Cells 2 Flashcards
What are microbes?
Microbes are microscopic organisms (microorganisms) that cannot be seen by the naked eye and require a microscope to be viewed.
Where are microbes found?
Microbes are found everywhere — in the air, soil, food, water, and even inside our bodies.
What are the main types of microbes?
Viruses, bacteria, and protozoa.
Can viruses be seen with a light microscope?
No, viruses are very small and can only be seen with an electron microscope.
Are viruses made of cells?
No, viruses are not made of cells and are often called virus particles or virions.
Can viruses be killed by antibiotics?
No, viruses cannot be killed by antibiotics like penicillin.
What are examples of diseases caused by viruses?
Influenza, common cold, measles, mumps, rubella (German measles), smallpox, chickenpox, HIV (can lead to AIDS), and rabies.
What type of organisms are bacteria?
Bacteria are unicellular (single-celled) organisms.
Are all bacteria harmful?
No. While some cause disease, many bacteria are useful, such as decomposing dead organisms and digesting cellulose.
What are examples of diseases caused by bacteria?
Cholera, tuberculosis, septicaemia (blood poisoning), pneumonia, and gastroenteritis.
What is the outer layer of a bacterial cell called?
The cell wall — it provides shape and protection.
What is found inside the cytoplasm of a bacterial cell?
A circular loop of DNA, ribosomes, and enzymes.
Does a bacterial cell have a nucleus?
No, bacteria are prokaryotic and do not have a true nucleus — their genetic material floats freely in the cytoplasm.
Are protozoa single-celled or multicellular?
Protozoa are generally single-celled organisms.
Do bacteria have membrane-bound organelles?
No, they lack membrane-bound organelles like mitochondria or chloroplasts.
Where can Amoeba, a type of protozoan, be found?
In backyard ponds and drains.
What are examples of diseases caused by protozoa?
Malaria, sleeping sickness, and dysentery.
How does an amoeba capture food?
It sends out a pseudopodium (false foot) toward the food and engulfs it.
What happens after the food is engulfed?
A food vacuole is formed inside the amoeba, enzymes digest the food, nutrients are absorbed, and waste is released.
What is a unicellular organism?
An organism made up of a single cell (e.g., Amoeba, Chlorella, bacteria).
What is a multicellular organism?
An organism made up of many cells (e.g., humans, trees, animals).
Are cells in unicellular organisms specialised?
No, but they can perform all life functions independently.
Are cells in multicellular organisms specialised?
Yes, different cells are specialised to carry out specific functions.
What is cell specialisation?
It is when a cell develops features that make it suited to a specific function (e.g., muscle cell contracts, nerve cell transmits impulses).
