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26 Cards in this Set
- Front
- Back
What is dormancy?
What can dictate this? |
-the period of inactivity
-winter, drought, etc |
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What determines the length of dormancay?
What is it in Vermont? |
-geographic location and plant species
-October through April |
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What are the two phases of dormancy?
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1) Rest period: will NOT grow
2) Dormant yet reactive: plant will grow if given a favorable environment (Feb-April) |
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-What is a nice stem to force into flower?
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-forsythia
-crab apples -hyacinths |
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What occurs during the vegetative phase of plant growth?
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-food resources to produce leaves, stems, and roots
-juvenile phase where reproduction can't occur but plant appears mature |
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What occurs during the reproductive phase of plant growth?
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-sugars and starches are stored
-the plant flowers, produces seeds and fruit |
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What is senescence?
How does it vary? |
-rapid or gradual cycle until death
-in hardy perennials, only above ground part senescences -in wood trees and shrubs, only fruits and leaves scnescence |
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What regulates a plants vegetative and reproductive cycles?
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-age/maturity of the plant
-CHO/nitrogen balance |
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What does CHO/Nitrogen balance have to do with reproduction?
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-CHO's come from photosynthesis in leaves
-Nitrogen is taken up by roots -Too much Nitrogen can prevent a plant from flowering (reproduction) |
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What makes up a cell wall?
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-polysaccharides (long chains of simple sugars like glucose)
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What is cellulose in terms of glucose composition?
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-unbranched polymer of several 1000 glucose molecules
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What is hemicellulose?
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-like cellulose, but branched
-combustible -indigestible by mammals, but ruminants have special bacteria to do this in stomach) |
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Who made the first microscope and when?
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-Robert Hooke in 1665
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What makes cells hard?
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-lignin (polymers of phenolic acid)
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What is the purpose of lignin?
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-hardens cellulose walls
-resists microbial decomposition -causes yellowing in paper |
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What are the three layers of cell walls and what makes up each?
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-primary cell wall (cellulose and pectin)
-middle lamella (pectin) -secondary cell wall (cellulose and lignin) *may not always be present |
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What causes fruit rot?
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-bacteria/fungi breaking down pectin
-similar to mortar between bricks |
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What are the pores and strands that connect cells?
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-plasmodesmata
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What percentages make up cells?
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-85-90% water
-10-15% organic and inorganic substances whether dissolved (CHO's) or colloidal (proteins and fats) |
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What is mRNA?
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-relays genetic information from nucleus to ribosomes (often attached to ER, where proteins are made)
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What is in the nucleus of a cell?
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-chromosomes
-DNA |
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What are plastids and where are they found?
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-found in cytoplasm
-leucoplasts (colorless) -chromoplasts (colored) |
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What is a chloroplast?
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-a chromoplast that contains chlorophyll
-photosynthesis occurs here -have grana (stacked) -has stroma (surrounds grana where CO2 is converted to CHO's) |
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What is mitochondria?
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-power center for cell which has proteins and phospholipids
-makes ATP which carries energy |
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What are vacuoles?
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membrane-lined cavities in the cytoplasm filled with cell sap and controls turgor
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What makes up cell sap?
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-water, salts, and organic materials
(90% water, 8% sugar, 2% minerals/AA/other) |