Gas Exchange in Plants

What is gas exchange?

the physical process by which gases move passively by diffusion across a surface

When does a large amount of gas exchange happen?

during photosynthesis with adaptations within leaves

When are stomata usually open?

during the day and closed at night

What is the mesophyll?

photosynthetic part of a leaf, located in the epidermis

When do CAM plants photosynthesis?

during the day

When do CAM exchange gases?

at night

What is the first stage of gas exchange at night in CAM plants?

take in CO2 through their open stomata

What is the second stage of gas exchange at night in CAM plants?

The CO2 joins with PEP to form the 4-carbon oxaloacetic acid

What is the third(final) stage in gas exchange at night in CAM plants?

converts the 4-carbon oxaloacetic acid to a 4-carbon malic acid that accumulates during the nigh in the central vacuole on the cells

What is the first stage of gas exchange in the morning in CAM plants?

the stomata closes(conserves moisture and reduces diffusion)

what is the second stage of gas exchange in the morning in CAM plants?

the accumulated malic acid leaves the vacuole and is broken down to release CO2

what is the third (final) stage of gas exchange in the morning in CAM plants?

The CO2 is taken up into the Calvin cycle

What is the petiole?

the stalk

what is the stipule?

outgrowth at petiole base

What is the blade?

the broad, expanded part of a leaf, also called the lamina

what are the characteristics of a simple leaf?

blades are undivided, may have teeth or lobes

what are the characteristics of compound leaves?

blade divided into leaflets

What are modified leaves?

plants that have diversified to exploit a variety of habitats

What are shade leaves?

leaves produced in shaded areas, larger surface area and thinner with less mesophyll

What are bracts?

floral leaves, large modified leaves that surround true flower, can be small

What are spines?

leaves on cacti, not like thorns or prickles, outgrowths from the epidermis

What are reproductive leaves?

tiny complete plantlets, when separated from leaf plantlets can grow into independently into full sized plants

What are window leaves?

succulent cone-shaped leaves with transparent tip (admits light to hollow interior for photosynthesis

What are insectivorous leaves?

leaves modified to trap insects,

What are trichomes?

hair like growth from an epidermal cell (secretes oils or substances that deter insects)

what are spongy mesophyll cells?

loosely arranged, irregular shaped cells located in the middle layer of a plant leaf, in dicots

What are palisade mesophyll cells?

specialized, pillar-shaped plant cells found inside leaves of most flowering plants, found in dicots

How are mesophyll cells arranged in monocots?

lacks specialized structures

How are seeds formed in monocots compared to dicots?

one cotyledon (corn), dicots have two (sunflower)

How is the vascular structure different in monocots and dicots?

monocots have scattered vessels, dicots on ringed

How are leaves different on monocots to dicots?

monocots have parallel veins (lilies), dicots have net like veins (oak)

How are petals different in monocots and dicots?

monocots are in multiples of three, dicots are in multiples of four and five

What have monocot traits?

major grains (rice, wheat), grasses, sugar cane, flowers like lilies, daffodils, irises

What have dicot traits?

trees like maple, oak, flowers (sunflowers, dandelions)