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Questions and Answers
What is the primary objective of cleaning in MDRD?
What is a characteristic of cell life?
What is not soluble in water?
What is necessary for life to exist?
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What is the process of obtaining oxygen and removing carbon dioxide?
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What is the process of changing absorbed substances into chemically different forms?
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What is the term for the breakdown of food substances into simpler forms?
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What is the process of removing waste produced by metabolic reactions?
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What is the characteristic shape of Vibrio?
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Which of the following is NOT a characteristic of prokaryotic cells?
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What is the primary function of flagella in prokaryotic cells?
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What is the composition of the cell wall in prokaryotic cells?
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What is the method of cell division in prokaryotic cells?
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What is the function of ribosomes in prokaryotic cells?
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What is the process by which a small protrusion expands outward from a Mother cell to form a new Daughter cell?
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What is the term for the lengthening of a cell as it grows?
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What is the term for the process by which a cell divides into two identical daughter cells?
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What is the optimal temperature for microbial growth?
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What is the importance of oxygen for aerobic respiration?
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What is the result of low oxygen levels for microorganisms?
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What is the term for the creation of multiple nuclei in a cell?
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What is the term for the growth of cells in a linear fashion?
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What is the importance of nutrients for microbial growth?
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What is the result of high temperatures on microbial growth?
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What does the Greek word 'Bacterion' mean?
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Where can bacteria be found?
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How often can bacteria reproduce?
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What is the characteristic of anaerobic bacteria?
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What is the characteristic of facultative anaerobes?
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What percentage of bacteria are pathogenic?
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What did Louis Pasteur's experiment prove?
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What is the shape of Streptococcus bacteria?
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What type of microorganisms are absolutely dependent upon atmospheric oxygen to survive?
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Which type of microorganisms grows better in the presence of oxygen, but can still grow without it?
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What is the optimal pH range for the growth of most bacteria?
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Which type of microorganisms thrive in acidic environments with a pH below 7?
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What is the typical pH range for the growth of acidophiles?
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What is the name of the bacterium that can cause stomach ulcers and stomach cancer?
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What is a common symptom of Helicobacter pylori infection?
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Which type of microorganisms cannot tolerate oxygen and will die in its presence?
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Study Notes
Classification of Microorganisms
- Microorganisms can be classified into six categories: bacteria, viruses, fungi, prions, protozoa, and rickettsia and chlamydia.
Cell Structure
- The cell is derived from the Latin word "cellular," meaning small room.
- It is one of the most basic forms of life and is common to all living things.
- There are over a million different types of cells, some of which are single-celled and others that function as part of a larger organism.
Characteristics of Cell Life
- Cells exhibit characteristics such as movement, responsiveness, growth, circulation, reproduction, respiration, assimilation, digestion, excretion, and absorption.
- Life depends on five environmental factors: water, food, oxygen, heat, and pressure.
- Metabolism is the process by which cells obtain, release, and utilize energy.
Bacteria
- Bacteria are derived from the Greek word "bacterion," meaning small rod or staff.
- They are easily adaptable to any living conditions and can be found in every possible habitat on the planet.
- There are more bacterial cells than human cells in the human body.
- Bacteria can reproduce every 20 minutes.
- Not all bacteria are harmful, with less than 1% of bacteria causing disease.
- Some bacteria are helpful and can produce food, keep soil fertile, aid in digestion, and produce disease-fighting chemicals.
Germ Theory
- Louis Pasteur developed the modern germ theory, which states that microorganisms cause disease.
- Pasteur's experiment proved that food spoils due to contamination by invisible bacteria present in the air, rather than spontaneous generation.
Bacterial Shapes
- Bacteria can have different shapes, including:
- Bacillus (rod-shaped)
- Coccus (round)
- Streptococcus (round in chains)
- Staphylococcus (clustered)
- Diplococcus (paired)
- Spirillum (corkscrew-shaped)
- Vibrio (comma-shaped)
Cell Structure - Prokaryotic Cell
- Prokaryotic cells have the following characteristics:
- No nucleus
- No membrane-bound organelles (only ribosomes)
- All are unicellular
- Smaller and more simple than eukaryotic cells
- A single, closed circle chromosome contained within the nucleoid
- Additional circular DNA molecules (plasmids)
- Cell walls made of peptidoglycan (polymer of NAG and NAM cross-linked with polypeptide chain)
- Smaller ribosome unit: protein synthesis
- Divide by binary fission (not mitosis)
- Flagella: locomotion
Microbial Growth Methods
- Microbial growth methods include:
- Budding (common in yeast)
- Filamentous growth (common in fungi and some bacteria)
- Linear growth (in response to chemical stimuli)
Factors Regulating Growth
- Factors that regulate microbial growth include:
- Nutrients
- Environmental conditions: O2, temperature, pH, osmotic pressure, radiation, and atmospheric pressure
- Generation time
Optimal Microbial Temperature
- The optimal temperature for microbial growth varies depending on the species.
- At the minimum temperature, the plasma membrane begins to solidify and enzyme function slows.
- At the maximum temperature, the plasma membrane becomes too fluid and can no longer carry out cellular functions.
Optimal Microbial Oxygen Concentration
- The optimal oxygen concentration for microbial growth varies depending on the species.
- There are four types of oxygen classification for microorganisms:
- Obligate aerobes
- Facultative anaerobes
- Aerotolerant anaerobes
- Obligate anaerobes
Optimal Microbial pH Levels
- The optimal pH level for microbial growth varies depending on the species.
- Acidophiles grow best at pH 0.0-5.5, neutrophiles at pH 5.5-8.0, and alkalophiles at pH 8.5-11.5.
- Many bacteria and viruses can survive low pH levels, such as those found in the stomach.
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Description
This quiz covers the basics of microbiology, including the classification of microorganisms, bacterial cell structure, identification, and growth. It also touches on the different types of microorganisms.
