40 Questions
What is the characteristic of microorganisms when compared to other living organisms?
They are simpler in structure and complexity
What is the main difference between prokaryot and eukaryot cells?
The presence or absence of a nucleus
Which of the following is NOT a characteristic of living cells?
Ability to produce non-living offspring
What is the term for the process of removing toxic material and waste?
Excretion
Which of the following is an example of a eukaryot cell?
Protozoa
What is the term for the ability of cells to sense and respond to stimuli?
Sensitivity
Which of the following microorganisms is not a cell?
Virus
What is the term for the process of breaking down food to release energy?
Metabolism
What is the function of teichoic acid in Gram-positive bacteria?
To regulate cell wall enlargement and ion passage
What is the main function of the lipopolysaccharide layer in Gram-negative bacteria?
To protect the peptidoglycan layer from enzymes
What is the primary function of the cell wall in bacteria?
To maintain the shape of the cell
Which of the following is a characteristic of Gram-positive bacteria?
Thick peptidoglycan layer
What is the function of the periplasmic space in Gram-negative bacteria?
To provide a space for enzyme activity
What is the result of Gram staining in Gram-positive bacteria?
Purple color
What is the main difference between the cell walls of Gram-positive and Gram-negative bacteria?
Lipopolysaccharide layer presence
What is the role of the cell wall in protecting the cell against physical disruption?
It provides high resistance
What is the correct way to write the genus name of a microorganism?
upper case
What is the name of the yeast species used for beer production?
Saccharomyces cerevisiae
What is the characteristic of Staphylococcus aureus?
It has a golden color
What is the shape of Bacillus cereus?
Fungus rodlet
How should the scientific name 'CLOSTRIDIUM BOTULINUM' be written?
Clostridium botulinum
What is the arrangement of Cocci arranged in a square of four?
Tetrad
What is the characteristic of a living cell?
Ability to reproduce
What is the cause of rope spoilage in bread?
Bacillus subtilis
How do microorganisms typically reproduce?
Asexually, through simple cell division or binary fission
What is unique about the environments in which microorganisms can survive?
They can survive in a wide range of environments that are too extreme for other organisms
What is the role of microorganisms in nutrient cycling?
They play a vital role in nutrient cycling, decomposition, fermentation, and digestion
Who introduced the binomial system of nomenclature for microorganisms?
Carl Linnaeus
What is the correct format for writing the name of a microorganism in the binomial system?
Genus in all uppercase letters and species in all lowercase letters
What is the purpose of the rules of nomenclature for microorganisms?
To provide a universal system for naming microorganisms
What is the correct way to write the names of taxa in handwritten form?
Underlined
What is the term for the first name of an organism in the binomial system of nomenclature?
Genus
What is the main component of the cell membrane?
Phospholipid and proteins
What is the function of flagella in motile bacteria?
To propel bacteria through liquids
What is the role of fimbriae in bacteria?
To attach the cell to a surface
What is the function of the capsule in bacteria?
To prevent phagocytosis
What is the term for the layer of bacteria cell that is tightly bound to the cell wall?
Capsule
What is the function of pili in bacteria?
To transfer DNA from one cell to another
What is the role of cations such as Mg2+ and Ca2+ in the cell membrane?
To combine with negative charge of phospholipids and help stabilize the membrane structure
What is the function of the slime layer in bacteria?
To protect the cell from desiccation and help trap nutrients near the cell
Study Notes
Cell Classification
- There are two main categories of cells: Prokaryot and Eukaryot.
- Prokaryot: "Pro" means before, and "karyon" means kernel or nucleus, referring to cells that lack a true nucleus.
- Eukaryot: "Eu" means true, and "karyon" means kernel or nucleus, referring to cells that have a true nucleus.
Characteristics of Living Cells
- 7 characteristics of living cells:
- Removal of toxic materials and waste of metabolism
- Excretion
- Ability to produce offspring
- Ability to sense and respond to stimuli
- Consuming material from surrounding for growth and energy
- Breaking down food to release energy
- Increasing in number of cells
Microorganisms
- 5 major groups of microorganisms:
- Bacteria
- Fungi
- Virus
- Protozoa
- Algae
Differences between Microorganisms and Other Living Organisms
- 5 key differences:
- Size: Microorganisms are much smaller than other living organisms.
- Complexity: Microorganisms are simpler in structure and complexity compared to other living organisms.
- Reproduction: Microorganisms reproduce rapidly and can produce millions of offspring in a short period.
- Diversity: Microorganisms are incredibly diverse and can survive in a wide range of environments.
- Importance: Microorganisms play a vital role in several processes such as nutrient cycling, decomposition, fermentation, and digestion.
Nomenclature of Microorganisms
- Microorganisms are named according to the binomial system, introduced by Carl Linnaeus.
- The binomial system consists of a genus and species.
- Rules of nomenclature:
- Use binary names
- Capitalize the genus name
- Italicize or underline the names of all taxa
Cell Components
- Gram-positive bacteria: contain teichoic acids, which are negatively charged and help regulate the cell wall's negative charge.
- Gram-negative bacteria: contain lipopolysaccharides, which function as a second membrane structure that protects the peptidoglycan.
Cell Wall Functions
- Act as an antigen
- Inhibit phagocytosis
- Give and maintain the shape of the cell
- Protect the cell against mechanical and osmotic stress
- Separate the interior of the cell from the outer environment
- Enable transport of substances in and out of the cell
Gram Positive vs Gram Negative Bacteria
- Gram-positive bacteria: thick cell wall, peptidoglycan 40-90%, no outer layer, flat surface, periplasmic space is absent.
- Gram-negative bacteria: thin cell wall, peptidoglycan 5-10%, outer layer-lipopolysaccharide, waving surface, periplasmic space is present.
Cell Membrane/Plasma Membrane
- Main components: phospholipid and proteins.
- Functions:
- Regulate the passage of substances into and out of the cell
- Agent for selective transport or uptake of material
External Structures
- Flagella: used for movement, arrangement can vary.
- Fimbriae: used for attachment of cell to a surface.
- Pili: used for bacteria conjugation involved in DNA transfer.
- Capsule/Slime Layer: protects the cell from desiccation, prevents phagocytosis, and helps in adhesion or attachment.
Overall Structure of Prokaryotic and Eukaryotic Cell
- Prokaryotic cell: lacks a true nucleus and has a single circular chromosome.
- Eukaryotic cell: has a true nucleus and linear chromosomes.
Flagella Arrangement
- There are four arrangements of flagella: monotrichous, lophotrichous, amphitrichous, and peritrichous.
Learn about the two main categories of cells, Prokaryot and Eukaryot, and the 7 characteristics of living cells. Understand the differences between cells with or without a true nucleus.
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