Untitled Quiz

Taxonomy

• Classifying living things involves 8 characteristics: made of cells, reproduce, need and use energy, grow and develop, respond to stimuli, move, exchange gases, and excrete waste.
• Classifying is important for identifying species, farming practices, medical disease identification, treatment with medicinal plants, invasive species control, conservation biology, and global communication of species.
• The morphological species concept focuses on an organism's physical characteristics (body size, shape, etc.) to determine if similar organisms are different species.
• This approach is simple, but populations often contain non-identical individuals.
• The biological species concept defines a species as a group of organisms that can interbreed and produce viable, fertile offspring in nature.
• This allows identification of species easily—the same if two can live to mate and produce.
• It's not applicable to all species—asexual reproducers and extinct species.

Morphological Species Concept

• Focuses on observable physical characteristics.
• Compares body size, shape, and structural features.
• Scientists decide if similarities indicate different species or not.

Biological Species Concept

• Defines species based on interbreeding potential.
• Organisms that can interbreed in the wild and produce fertile offspring are the same species.
• Useful for identifying species that reproduce sexually in nature.

Phylogenetic Species Concept

• Focuses on evolutionary relationships.
• Identifies a species as a distinct cluster of organisms with a unique evolutionary history.
• Incorporates modern DNA analysis.
• Useful for extinct species.

Naming Species

• Binomial nomenclature is a two-part naming system.
• Genus name (first part, capitalized) species name (second part, lowercase).
• Scientific names are always italicized.
• Standardized naming across the world is necessary

Classifying Species

• Species concepts categorize and determine which groups of organisms make up a species.
• Binomial nomenclature assigns formal names to each species.
• Classification organizes organisms into categories based on common characteristics and evolutionary relationships.
• The system is hierarchical (nested).

Bacteria

• Cell Wall Structure: Gram-positive bacteria have a thick cell wall; Gram-negative bacteria have a thin cell wall.
• Shapes: Coccus (spherical), Bacillus (rod-shaped), Spirillum (spiral-shaped)
• Gram Stain: Used to differentiate bacteria based on their cell wall structure. Gram-positive bacteria stain purple; Gram-negative stain pink.
• Energy Production: Aerobic (need oxygen), anaerobic (don't need oxygen), and facultative (can survive with or without).

Bacteria Diseases

• Bacteria cause various diseases like strep throat, skin infections, and flesh-eating diseases.
• Examples: Streptococcus, Staphylococcus, E. coli, Lyme disease

Viruses

• Characteristics: Too small to be seen by light microscopy; not made of cells; dependent on host cells for survival and reproduction.
• Structure: Contains genetic material (DNA or RNA) enclosed in a protein coat (capsid).
• Reproduction: Replicate inside host cells, using host cell machinery.

Virus Reproduction

• Lytic cycle—destroys infected cell
• Lysogenic cycle—viral DNA integrates into host cell's DNA, and replicated without destroying host cell

Classification

• Viruses with DNA: Typically stable.
• Viruses with RNA: Higher mutation rate.
• Classifications based on: Morphology, the disease caused, and genetic material.

Retroviruses

• Use reverse transcriptase enzyme for RNA to DNA conversion.
• Viral DNA integrates into host DNA (provirus).

Herpesvirus

• Causes reactivation with a fever.
• Often inactive virus.

Prions

• Infectious protein particles.
• Cause neurological diseases by misfolding normal proteins, in chain reaction.
• Spongiform encephalopathy (mad cow).
• Ex: Mad Cow disease, Creutzfeldt-Jakob disease.

Protista

• Eukaryotic organisms, mostly unicellular.
• "Misfits"—neither plant, animal, or fungi.
• Classified as animal-like, fungus-like, or plant-like, based on their mode of nutrition and other characteristics.
• Important as food sources for other organisms, some are parasites.

Endosymbiosis Theory

• Explains the formation of eukaryotic organelles like mitochondria and chloroplasts.

Application of Viruses in Biotechnology

• Biological insecticides
• Gene therapy
• Genetic engineering