The manager in a factory is responsible for controlling everything that happens within the factory and decides what the factory makes.

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1 The manager in a factory is responsible for controlling everything that happens within the factory and decides what the factory makes. This is similar to the role of the nucleus in a cell. The nucleus controls all of the activity that happens in the cell. The nucleus also decides what proteins the cell should make and the nucleus stores all of the instructions for making proteins. The nucleus of a cell contains the cell's DNA, which is the genetic code for the entire organism. The genetic code is a set of instructions that determines what an organism is like, how it behaves, and how it survives in its environment. The nucleus is large and oval shaped. XTRA FACTOR QUESTION: Nucleus Why is it important that sperm and egg cells have a nucleus?

2 The air within the factory fills all available space. This is similar to the cytoplasm because the cytoplasm fills all available space within the cell. The cytoplasm includes everything between the cell membrane and the nucleus. The cytoplasm consists mostly of water, salts, some proteins, and contains many small structures called organelles. The cytoplasm is where most of the chemical reactions happen within the cell. It s a clear, thick, jellylike material. XTRA FACTOR QUESTION: Cytoplasm Cytoplasm can be compared to air in a factory. Why is this not a very good comparison?

3 The shipping and receiving department controls what enters and leaves the factory. It is where the factory makes contact with the outside world. This is very similar to the cell membrane which is responsible for controlling what enters and leaves the cell. The cell membrane is a barrier between the cell and its environment. XTRA FACTOR QUESTION: Cell membrane Some molecules such as glucose, can pass easily through the cell membrane but other molecules, such as starch, cannot pass easily through the cell membrane? Why can some molecules pass through the cell membrane more easily than others?

4 The conveyor belts in factories are responsible for carrying products through the factory. This is very similar to the endoplasmic reticulum which is an organelle responsible for transporting materials within the cell. There are two types of endoplasmic reticulum known as smooth ER and rough ER. The rough ER has ribosomes attached to it and provides a surface along which the process of protein assembly can happen. The smooth ER does not have ribosomes. The endoplasmic reticulum looks like a network of thin tubes. Ribosomes are sometimes attached to the endoplasmic reticulum. XTRA FACTOR QUESTION: Endoplasmic reticulum Why is it important that cells have an endoplasmic reticulum?

5 The packaging machines in a factory are responsible for putting the finished products into boxes so that they can be transported around and out of the factory. This is very similar to the role of the golgi apparatus in a cell. The golgi apparatus package and export the proteins that the ribosomes have made. The golgi apparatus looks like a stack of flattened sacs within a cell. XTRA FACTOR QUESTION: Golgi apparatus Why is the golgi apparatus often compared to a packaging machine?

6 The maintenance team in a factory are responsible for keeping everything orderly, getting rid of the rubbish, and dismantling and disposing of old machinery. The maintenance team also function as a second line of defence. If someone gets past the security guard at the front door, it is usually the maintenance team who catches the trespassers and chases them out. This is very similar to the role of the lysosomes in a cell. Lysosomes are organelles produced by the golgi apparatus. Lysosomes digest old parts of the cell. The old parts of the cell are broken down and digested by powerful enzymes in the lysosomes. Lysosomes are small and round. XTRA FACTOR QUESTION: Lysosomes Lysosomes are often compared to a maintenance team in a factory. Why?

7 The workers in the assembly line of a factory are responsible for building the products for the factory. This is very similar to the role of ribosomes in cells. Ribosomes are responsible for making proteins in cells. Ribosomes are very small and round. They are either floating freely in the cytoplasm or they are sometimes found attached to the endoplasmic reticulum. XTRA FACTOR QUESTION: Ribosomes Ribosomes are sometimes attached to the endoplasmic reticulum. What do you think the reason for this is?

8 The pillars and support structures in the factory are responsible for strengthening the factory, keeping the shape of the factory and stopping the roof from caving in. They carry out a very similar role to the cytoskeleton in a cell. The cytoskeleton in a cell maintains the cell's shape. The cytoskeleton also helps the cell to move organelles within the cell and help the cell to move around. Thy cytoskeleton looks like threads of a spider web within cells. XTRA FACTOR QUESTION: Cytoskeleton Why is the cytoskeleton in a cell is not similar to the pillars and support structures in a factory?

9 The power plant in a factory is responsible for making energy that the factory needs to run. Most factories have power plants in which generators burn fuel to produce heat. The power plant is very similar to the mitochondria in a cell. Mitochondria is the site of respiration in a cell. Respiration is when sugar (glucose) molecules are broken down to release energy. The mitochondria look peanut shaped. XTRA FACTOR QUESTION: Mitochondria Our muscles are made up of millions of muscle cells. Why do muscle cells contain many more mitochondria than other specialised animal cells?