microbial cell Flashcards
what is microbiology
“The study of micro-organisms, their physiology, biochemistry and genetics in single culture, in complex environments and their interactions with host organisms”
Name two main themes in microbiology.
Understanding basic life processes (using microbes as models for cellular processes).
Applying knowledge of microbes for human benefit (e.g., in medicine, agriculture, and industry).
What are microorganisms?
Life forms too small to be seen by the human eye. They are diverse in form and function, inhabit all environments supporting life, and can be single-celled, multicellular, or form complex structures.
When did the first cells appear on Earth?
Between 3.8 and 3.9 billion years ago.
What is the role of microbes in agriculture?
Positive roles: Nitrogen fixation, cellulose degradation in the rumen, and nutrient regeneration in soil and water.
Negative roles: Causing diseases in plants and animals.
What is the significance of bacterial cell walls?
Maintains cell shape.
Provides rigidity via peptidoglycan structure.
Differentiates Gram-positive and Gram-negative bacteria (via Gram staining).
What are the characteristics of Gram-positive and Gram-negative bacteria?
Gram-positive: Retain crystal violet stain (purple); thicker peptidoglycan layer.
Gram-negative: Do not retain crystal violet stain; counterstained pink with fuchsin; have an outer membrane with lipopolysaccharide (LPS).
What are bacterial endospores?
Dormant structures that persist for long periods, are dehydrated, and resistant to environmental stresses. They can germinate to form new vegetative cells.
What are the functions of the cytoplasmic membrane?Back:
Acts as a barrier separating the cytoplas
Facilitates energy production (e.g., via electron transport chain).
Aids in signal transduction and cell wall synthesis.
What are pili, and what is their function?
Small hair-like structures used for attachment to surfaces, other cells, or tissues. Specialized pili are involved in DNA transfer during bacterial conjugation.
How do bacterial flagella function?
Flagella are large hair-like structures that rotate to allow bacterial motility. They are powered by proton motive force and are used in processes like chemotaxis and phototaxis.
What are magnetosomes?
Magnetic iron oxide inclusions that allow cells to migrate along magnetic field lines. Applications include medicine, drug delivery, and bioremediation.
What is the significance of the human microbiome?
It includes all microorganisms residing on and in the human body, influencing health, immunity, and metabolism.
What are some industrial uses of microbes?
Pproduction of antibiotics, enzymes, chemicals, and biofuels. They are also used in bioremediation to clean up pollutants.
Why is peptidoglycan important in bacterial cells?
It provides rigidity to the cell wall, maintains cell shape, and is a target for antibiotic mechanisms of action
