Biology Lecture Flashcards: Kingdoms, Evolution, Prokaryotes/Eukaryotes, Protists, Viruses, Taxonomy

A comprehensive set of flashcards covering life characteristics, kingdoms, evolutionary timeline, origin theories, origin of life experiments, endosymbiotic theory, prokaryotic/eukaryotic features, taxonomy, viruses, and Protista diversity.

Name the seven characteristics of life.

Cells; respond to environment; grow; reproduce; obtain food/energy; maintain homeostasis/metabolism; contain genetic material.

Which kingdom is considered the first to evolve?

Monera (prokaryotic).

What are the five traditional kingdoms?

Monera, Protista, Fungi, Plantae, Animalia.

Which kingdom was first to evolve and consisted of prokaryotes?

Monera.

Approximately when did Earth begin to exist (in billions of years ago)?

About 4.5 billion years ago.

Around what time did prokaryotes begin existing?

About 3.5 billion years ago.

When did oxygen-generating photosynthesis appear?

Around 2.7 billion years ago.

When did single-celled eukaryotes first appear?

About 2.1 billion years ago.

When did multicellular eukaryotes first appear?

About 1.5 billion years ago (in the oceans initially).

When did the diversification of animals occur?

About 550 million years ago.

During which era did land plants first appear?

Paleozoic; plants were among the last to colonize land.

What is notable about animal phyla diversification around 550 mya?

All animal phyla appeared at roughly the same time, and all phyla still exist.

What are the two origin theories of life?

Spontaneous generation and Biogenesis.

Who conducted key experiments supporting Biogenesis?

Louis Pasteur.

What did Pasteur’s swan-neck flask experiments demonstrate?

Air alone does not create life; microorganisms come from existing life; intact necks prevent contamination.

What does Pasteur’s sealed-broth experiment show?

No organisms appeared unless the flask was exposed to contaminants.

What does the swan-neck (U-shaped) experiment show when the neck is intact?

No organisms appear; contamination occurs only if the neck is broken.

What is the first life likely to have been in terms of oxygen use?

Anaerobic.

Where did life most likely originate?

Underwater in volcanic vents and similar environments on early Earth.

Who proposed that early Earth conditions favored abiotic synthesis of organic compounds?

Alexander Oparin and J.B.S. Haldane.

What is an organic compound?

A molecule (or set of molecules) containing carbon skeletons; often associated with life-related chemistry.

What did the Miller–Urey experiment test?

The Oparin–Haldane hypothesis by attempting to synthesize organic molecules from inorganic precursors under early-Earth-like conditions.

What did Miller–Urey produce in their experiment?

Sugars and amino acids from inorganic precursors using electrical discharges (sparks).

Where did life most likely originate according to current hypotheses?

Underwater, in volcanic vents and similar environments.

What are the stages in the hypothetical origin of life (Stage 1) abiotically?

Spontaneous formation of lipids, carbohydrates, amino acids, proteins, nucleotides.

What is Stage 2 of the hypothetical origin of life?

Formation of protein–RNA systems and lipid spheres; RNA is unstable.

What is Stage 3 of the hypothetical origin of life?

DNA is created as a more stable genetic molecule.

What is Stage 4 of the hypothetical origin of life?

First cells (protobionts) formed abiotically with proteins, sugars, genetic material, and fats.

What is Stage 5 of the hypothetical origin of life?

Living cells evolved: prokaryotic and eukaryotic cells.

What general limitation does Miller–Urey have regarding biological molecules?

It can form simple organics but not yet nucleotides to nucleic acids or amino acids to proteins.

What naturally forms vesicles and surrounds nucleic acids and proteins?

Phospholipids.

Which group gave rise to plants, fungi, and animals?

Protista.

Name key components of a prokaryotic cell (structure).

Outer capsule, pilus, flagella (some lack), cell wall, plasma membrane, cytoplasm with ribosomes, DNA in the nucleoid.

What are the three common shapes of bacteria?

Bacilli (rod), Cocci (spherical), Spirochetes (spiral).

What does Gram-positive mean in Gram staining?

Purple stain; thick peptidoglycan cell wall.

What does Gram-negative mean in Gram staining?

Pink stain; thin peptidoglycan layer.

Define autotrophs and heterotrophs with their subtypes.

Autotrophs synthesize their own organic molecules (photoautotrophs use light; chemoautotrophs use inorganic chemicals). Heterotrophs obtain energy and carbon from organic compounds (photoheterotrophs and chemoheterotrophs).

What is an obligate aerobe?

An organism that requires oxygen for cellular respiration.

What is an anaerobe?

An organism that does not require oxygen for energy production.

What is a facultative aerobe?

An organism that can grow with or without oxygen, switching respiration modes as needed.

Are prokaryotes generally larger or smaller than eukaryotes?

Smaller.

How do bacteria commonly reproduce?

Asexually by binary fission; some exchange DNA via Pili (sexual-like recombination).

What is symbiosis?

A close ecological relationship between two species; mutualism, commensalism, parasitism.

Which domain includes all eukaryotic kingdoms?

Eukarya.

Where is DNA located in an animal cell?

In the nucleus.

What distinguishes plant cells from animal cells?

Cell wall made of cellulose, chloroplasts for photosynthesis, and a large central vacuole.

What is Protista?

A miscellaneous kingdom of mostly unicellular or simple multicellular eukaryotes; polyphyletic; grouped by ecological role.

Name pigments typical of Chrysophyta (golden brown algae).

Chlorophylls A and C.

What are diatoms known for?

Diverse, mostly unicellular algae with silica cell walls; major oxygen producers; source of diatomaceous sand.

What is the phylum for brown algae?

Phaeophyta.

What is Laminaria and how does it reproduce?

A brown alga; reproduces through sperm and egg (sexual reproduction).

What are Rhodophyta and a key use of red algae?

Red algae; mostly multicellular; chlorophyll A and D; cell walls of cellulose; carrageenan and agar are derived from them.

What pigments do Chlorophyta (green algae) possess?

Chlorophylls A and B.

Which green algae are examples of unicellular and colonial forms (e.g., Chlamydomonas, Volvox) and which are multicellular (e.g., Ulva)?

Chlamydomonas (unicellular); Volvox (colonial); Ulva (multicellular).

What is Euglenophyta characterized by?

Mixotrophic protists; mostly unicellular; two flagella; no cell wall; stigma; chloroplasts.

Which phylum includes dinoflagellates and features two flagella and a cellulose carapace?

Dinoflagellata.

What are zooxanthellae?

Mutualistic dinoflagellates living inside corals; provide color and sugars; can cause coral bleaching under stress.

What is a red tide and which phylum often contributes to it?

A harmful algal bloom caused by dinoflagellates; some species release toxins.

What is Giardia lamblia classified under?

Diplomonadida (an early/primitive protist with multiple flagella and no mitochondria).

What is Trichomonas vaginalis classified as?

Parabasalia.

What is Choanoflagellida and its significance?

A phylum of unicellular/colonial organisms with a collar around a flagellum; considered related to the origin of animals.

Name the kinetoplastids and a major disease they cause.

Kinetoplastida; e.g., Trypanosoma; causes African sleeping sickness and Chagas disease.

What is Apicomplexa?

All parasites; non-motile; includes Plasmodium (malaria) and its life stages: sporozoite, merozoite, gametocyte.

Describe the Plasmodium life cycle stages mentioned.

Sporozoite (in mosquitoes), merozoite (in liver and red blood cells), gametocyte (in red blood cells; taken up by mosquitoes).

What is Ciliophora (ciliates) known for?

Unicellular; cilia all over body; examples include Paramecium and Stentor; have oral groove, food vesicles, macronucleus and micronucleus; conjugation and binary fission.

What is the function of the macronucleus and micronucleus in Paramecium?

Macronucleus controls everyday cellular activities; micronucleus is involved in sexual exchange (conjugation).

What organism is associated with Amoeba?

Rhizopoda.

What characterizes Actinopoda?

Radiating, ray-like pseudopods; silica-based; unicellular; heterotrophic.

What is Foraminifera?

Amoeba-like protists with calcium carbonate shells; chambered, common in oceans.

What are Oomycota (water molds) known for?

Marine, freshwater, terrestrial; zoospores; many parasites and decomposers; includes organisms like powdery mildew.

What is oogonium in Oomycota?

Egg-nucleus-containing structure used in sexual reproduction.

What are Myxogastrida?

Plasmodial (acellular) slime molds; single plasmodium with many nuclei; reproduce by spores.

What are Dictyostelida?

Cellular slime molds; multiple cells; cellulose cell walls; form a pseudoplasmodium (aggregate of cells).