Fungi and Bacteria Quiz

Microorganisms: Friend or Foe

• Microorganisms are organisms too small to be seen with the naked eye.
• Microbiology is the study of microorganisms.
• Antonie van Leeuwenhoek was the first scientist to observe small moving organisms in lake water using a microscope. He named them "animalcules".
• Microorganisms are omnipresent, found in air, water, soil, and inside living organisms.
• They can survive extreme conditions like hot springs and polar regions, as well as acidic and alkaline environments.
• Under unfavorable conditions, they form tough coverings called cysts.
• Microorganisms are microscopic and unicellular.
• Types of microorganisms include bacteria, protozoa, algae, fungi, and viruses.

What are Microorganisms?

• Microorganisms are living things too small to be seen without a microscope.
• The study of microorganisms is called microbiology.
• Antonie van Leeuwenhoek was a scientist who first observed microorganisms.

Where do Microorganisms live?

• Microorganisms are found everywhere.
• They can survive in a wide range of conditions, from hot springs to polar regions.
• They can survive in acidic and alkaline environments.
• Under unfavorable conditions, they form a tough covering called a cyst.

Characteristics of Microorganisms

• They are microscopic
• They are mostly unicellular.
• They can be categorized into groups like bacteria, protozoa, algae, fungi, and viruses.

Classification of Microorganisms

• Bacteria: Unicellular, prokaryotic, diverse shapes, examples include Lactobacillus.
• Fungi: Saprophytic, can be unicellular or multicellular, examples include Penicillium, Aspergillus.
• Algae: Photosynthetic microorganisms, examples include Spirogyra.
• Protozoa: Unicellular, eukaryotic, examples include Amoeba.
• Viruses: Neither living or nonliving, examples include bacteriophage, HIV, caliciviruses.
• Some microorganisms are useful and others are harmful.
• Based on the number of cells: Unicellular (e.g., protozoa) and multicellular (e.g., some fungi and algae).
• Based on significance: Bacteria, Fungi, Protozoa, Algae, and Viruses; some are useful and some are harmful. Examples: -Useful: Lactobacillus, Yeast, Tetrahymena pyriformis, Red Algae, Lambda phage. -Harmful: Haemophilus influenza, Rhizopus, Plasmodium, Gymnodinium, Picorna.

Uses of Microorganisms

• Used in food preparation: e.g., curd, bread, and cake.
• Used in cleaning up the environment.
• Used in the preparation of medicines, particularly antibiotics (e.g., penicillin).
• Used to increase soil fertility by fixing nitrogen.

What is Bacteria?

• Bacteria are unicellular microorganisms with cell walls but lack organelles and an organized nucleus.
• Some bacteria can cause disease.
• Bacteria often form colonies.
• Bacteria can be autotrophic (make their own food) or heterotrophic (feed off other organisms).
• Bacterial size ranges between 0.5 and 5 micrometers.
• They contain genetic material enclosed within a rigid cell wall made up of peptidoglycan.
• Bacteria do not have a nucleus but have genetic material in the nucleoid. Some bacteria have plasmids.

The Main Characteristics of Bacteria

• Bacteria lack a nucleus.
• Genetic material (DNA) exists as chromosomal threads inside the cytoplasm.
• It is known as the nucleoid.
• Some bacteria have plasmids, which are small DNA molecules carrying extra genes.

Size of Bacteria

• Bacteria range in size from 0.05 to 100 um.
• The size varies depending on the type of bacteria.
• Viruses are measured in nanometers and are even smaller than the smallest bacteria.

Evolution of Bacteria

• Bacteria are considered the first life forms on Earth.
• About 4 billion years old.
• All other life forms on Earth are believed to have evolved from bacteria.
• A hyperthermophile is a bacteria that can live in extremely hot environments. This ancient type of bacteria is thought to be the ancestor of bacteria and archaea.
• Endosymbiosis is the symbiotic relationship between different bacteria that eventually gave rise to the first proto-eukaryotic cell, which gradually gave rise to eukaryotes.

Ecology (Habitat) of Bacteria

• Psychrophiles (<15°C)
• Mesophiles (15-60°C)
• Thermophiles (>60-80°C)
• Halophiles (2-5M NaCl)
• Acidophiles (pH<3)
• Alkaliphiles (pH>10)
• Barophiles (>100 MPa)
• Radiophiles

Shapes and Arrangement of Bacteria

• Cocci (spherical): Coccus, Diplococci, Staphylococci, Streptococci, Sarcina, Tetrad.
• Bacilli (rod-shaped): Coccobacillus, Bacillus, Diplobacilli, Streptobacilli, Palisades
• Others: Vibrio, Spirillum, Spirochete, Filamentous, Appendaged bacteria, Hypha, Stalk

Structure of a Bacterial Cell

• Capsule
• Cell wall
• Plasma membrane
• Nucleoid
• Ribosomes
• Plasmid
• Flagellum
• Pilus

Structure of Bacteria

• All cells have 3 main components, DNA, surrounding membrane, and cytoplasm.
• Some bacteria also have cell walls, resisting osmotic pressure, flagella, for movement, pili for attachment and capsules for protection.

External Structure of a Bacteria

• Flagella are hair-like processes for motility and chemotaxis.
• Parts of flagella: basal body, hook, and filament.
• Types of flagellar arrangement: Atrichous, Monotrichous, Amphitrichous, Cephalotrichous, Peritrichous, Lophotrichous.
• Pili/Fimbriae are short, numerous, and non-helical appendages.
• Aids in adherence to host cells and bacterial conjugation.
• Capsules are viscous, outermost layers that aid in adherence, prevent desiccation and confer resistance to phagocytosis.

Sheath and Prosthecae

• Sheaths: hollow tube-like structures enclosing chain-forming bacteria (mostly aquatic).
• Provide mechanical strength to the chain.
• Prosthecae: semi-rigid extensions of the cell wall and plasma membrane.
• Increase nutrient absorption and aid in adhesion.

Cell Wall

• Outermost layer encasing the cytoplasm, confers shape and rigidity.
• Composed of peptidoglycan (complex polysaccharides).
• Contains bacterial antigens which play an important role in virulence and immunity.
• Bacteria are classified into gram-positive and gram-negative based on cell wall thickness.

Gram-Positive and Gram-Negative Bacteria

• Gram-positive bacteria have a thicker cell wall composed primarily of peptidoglycan, appear purple under a staining technique.
• Gram-negative bacteria have a thinner cell wall with an extra outer membrane, containing lipopolysaccharide. They stain pink.

Classification of Bacteria

• Based on oxygen requirements: Aerobic, Facultative anaerobes, Anaerobic
• Based on temperature preference: Psychrophile, Mesophile, Thermophile
• Other factors: Halophile, Acidophile, Alkaliphiles, Barophile, Radiophile

According to disease-causing ability of bacteria

• Pathogenic bacteria - those that cause diseases in humans
• Non-pathogenic bacteria - those that cannot cause diseases in humans

Reproduction of Bacteria

• Binary fission: bacteria divides into two identical daughter cells. This method begins with DNA replication, elongation and splitting. Each daughter cell is a clone of the parent cell.

Reproduction Cont'd: (Asexual Reproduction)

• Spore production: Spores (tiny, lightweight reproductive units) are produced in vast numbers and can survive harsh conditions.
• Fragmentation: A process where pieces of the organism break off to create a new organism.
• Budding: A process where a new organism grows as an outgrowth from the parent organism.
• Fission: A process where a single cell divides into two identical daughter cells.

Reproduction Cont'd:

• Several types of reproduction include fragmentation, budding, and fission. Fragmented hyphae, budding (small outgrowths) and fission (division) can all result in new individuals.
• Sexual reproduction involves the fusion of nuclei from compatible mating types.

Classification Of Fungi

• Myxomycota: fungi with plasmodium (mobile multinucleate mass of cytoplasm without a cell wall)
• Eumycota: fungi with cell walls and filaments.

Phyla

• Chytridiomycota
• Zygomycota
• Ascomycota
• Basidiomycota
• Deuteromycota

Microorganisms as Producer

• Phytoplankton
• They are microorganisms that float on the surface of oceans, ponds and lakes.
• They are important as producers in aquatic ecosystems.
• They contain chlorophyll and undergo photosynthesis.

Microorganisms as Decomposers

• Saprophytic fungi and saprophytic bacteria
• They decompose the organic materials from dead organisms.
• Decomposers break down complex organic materials into simple compounds.

Microorganisms as Parasites

• Parasites live on other organisms (host). They depend on the host for nourishment.
• Some examples of parasitic microorganisms include Plasmodium. These parasites often cause significant harm to the host.

Microorganisms as Symbionts

• Close relationships with other organisms.
• Ectomycorrhiza lives in the soil around plant roots. Mycorrhizae are a type of symbiosis.
• Protozoa Trichonympha sp. lives in the digestive tracts of termites. Endosymbiotic relationship.

Definition of Pathogens and Vector

• Pathogens: microorganisms that can cause disease.
• Vectors: organisms that transmit pathogens. An example of vector transmission is malaria (via mosquito bites)

Disease Caused By Bacteria and Virus

• Specific examples of diseases and the pathogen responsible and mode of transmission are listed.

Factors Affect Growth Of Microorganism

• Various factors affecting microorganism growth are listed (temperature, pH, light intensity, nutrients, humidity).

The Importance of Immunity

• Prevent human from infection.
• Help the infected person recovers fast.
• Prevent outbreaks and spread of diseases.

Role of Microorganisms

• Dead bacteria and viruses produce vaccines.
• Bacteria in the intestines help with digestion.

Harmful Effects of Microorganisms

• Some microorganisms can produce poisonous substances (e.g., from bacteria) and attack or destroy host cells or tissues.

Classification of Vaccines

• Whole-agent vaccine, Inactivated(killed) and Attenuated(weakened) vaccines, Subunit vaccine

Mnemonics

• Tips to remember the types of viral diseases.

How Antibiotic Resistance Spreads

• Spread details of how antibiotic resistance in bacteria is produced and spreads to other individuals (animals and humans).

Steps in the Multiplication of Animal Viruses

• Steps of viral multiplication within animal cells are explained.

Bacteriophages

• Viruses that infect bacteria are called bacteriophages.
• They have diverse shapes (icosahedral, filamentous, and complex).
• They may have DNA or RNA as genetic material.
• The lytic cycle and lysogenic cycle are the two major categories of bacteriophage replication.

Animal Viruses

• Viruses that infect humans and animals.
• They can be DNA or RNA viruses.
• They may consist solely of nucleic acids surrounded by protein coats.

Classification of Virus Families and Associated Symptoms

• A table listing virus families, specific viruses within them, and the diseases they cause.

Steps in the Multiplication of Animal Viruses

• Steps of viral multiplication within animal cells are explained.

Bacteriophage vs. Animal Virus

• Table detailing the differences between bacteriophages and animal viruses in terms of attachment, penetration, uncoating, synthesis site, assembly site, release mechanism, and chronic infections.

Antiviral Agents

• Antibiotics act by inhibiting bacterial metabolic activities.
• Antiviral agents are used to treat viral infections. Antiviral agents target viral functions or cellular functions needed by the virus, but they are not effective against bacteria.

Viruses and Cancer

• Complex, multi-step processes.
• Often involve oncogenes. Some viruses can carry oncogenes into the host cell, which can alter the cellular regulation causing uncontrolled cell growth of cancer.
• Host proto-oncogenes may be transformed by viruses.
• A table connecting specific viruses with associated human cancers.

Possible Mechanisms by which Viruses Cause Cancer

• Mechanisms of how viruses transform host cells promoting cancer development.

Human Immunodeficiency Virus (HIV)

• The causative agent of AIDS.
• Enveloped, single-stranded RNA virus.

Mimivirus

• Extremely large dsDNA virus recovered from amoebas.
• There is evidence that it might cause pneumonia

Plant Viruses

• Obligate intracellular parasites.
• Mostly rod-shaped, with protein discs.
• Often lack an envelope and have an RNA genome (single stranded).
• Double-stranded RNA or DNA genomes are possible in some cases.

Viroid and Prions

• Viroids are infectious RNA molecules causing plant diseases.
• Prions are infectious protein molecules causing animal/human diseases (e.g., Kuru).

Role of Yeasts in Food Spoilage

• Yeasts attack food and drink, causing spoilage due to their diverse environmental requirements.
• Some yeast species can be dangerous to humans, producing mycotoxins and causing allergic reactions or infections.

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