Diversity of living things Unit Test Flashcards
What is the endosymbiotic theory?
The theory that eukaryotic cells evolved from prokaryotic cells by engulfing other prokaryotes that became organelles.
Which organelles support the endosymbiotic theory?
Mitochondria and chloroplasts.
What evidence supports the endosymbiotic theory?
Mitochondria and chloroplasts have double membranes, their own DNA, ribosomes similar to bacteria, and replicate independently by binary fission.
What are the main structural components of a virus?
Capsid (protein coat), genetic material (DNA or RNA), and sometimes a lipid envelope.
What are the two main types of viral replication cycles?
Lytic cycle (virus replicates rapidly, killing host cell) and lysogenic cycle (virus DNA integrates into host genome and replicates with it).
Why are viruses considered non-living?
They cannot reproduce on their own and do not carry out metabolism.
How do viruses enter host cells?
They bind to specific receptors on the host cell surface.
What are some diseases caused by viruses?
AIDS, COVID-19
How do vaccines work?
They stimulate the immune system to produce memory cells without causing disease.
What are the main shapes of bacteria?
Coccus (spherical), bacillus (rod-shaped), spirillum (spiral).
What are the key differences between bacteria and archaea?
Archaea lack peptidoglycan in their cell walls and live in extreme environments.
How do bacteria reproduce?
Binary fission
What are extremophiles?
Archaea that thrive in extreme conditions, such as thermophiles (heat), halophiles (salt), and methanogens (methane).
What are endospores?
Dormant, resistant bacterial cells that survive harsh conditions.
What are protists?
A diverse group of eukaryotes that don’t fit into the plant, animal, or fungi kingdoms
What are the three main groups of protists?
Animal-like (protozoa), plant-like (algae), fungus-like (slime molds and water molds)
How do animal-like protists move?
Using cilia (Paramecium), flagella (Euglena), or pseudopodia (Amoeba).
What is an example of a disease-causing protist?
malaria
What are plant-like protists and their importance?
Algae (e.g., diatoms, red algae) perform photosynthesis and produce oxygen.
What are the main structures of fungi?
Hyphae (thread-like filaments), mycelium (network of hyphae), and spores.
What is the main cell wall component of fungi?
Chitin
How do fungi reproduce?
Asexually or sexually
What are the main types of fungi?
bread mold, mushrooms, yeasts
What is mycorrhizae?
A mutualistic relationship between fungi and plant roots that helps plants absorb nutrients.
Bacteria
Structure:
Prokaryotic (no nucleus), unicellular, cell wall with peptidoglycan.
Energy Acquisition:
Autotrophic (photosynthetic like cyanobacteria or chemosynthetic)
Heterotrophic (decomposers, pathogens, symbiotic bacteria)
Reproduction:
Asexual (binary fission)
Genetic variation through conjugation, transformation, transduction
Classification:
Based on shape (coccus, bacillus, spirillum)
Gram staining (Gram-positive has thick peptidoglycan; Gram-negative has thin peptidoglycan + outer membrane)
Metabolism (aerobic vs. anaerobic)
Archaea
Structure:
Prokaryotic, unicellular, cell wall without peptidoglycan, different membrane lipids than bacteria.
Energy Acquisition:
Autotrophic (chemosynthesis)
Heterotrophic (some absorb organic molecules)
Reproduction:
Asexual (binary fission, budding, fragmentation)
Classification:
Based on habitat:
Methanogens (produce methane, live in anaerobic environments)
Halophiles (thrive in salt)
Thermophiles (live in extreme heat)
Protista
Structure:
Eukaryotic, mostly unicellular, some multicellular (algae).
Energy Acquisition:
Autotrophic (algae, Euglena)
Heterotrophic (protozoa, slime molds, amoeba)
Reproduction:
Asexual (binary fission, budding)
Sexual (conjugation in some, alternation of generations in algae)
Classification:
Animal-like (protozoa, heterotrophic, motile)
Plant-like (algae, photosynthetic)
Fungus-like (slime molds, absorb nutrients)
Fungi
Structure:
Eukaryotic, mostly multicellular (except yeast), cell wall made of chitin.
Energy Acquisition:
Heterotrophic (absorptive nutrition, decomposers, parasitic, mutualistic like mycorrhizae)
Reproduction:
Asexual (spores, budding in yeast)
Sexual (spore formation from two mating types)
Classification:
Zygomycota (bread mold)
Basidiomycota (mushrooms)
Ascomycota (yeasts, truffles)
Plantae
Structure:
Eukaryotic, multicellular, cell wall made of cellulose, contains chloroplasts.
Energy Acquisition:
Autotrophic (photosynthesis, using chlorophyll a & b)
Reproduction:
Asexual (vegetative reproduction, spores in ferns, binary fission in algae)
Sexual (pollen, seeds, flowers, alternation of generations in ferns/mosses)
Classification:
Nonvascular plants (bryophytes - mosses, liverworts)
Vascular plants (ferns, gymnosperms, angiosperms)
Animalia
Animalia
Structure:
Eukaryotic, multicellular, no cell walls, complex organ systems.
Energy Acquisition:
Heterotrophic (ingestion and internal digestion of food)
Reproduction:
Mostly sexual reproduction, some asexual (budding, fragmentation in sponges)
Classification:
Based on body symmetry, presence of a backbone, embryonic development:
Invertebrates (sponges, mollusks, arthropods, etc.)
Vertebrates (fish, amphibians, reptiles, birds, mammals)
Xylem VS Phylum
Xylem is dead, only goes up, and is for water and minerals. Phloem is for sugars, goes up and down, and is alive
Lytic Cycle
- Attachment - Virus binds to specific receptors on host cell membrane.
- Entry - Viral DNA or RNA is injected into the host cell.
- Replication - Host cell machinery replicates viral genetic material and proteins.
- Assembly - New viruses are assembled inside the host cell.
- Lysis & Release Host cell bursts (lysis), releasing new viruses to infect other cells.
🔹 Fast process (happens in hours or days)
🔹 Destroys host cell
Lysogenic Cycle
- Attachment - Virus binds to host cell and injects genetic material.
- Integration - Viral DNA integrates into host genome (now called a prophage).
- Dormancy - Viral DNA stays dormant, replicating with host cell’s DNA for many generations.
- Activation - Stress or environmental triggers activate the viral DNA.
- Lytic Cycle Begins - Virus enters lytic cycle, destroying the host cell and releasing new viruses.
🔹 Long, hidden phase (can last years)
🔹 Does NOT destroy host cell immediately
