Definitions chapter 6: Plant adaptations to the environment

Question 1

Photosynthesis

Answer 1

Use of light energy by plants to convert carbon dioxide and water into simple sugars

Question 2

Rubisco

Answer 2

Enzyme in photosynthesis that catalyzes the initial transformation of CO2 into sugar

Question 3

C3 Plant

Answer 3

Any plant that produces as its first step in photosynthesis the three-carbon compound phosphoglyceric acid

Question 4

Net Photosynthesis

Answer 4

Difference between the rate of carbon uptake in photosynthesis and carbon loss in respiration - net gain of carbon

Question 5

Light Compensation Point

Answer 5

Depth of water or level of light at which photosynthesis and respiration balance each other

Question 6

Light Saturation Point

Answer 6

Amount of light at which plants achieve the maximum rate of photosynthesis - further increase in light does not lead to increase in photosynthesis

Question 7

Photoinhibition

Answer 7

The slowing or stopping of a plant process by light

Question 8

Mesophyll

Answer 8

Specialized tissue located between the epidermal layers of a leaf; palisade mesophyll consist of cylindrical cells at right angles to upper epidermis and contains many chloroplasts; spongy mesophyll lies next to the lower epidermis and has interconnecting, irregularly shaped cells with large intercellular spaces.

Question 9

Stomata

Answer 9

Pores in the leaf or stem of a plant that allow gaseous exchange between the internal tissues and the atmosphere

Question 10

Turgor Pressure

Answer 10

The state in a plant cell in which the protoplast is exerting pressure on the cell wall due to intake of water by osmosis

Question 11

Osmotic Potential

Answer 11

The attraction of water across a membrane; the more concentrated a solution, the lower is its osmotic potential

Question 12

Matric Potential

Answer 12

Tendency of water to adhere to surfaces

Question 13

Water-Use Efficiency

Answer 13

Ratio of photosynthesis per unit water lost (transpiration)

Question 14

Boundary Layer

Answer 14

A layer of still air close to or at the surface of an object

Question 15

Shade Tolerant

Answer 15

Able to grow and reproduce under low light conditions

Question 16

Shade Intolerant

Answer 16

Growing and reproducing best under high light conditions; growing poorly and failing to reproduce under low light conditions

Question 17

C4 Photosynthetic Pathway

Answer 17

Photosynthetic pathway involving two distinct types of photosynthetic cells: the mesophyll cells and the bundle sheath cells. CO2 initially reacts with PEP to form 4-carbon compounds in the mesophyll cells. These compounds are then transported into the bundle sheath cells where they are converted into CO2 and undergo the C3 photosynthetic pathway (Calvin cycle)

Question 18

Bundle Sheath Cells

Answer 18

Cells surrounding small vascular bundles in the leaves of vascular plants

Question 19

PEP Carboxylase

Answer 19

The enzyme phosphoenolpyruvate carboxylase that catalyses the fixation of CO2 into four-carbon acids, malate, and aspartate

Question 20

CAM Pathway (crassulacean acid metabolism)

Answer 20

Photosynthetic pathway (using same processes involved in C4 pathway) that separates the processes of carbon dioxide uptake and fixation when growing under arid conditions; it takes up gaseous carbon dioxide at night, when stomata are open, and converts it into simple sugars during the day, when stomata is closed

Question 21

Macronutrients

Answer 21

Essential nutrients plants and animals need in large amounts

Question 22

Micronutrients

Answer 22

Essential nutrients needed in very small quantities by plants and animals