cells and cell transport
- All living things are made up of cells
- Parts animals and plants have in common
- Nucleus Contains genetic material, which controls the activities of the cell Cytoplasm Most chemical processes take place here, controlled by enzymes Cell membrane Controls the movement of substances into and out of the cell Mitochondria Most energy is released by respiration here Ribosomes Protein synthesis happens here
Extra plant cells in plants Cell wall Strengthens the cell Chloroplasts Contain chlorophyll, which absorbs light energy for photosynthesis Permanent vacuole Filled with cell sap to help keep the cell turgid
bacterial cells and yeast
- A bacterium is a single-celled organism.
- A bacterial cell has a different structure to an animal or plant cell. It has cytoplasm, a membrane and a surrounding cell wall, but the genetic material in a bacterial cell is not in a distinct nucleus.
- Yeast is a single-celled organism. Like bacterial cells, yeast cells have cytoplasm and a membrane surrounded by a cell wall. But unlike bacterial cells, yeast cells have a nucleus.
Cells may be specialised for a particular function. Their structure will allow them to carry this function out.
specialised cells- leaf cells+root hair cells
specialised cells-sperm cell+red blood cells
diffusion of cells
Dissolved substances have to pass through the cell membrane to get into or out of a cell. Diffusion is one of the processes that allows this to happen.
Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move. This is true in gases and for particles dissolved in solutions. for example.
Gut Digested food products Gut cavity Blood in capillary of villus
Remember, particles continue to move from a high to a low concentration while there is a concentration gradient.
In the lungs, the blood will continue to take in oxygen from the alveolar air spaces provided the concentration of oxygen there is greater than in the blood. Oxygen diffuses across the alveolar walls into the blood, and the circulation takes the oxygen-rich blood away.