Exam 2 Flashcards
What do plants use water for?
Photosynthesis, temperature regulation, and stability.
Brownian motion
Ions and molecules are in constant random motion
Diffusion
Influenced by pressure, temperature, and density of the medium.
Osmosis
Diffusion through a semipermeable membrane where the concentrations equilibrate. The area of the higher concentration goes to the area of the lower concentration.
Cell water potential
Water enter cells through osmosis
Osmotic potential
The potential of water molecules to move from a hypotonic solution (more water, less solutes) to a hypertonic solution (less water, more solutes) across a semi-permeable membrane.
Pressure potential
Water moves from cells with higher wetness to cells that are dry.
Transpiration
The loss of water vapor from the leaves to the atmosphere. Occurs from root to leaf, water vapor exits stomata during photosynthesis
Guard cells
Epidermal cells, two of which create a stoma (singular stomata). They regulate gas exchange between the leaf and the atmosphere.
How guard cells open and close
By changing the turgor pressure. The more inflated the stomata is (more water and solutes in it) the more open they are.
Environment influence on transpiration rates
Transpiration increases with temperature, sunlight, high soil moisture, and wind velocity. Too high of a temperature causes a decrease in transpiration (due to the stomata closing), and high CO2 rates decrease transpiration.
Translocation
Movement of food substance throughout a plant via water.
Pressure-flow-hypothesis
Food is actively loaded into phloem from source. Water enters xylem and phloem via osmosis. Pressure gradient drives food down the phloem. Food is then actively removed from the sink.
CAM plants
Opens stomata at night versus the day. This type of plant collects CO2 at night to use the next day when the plant performs photosynthesis with its stomata closed. (EX: Cacti and orchids)
What do plants get from soils?
Nutrients, water, and stability
Why are desert soils infertile?
There is no rain to weather down the soil, which means there are no nutrients in the soil. Without nutrients or water in the soil, plants have nothing to grow from.
Sandy soils
Large pore size, obtain oxygen, and water, has good root growth, and is easy to work with. Water and nutrients drain out quickly.
Clay soils
Water drains slowly through this soil type, nutrients hold on better, but it has small pores and low oxygen levels, and it is harder to work with.
Loams
(Sand, silt, and clay combined) Best for agriculture due to different-sized pores, more space for growth, sand has a high pore size, clay holds moisture, clay and silt hold nutrients, and silt is “workable”.
Organic matter
Compounds that have a carbon base. Usually, C, H, O, and N. Produced by the decomposition of plants and animals.
Living and non-living things found in soil
Nutrients, water, microorganisms (bacteria and fungi), seeds, worms, organic matter, rocks, silt, sand, clay, roots, plant parts, and vertebrates (moles, prairie dogs, groundhogs, etc.).
Topsoil
Newly decomposed living organism, lots of organic material
B-horizon
Broken down materials and inorganic material
Parent material
Weather igneous and sedimentary rocks
Bedrock
The bottom layer of the soil
Soil water content
Soil structure, density of vegetation,location of ground water table
Wilting point
Point at which water is no longer available to plants, dependent on soil texture
Field capacity
Point at which soil can hold NO MORE water
Best pH in soil for plants
7
Metabolism
Any biochemical processes inside a living organism. Examples include photosynthesis, respiration, digestion, growth, movement in a living organism, and translocation.
Enzymes
Proteins that speed up and ultimately regulate metabolic processes
ATP
Adenosine triphosphate. Powers many chemical reactions, also known as “energy packets”. 3 phosphate groups, a lot of pent-up energy that is stored, and after splitting it creates ADP
The importance of photosynthesis
Without it the food chain would collapse, living organisms would slowly die, plants wouldn’t be able to convert CO2 into sugars, and the regulation of carbon on earth would end.
Major ingredients of photosynthesis
CO2, H2O, light, chlorophyll, enzymes, glucose, and oxygen + water.