transport across a cell membrane
what is the passive transport ?
transport of smaill molecules without energy loss
what is the transpiration?
the loss of water as vapor
What main carbohydrates (sugars) are transported through the phloem from a source to a sink?
Glucose, fructose, and sucrose.
what is the active transport ?
transport of large molecules by energy loss
how many liters plants lose while water vapor ?
they lose about 5 liters
What is the primary difference in the direction of movement between xylem and phloem transport?
Water and minerals in the xylem move in one direction (roots to shoots), while phloem sap travels in both directions (up and down).
name types of active transport and what they do
phagocytosis-take in solid materials
pinocytosys-take in liquid materials
what is the stomata ?
pores on the underside of the leaf which accelerate gase exchange and transpiration
How does ambient temperature affect the rate of translocation, and what is the optimum temperature range for this process?
he optimum temperature range is 20C–30C; extreme high 50C or low temperatures slow down and eventually stop translocation.
explain how do the active transport work
Active transport is the process by which a cell moves molecules or ions across its membrane from an area of lower concentration to an area of higher concentration—a direction known as moving against the concentration gradient
what does he transport rate depends on?
transportion rate is higher when the stomata are open, and is lower whan they are closed
According to the text, how does light intensity directly influence the production of sucrose and cell wall enlargement in plants?
Without light, photosynthesis stops and no sucrose is produced, whereas intense light generates cellulose accumulation and cell wall enlargement, protecting the plant from insects.
explain why do the active trasport need ATP
Active transport requires ATP because it forces molecules to move from a low-concentration area to an already crowded high-concentration area, which goes against the natural flow of diffusion.
what impotance of transportation ?
saves plants from overheating and helps cool the plant;
creates a continuons flow of water from the root to the leaves;
transports soluble minetrals and water within the plant;
Why are companion cells essential for the translocation of organic compounds, and why is water necessary for carrying sugars through sieve tube
Companion cells control the activities of sieve tube elements, and water dissolves organic compounds to form phloem sap, enabling transport through sieve tubes.