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Biology Topic 1 - Coggle Diagram
Biology Topic 1
Eukaryotic cells
Eukaryotic cells are found in plants, animals, fungi and protists (single-celled organisms that don’t fit other categories).
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Plasmids
Prokaryotic cells may have one or more small rings of DNA, which are called plasmids.
These plasmids can replicate (have copies made) and move between cells so that genetic information can be shared.
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Active site
To catalyse (speed up) a reaction, the reacting chemical (substrate) must bind to the enzyme's active site.
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Concentration gradient
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The bigger the difference in concentration between two areas, the greater the concentration gradient and the faster the rate of diffusion.
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Nucleus
The nucleus is the control centre of the cell.
It contains chromosomes (which contain the cell's genetic material).
Cytoplasm
Cytoplasm is a jelly-like fluid that fills the cell.
It is where most of the cell’s chemical reactions take place.
Sperm cell
Sperm cells are specialised (can perform a specific function). Sperm cells are specialised to fertilise egg cells. To do this, they need to travel long distances relatively to their size. They then break through to the egg cell and fertilise it (combine the sperm DNA with the egg DNA).
Cilia
The cells have hair-like structures on them called cilia, which can be moved in unison (all together).
Resolution
Resolution is the ability to distinguish between (tell apart) two or more objects that are close together.
Light microscopes
A light microscope passes light through a specimen, and creates a magnified image using lenses.
The first light microscope was made using two lenses in the late 16th century. It had a resolution better than the human eye itself.
Electron microscope
Electron microscopes work in a similar way to light microscopes. However, electrons are passed through the specimen instead of light.
They can now resolve distances of 1nm (better resolution) with magnifications of ×500,000.
Diffusion
Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration. It describes the movement of particles in fluids (liquids and gases). The particles all move randomly.
Osmosis
Water will move so that the concentrations become the same on both sides of the membrane.
Water will move across the membrane from a dilute solution (with lots of water molecules), to a more concentrated solution (fewer water molecules).
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