Botany Flashcards
Why are plants important to humans?
Food, rubber from sap, herbal tea, medic ice, natural insecticides, cotton, and wood
What makes a plant a plant?
- Eukaryotic cells
- Multicellular organisms with specialized tissues
- Cell wall with cellulose
- Photosynthesis
- Store glucose as starch
- DNA similarities
What organs do plants have?
Stem, leaf, root
Why are fungi not plants?
Glucose is stored as glycogen, cell walls are made of chitin, tissues CAN be unicellular, not photosynthetic
Why are algae not plants?
- Do not develop embryos
- Don’t have chlorophyll
- Cels/tissues aren’t specialized
How are plants classified?
- vascular system, seeds, flowers
Describe Bryophytes
Small, found in moist shady areas, no seeds, no flowers, no vascular system
Describe Pteridophytes
Have vascular system, no seed, no flower, true tissues, embryo, large leaves called frands
Describe gymnosperms
Have naked seeds, vascular system, true tissues, embryo, not a proper clade, have needles
Describe angiosperms
Flowers, seeds, vascular system, true tissues, embryos
What are the 6 meristems? their functions?
- Shoot apical meristem (produces cells at top of stem)
- Root apical meristem (located at bottom, produce cells at roots)
- Lateral meristems (adds branches to shoot)
- Cork cambium (produces barck and cork)
- Vascular cambium (produces vascular tissues)
Growth of plant stages:
- cell division in meristems
- Elongation of new cells
- Differentiation and specialization
Types of adult tissues:
Ground (carry out metabolic processes), dermal(protect plant and interact with environment), vascular(transport water, minerals, and sap)
Describe Monocot
- 1 cotyledon
- 3 or multiple of 3 leaves
- parallel leaf veins
- VB are spread out in stem
- VB are in circle in root
Describe Dicot
- 2 cotyledon
- 4 or 5 leaves
- net array of leaf veins
- VB are in a circle in stem
- VB are in X in root
Why is it good to be wood?
- Tree can grow taller
- Lasts longer (has protection)
Why is it bad to be wood?
- Secondary growth takes more energy
- Needs a defines mechanism
- Likely to be attacked by animals
What does xylem consist of?
- fibers, parenchyma, and conducting cells
What must be present for the cohesion - tension model to work?
- continuous water flow
What are plasmodesmata?
- holes that allow for water to transport between cells
Conducting cells:
- no cytoplasm
- start alive then die
- secondary cell wall with lignin
Vessel elements:
- larger than tracheids, top and bottom digest to form one tube, holes on walls
- in angiosperms
Tracheids:
- less efficient, connect each other through pits
- In angiosperms and gymnosperms
Explain cohesion - tension model
…
What does xylem transport rely on?
- adhesion (water sticks to hydrophilic molecules)
- cohesion ( water sticks to water)
- Transpiration
What decreases inspiration?
- Thick waxy cuticle
- Stomata lower on epidermis
- smaller leaf surface area
- more epidermal layers
What increases transpiration?
- dry air
- wind
- High temperatures
- high number of stomata
What do phloem consist of?
- fibers, parenchyma, sieve tube members (conducting cells), and companion cells
Describe companion cells:
- Keep sieve tube element cells alive
- control phloem (allow sugar in and out)
Describe translocation/pressure flow model:
…
What are the groups of phytohormones?
- auxins
- gibberellin
- cytokinin
- abscisic acid
- ethylene
What does cytokinin do?
- increases mitosis
- delays senescence
- delay degradation of chloroplasts
What does auxin do?
- cell elongation (vacuole fills with water stretching the cell, weakens wall to increase water intake)
What does gibberellin do?
releases amylase from seed cells which breaks down stored starch in the seed to supply sugar for cell respiration and growth
What does abscisic acid do?
- must be broken down to allow for seed growth
- Gibberellin cannot work until there is more gibberellin
- Closes stomata and therefore reduces inspiration
What does ethylene do?
- ripens fruit
- induces leaf abscission
