Key Concepts in Viruses, Prokaryotes, and Plant Biology

These flashcards cover key vocabulary and concepts related to viruses, prokaryotes, and plant biology, providing definitions and explanations for major terms.

Virus

A small infectious agent that consists of a genome (DNA or RNA) enclosed in a capsid, which may have a viral envelope derived from host membranes.

Lytic Cycle

A viral replication process involving viral replication, assembly, host cell lysis, and release of virions.

Lysogenic Cycle

A viral cycle where the viral DNA integrates into the host chromosome as a prophage, replicating during cell division and can be induced to enter the lytic cycle.

Retrovirus

A type of virus, like HIV, that reverse transcribes its RNA genome into DNA using reverse transcriptase.

Plasmid

A small, circular, self-replicating DNA molecule separate from the chromosome, often carrying genes for antibiotic resistance.

Transformation

The uptake of free DNA by a prokaryotic cell.

Conjugation

The direct transfer of DNA between two prokaryotic cells via a sex pilus.

Symbiosis

A mutually beneficial relationship between different organisms, such as fungi and algae in lichens.

Mycorrhizae

A mutualistic association between fungi and plant roots that enhances nutrient uptake.

Homospory

The production of one type of spore that develops into a bisexual gametophyte.

Heterospory

The production of two distinct types of spores: microspores (male) and megaspores (female).

Xylem

Tissue responsible for water and mineral transport in plants, functioning passively under negative pressure.

Phloem

Tissue responsible for transporting sugars in plants using positive pressure; requires ATP for loading.

Guard Cells

Specialized cells that regulate the opening and closing of stomata by controlling water movement.

Rhizosphere

The soil zone influenced by roots and associated microbes, important for nutrient absorption and interactions.

Nitrogen Fixation

The process by which bacteria convert atmospheric nitrogen (N₂) into ammonia (NH₃) for plant use.