We have just come to the end of our first Biology unit (B1), and I would like to share the top 5 things people should know from this unit.
1 – Diffusion is the way in which particles move from areas of high concentration to low concentration until they reach dynamic equilibrium and have a net movement of 0.
2 – Osmosis is similar to diffusion. However, it only occurs through a partially permeable membrane and in fluids. It is the movement of water from an area of dilute (high water potential/hypotonic) solution to a more concentrated (hypertonic/low water potential). This process occurs until it has reached an isotonic (equilibrium) level.
3 – There are a few key differences between plant cells and animal cells. Plant cells are structured to best capture sunlight, they have chlorophyll which allows them to do that. They also have a large permanent vacuole which helps keep the cell turgid and pushes against the cell wall (also found only in plant cells) and maintains its structure. Animal cells do not have a cell wall, chlorophyll or a permanent vacuole. This is because they do not need it, and it would be a waste of energy for the cell.
4 – Osmosis in cells (especially plant cells) is another crucial aspect to remember. A plant cell’s membrane slowly detaches itself from the cell wall as the vacuole loses water. Eventually, when the membrane is completely detached and vacuole is a negligible size, the plant cell has reached the state of plasmolysis.
5 – There are also other cells which are designed specifically for their function. For example, red blood cells have a concave shape and no nucleus so there is maximised space for oxygen absorption. Root hair cells in a plant do not have chlorophyll as it would be pointless and a waste of energy for them to try to utilize the sunlight while they are under the soil. Instead, they have a special shape to maximise the absorption of water.