |
root apical meristem |
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Hypocotyl VS Epicotyl |
embryonic shoot below the point of attachment of cotyledon embryonic shoot above the point of attachment of cotyledon |
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Where are microspores produced in meiosis |
anther (in the anther there are chambers called microsporangia in which create pollen)
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In a human diet, what part of a plant do we mainly consume? |
endosperm because it contains the most nutrients |
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Function: Tube Cell |
creates pollen tube during fertilization |
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Double fertilization produces.. |
diploid zygote and triploid endosperm |
