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Eukaryotic cells include plant and animal cells. They have a cell membrane, cytoplasm and their genetic DNA is encased in a nucleus. Prokaryotic cells (bacteria) are much smaller in comparison. They have ...

A reaction can only be catalysed (sped up) if an enzyme's active site matches the shape of its substrate molecules- the substrate fits into the active site like a key into a lock. This shape is highly spe...

Active transport is the movement of a substance against its concentration gradient across a selectively permeable membrane. In order for an organism to carry out active transport energy is required to ove...

Biology exams rely heavily on recollection and your knowledge of key facts and processes. If you have memorised these and have a good understanding of them, questions are often just a case of manipulating...

Osmosis is the movement of water across a semi-permeable membrane, down the concentration gradient. This means that if there is more water on one side of a membrane, it will move to the other side until b...