Science Flashcards
What is an infectious disease?
An infectious disease is a disease that is caused by an organism or infective agent. These causative agents are known as pathogens.
What is a pathogen?
A pathogen can be defined as any organism or infective agent that lives in or on another living organism, and causes a disease.
Prions
Is a protein that is capable of causing disease.
Do not contain any genetic material (DNA or RNA).
They are smaller than all other pathogens.
Viruses
Viruses are acellular/non-cellular pathogens.
They contain genetic material.
They range in size from 30 to 300 nm.
Bacteria
Bacteria are cellular organisms.
Their genetic material is a single large chromosome.
Vary in size from 0.5 to 100 μm.
Protozoans
Protozoans are cellular organisms.
Possess a membrane-bound nucleus.
Less than 50 μm in size.
Fungi
They can be unicellular, such as yeasts, or multi-cellular, for example mushrooms.
Are not capable of producing their own food.
2–10 µm in diameter and up to several centimeters in length.
Macro-Parasites
Are parasites that are visible to the naked eye.
Endoparasites live inside the host’s body.
Ectoparasites are parasites that live on the outside of the body
What is the cause of tetanus?
Tetanus is an infection caused by a bacterium called Clostridium tetani.
Symptoms of tetanus
Jaw cramping. Involuntary muscle tightening. Painful muscle stiffness all over the body.
Treatment of tetanus
Treatment is antibiotics and muscle relaxants.
How to prevent tetanus?
Tetanus can be prevented through immunization with tetanus-toxoid-containing vaccines.
How to control tetanus?
Immunization is the most effective way to control tetanus.
What is the cause of influenza?
It is caused by influenza viruses that infect the nose, throat, and lungs.
Symptoms of influenza
Fever, coughing, sore throat, runny nose and headaches.
Treatment of influenza
Influenza is treated primarily with rest and fluid to let the body fight the infection on its own.
How to prevent influenza?
Avoid close contact with other sick people, stay home when you are sick and cover your mouth and nose when you sneeze.
How to control influenza?
Immunization against the influenza is an effective way of controlling it.
What is a galaxy?
A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity. Nearly all large galaxies are thought to also contain supermassive black holes at their centres.
What is a star?
A star is a large, spherical celestial body consisting of a mass of gas that is hot enough to sustain nuclear fusion therefore producing radiant energy.
What is a Nebula?
A nebula is an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars.
What is a galaxy cluster?
A galaxy cluster is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity.
Where are we in Space?
We are in the Milky Way which is part of the virgo supercluster and our solar system is found on the Orion arm of the spiral.
Why is gravity the dominant force in defining the structure of the Universe?
Gravity is the dominant force at an astronomical scale because it has the longest range and because there is no negative mass.
Life cycle of a small star
Star → Red Giant → Planetary Nebula → White Dwarf
Life cycle of a big star
Star → Red Supergiant → Supernova → Neutron Star or Black Hole
