Biology Chapter 1 AQA Additional Science

Biology Chapter 1 AQA Additional Science

1. Animal and Plant Cells

   • Most human cells are like normal animal cells, they contain a nucleus, cytoplasm, cell membrane, ribosomes and mitochondria.
   • Plant cells mostly have the same components as animal cells, but also a cell wall, a vacuole and chloroplasts.

2. Bacteria and Yeast

   • A bacteria cell contains a cytoplasm, a cell membrane and a cell wall. The genes are not in a distinct nucleus!
   • Yeast is a single celled organism each cell consists of a nucleus, cytoplasm, and a membrane, they also have a cell wall.
   • The anaerobic respiration of yeast is also referred to as fermentation!

3. Specialised Cells

   • Examples of these are sperm cells, fat cells, cone cells and also root hair cells.
   • When a cell is specialised it means it has been adapted or created to do a specific job.
   • Other examples are red blood cells, egg cells and nere cells (neurons).

4. Diffusion

   • Substances that are dissolved such as oxygen move in and out of cells through diffusion.
   • Diffusion is the movement of particles from a high to a low concentration through a semi-permable membrane.
   • Diffusion is faster when the difference in concentration is higher.

5. Tissues and Organs

   • A tissue is simply a group of cells with a similar function.
   • Tissues are what organs are made up of. There may be different types of tissue in one organ.

6. Organ Systems

   • An organ system is a group of organs assigned to a specific function.
   • Some examples are: Digestive System and the Central Nervous System.
   • Plant organs include; Stem, roots and leaves.