BIOLOGY BLOCK 3

What is taxonomy?

The science of classifying organisms based on shared characteristics.

What is the taxonomic hierarchy?

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

What is a mnemonic to remember the taxonomic hierarchy?

Dear King Philip Came Over For Good Soup.

What is a species?

A group of organisms capable of producing fertile offspring.

What is a genus?

A group of closely related species.

What are prokaryotes?

Unicellular organisms lacking a nucleus and membrane-bound organelles.

What are the characteristics of prokaryotes?

Circular DNA, Haploid, Binary fission, and No membrane-bound organelles.

What is binary fission?

Asexual reproduction in which one cell divides into two genetically identical daughter cells.

What is a nucleoid?

The region where prokaryotic DNA is located.

What are pili?

Hair-like structures used for attachment and DNA transfer.

What are fimbriae?

Short structures that help bacteria adhere to surfaces.

What are bacteria?

Prokaryotes whose cell walls contain peptidoglycan.

What is peptidoglycan?

A rigid polymer that provides structural support to bacterial cell walls.

What are Gram-positive bacteria?

Bacteria with thick peptidoglycan layers that stain purple.

What are Gram-negative bacteria?

Bacteria with thin peptidoglycan layers, an outer membrane, and stain pink.

What is lipopolysaccharide (LPS)?

A component of Gram-negative bacteria that acts as an endotoxin.

What are teichoic acids?

Molecules found in Gram-positive bacterial cell walls.

What is an endospore?

A dormant, highly resistant bacterial structure that survives harsh conditions.

What is the shape of a bacillus?

Rod-shaped bacterium.

What is the shape of a coccus?

Spherical bacterium.

What is the shape of a spirillum?

Spiral-shaped bacterium.

What is strepto- in bacteria?

Bacteria arranged in chains.

What is staphylo- in bacteria?

Bacteria arranged in clusters.

What are cyanobacteria?

Photosynthetic Gram-negative bacteria that contributed to Earth's oxygenation.

What are nitrogen-fixing bacteria?

Bacteria that convert atmospheric nitrogen into biologically usable forms.

What are archaea?

Prokaryotes that share characteristics with both bacteria and eukaryotes.

What is an extremophile?

An organism adapted to extreme environments.

What are methanogens?

Anaerobic archaea that produce methane.

What are thermophiles?

Heat-loving archaea found in hot environments.

What are halophiles?

Salt-loving archaea found in high-salt environments.

What is Taq polymerase?

A heat-stable enzyme originally isolated from thermophilic organisms and used in PCR.

What is an autotroph?

An organism that produces its own organic molecules.

What is a heterotroph?

An organism that consumes organic molecules produced by others.

What is a phototroph?

An organism that uses light as its energy source.

What is a chemotroph?

An organism that uses chemical reactions as its energy source.

What is an obligate aerobe?

An organism that must live in the presence of oxygen.

What is an obligate anaerobe?

An organism that cannot survive in oxygen.

What is a facultative anaerobe?

An organism that can use oxygen when available but survive without it.

What is a microaerophile?

An organism that requires low oxygen levels.

What is a protist?

A diverse group of eukaryotic organisms that are not plants, animals, or fungi.

What is a plant-like protist?

Photosynthetic protist containing chloroplasts.

What is an animal-like protist (protozoan)?

Motile heterotrophic protist.

What is a fungus-like protist?

Spore-producing decomposer that resembles fungi.

What is an amoeba?

An animal-like protist that moves using pseudopodia and captures food through phagocytosis.

What is a pseudopodium?

A temporary extension of cytoplasm used for movement and feeding.

What is a flagellate?

A protist that moves using flagella.

What is a ciliate?

A protist that moves using cilia.

What is a paramecium?

A common ciliate.

What is a sporozoan?

A parasitic protist that reproduces using spores.

What is Plasmodium?

The protozoan parasite that causes malaria.

What are algae?

Photosynthetic organisms that function as primary producers.

What are green algae?

Evolutionary ancestors of terrestrial plants.

What are red algae?

Mostly multicellular algae found in marine environments.

What are brown algae?

Multicellular algae including kelp and seaweeds.

What is an algal bloom?

Rapid growth of algae caused by excess nutrients.

What is eutrophication?

Nutrient enrichment of water leading to algal blooms and oxygen depletion.

What are fungi?

Eukaryotic heterotrophs that absorb nutrients from their environment.

What is chitin?

The structural polysaccharide found in fungal cell walls.

What is a saprophyte?

A decomposer that digests dead organic material externally.

What is yeast?

A unicellular fungus.

What is a hypha?

A thread-like fungal filament.

What is mycelium?

A network of hyphae.

What are septate hyphae?

Hyphae separated by internal walls called septa.

What are coenocytic hyphae?

Hyphae lacking septa and containing multiple nuclei.

What is a spore?

A haploid reproductive cell capable of developing into a new organism.

What is a sporangium?

The structure where spores are produced.

What is a rhizoid?

A fungal structure that anchors the organism.

What is plasmogamy?

Fusion of fungal cytoplasm.

What is karyogamy?

Fusion of fungal nuclei.

What is lichen?

A mutualistic association between fungi and algae.

What is Plantae?

Multicellular photoautotrophs with cellulose cell walls.

What is alternation of generations?

A life cycle alternating between haploid gametophyte and diploid sporophyte stages.

What is a sporophyte?

The diploid stage that produces spores by meiosis.

What is a gametophyte?

The haploid stage that produces gametes by mitosis.

What is a spore?

A haploid dispersal cell.

What is a gamete?

A haploid reproductive cell.

What is a tracheophyte?

A vascular plant containing xylem and phloem.

What is xylem?

Tissues that transport water and minerals upward in plants.

What is phloem?

Tissues that transport sugars throughout the plant.

What is a vessel element?

A xylem cell specialized for water transport.

What is a tracheid?

A xylem cell that also provides structural support.

What is a sieve-tube element?

A phloem cell that transports sugars.

What is a companion cell?

A cell that supports sieve-tube elements.

What is an angiosperm?

A flowering plant that produces seeds enclosed in fruit.

What is double fertilization?

A process where one sperm fertilizes the egg and another fertilizes the central cell.

What is an endosperm?

Triploid nutrient-rich tissue that nourishes the embryo.

What is pollen?

The male gametophyte.

What is an ovule?

The structure that develops into a seed.

What is an ovary?

The structure that develops into a fruit.

What is a seed?

A mature ovule containing an embryo.

What is fruit?

A mature ovary that aids seed dispersal.

What is a cotyledon?

A seed leaf that transfers nutrients to the embryo.

What is a monocot?

A flowering plant with one cotyledon.

What is a dicot?

A flowering plant with two cotyledons.

What is an apical meristem?

A region that produces primary growth (lengthening) in plants.

What is a lateral meristem?

A region that produces secondary growth (widening) in plants.

What is an epidermis in plants?

The protective outer layer of a plant.

What is a cuticle?

A waxy layer that reduces water loss in plants.

What is the palisade mesophyll?

The primary site of photosynthesis in leaves.

What is the spongy mesophyll?

A layer that contains air spaces for gas exchange.