Cell Biology Quiz on Bacterial Structures

The idea that living organisms can arise spontaneously from non-living matter.

Microscopes allowed scientists to observe and study microbes, leading to numerous discoveries in microbiology.

Pasteur demonstrated that microbes are responsible for fermentation and disease, and developed pasteurization.

Koch established the link between specific microbes and specific diseases.

A set of criteria used to establish a causal relationship between a microorganism and a disease.

The process of isolating and growing a pure culture of a single type of microbe.

The three domains of life are Bacteria, Archaea, and Eukarya.

The hypothesis that RNA was the first genetic material, preceding DNA.

A complex of multiple ribosomes translating the same mRNA molecule simultaneously, enhancing protein synthesis efficiency.

A process where translation begins while transcription is still ongoing, enabling rapid protein production in prokaryotes where both processes occur in the cytoplasm.

Proteins that assist in proper protein folding and prevent misfolded proteins from aggregating, crucial for maintaining cellular function and preventing disease.

The movement of newly synthesized proteins from the site of synthesis (ribosomes) to their specific destinations within the cell (e.g., organelles, cell membrane), ensuring proper function and preventing mislocalization.

A protein secretion system in bacteria that translocates proteins across the cell membrane, with two main branches: SecA-dependent pathway for folded proteins and SecYEG-dependent pathway for unfolded proteins.

A component of the outer membrane of Gram-negative bacteria, composed of lipid A, core polysaccharide, and O-specific polysaccharide. It is recognized by the immune system and can trigger a strong inflammatory response, leading to sepsis in severe cases.

The innermost part of LPS, deeply embedded in the outer membrane. It is a hydrophobic molecule consisting of two glucosamine sugars with fatty acyl chains attached.

The variability in the O-specific polysaccharide of LPS, which is a chain of sugar molecules, allows for classification of different bacterial species.

A transport protein embedded in the outer membrane of Gram-negative bacteria that facilitates the passage of small hydrophilic molecules, such as sugars and amino acids.

A small protein that links the outer membrane to the peptidoglycan layer in Gram-negative bacteria. It helps maintain the structural integrity of the cell envelope.

A region located between the inner and outer membranes of Gram-negative bacteria, containing peptidoglycan and several important enzymes and proteins. It plays a vital role in metabolism, transport, and defense.

A type of active transport system where the energy released by the movement of one molecule down its concentration gradient is used to drive the movement of another molecule against its concentration gradient.

A type of active transport system where the movement of one molecule down its concentration gradient is used to drive the movement of another molecule in the opposite direction.

The outer layer of a bacterial cell, which plays a vital role in protection, shape, and interaction with the environment.

All living organisms, from bacteria to plants and animals, possess a cell membrane that encloses their cytoplasm. Due to their shared evolutionary history, their basic structures resemble each other.

The cell membrane's primary function is to act as a selective barrier controlling what enters and leaves the cell. It also plays crucial roles in energy production, cell signaling, and transport.

Bacterial cytoplasmic membranes are phospholipid bilayers, with phospholipids consisting of a hydrophilic head and a hydrophobic tail. These molecules spontaneously arrange themselves in bilayers with hydrophilic heads facing outward and hydrophobic tails pointing inward.

Bacterial cell walls are rigid structures that maintain the shape of the cell and protect it against osmotic stress, which can cause the cell to burst. They primarily consist of peptidoglycan, a unique polymer not found in other domains of life.

Peptidoglycan is a complex polymer composed of repeating sugar units linked by short peptides. The sugar backbone consists of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues, linked to each other by peptide cross-links.

Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin peptidoglycan layer and an additional outer membrane. The presence or absence of this outer membrane allows the bacteria to be distinguished by Gram staining, a technique used for bacterial identification.

The peptidoglycan layer is somewhat permeable, allowing small molecules like water and nutrients to pass through. However, it restricts the entry of larger molecules and can inhibit the penetration of certain antibiotics.

Organisms that thrive in extremely cold environments, typically below 15°C.

Organisms that grow optimally at moderate temperatures, typically between 20°C and 45°C.

Organisms that thrive in extremely hot environments, typically above 45°C.

Organisms that thrive in extremely hot environments, typically above 80°C.

Organisms that thrive in acidic environments, typically with pH values below 3.

Organisms that thrive in alkaline environments, typically with pH values above 9.

The time required to reduce the number of microbes by 90% at a specific temperature.

A device that uses high pressure steam to sterilize materials by killing all microorganisms and their spores.

A close and often long-term interaction between two different species where at least one species benefits.

A symbiotic relationship where both organisms benefit from the interaction.

A symbiotic relationship where one organism benefits while the other is neither harmed nor helped.

A symbiotic relationship where one organism benefits at the expense of the other.

An organism that cannot survive without its symbiotic partner.

Complex organisms composed of a fungus (usually ascomycete) and an alga (usually a green alga).

Organisms that consume other organisms. Predators can be single-celled (like amoebae) or multicellular (like lions).

A complex, multi-species microbial community that can thrive in diverse environments.