EE BIOL 162 Study Guide - Midterm Guide: Irradiance, Starch, Action Spectrum
8 Jun 2018
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EEB 162 Plant Physiology Mid-Term Study Guide
What is a Plant?
1. What are 3 features of cells that are distinctive and typical of plants?
• (1) Cellulose cell walls
• (2) Vacuoles
• (3) Chloroplasts
2. What are 5 characters that might define a good model plant?
• (1) Small genome size (i.e. easy to sequence)
• (2) Easy to grow in a small amount of space and fast growing (ex/ mustard plant)
• (3) Observable traits that are more dramatic (ex/ the snapdragon have a large flower =
flower developmental genetics)
• (4) Crop species whose genome is more readily available and more possible for genetic
mutations (ex/ corn, rice, wheat, tobacco)
• (5) Easy to transport the plant (i.e. easy to study)
3. What are the three major kinds of plant tissues and their functions?
• (1) Dermal Tissue
o Prevents H2O loss
o Lets light pass through for photosynthesis
• (2) Ground Tissue
o Helps conduct photosynthesis and metabolism
o Provides support for the plant
• (3) Vascular Tissue
o Transports nutrients and H2O
4. What are the major plant tissues and where in the plant are they located?
• Dermal Tissue – located on the surface of plant (roots, leaves, stems)
o Epidermis: single layer of cells (upper pavement and lower)
o Cuticle: waxy layer to prevent H2O loss
o Guard cells: regulate gas exchange in stomata
o Root hairs: increase SA and water uptake
• Ground Tissue – located in the leaves and stems
o Parenchyma
▪ Thin-walled
▪ Metabolically active cells
▪ Functional in metabolism and photosynthesis
o Collenchyma
▪ Narrow, elongated cells with thick primary walls
▪ Provide structural support to the growing plant body
▪ Can stretch as organs grow (usually found in stem periphery, petioles)
o Sclerenchyma
▪ Consists of two types of cells: sclerids and fibers
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• Both have thick secondary walls and are frequently dead at
maturity
▪ Sclerids
• Occur in a variety of shapes, ranging from roughly spherical to
branched
• Widely distributed throughout the plant
▪ Fibers
• Narrow, elongated cells that are commonly associated w/ vascular
tissues
▪ Provides mechanical support particularly to non-elongating parts of the
plant
• Vascular Tissue – located in the stems
o Xylem (up)
▪ Functions in conduction of water and nutrients
▪ Conducting tissue composed of tracheids (gymnosperms) and vessels
(angiosperms)
▪ Vessels are composed of vessel elements
▪ Parenchyma and sclerenchyma are also present in xylem
o Phloem (down)
▪ Functions in conduction of sugars and signal molecules
▪ Conducting tissue composed of sieve cells (gymnosperms) and sieve tubes
(angiosperms)
▪ Sieve tubes are composed of sieve elements
▪ Parenchyma and fibers are also present in phloem
5. What is the symplast? And what is the apoplast? Which one is better for water/large
biomolecule transport?
• Symplast
o Diffusional space in cytoplasm
o One transport pathway in which all living tissue in the plant is connected
o Phloem is part of the symplast
o Better system for conducting large biomolecules → biomolecules are “expensive”
so only want to send it to target areas; transportation through symplast is more
controlled and concentrated to target areas
• Apoplast
o Diffusional space in cell walls
o A potential transport pathway in which the cell walls form a continuous space
(nonliving tissue in the plant)
o Outside of the protoplasts
o Xylem is part of the apoplast
o Better for water transport, water can travel faster because it does not have to move
through the plasma membrane
6. Approximately how many species exist of gymnosperms and angiosperms?
• Gymnosperms = ~700 species
• Angiosperms = ~250,000 species
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7. In which ways are plants diverse?
• Taxonomic diversity
o Gymnosperms = ~700 species
o Angiosperms = ~250,000 species
• Life form diversity
o Immense size variation
▪ Duckweed (<1mm diameter, 150 micrograms)
▪ Redwood and giant sequoia (100 m tall and 1.2 million kg)
• 12 orders of magnitude in mass!
o Growth form
▪ Trees (woody, single stem)
▪ Shrubs (woody, multiple stems, shorter)
▪ Herbs (non-woody)
▪ Climbers (vines)
o Variation in habit
▪ Clonal populations
▪ Epiphytes
▪ Carnivorous plants
• Biochemical and structural diversity
o Biochemistry and metabolism
▪ C3, C4, and CAM photosynthesis
o Nutrient and pigment concentrations
o Hormone sensitivity
o Flowering cues
o Structure
▪ Wide variation in cell sizes in each tissue, leaf size, colors, etc.
• Whole plant adaptation to habitat
o Irradiance habitats
▪ Plants thriving from <1% to 100% full daylight
o Moisture supplies
▪ Plants exist on chronically dry soil and on ever-wet soil (or submerged in
water)
o Temperature range
▪ Plants exist where temperature reach < -40oC and > 40oC
Water and Plant Cells, and Water Transport
8. Why do plants need water (Three reasons??
• Mass of the plant cells
o Water makes up most of the mass of the plant cells (i.e. bulk of the content of
vacuole, tissues)
o Plants must maintain its hydration w/in narrow limits or else:
▪ Growth will cease
▪ Tissue becomes stress
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find more resources at oneclass.com
Document Summary
It is effective because it is passive cooling unlike sweating. Evaporation of water during transpiration dissipates heat energy, which keeps the plant cool. Water has a high heat capacity and is able to wick away heat from the plant leaves. A cell has a solute potential of -0. 5 mpa and a pressure potential of 0. 2 mpa; it is placed in a sugar solution of water potential 0. 8 mpa. For the cell at equilibrium what are the solute and pressure potentials and overall water potential: = s + p + g, where for osmosis, g is negligible, so = s , concepts: Cell a which has a solute potential of -0. 6 mpa and a pressure potential of 0. 1 mpa is placed next to cell b, which has solute potential of -0. 65 mpa and a pressure potential of 0. 1 mpa. What are the advantages of each: relative water content (rwc) = (fresh mass dry mass) / (saturated mass dry mass) x.
