Bacteria: Structure, Reproduction, Growth, and Biotechnology

Vocabulary flashcards covering the biology of bacteria, including cell structures and organelles, reproductive mechanisms, nutritional adaptations, economic applications, antibiotic resistance, growth curves, and industrial bioprocessing systems.

Prokaryotes

Organisms that have no membrane-enclosed nucleus or membrane-enclosed organelles.

Bacterial Shapes

The three morphological classifications of bacteria: spherical (cocci), rod-shaped (bacillus), and spiral (spirilla).

Cocci

Spherical-shaped bacteria, such as the bacteria responsible for pneumonia.

Bacillus

Rod-shaped bacteria, such as the bacteria responsible for tuberculosis (TB).

Spirilla

Spiral- or helical-shaped bacteria, such as the bacteria responsible for cholera.

Bacterial Cell Wall

An outer cellular layer responsible for providing shape and structure to the bacterium.

Bacterial Cytoplasm

The fluid interior of a bacterial cell that contains ribosomes and storage granules, but lacks mitochondria and chloroplasts.

Nuclear Material (Bacteria)

A single circular chromosome of DNA not bound within a nucleus.

Capsule

A specialized protective outer layer present in some bacteria.

Flagellum

A specialized whip-like cellular appendage used by bacteria for movement.

Plasmid

A small circular piece of DNA in a bacterium containing genes for drug resistance.

Pilus

A surface structure that allows bacteria to adhere or stick to surfaces.

Binary Fission

The asexual reproduction process in bacteria in which the chromosome attaches to the plasma membrane, DNA is replicated, the cell elongates, chromosomes separate, and the cell wall divides the parent into two identical daughter cells.

Endospore

A dormant, tough-walled capsule enclosing a replicated strand of bacterial DNA that allows bacteria to withstand unfavourable conditions.

Autotrophic Bacteria

Bacteria capable of producing their own food using either light energy or energy from chemical reactions.

Photosynthetic Bacteria

Autotrophic bacteria that use light energy to manufacture food, such as purple sulphur bacteria.

Chemosynthetic Bacteria

Autotrophic bacteria that use energy released from chemical reactions to make food, such as nitrifying bacteria that convert ammonia to nitrates in the nitrogen cycle.

Heterotrophic Bacteria

Bacteria that obtain nutrition by taking in organic food made by other organisms.

Saprophytic Bacteria

Heterotrophic bacteria that feed on and decompose dead organic matter, such as bacteria of decay in soil.

Parasitic Bacteria

Heterotrophic bacteria that take their food from a living host, frequently causing disease.

Pathogens

Micro-organisms capable of causing disease in a host organism.

Bacillus anthracis

A pathogenic bacterium that causes anthrax in humans, which can enter through wounds to multiply and impair nerve and muscle activity.

Lactobacillus

A genus of beneficial bacteria utilized commercially to ferment milk into products such as cheese and yoghurt.

Antibiotics

Chemical substances produced by micro-organisms that inhibit the growth of or kill other micro-organisms without damaging human tissue.

Antibiotic Resistance

The condition arising when genetic mutations allow bacteria to survive antibiotic exposure, reproduce rapidly by binary fission, and multiply unchecked.

MRSA

A strain of multi-resistant bacteria capable of resisting all conventional antibiotics.

Bacterial Growth Curve

A graphical representation plotting the logarithmic scale of bacterial numbers over time through lag, log, stationary, decline, and survival phases.

Lag Phase

The initial period in bacterial population growth where cell count remains constant as bacteria adapt to their environment.

Log Phase

The period of rapid, exponential bacterial reproduction brought about by ideal conditions of food, moisture, and oxygen.

Stationary Phase

The phase where there is no net increase in bacterial numbers because growth rate slows due to depletion of food, space, or oxygen.

Decline Phase

The phase of rapid population reduction where the bacterial death rate exceeds the reproduction rate.

Survival Phase

The phase in which a small number of bacteria persist through adverse conditions by remaining dormant as endospores.

Bioreactor

A vessel in which biological reactions occur and living cells are cultivated to yield a specific commercial product.

Batch Food Processing

A bio-processing system where a fixed quantity of sterile nutrients is inoculated, micro-organisms progress through a typical growth curve, and the vessel is cleared, harvested, and re-sterilised prior to the next batch.

Continuous Flow Food Processing

A bio-processing system where fresh nutrients are constantly added while culture medium and product are continually removed, maintaining the micro-organisms indefinitely in the log phase.