Microorganisms, such as bacteria, viruses, and fungi can do many harmful things to our bodies. Any organism that invades the body of a host and causes harm in order to survive is called a “pathogen”. Some pathogens actually enter cells and cause damage while others remain outside our cells, and use special proteins to insert toxins into our body’s cells.

An example of an organism that can enter the cell and damage your organelles is Salmonella. This bacterium is the most common cause of food poisoning. If anyone has ever warned you not to each a raw egg or raw chicken, it is because there is a chance it is contaminated with this bacterium, and will get you very sick.

Salmonella are engulfed by your body’s macrophage cells. The job of these cells is to find invading organisms, engulf them, and kill them. Typically, the macrophage will engulf an organism into a compartment called the “phagosome”, which then fuses with an organelle called the lysosome. The job of the lysosome is to break down debris with acid. Salmonella, however, have evolved to escape being killed in the lysosome by secreting proteins that prevent the phagosome from fusing with the lysosome. This protects the Salmonella, which are also able to secrete proteins that alter the phagosome to make it a favorable environment for Salmonella to live in. Not only does Salmonella prevent the phagosome from fusing with the lysosome, but they prevent normal trafficking of cellular debris to this compartment. The tuberculosis bacterium also survives in the cell in a similar way, preventing fusion of the phagosome with the lysosome and altering transport of cellular debris to the lysosome.

Salmonella and Chlamydia trachomatis (the bacterium that causes the STI Chlamydia) can also affect formation and function of microtubules. Microtubules are important in both providing structure to our cells as well as allowing transport of proteins and lipids throughout the cell. Without this transport system, our cells would not be able to form organelles, such as the golgi apparatus, which are made of complex lipid membranes. Disruption of microtubule formation has a widespread affect on the structure and repair of many organelles within the cell.

These invading organisms do not necessarily target our body’s organelles directly. They try to manipulate parts of the cell to aid in their own survival, which typically has negative consequences for our organelles and cells.

Hope that helped! Let me know if you have anymore questions!

Organelles are found inside cells. They're a lot larger than molecules. The nucleus and the mitochondria are the most famous organelles.

Mitochondria are affected especially by what we do with our bodies. Scientists still have a lot to learn about how we affect our mitochondria, but they think we help our mitochondria by eating a good diet and not being overweight. We hurt our mitochondria by being obese and eating too many unhealthy foods. Exercise helps give us lots of healthy mitochondria, too.

A lot of viruses cause diseases by going into the nucleus, because viruses need help from our genes, so that the viruses can reproduce themselves. Our genes are in the nucleus in our cells. There is a book called "Viruses and the Nucleus." You can look inside this book on amazon.com, but it has a lot of details that are complicated:

One virus that gets into the human genome is the influenza virus.