1. what is osmosis what type of transport is it

Water moves from a high to a lower concentration across a partially permeable membrane and down a concentration gradient. Active transport. If the plant cells become hypertonic, as occurs in drought or if a plant is not watered adequately, water will leave the cell.

Plants lose turgor pressure in this condition and wilt. Text adapted from: OpenStax, Concepts of Biology. OpenStax CNX. Skip to content Osmosis is the diffusion of water through a semipermeable membrane according to the concentration gradient of water across the membrane.

Figure 3 In osmosis, water always moves from an area of higher concentration of water to one of lower concentration of water. In this system, the solute cannot pass through the selectively permeable membrane. Tonicity Tonicity describes the amount of solute in a solution.

Figure 4 Osmotic pressure changes the shape of red blood cells in hypertonic, isotonic, and hypotonic solutions. Figure 5 The turgor pressure within a plant cell depends on the tonicity of the solution that it is bathed in. Previous: Passive Transport: Facilitated Transport. Next: Active Transport. Disease Defences 4. Gas Exchange 5. Homeostasis Higher Level 7: Nucleic Acids 1. DNA Structure 2. Transcription 3. Translation 8: Metabolism 1. Metabolism 2. Cell Respiration 3. Photosynthesis 9: Plant Biology 1.

Xylem Transport 2. Phloem Transport 3. Plant Growth 4. Plant Reproduction Genetics 1. Meiosis 2. Note that the substance indicated by the triangles is being transported from the side of the membrane with little of the substance to the side of the membrane with a lot of the substance through a membrane protein, and that ATP is being broken down to ADP. In some cases, the use of ATP may be indirect. On the left side of the picture below, a substance represented by an X is being transported from the inside of the cell to the outside even though there is more of that substance on the outside indicated by the letter X being larger on the outside of the cell.

This is primary active transport. In the picture on the right side, substance S, already at higher concentration in the cell, is brought into the cell with substance X. Since S is being transported without the direct use of ATP, the transport of S is an example of secondary active transport. For substance X primary active transport of X is occurring. The high concentration of X outside the cell is being used to bring in substance S against its concentration gradient.

It is possible for large molecules to enter a cell by a process called endocytosis, where a small piece of the cell membrane wraps around the particle and is brought into the cell.

If the particle is solid, endocytosis is also called phagocytosis. If fluid droplets are taken in, the processes is called pinocytosis. Illustration of endocytosis. Note that the particle entered the cell surrounded by a piece of cell membrane. The opposite of endocytosis is exocytosis.