Diversity of Microbes and Protists

Prokaryotic cells lack membrane-bound organelles and have a single circular chromosome (nucleoid) located in the cytoplasm. They possess a cell wall, a plasma membrane, cytoplasm, and ribosomes.

A rigid outer layer outside the plasma membrane, providing protection and shape. Its composition differs between Bacteria and Archaea.

Prokaryotes are commonly classified as cocci (spherical), bacilli (rod-shaped), or spirilla (spiral-shaped).

The region in a prokaryotic cell where the single circular chromosome is located.

An outer layer, present in some prokaryotes, that helps with attachment to surfaces and protects against dehydration.

Small, circular DNA molecules found in some bacterial species, separate from the main chromosome.

Flagella are used for movement, while pili are used for attachment and conjugation in some prokaryotic cells.

Prokaryotes are categorized into two domains: Bacteria and Archaea. These differ in their cell wall and membrane structures.

A protective layer surrounding some prokaryotic cells, providing shape and rigidity, and preventing osmotic lysis.

A polymer found in bacterial cell walls, composed of polysaccharide chains cross-linked to peptides (short chains of amino acids).

Bacteria with thick peptidoglycan cell walls, react differently to Gram staining.

Bacteria with thin peptidoglycan cell walls and an outer membrane.

Cell walls of archaea differs from bacteria – not composed of peptidoglycan; instead, made up of pseudopeptidoglycan or other polysaccharides, glycoproteins, and S-layers.

The primary asexual method of reproduction in prokaryotes.

Cell bursting caused by a difference in water pressure inside and outside the cell.

Different chemical composition compared to bacterial membranes; structures can comprise monolayers instead of bilayers.

Prokaryotes that obtain energy from sunlight.

Prokaryotes that obtain energy from chemical compounds.

Disease-causing prokaryotes that are bacteria.

A disease transmitted from animals to humans.

Historic pandemic that killed a quarter of the Athenian population.

Illnesses caused by bacteria.

Drugs that kill or slow the growth of bacteria.

Practices that improve public health by preventing the spread of contaminants like sewage.

A situation where bacteria are becoming resistant to antibiotics, making infections harder to treat.

Illness caused by eating food contaminated with harmful bacteria, viruses, or parasites.

A serious illness caused by a toxin produced by the bacterium Clostridium botulinum.

A dangerous strain of E. coli that can cause severe illness and even death.

Previously, botulism from canned food was common. Now, produce contaminated by animal waste is a major source of foodborne illness.

Symptoms of food poisoning can vary but commonly include nausea, vomiting, diarrhea, abdominal cramps, and fever.

Food safety is essential to prevent the spread of foodborne illnesses and protect public health.

The Centers for Disease Control and Prevention (CDC) plays a crucial role in monitoring foodborne illnesses, investigating outbreaks, and providing guidance on food safety practices.

The theory that explains the origin of mitochondria and chloroplasts in eukaryotic cells. It proposes that these organelles were once free-living prokaryotes that were engulfed by larger prokaryotes and formed a symbiotic relationship.

Mitochondria, the powerhouse of eukaryotic cells, are believed to have originated from aerobic bacteria that were engulfed by a host cell. This relationship provided the host cell with efficient energy production and the bacteria with a safe environment.

Chloroplasts, found in plant and algal cells, are thought to have originated from photosynthetic cyanobacteria that were engulfed by a host cell. This provided the host cell with the ability to perform photosynthesis, while the cyanobacteria gained protection.

Prokaryotes, single-celled organisms without a nucleus or membrane-bound organelles, were the first life forms on Earth. They evolved about 3.5 billion years ago and existed for over a billion years before eukaryotes emerged.

Early prokaryotes evolved the ability to perform photosynthesis, using sunlight to convert carbon dioxide and water into organic compounds. This process released oxygen into the atmosphere, changing Earth’s environment.

Photosynthetic bacteria gradually added oxygen to the Earth’s atmosphere over millions of years. This oxygenation had a profound impact, leading to new forms of life and the extinction of some anaerobic organisms.

Some prokaryotes evolved mechanisms to use oxygen to store energy from organic molecules. This process, known as aerobic respiration, became a highly efficient way to extract energy from food.

Infoldings of the inner mitochondrial membrane, resembling textured bacterial surfaces. They increase surface area for energy production.

Circular DNA molecule found within mitochondria, encoding for some mitochondrial proteins. It resembles bacterial DNA.

Chloroplasts are believed to have evolved from endosymbiosis with photosynthetic cyanobacteria, explaining their similarities.

A general term for a group of organelles in plant cells, including chloroplasts. They are involved in storage of various substances.

Mitochondria are essential for cellular respiration, the process of energy production. All eukaryotic cells require energy to survive.

Chloroplasts are responsible for photosynthesis, the process of producing food from sunlight. Plants and algae use this process to obtain nutrition.

The first eukaryote likely arose from a series of endosymbiotic events, involving prokaryotes like bacteria and cyanobacteria.