Lecture Quiz #3 Flashcards
Why do we have plant names?
Allow us to communicate about plants that we use, grow, and encounter in the wild
Advantages of Common Names
- Use begins in childhood
- Easy to remember
- Usually in the local language
Disadvantages of Common Names
- Vary regionally
- May be misleading
- Many different plants share the same common name
Advantages of scientific names
- No two species share the same scientific name
- Uniform from region and language
Disadvantages of Scientific Names
- Often difficult to remember
- Written in latin
- Not used by most people
Binomial System of naming plants
- Carl Linnaeus
- Abbreviated names to two parts
Scientific Names
- Two word Latin Name (binomial)
- First word is genus to which the plant is assigned
- Second word is scientific epithet
- Ex. Ginkgo biloba
Commemorative Scientific Names
- Names of geographic locations
- Names of influential or particularly knowledgeable people
Correctly Writing Scientific Names
- A latin binomial or a scientific name is always italicized
- Genus is always capitalized
- Specific epithet is never capitalized
Taxon
A taxonomic group of any rank, e.g. species, genus, family, etc.
Genus
group of species w/ shared ancestry and characteristics
Cultivars
- Cultivated varieties
- Traits maintained by propagation
Citrus spp.
- Three ancestral species of citrus: Citron, pomelo, mandarin
- Crosses between them and their offspring
Water is a strange molecules
- Polar molecule
- Adhesion: Sticks to other molecules
- Cohesion: water sticks to itself
Diffusion
- Movement of molecules from areas of high concentration to low concentration
- After some time, a state of equilibrium is reached
Osmosis
Passive diffusion of water through a differentially permeable membrane
Water movement from roots to xylem tissue
- Epidermal cells with root hairs absorb water and minerals from surrounding soil by diffusion
- Can happen symplastically (through cells) or apoplastically (between cells)
Turgor pressure
- pressure that is exerted against the cell wall as a result of water entering the cell
- Full of water
Plasmolysis
- Cells lose water and become “flaccid”
- Lacking water
Transpiration
- Regulated by opening and closing of stomata
- Differential cell wall thickness of the guard cells results in deformation, opening a gap between them
Stomata close as a result of
- Darkness
- High CO2 in the plant
- Low water in cells
- High temperatures
Cohesion-Tension Hypothesis
- Transpiration and the cohesion of water causes an upward pull of water from soil to roots to leaves
- The adhesion of water to walls of xylem cells also helps resist gravity (but also increases friction)
Boreal forests (Taiga) with gymnosperms
- High latitude forests with mostly gymnosperm trees
- Gymnosperms only produce tracheids in their xylem tissue
- Tracheids are more narrow than vessels, less prone to collapse under stress
Xylem can be damaged
- Cells collapse when too much tension is placed on water column
- Air bubbles form inside cells if cells leak air or if water freezes
- Early wood (vessels) more prone to damage than late wood (tracheids)
Small cells are stronger
- Tracheids can isolate embolisms in one cell
- Vessels are connected like pipes (if one fails, all fail)
Factors that limit tree height
- Tension on the water column
- Leaf density
- Photosynthetic rate
- Gas exchange
Phloem
- Transports sugar and other organic substances
- Composed of different types of cells: Sieve tube members, companion cells, phloem fibers, phloem parenchyma
Pressure-Flow/Bulk Flow Hypothesis
- Sugars are produced in the leaves (photosynthesis)
- Sugar is transported into companion cells via Active Transport or a Polymer Trap Mechanism
Where does a plant’s mass come from?
Carbon Dioxide
Photosynthesis and Respiration
- Photosynthesis produces sugars and oxygen
- Cellular respiration produces CO2 and water
Photosynthesis Eqn
6 CO2 + 6 H2O + Light energy > C6H12O6 + 6 O2
Life Requires Energy
- Cells need energy to perform work and to reproduce:
- Synthesize molecules
- Cellular division
- Active transport
- Metabolism
ATP
- Adenosine triphosphate: molecule that powers reactions in cells
- Stores potential energy in chemical bonds
- ATP: fully charged
- ADP: depleted, no energy
NADPH
Nico
