Final Exam Study Guide (1)

Photosynthesis increase when light intensity is doubled

Increases, but less than doubling.

Palisade layer function in leaves

Acts like fiber optics, channeling light deeper into the leaf.

Root uptake of nutrients and water

Occurs near growing root tips and in root hairs due to greater surface area.

Phloem sugar transport mechanism

Sugar is pumped into phloem at the source, increasing osmotic pressure and driving water into the phloem.

Latent heat definition

The energy required to evaporate water.

Vapor pressure deficit (VPD) lowest conditions

Cool, moist conditions.

Effect of leaf size on temperature

Larger leaves are warmer due to lower boundary layer conductance.

True or false: leaves emit light in darkness

True, they emit longwave (thermal infrared) radiation.

Difference between flow and flux

Flow is movement per unit time; flux is movement per unit time per unit area.

Net CO₂ assimilation rate and respiration rate

Equal in darkness.

Relative humidity definition

The vapor pressure of water as a fraction of its saturating value.

Harvest index (HI) definition

The ratio of yield to total biomass produced.

Empirical vs. mechanistic models

Empirical models rely on observed data; mechanistic models are based on biological principles.

Penman-Monteith equation purpose

Predicts evapotranspiration based on energy balance and aerodynamic factors.

True or false: crop systems models

True; they combine empirical and mechanistic approaches.

Radiation use efficiency definition

Efficiency in converting intercepted light into biomass.

Beneficial uses of viruses in plant science

Used as vectors for genetic modification and biological control agents.

Nodule function in plants

Specialized root structure housing nitrogen-fixing bacteria to convert atmospheric nitrogen.

Mycorrhiza definition

Symbiotic association between fungi and plant roots enhancing nutrient and water uptake.

Virulence meaning

The degree of pathogenicity of an organism.

Most important greenhouse condition

Water vapor is the most significant natural greenhouse gas.

Role of atmospheric CO₂ in glacial cycles

CO₂ levels fluctuated with glacial and interglacial periods, affecting temperature changes.

Temperature increase effect of CO₂ and water vapor feedback

1°C direct effect leads to approximately 2°C increase.

Effect of anthropogenic aerosols on climate

Cooling effect by reflecting sunlight and promoting cloud formation.

Effect of rising CO₂ concentration on stomatal conductance

Decreases stomatal conductance.

Nitrogen limitation under elevated CO₂

Increased CO₂ enhances growth, raising nitrogen demand beyond soil supply.

Reasons yield might not increase with climate warming

Shorter growing seasons, increased respiration, and heat stress.

Reasons climate warming might not enhance photosynthesis

Stomatal closure, enzyme inefficiency, and drought stress.

Notable characteristic of Rubisco

Most abundant protein on Earth and catalyzes CO₂ fixation.

Importance of water for plants

Maintains turgor pressure and supports transpiration.

Casparian strip function in roots

Controls water and nutrient uptake through selective membranes.

C₄ vs C₃ photosynthesis advantages

C₄ photosynthesis is better in hot, dry, and high-light environments.

Ultimate electron donor and acceptor in photosynthesis

Donor: Water (H₂O), Acceptor: NADP⁺.

Essential macronutrients for plants

Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S).

Meristem definition

Region of actively dividing cells responsible for plant growth.

Sporophyte and Gametophyte roles in plants

Sporophyte produces spores; Gametophyte produces gametes.

Why choose clonal propagation over seeds

Ensures uniformity and preserves desirable traits.

Best area for taking cuttings for propagation

More basal area due to stored nutrients and hormones.

Are colorful, fleshy structures containing seeds always fruits?

No, some seeds are enclosed in structures that are not true fruits.

True or False: US acreage planted with genetically engineered crops

False; a significant portion of major crops are genetically engineered.