Transpiration And Translocation Flashcards
What is xylem?
“Pipelines” that move water and nutrients from roots to shoots
Thick lignified secondary cell walls
“Pulling” process for transpiration
What is phloem?
Moves products of photosynthesis from leaves to other parts of the plants?
“Pushing” process
What is transpiration?
Loss of water vapor through the stomata
CO2 moves in, it’s an exchange
(Water vapor more concentrated in the leaf than outside air)
Regulated by guard cells that open when the leaf is full of moisture, closes when moisture is low.
What is water cohesion?
Water sticks to itself - it’s how water droplets form.
Force of attraction between water molecules.
What is water adhesion?
Waters tendency to cling and stick to other surfaces.
Force of attraction between water molecules and other molecules.
What is the transpiration stream?
Root takes in water. The water forms a continuous chain up the xylem right to the tip of the leaf.
The cohesion helps draw the water molecules, and the adhesion helps keep it along the xylem.
This is a passive process that does not require an energy expenditure from the plant.
How does water enter roots?
Water enters root hairs via osmosis.
Can move between and in-between cells.
What are the 5 steps of transpiration?
1 water evaporates from the leaf and exits from the stomata
2 water enters the roots via osmosis
3 water molecules are cohesive, one exits and another enters
4 water molecules adhereto the sides of the xylem
5 tension is created by the constant upward pull of water evaporating
What are things that affect and impact transpiration?
Water limitations on site.
Stomatal control - for example desert plants only open at night
Healthy roots - mycorrhiza in the soil to help, for example
Weather conditions - Transpiration increases on hot days, decreases with humidity.
What is Translocation?
The process of moving the products of photosynthesis from where it happens to throughout the plants, where needed.
Active process, requires energy expenditure.
What are companion cells?
Phloem has companion cells that do the metabolic processes for the phloem. They provide the energy through their mitochondria to allow phloem to the pulling of photosynthetic products
What is the process of translocation?
1) photosynthesis creates sugars at the source of where it occcu4s
2) companion cells actively transport sugars into the sieve cells of the phloem
3) increased sugar in the phloem causes water to enter and turgor pressure to build
4) increased pressure drives the fluid down
5) sugar is actively removed where it’s needed, pressure drops and water returns back to xylem
What are the definitions for taxonomy and phylogeny?
Taxonomy = science of categorizing things
Phylogeny = evolutionary history and relations of organism groups
What makes a plant a plant?
Eukaryotic cells (with nuclear, multicelluar)
Rigid cell walls
Alternation of generations
Mechanisms for moving water and minerals up and down.
What defines non vascular plants?
Gametophyte dominant generation
Absorbs moisture through surface
Typically small, lacks structural support
Requires water to reproduce
What defines a seedless vascular plant?
Sporophyte dominant phase
Flagellated sperm
Spores not seeds
What’s the difference between gymnosperm and angiosperm?
Gymnosperm = usually cones bearing plants, gametophye greatly reduced, pollinated by wind.
Angiosperm = flowering plants, double fertilization occurs producing food for embryo, pollinated by other animals/insects
What is needed and produced by photosynthesis?
Needed = co2, h2o, light energy
Produced = glucose, oxygen, heat
What are the two stages of photosynthesis?
Stage 1 = light dependent, happens in the thykaloids of the chloroplast, requires water, sunlight, pigments
Stage 2 = light independent, Calvin cycle, happens in the stroma
What is the light dependent stage of photosynthesis?
Light and water react with pigments
Water is split, o2 is the byproduct
ATP and NADPH is created for the Calvin cycle to power it
What is the light independent stage or Calvin cycle?
ATP and NADPH is used to split co2
Carbon is fixed and and glucose produced
Many cycles occur
What are the end products of photosynthesis?
Energy as storage atp
Heat
Carbohydrates
Cellulose
What does cellular respiration do?
Converts energy stored in the form of glucose into usable chemical energy
What is meiosis and mitosis?
Meiosis = mother cell divides twice. Produces 4 daughter nuclei
Mitosis = mother cell produces 2 daughter nuclei, maintains ploidy. Growth or repair of cells