Acellular: - Non-cellular life, or acellular life refers to life forms that exist without cellular structure.
Unicellular: - A unicellular organism, also called a single-celled organism, consists of only one cell.
Multi-cellular: - Multi-cellular organisms are composed of multiple cells, distinguishing them from unicellular organisms.
Nucleus (plural: nuclei): - The nucleus regulates the cell's activities (e.g., growth, metabolism) and carries genes, which contains hereditary information.
DNA and RNA: - Deoxyribonucleic acid (DNA) is a polymer made of two polynucleotide chains that coil to form a double helix, carrying genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses.
DNA and ribonucleic acid (RNA) are categorized as nucleic acids.
Prokaryotic: - A prokaryote is characterized as a single-celled organism lacking a nucleus and other membrane-bound organelles.
Eukaryotic: - Eukaryotes possess cells with a nucleus enclosed by a nuclear envelope.
Cell Wall: - A cell wall is a structural layer surrounding certain cell types, located just outside the cell membrane, which may be tough, flexible, or rigid.
Cell Membrane: - Also known as the plasma membrane, this structure is found in all cells and separates the cell's interior from the external environment. It consists of a lipid bilayer that is semipermeable, regulating the transport of materials in and out of the cell.
Pathogen: - A pathogen is defined as any organism or agent capable of causing disease, also referred to as an infectious agent or germ.
Antibiotics: - Antibiotics are antimicrobial substances effective against bacteria, serving as the primary antibacterial agents for treating bacterial infections. They either kill bacteria or inhibit their growth.
Heterotrophic: - A heterotroph is an organism that cannot synthesize its own food and obtains nutrition by consuming other organisms. In food chains, heterotrophs are classified as primary, secondary, and tertiary consumers, but not producers.
Autotrophic: - Autotrophic organisms, such as green plants, produce complex organic compounds (e.g., glucose) from simple inorganic sources (e.g., water and carbon dioxide).
Saprophyte: - A saprophyte is a plant, fungus, or microorganism that thrives on dead or decaying organic matter.
Binomial Scientific Names: - The scientific name of a species, established through binomial nomenclature, consists of two parts:
Generic name (Genus name)
Specific name (species name)
Example: Homo sapiens / Homo sapiens
BACTERIA
Important Facts About Bacteria:
Unicellular: Organisms are composed of a single cell.
Surrounded by Cell Wall and Cell Membrane: Bacteria have both structures.
No True Nucleus – Prokaryotic: Lacks a true nucleus.
Genetic Material: Only one loop of DNA present.
Flagella: Helps in movement.
Reproduction: Bacteria can reproduce through cell division.
Habitat: Bacteria are found everywhere on Earth.
Shapes: Typically found in shapes of spheres, rods, or spirals.
Example of a Disease Caused by Bacteria:
Tuberculosis (TB):
A contagious infection primarily affecting lungs, caused by Mycobacterium tuberculosis. It can also affect other body parts including the brain and spine.
Symptoms: Include severe cough, chest pain, and weakness.
Treatment for TB:
Treatment duration is at least six months for new patients; re-infected patients may need treatment for at least eight months.
Common issue: patients often stop medication when feeling better, risking re-infection.
TREATMENT FOR BACTERIAL INFECTIONS
Antibiotics: Key methods through which antibiotics kill bacteria include:
Targeting the cell wall or membranes surrounding the bacterial cell.
Interfering with the DNA and RNA synthesis machinery of the bacterium.
Inhibiting the machinery responsible for protein production in the bacterium.
Antibiotic Resistance: This phenomenon occurs when bacteria develop the ability to defeat the medications designed to kill them, leading to complications in treatment.
VIRUSES
Characteristics:
Viruses are classified as parasites that utilize host cells for replication.
Components include:
A protein capsule surrounding the virus.
Genetic material (DNA or RNA).
Viruses are acellular and may not be considered living organisms.
Example of a Disease Caused by Viruses:
HIV/AIDS:
The human immunodeficiency virus (HIV) targets the immune system by attacking white blood cells, making individuals more susceptible to other infections.
If untreated, HIV may lead to acquired immunodeficiency syndrome (AIDS).
Current Information: There is no effective cure for HIV, but proper medical management can help control the virus.
Preventing Viral Infections:
Strategies include:
Administering vaccines.
Utilizing specific medications that inhibit virus replication.
PROTISTA
Characteristics of Protista:
Generally unicellular organisms.
Typical cellular structure includes a cell membrane, cytoplasm, and a nucleus, qualifying them as eukaryotic organisms with true nuclei containing genetic material.
Example of a Disease Caused by Protista:
Malaria:
Caused by the Plasmodium protist, transmitted through the blood by the Anopheles mosquito.
Effects include destruction of red blood cells, leading to anemia. Severe cases can be fatal due to blood vessels getting clogged and preventing blood flow to vital organs.
Management of Malaria:
Treatment involves medication to alleviate symptoms as well as the use of insecticides or mosquito nets to prevent transmission.
FUNGI
Characteristics of Fungi:
Some fungi, like bread mold and mushrooms, act as saprophytes by feeding on dead organic material.
Other fungi can be parasitic, deriving nutrients from a living host.
Fungi lack chlorophyll and therefore cannot perform photosynthesis.
Example of a Disease Caused by a Fungus:
Athlete’s Foot (Caused by Candida Albicans): An infection resulting from fungal growth.
ALGAE
Characteristics of Algae:
Algae can be either microscopic or macroscopic in size.
Many algae possess chlorophyll, allowing them to produce their own food through photosynthesis, classifying them as autotrophic organisms.
Algae are not classified as flowering plants, since their reproductive structures do not form flowers.
PREVENTING THE SPREAD OF DISEASES
Key Prevention Methods:
Wash hands frequently to minimize contamination.
Boil drinking water to kill pathogens.
Sterilize implements like baby bottles, needles, and toothbrushes.
Utilize vaccines to enhance immunity against diseases.
SCIENTIFIC CONTRIBUTIONS
Alexander Fleming: Noted for his discovery related to antibiotics.
Louis Pasteur: Recognized for his extensive work in microbiology and vaccination.