Exam 3 Review Flashcards
Which of these organisms are classified as land plants, but not as vascular plants?
a. lycophytes
b. angiosperms
c. liverworts
d. gymnosperms
e. algae
c. liverworts – live on land, but rely on surface water for hydration
Why do bryophytes need to be able to tolerate desiccation? Select all that apply
a. they dry out with the environment
b. they have little water storage capacity
c. they are restricted to sunny habitats
d. they are restricted to saline habitats
a. they dry out with the environment
b. they have little water storage capacity
Which properties of guard cells allow them to open and close a stoma? Select all that apply
a. tangentially organized cellulose fibers
b. a single guard cell forms the stomata
c. the ability of guard cells to change their ion concentration
d. the lack of cytoplasm in guard cells
a. tangentially organized cellulose fibers
c. the ability of guard. cells to change their ion concentration
d. the lack of cytoplasm in guard cells
Rubisco’s affinity for CO2 versus 02 is inversely related to temperature, resulting in ___ as temperatures rise
a. increased photosynthesis
b. increased photorespiration
c. a slowing rate of enzymatic reaction
d. higher dissolved 02 levels in the chloroplast
b. increased photorespiration
Grapes growing on a vine are observed to shrink slightly during the day and increase in size at night. This is because:
a. during the day, transpiration pulls on the water in the whole plant, causing the grapes to shrink slightly.
b. developing fruits, such as grapes, transpire a lot of water to stay cool.
c. photosynthesis to produce sugar occurs in the light, but respiration and, therefore, the growth of new cells occurs mostly in the dark.
d. in leaves, phloem flow to growing sinks only occurs when the stomata are closed, because the transport capacity of the xylem is too small to supply water for both transpiration and phloem flow.
a. during the day, transpiration pulls on the water in the whole plant, causing the grapes to shrink slightly
What explains the higher density of microorganisms near roots?
a. The microorganisms are plant pathogens that are attempting to infect the roots.
b. Microorganisms are attracted by the same mineral nutrients that the roots absorb.
c. Microorganisms can take advantage of the much higher O2 levels that result from xylem transport.
d. A fraction of the carbohydrates transported to the roots leaks into the soil
d. a fraction of the carbohydrates transported to the roots leaks into the soil
what did groups of green algae that transitioned to land from water struggle with?
- they had no way of obtaining water which was required for reproduction (swimming gametes)
What were some of the adaptations land plants had to adopt?
- new structures such as vascular tissues to deliver water
- changes in their reproduction to not require water
- altered photosynthesis to conserve water
How have land plants adapted?
- they can survive with less water and deliver water to tissues 100m in the air (ex. trees)
- desiccation still plays a major challenge for land plants
- vascular plants work with fungi and bacteria found in soil to gain nutrients
What type of group do land plants form? (phylogeny)
- monophyletic group
- descends from green algae
What two groups are land plants divided into?
- bryophytes (mosses, liverworts, and hornworts 5% of land species)
- vascular plants (the remaining 95% of all land species)
Explain desiccation tolerance in bryophytes
- as bryophytes dry out, they lose the ability to carry out photosynthesis
- many are able to tolerate extreme dehydration via desiccation tolerance without damage to membranes or macromolecules.
- their biochemical traits allow these cells to survive in dry conditions
Explain the general anatomy of a vascular plant
- above ground: leaves, stems, and reproductive organs – they all collectively form the shoot
- below ground: roots used for absorbing water and nutrients
- all the structures have vascular tissue inside them used to distribute water and sugars from the roots up
Explain the anatomy of the leaf of a plant
- leaf is the main site of photosynthesis
- it has three major tissues (epidermis, mesophyll, and the veins)
- the epidermis: sheets of cells that line upper and lower surfaces
- the mesophyll: loosely packed photosynthetic cells
- the veins: system of vascular conduits that connects leave to the rest o the plant; brings water and nutrients in and takes sugars from photosynthesis out
Explain how CO2 is moved through leaves
- mesophyll cells is surrounded by a lot of air which is where the cells obtain CO2
- pores in the epidermis (the stomata) connect the air spaces in leaves to the air surrounding the leaf
- CO2 is moved through the stomata by diffusion
-this process of getting CO2 for photosynthesis causes water vapor loss - Transpiration is when water vapor evaporates from leaves
Leaf stomata
- the waxy cuticle of the leaf that limits water loss
- limits the ability for CO2 to diffuse into the cell
- small pores are the leaf is called the stomata which allows CO2 to diffuse into the cell
- there can be a lot of stomata on a leaf because they’re very small but less that 1-2% of the leaf surface is covered in them
- even with the stomata, the epidermis is still a significant barrier to the diffusion of CO2 and water vapor
