Biological Classification and Prokaryotic Life

These flashcards cover the key concepts related to biological classification and the characteristics of prokaryotic life as discussed in the lecture notes.

Five Kingdom Classification

A system that categorizes living organisms into five distinct kingdoms: Monera, Protista, Fungi, Plantae, and Animalia.

Eukaryotic

Cells with a nucleus and organelles, can be unicellular or multicellular.

Prokaryotic

Cells that lack a nucleus and organelles, typically unicellular.

Photosynthesize

The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Motile

Capable of movement; organisms that can move independently.

Nonmotile

Incapable of movement; organisms that do not move from place to place.

Robert Harding Whittaker

The biologist who proposed the Five Kingdom classification system.

LUCA (Last Universal Common Ancestor)

The most recent common ancestor of all currently living organisms.

Biofilms

Collections of microorganisms that attach to surfaces and each other, embedded in a slimy layer or matrix.

Schaeffer-Fulton Staining

A method used to visualize bacterial endospores.

Fruiting bodies

Structures formed by some microorganisms, such as Myxobacteria, during sporulation under starvation conditions.

Gram-negative

Bacteria that do not retain the crystal violet stain used in Gram staining, typically having a thin peptidoglycan layer.

Capsule

A protective outer layer surrounding some bacteria, made of polysaccharides.

Bacilli

Rod-shaped bacteria.

Cocci

Round-shaped bacteria.

Spirilla

Spiral-shaped bacteria.

Vibrio

Curved rod-shaped bacteria.

Ciliates

A group of protozoans characterized by the presence of hair-like structures called cilia.

Five Kingdom Classification

A system that categorizes living organisms into five distinct kingdoms: Monera, Protista, Fungi, Plantae, and Animalia.

Eukaryotic

Cells with a nucleus and organelles, can be unicellular or multicellular.

Prokaryotic

Cells that lack a nucleus and organelles, typically unicellular.

Photosynthesize

The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Motile

Capable of movement; organisms that can move independently.

Nonmotile

Incapable of movement; organisms that do not move from place to place.

Robert Harding Whittaker

The biologist who proposed the Five Kingdom classification system.

LUCA (Last Universal Common Ancestor)

The most recent common ancestor of all currently living organisms.

Biofilms

Collections of microorganisms that attach to surfaces and each other, embedded in a slimy layer or matrix.

Schaeffer-Fulton Staining

A method used to visualize bacterial endospores.

Fruiting bodies

Structures formed by some microorganisms, such as Myxobacteria, during sporulation under starvation conditions.

Gram-negative

Bacteria that do not retain the crystal violet stain used in Gram staining, typically having a thin peptidoglycan layer.

Capsule

A protective outer layer surrounding some bacteria, made of polysaccharides.

Bacilli

Rod-shaped bacteria.

Cocci

Round-shaped bacteria.

Spirilla

Spiral-shaped bacteria.

Vibrio

Curved rod-shaped bacteria.

Ciliates

A group of protozoans characterized by the presence of hair-like structures called cilia.

Kingdom Monera

Composed of prokaryotic organisms, including bacteria and archaea. They are typically unicellular and lack a membrane-bound nucleus and organelles.

Kingdom Protista

A diverse group of eukaryotic organisms that are not plants, animals, or fungi. Most are unicellular, but some are multicellular; they can be autotrophic or heterotrophic.

Kingdom Fungi

Eukaryotic, heterotrophic organisms that absorb nutrients from their environment. They have cell walls made of chitin and can be unicellular (yeasts) or multicellular (molds, mushrooms).

Kingdom Plantae

Multicellular, eukaryotic, autotrophic organisms, primarily characterized by photosynthesis, rigid cell walls made of cellulose, and alternation of generations.

Kingdom Animalia

Multicellular, eukaryotic, heterotrophic organisms that ingest food. They lack cell walls and are typically motile, with specialized tissues and organs.

Gram-positive

Bacteria that retain the crystal violet stain in Gram staining, appearing purple/blue under a microscope. They have a thick peptidoglycan layer.

Endospores

Dormant, tough, and non-reproductive structures produced by certain bacteria to ensure their survival during periods of environmental stress.

Flagella

Whip-like appendages found on the cells of some bacteria, archaea, and eukaryotes, used primarily for locomotion (movement).

Pili (Fimbriae)

Hair-like appendages found on the surface of many bacteria, primarily involved in attachment to surfaces and other cells.

Peptidoglycan

A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall.

Types of Flagellar Arrangement in Bacteria

Describes the distribution of flagella on the bacterial cell surface:

• Monotrichous: A single flagellum at one pole.

• Lophotrichous: A tuft of flagella at one pole.

• Amphitrichous: A single flagellum at each pole.

• Peritrichous: Flagella distributed all over the entire cell surface.

Slime Layer

A diffuse, unorganized, and easily removable layer of extracellular polymeric substance (EPS), typically polysaccharides, found outside the bacterial cell wall. Unlike a capsule, it's less tightly bound, primarily aiding in adhesion and preventing dehydration.

Taxis (in Bacteria)

The directed movement of a motile organism or cell in response to specific environmental stimuli. Key types include:

1. Chemotaxis: Movement towards or away from chemical signals.
2. Phototaxis: Movement in response to light.
3. Magnetotaxis: Movement in response to a magnetic field.

Archaea

A domain of single-celled prokaryotic microorganisms representing an independent lineage distinct from bacteria and eukaryotes. Often found in extreme environments, archaea differ from bacteria in cell wall composition (lacking peptidoglycan), membrane lipid structure, and ribosomal RNA sequences, among other characteristics.