Viruses, Bacteriophages, and Infections

• Viruses are microscopic infectious agents that replicate inside living cells.
• They consist of genetic material (DNA or RNA) and a protein coat called a capsid, sometimes with a lipid envelope.

Capsid

• The capsid is a protective protein shell around a virus's genetic material.
• It comes in various shapes and is key to infecting host cells.

Bacteriophage

• Bacteriophages are viruses that infect bacteria.
• They have a nucleic acid core and a protein coat.
• Bacteriophages can destroy bacteria through lytic or lysogenic infections.

Lytic Infection

• In lytic infections, viruses use the host cell's machinery to replicate.
• This process produces new viral particles and causes the cell to burst (lyse), releasing viruses.

Lysogenic Infection

• Viruses integrate their DNA into the host cell's DNA in lysogenic infections.
• The virus remains dormant until it enters the lytic cycle.

Prophage

• Prophage refers to the viral DNA integrated into the host's genome during a lysogenic infection.
• It remains inactive through cell divisions.

Retrovirus

• Retroviruses use reverse transcription to convert RNA to DNA which integrates into the host’s genome.
• HIV is an example.

Prokaryote

• Prokaryotes are single-celled organisms lacking a nucleus and membrane-bound organelles.
• Bacteria and archaea are prokaryotes.

Bacillus

• Bacillus refers to rod-shaped bacteria, which can be beneficial or pathogenic.

Coccus

• Coccus refers to spherical bacteria that can exist in arrangements like diplococci, streptococci, and staphylococci.

Spirillum

• Spirillum refers to spiral or corkscrew-shaped bacteria.
• Many have flagella for movement.

Obligate Anaerobe

• Obligate anaerobes cannot survive in the presence of oxygen.
• They rely on anaerobic processes for metabolism.

Obligate Aerobe

• Obligate aerobes require oxygen for growth and survival.
• They use aerobic respiration for energy.

Facultative Anaerobe

• Facultative anaerobes can survive with or without oxygen.
• They switch between aerobic respiration and fermentation.

Binary Fission

• Binary fission is asexual reproduction in prokaryotes.
• A single cell divides into two identical daughter cells.

Endospore

• Endospores are resistant, dormant structures formed by some bacteria.
• They protect genetic material under unfavorable conditions.

Conjugation

• Conjugation is a genetic exchange process in prokaryotes.
• It promotes genetic diversity.

Pathogen

• Pathogens are organisms that cause disease in a host.
• This includes bacteria, viruses, fungi, and parasites.

Vaccine

• Vaccines are biological preparations that provide active acquired immunity.
• They often contain weakened or inactivated parts of a pathogen.

Antibiotic

• Antibiotics are antimicrobials that treat bacterial infections.
• They kill bacteria or inhibit their growth.

Emerging Disease

• Emerging diseases are those newly appearing in a population or increasing in incidence.
• These are often due to evolving pathogens.

Prion

• Prions are misfolded proteins that cause other proteins to misfold.
• They lead to neurodegenerative diseases without genetic material.

Superbugs

• Superbugs are bacteria resistant to multiple antibiotics.
• This often arises from overuse and misuse of antibiotics.

Bacteria vs. Archaea

• Bacteria have peptidoglycan in their cell walls, while Archaea do not.
• Archaea have unique membrane lipids for thriving in extreme environments.
• Archaeal ribosomes are more similar to eukaryotes.
• Extremophiles exemplify archaeal adaptation to extreme conditions.
• Bacteria are classified by shape, metabolism, and oxygen needs.
• Archaea are categorized by environmental niches.

Prokaryote Dimensions

• Prokaryotes range from 0.1 to 5.0 micrometers in diameter.
• This is smaller than eukaryotic cells, enabling rapid metabolism and reproduction.

Shapes

• Common prokaryote shapes include cocci (spherical), bacilli (rod-shaped), spirilla (spiral), and vibrio (comma-shaped).

Adaptation

• Their small size supports efficient nutrient uptake and waste removal, speeding growth.

Prokaryote Movement

• Prokaryotes move via flagellar propulsion and surface slithering.
• This movement help locate nutrients and evade predators.

Nutrition

• Prokaryotes can be autotrophic (photosynthesis or chemosynthesis) or heterotrophic (obtaining nutrients from organic matter).

Reproduction

• Reproduction occurs mainly through binary fission, allowing exponential population growth.

Decomposers

• Bacteria break down organic matter and recycle nutrients.

Cyanobacteria

• Cyanobacteria are primary producers in aquatic ecosystems, contributing to oxygen and forming the base of the food web.

Bacteria Role

• Nitrogen-fixing bacteria convert atmospheric nitrogen into ammonia, usable by plants.

Disease Mechanisms

• Bacteria cause disease by producing toxins or damaging host tissues.
• Viruses invade host cells, using them to replicate, leading to cell death and disease.

Disease Controls

• Control measures for bacteria include antibiotics.
• Antiviral medications and vaccines manage viral infections.

Disease Spread

• Emerging diseases spread rapidly due to global travel and changing ecosystems.
• New or evolved pathogens resist current treatments.
• Quick emergence can outpace public health responses.

Defining Protists

• Protists area diverse group of eukaryotic microorganisms.
• Protists are classified as protozoa, algae, and fungi-like protists.
• Protists are found in various environments
• Photosynthesis or nutrient absorption occurs in protists.

Pseudopod

• Pseudopods are temporary cytoplasmic extensions of cells like amoebas
• They are used for movement and feeding through phagocytosis.

Cilium

• Cilia are short, hair-like structures for movement or fluid movement
• They beat in coordination.

Flagellum

• Flagella is a long, whip-like structure that propels organisms.

Spore

• Spores are a reproductive unit that develops into a new organism.
• They are often resistant to harsh conditions.

Protist Conjugation

• Conjugation involves the exchange of genetic material in protists and bacteria.

Alternation of Generations

• Alternation of generations alternates between diploid (sporophyte) and haploid (gametophyte) generations.
• The sporophyte produces spores (meiosis), then gametophytes produce gametes (mitosis).
• This occurs in plants and protists.
• It enhances genetic variation for adaptation.

Sporangium Definition

• Sporangium is a structure in plants, fungi, and protists.
• Spores are produced and stored in a sporangium.
• Spores release under favorable conditions.

Protists

• Protists are unicellular eukaryotic organisms, that are distinct from plants, animals, and fungi.
• Protists exhibit characteristics of multiple kingdoms, leading to their classification as a 'catch-all' group.
• Classification is based on nutrition (autotrophic vs. heterotrophic), movement (cilia, flagella, pseudopodia), and cellular structure.
• Example include algae (plant-like), protozoa (animal-like), and slime molds (fungi-like).
• The classification reflects evolutionary relationships and ecological roles within ecosystems.

Protist Ancestry

• Protists are the most primitive eukaryotes
• Protists evolved from ancestral prokaryotic cells.
• They share a common ancestry with plants, animals, and fungi.
• Diversity illustrates the evolutionary adaptations that led to the current eukaryotic kingdoms.

Protist Motility

• Protists uses cilia, flagella, and pseudopodia to move.
• Cilia are short hair-like structures found in paramecium.
• Flagella are long, whip-like structures that rotate or undulate found in euglena.
• Pseudopodia are extensions of cytoplasm found in amoebas.

Protist Duplication

• Protists reproduce asexually (binary fission, budding, spore formation) and sexually (conjugation).
• Sexual reproduction increases genetic diversity
• Understanding reproduction in protists is crucial for studying their ecological roles and evolutionary biology.

Photosynthetic Protists

• Photosynthetic protists, especially phytoplankton, are primary producers in aquatic ecosystems.
• They convert sunlight into chemical energy, forming the base of food webs.
• Photosynthetic Protists contribute significantly to global oxygen production and carbon cycling.
• Their populations serve as indicators of ecosystem health and nutrient cycling.

Heterotrophic Protists

• Heterotrophic protists obtain food through phagocytosis, absorption, and predation.
• Phagocytosis engulfs food particles or microorganisms.
• Absorption involves taking in dissolved organic matter.

Chitin

• Chitin is a structural polymer found in fungal cell walls.
• It provides strength and rigidity.

Hypha

• Hyphae are Thread-like structures that form the mycelium.
• These are crucial for nutrient absorption and growth.

Fruiting Body

• A fruiting body is the reproductive structure of fungi.
• Fruiting bodies produce and disperse spores.

Mycelium

• The mycelium is the vegetative part of a fungus.
• This is responsible for decomposition and nutrient cycling.

Lichen

• Lichens are symbiotic associations between fungi and photosynthetic partners.
• They are capable of thriving in diverse environments.

Mycorrhiza

• Mycorrhiza are symbiotic relationships between fungi and plant roots.
• They enhance nutrient uptake.

Mushroom Structure

• Fungi comprise hyphae forming a mycelium.
• They reproduce through spores, dispersed by wind, water, or animals.
• Fungi absorb nutrients from their environment and can be classified based on reproduction.

Basidiomycota

• Basidiomycota produce mushrooms and other fruiting bodies.
• Basidia produce spores.

Zygomycota

• Zygomycota includes molds like bread mold.
• Spores are developed through zygospores..

Ascomycota

• Ascomycota are known as sac fungi.
• Spores are developed in sac-like structures called asci.

Chytridiomycota

• Chytridiomycota are aquatic fungi with flagellated spores.
• They often decompose organic matter.

Deuteromycota

• Deuteromycota are fungi with no known sexual reproduction.
• These are often referred to as imperfect fungi.

Fungi Replication

• Fungi use asexual (budding, fragmentation, spore formation) and sexual (fusion of hyphae) reproduction.
• Sexual reproduction involves formation of specialized structures that produce spores.

Fungi Impact

• Fungi contribute to homeostasis through decomposition
• Fungi form parasitic relationships, affecting host organisms and ecosystems.
• Lichens serve as bioindicators.
• Mycorrhizae enhance plant growth which influences plant community dynamics.