Life, Cells, and Classification Exam Review
Life
Define Biology.
Biology is the scientific study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy.
Define and explain theory and law.
Scientific Theory: A well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Theories are comprehensive explanations, not mere guesses.
Scientific Law: A statement based on repeated experimental observation that describes some aspect of the universe. Laws describe what happens under specific conditions, while theories explain why.
Describe 5 foundational pillars of life.
Organization: Living things exhibit a highly organized structure, from cellular to organismal levels.
Energy Utilization: Organisms acquire and use energy (metabolism) to maintain organization, grow, and reproduce.
Homeostasis: Maintenance of a stable internal environment despite external changes.
Reproduction: The ability to produce offspring, ensuring continuity of species.
Evolution/Adaptation: Populations of organisms change over generations to adapt to their environments.
Define and explain 9 characteristics of life.
Cellular Composition: All living things are composed of one or more cells.
Organization: Complex and ordered structure.
Metabolism: Chemical processes that sustain life.
Homeostasis: Regulation of internal conditions.
Growth and Development: Increase in size and complexity.
Reproduction: Creation of new individuals.
Response to Stimuli: Interaction with and reaction to the environment.
Adaptation through Evolution: Genetic change in populations over time.
Heredity: Passing genetic information to offspring.
Understand energy requirements for organization.
Living organisms require a continuous input of energy to maintain their highly ordered structures and counteract the natural tendency towards increasing entropy ( ext{disorder} ) as dictated by the second law of thermodynamics. This energy is used for metabolic processes, growth, and repair.
Contributions of Scientists:
Aristotle: Early classification of organisms, ideas on spontaneous generation.
Hippocrates: "Father of Medicine," emphasized observation in medical practice.
Antonie van Leeuwenhoek: Improved the microscope; first to observe microbes.
Joseph Lister: Pioneered antiseptic surgery.
Alexander Fleming: Discovered penicillin.
Jonas Salk: Developed the inactivated polio vaccine (IPV).
Albert Sabin: Developed the oral polio vaccine (OPV).
Francesco Redi: Disproved spontaneous generation of maggots.
John Needham: Conducted experiments that seemed to support spontaneous generation for microbes (later disproved).
Lazzaro Spallanzani: Challenged Needham by showing no microbial growth in boiled, sealed broths.
Louis Pasteur: Definitively disproved spontaneous generation with swan-neck flask experiments; developed pasteurization and vaccines.
James Hutton: "Father of Modern Geology," proposed uniformitarianism and deep time.
James Lovelock: Proposed the Gaia hypothesis.
Differentiate between abiogenesis and biogenesis.
Abiogenesis: The natural process by which life arises from non-living matter.
Biogenesis: The principle that living organisms can only arise from other living organisms.
Explain spontaneous generation and Redi's experiment to disprove it, including relevant scientists.
Spontaneous Generation: The now-disproven theory that life could arise spontaneously from non-living matter.
Redi's experiment (1668): Francesco Redi placed meat in three jars: one open, one sealed, and one covered with gauze. Maggots only appeared on meat accessible to flies (open jar) or on the gauze where flies landed, but not in the sealed jar. This showed that maggots came from flies, not spontaneously from decaying meat. Other scientists involved in the debate included John Needham, Lazzaro Spallanzani, and Louis Pasteur.
Describe levels of organization.
Atoms
Molecules
Organelles
Cells
Tissues
Organs
Organ Systems
Organisms
Populations
Communities
Ecosystems
Biosphere
Evolution
Understand geologic and organic evolution.
Geologic Evolution: Refers to the gradual physical changes of the Earth over vast time periods (e.g., continental drift, erosion).
Organic Evolution (Biological Evolution): The process by which populations of organisms change over successive generations, mainly through natural selection, mutation, and genetic drift.
Evidence of Evolution:
Fossils: Provide a historical record of life, showing changes in organisms over geological time and transitional forms.
Comparative Anatomy: Similarities and differences in the structure of different species indicate common ancestry or adaptation to similar environments.
Embryology: Comparing the developmental stages of different organisms reveals shared ancestral features.
Molecular Similarities: Comparison of DNA, RNA, and protein sequences shows evolutionary relationships and common genetic code among organisms.
Geographic Distribution (Biogeography): The patterns of species distribution across the globe reflect evolutionary history and continental drift.
Comparative Anatomy: Homologous, Analogous, and Vestigial structures.
Homologous Structures: Structures in different species that are similar due to shared common ancestry, but may have different functions (e.g., the forelimb bones of humans, cats, whales, and bats).
Analogous Structures: Structures in different species that have similar functions but evolved independently, not from a common ancestor (e.g., the wings of birds and insects).
Vestigial Structures: Remnant structures that have lost most or all of their original function in a species but are homologous to functional structures in other species (e.g., human appendix, pelvic bones in whales).
The Cell
Importance of cell surface area and cell size.
The surface area to volume ratio critically limits cell size. As a cell grows, its volume increases faster than its surface area. The cell membrane (surface area) is responsible for exchanging nutrients and waste. If the volume becomes too large relative to the surface area, the cell cannot efficiently transport materials, leading to functional limitations.
Identify all cell parts, their functions, and presence in plant or animal cells.
Cell Wall: (Plant) Rigid outer layer, provides structural support and protection.
Cell Membrane: (Plant, Animal) Regulates passage of substances; maintains homeostasis.
Nucleus: (Plant, Animal) Contains genetic material (DNA); controls cell activities.
Nucleolus: (Plant, Animal) Inside the nucleus; produces ribosomes.
Cytoplasm/Cytosol: (Plant, Animal) Jelly-like substance filling the cell; site of many metabolic reactions.
Mitochondria: (Plant, Animal) Site of cellular respiration; produces ATP.
Ribosomes: (Plant, Animal) Synthesize proteins.
Endoplasmic Reticulum (ER): (Plant, Animal) Network of membranes.
Rough ER: (Plant, Animal) Studded with ribosomes; synthesizes and modifies proteins for secretion or membranes.
Smooth ER: (Plant, Animal) Lacks ribosomes; involved in lipid synthesis, detoxification, and calcium storage.
Golgi Apparatus: (Plant, Animal) Modifies, sorts, and packages proteins and lipids.
Lysosomes: (Animal) Contain digestive enzymes to break down waste (rare in plant cells).
Peroxisomes: (Plant, Animal) Involved in metabolic processes such as breaking down fatty acids and detoxification.
Vacuoles: (Plant - large central; Animal - small, numerous) Storage of water, nutrients, waste; maintains turgor pressure in plants.
Chloroplasts: (Plant) Site of photosynthesis; contain chlorophyll.
Cytoskeleton: (Plant, Animal) Network of protein filaments; provides structural support, shape, and facilitates movement.
Centrioles/Centrosome: (Animal) Involved in cell division and organizing microtubules.
Plasmodesmata: (Plant) Channels connecting adjacent plant cell cytoplasms.
Details of cell membrane: composition, polar and non-polar parts of phospholipid layer.
The cell membrane is primarily composed of a phospholipid bilayer with embedded proteins, cholesterol (in animal cells), and carbohydrates. This structure is described by the fluid mosaic model. Each phospholipid has a hydrophilic (polar) head that is attracted to water, and two hydrophobic (non-polar) fatty acid tails that repel water. In the bilayer, the polar heads face the aqueous environments inside and outside the cell, while the non-polar tails face each other, forming the membrane's core.
Differences and similarities between plant and animal cells.
Similarities: Both have a cell membrane, nucleus, mitochondria, ribosomes, ER, Golgi apparatus, peroxisomes, and a cytoskeleton.
Differences: Plant cells have a cell wall, chloroplasts, a large central vacuole, and plasmodesmata. Animal cells have centrioles/centrosomes and lysosomes (typically larger and more prominent).
Classification
Define taxonomy.
Taxonomy is the branch of science concerned with the classification, naming, and description of organisms.
Historical classification system: who and what was classified.
Early classification attempts by Aristotle grouped animals by habitat. The modern hierarchical system was largely developed by Carolus Linnaeus, who classified organisms based on shared physical characteristics.
Understand KPCOFGS (Kingdom, Phylum, Class, Order, Family, Genus, Species).
This mnemonic represents the hierarchical levels of taxonomic classification from broadest to most specific: Kingdom, Phylum, Class, Order, Family, Genus, Species.
Role of Carolus Linnaeus.
Carolus Linnaeus, a Swedish botanist, is known as the "father of modern taxonomy." He developed the binomial nomenclature system for naming species and established a hierarchical classification system based on observable characteristics.
Principles of scientific naming.
Scientific naming uses binomial nomenclature, where each species is given a unique two-part name: the Genus name (capitalized) and the species epithet (lowercase). Both parts are italicized (e.g., Homo sapiens).
Understanding phylogenetics.
Phylogenetics is the study of the evolutionary history and relationships among groups of organisms. It aims to reconstruct the "tree of life" based on shared ancestry.
Cladograms.
A cladogram is a branching diagram illustrating hypothesized evolutionary relationships (phylogeny) between organisms, based on shared derived characteristics. Each node represents a common ancestor.
Dichotomous keys.
A dichotomous key is a tool used