EEB 162 Middie Exam Study Guide.
THREE MAJOR KINDS OF PLANT TISSUES - answer✔Dermal
Ground
Vascular
Dermal Tissues - answer✔Epidermis, cuticle, guard cells, root hairs
Ground Tissues - answer✔i.Parenchyma: Thin-walled, metabolically active cells, functional in
metabolism and photosynthesis
ii. Collenchyma: Narrow, elongated cells with thick primary walls, provide
structural support to the growing plant body; can stretch as organs grow
iii. Sclerenchyma: Consists of two types of cells, sclereids and fibers. Both
have thick secondary walls and are frequently dead at maturity.
Sclerenchyma provides mechanical support particularly to nonelongating
parts of the plant
Vascular Tissue - answer✔i. Xylem: Functions in conduction of water and nutrients.
Conducting
tissue is composed of tracheids (gymnosperms) and vessels (angiosperms
and very rarely, gymnosperms). Vessels are composed of vessel
elements.
ii. Phloem: Functions in conduction of sugars and signal molecules
DESCRIBE THE DIVERSITY OF PLANTS AND PLANT PHYSIOLOGY: HOW MANY
SPECIES? - answer✔Gymnosperms: 700 species | Angiosperms: About 250, 000 species
WHAT KIND OF DIVERSITY IN GROWTH FORMS? - answer✔Trees (woody, single
stem), shrubs (wood, multiple stems, shorter), herbs (nonwoody),climbers
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WHAT KIND OF DIVERSITY IN PHYSIOLOGY? - answer✔C3, C4, CAM photosynthesis,
variety in nutrient and pigment concentrations, in
hormone sensitivity, flowering cues, wide variation in cell sizes in each tissue, leaf size, colors,
etc.
WHAT KIND OF DIVERSITY IN ADAPTATIONS TO DIFFERENT HABITATS? -
answer✔▪ Irradiance Habitats: Plants thriving from <1% to 100% full daylight
▪ Moisture Supplies: Plants exist on chronically dry soil and on ever-wet soil (or submerged in
water)
▪ Temperature Range: Plants exist where temperatures reach <-40C and > 40C
PLEASE GIVE THREE REASONS THAT PLANTS NEED WATER AND INDICATE
WHICH OF THE THREE REASONS ACCOUNTS FOR THE BULK OF THE WATER USED
- answer✔▪ Mass and Growth: Water makes up most of the mass of plant cells and so, plants
must maintain its hydration within narrow limits, or growth will cease, and tissue becomes
stressed, and the plant will die
i. If water is insufficient, stomata will close, stopping photosynthesis, and also potentially
causing plant overheating
▪ Transpirational Costs: Photosynthesis requires opening up stomata to access CO2, which
exposes the moist plant interior to the dry air, and thus, water is lost as a side effect. *This
process uses the most water
*BULK OF WATER USE
i. Transpirational Cooling: Evaporation of water dissipates heat energy and thus allows the plant
to exhibit passive cooling
▪ Productivity: Water is the most limiting resources for agricultural and ecosystem productivity.
It is needed for crop growth and production
WHY IS TRANSPIRATIONAL COOLING EFFECTIVE? - answer✔Evaporation of water
during transpiration dissipates heat energy, keeping plants
under bright sunlight up to a few degrees cooler than air. It is effective at keeping the plant cool
during warm temperatures
CAPILLARY RISE: 𝟏𝟒.𝟗 𝑿 𝟏𝟎−𝟔 𝒎𝟐 𝒓𝒂𝒅𝒊𝒖𝒔 HOW HIGH CAN WATER RISE IN A CELL
WALL PORE CAPILLARIES? (RADIUS = 100nm)? - answer✔𝟏𝟎𝟎𝒏𝒎
𝟏𝒎
x
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𝟏𝟎−𝟗𝒎
𝟏𝒏𝒎
= 1.0 x 10-7 m | 𝟏𝟒.𝟗 𝑿 𝟏𝟎−𝟔 𝒎𝟐
𝟏.𝟎 𝐱 𝟏𝟎−𝟕 𝐦
= 149 m
▪ HOW HIGH IN XYLEM VESSELS (RADIUS = 25m)?
▪
𝟐𝟓𝒎
𝟏𝒎
x
𝟏𝟎−𝟔𝒎
𝟏𝒎
= 2.5 x 10-5 m | 𝟏𝟒.𝟗 𝑿 𝟏𝟎−𝟔 𝒎𝟐
𝟐.𝟓 𝐱 𝟏𝟎−𝟓 𝐦
= 0.596 m
PLEASE EXPLAIN AND GIVE THE BASIS FOR TWO OF THE FOLLOWING FOUR
PROPERTIES OF WATER AND GIVE AN EXAMPLE OF WHY THE PROPERTIES ARE
IMPORTANT FOR PLANT LIFE.: WATER IS A SUPERSOLVENT. - answer✔Water is able
to dissolve a much wider range of compounds than any other liquid. Due to having both positive
and negative partial chargers, it can stabilize more molecules. Water is a super-solvent due to the
small size of molecules and due to its polar nature. It is especially good as a solvent for ionic
substances and for sugars and proteins with polar groups. This is important for plant life because
the hydrogen bonds that form between water molecules and organic ions stabilize the ions and
thus increase their solubility
WATER HAS A HIGH SPECIFIC HEAT - answer✔Water has a high specific heat (the energy
required to raise the temperature) because of hydrogen bonding. For example, if you heat copper
and water, copper heats up much faster than water. The movement (kinetic energy) of the
water is less than copper due to the stabilizing hydrogen bonds. This is important for plant life
because this is why plants can survive many different conditions
WATER HAS A HIGH TENSILE STRENGTH - answer✔Water has high tensile strength,
which is the pull a continuous column of water can withstand before breaking, due to cohesion.