Transport in Plants and Prokaryotes

Xylem and phloem are the two main types of tissue involved in transport in plants.
Xylem vessels transport water and minerals from the roots to the rest of the plant. This process is known as transpiration.
Root cells actively transport minerals into the root hairs from the soil. Water follows by osmosis.
The transpiration stream is a continual flow of water and minerals from the roots, up the stem to the leaves.
Transpiration is affected by several environmental factors including light, temperature, wind, and humidity.

Xylem vessels are long, hollow structures formed from dead cells. They have thick walls reinforced with a substance called lignin.
Phloem sieve tube elements are made of living cells. They lack many cellular structures to allow for free flow of substances.
Between the sieve tube elements are the companion cells which provide energy for active transport of substances into the phloem.
The phloem transports food made in the leaves (photosynthesis) to the rest of the plant for use or storage. This process is known as translocation.

Prokaryotes, which include bacteria and archaea, lack specialised structures for transport.
Therefore, molecules move across the cell membrane by diffusion, facilitated diffusion, and active transport.
Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration.
Facilitated diffusion uses transport proteins in the membrane to help certain molecules cross.
Active transport requires energy as it moves molecules against their concentration gradient.
The cell membrane of prokaryotes may have protein channels and protein pumps to assist in the transport of substances.
Osmoregulation is crucial in prokaryotes to prevent cells from bursting or shrivelling up due to differences in water concentration.