Biol 1108 Exam 3: The Sonoran Desert
Questions with Correct Answers 2026
Sonoran Desert - CORRECT ANSWER -Located in the SW US and NW Mexico
Summer: Scarce precipitation and high temperatures make Summers unsuitable for plant gr
owth
Spring: too dry for plant growth
Winter: best season for plant growth (especially annuals), but precipitation is very unpredic
table
Sun will almost never be a limiting reactant
Annuals - CORRECT ANSWER -
plants that germinate, grow, set seed and die in a single growing season
Cellulose - CORRECT ANSWER -molecule that makes up most of a plant's biomass
-Carbon in cellulose comes from air
Van Helmont's Experiment - CORRECT ANSWER --
grew a 5lb willow tree in 200lb of dried dirt for 5 years. After 5 years, the tree weighed 1
69 lb but the soil weighed the same amount
-Proves plants get C from the air
Roots - CORRECT ANSWER --Plant organ that obtains water
-Plant allocates resources here when dry
-Where water enters plant
, Leaves - CORRECT ANSWER --
Plant organ that creates/obtains carbon/sugar And collects light
-More leaves, more growth potential and faster growth, but more transpiration
-Where water exits plants through stomata
Stem - CORRECT ANSWER -
plant allocates resources here short term to compete with surrounding plants
Xylem - CORRECT ANSWER -
vascular tissue of plants that carries ONLY water through hollow/dead cells from roots to le
aves (one direction) using cohesion, adhesion, and negative pressure
Phloem - CORRECT ANSWER -
vascular tissue of plants that carries dissolved nutrient, hormones, sugars, etc., around a pl
ant in any direction using osmosis
Stomata - CORRECT ANSWER --
gaps that open and close that allow gases to enter and exit the leaves
-Primary function : gas exchange (constant exchange is ideal)
-Allow oxygen (and unfortunately water) to escape
-Allow CO2 to enter from the atmosphere
-Tradeoff: water loss for gas exchange
Guard Cells - CORRECT ANSWER --cells that surround stomata
-Kidney-shaped
-Stomata Open - guard cells turgid, abundant water
-Stomata Closed - guard cells flaccid, scarce water
-Can also force stomata to open using hormones and ion flow
Questions with Correct Answers 2026
Sonoran Desert - CORRECT ANSWER -Located in the SW US and NW Mexico
Summer: Scarce precipitation and high temperatures make Summers unsuitable for plant gr
owth
Spring: too dry for plant growth
Winter: best season for plant growth (especially annuals), but precipitation is very unpredic
table
Sun will almost never be a limiting reactant
Annuals - CORRECT ANSWER -
plants that germinate, grow, set seed and die in a single growing season
Cellulose - CORRECT ANSWER -molecule that makes up most of a plant's biomass
-Carbon in cellulose comes from air
Van Helmont's Experiment - CORRECT ANSWER --
grew a 5lb willow tree in 200lb of dried dirt for 5 years. After 5 years, the tree weighed 1
69 lb but the soil weighed the same amount
-Proves plants get C from the air
Roots - CORRECT ANSWER --Plant organ that obtains water
-Plant allocates resources here when dry
-Where water enters plant
, Leaves - CORRECT ANSWER --
Plant organ that creates/obtains carbon/sugar And collects light
-More leaves, more growth potential and faster growth, but more transpiration
-Where water exits plants through stomata
Stem - CORRECT ANSWER -
plant allocates resources here short term to compete with surrounding plants
Xylem - CORRECT ANSWER -
vascular tissue of plants that carries ONLY water through hollow/dead cells from roots to le
aves (one direction) using cohesion, adhesion, and negative pressure
Phloem - CORRECT ANSWER -
vascular tissue of plants that carries dissolved nutrient, hormones, sugars, etc., around a pl
ant in any direction using osmosis
Stomata - CORRECT ANSWER --
gaps that open and close that allow gases to enter and exit the leaves
-Primary function : gas exchange (constant exchange is ideal)
-Allow oxygen (and unfortunately water) to escape
-Allow CO2 to enter from the atmosphere
-Tradeoff: water loss for gas exchange
Guard Cells - CORRECT ANSWER --cells that surround stomata
-Kidney-shaped
-Stomata Open - guard cells turgid, abundant water
-Stomata Closed - guard cells flaccid, scarce water
-Can also force stomata to open using hormones and ion flow
