Biology: Review of Biological Principles, Reproduction, Genetics, Evolution, and Ecology

A comprehensive set of vocabulary-style flashcards covering core concepts from the lecture notes, including organic molecules, cell biology, genetics, evolution, and ecology.

Carbohydrate

Major energy source in living things; sugars and starches built from carbon, hydrogen, and oxygen in a 2:1 hydrogen to oxygen ratio.

Protein

Nitrogen-containing polymers of amino acids; 20 amino acids form diverse proteins including enzymes, hormones, antibodies, and structural components.

Lipid

Hydrophobic molecules (fats and oils) composed of glycerol and fatty acids; store energy, provide insulation, cushion organs, and form membranes; saturated vs. unsaturated.

Nucleic Acid

DNA and RNA; store genetic information and direct protein synthesis; made of nucleotides.

DNA

Deoxyribonucleic acid; double-stranded, forms a helix; stores genetic information; replication occurs during cell division.

RNA

Ribonucleic acid; usually single-stranded; serves as the messenger and adaptor in protein synthesis (mRNA, tRNA, rRNA).

Chloroplast

Organelle in plant cells where photosynthesis occurs; contains chlorophyll.

Golgi Body

Organelle that packages and distributes products to their destinations inside or outside the cell.

Lysosome

Organelle containing digestive enzymes to break down waste and food particles.

Mitochondria

Organelle that produces energy through cellular respiration; powerhouse of the cell.

Nucleus

Organelle that houses DNA and controls cellular activities.

Ribosome

Organelle where protein synthesis occurs; can be free-floating or attached to the rough ER.

Vacuole

Membrane-bound storage sac; large central vacuole in plant cells stores water and substances.

Cell (Plasma) Membrane

Phospholipid bilayer that encloses the cell; regulates transport and maintains homeostasis.

Cell Wall

Rigid layer outside the cell membrane in plants (and some bacteria) that provides support and protection.

Cytoplasm

Fluid inside the cell that houses organelles and is the site of many metabolic activities.

Endoplasmic Reticulum (ER)

Membrane system where chemical reactions occur; rough ER has ribosomes for protein synthesis, smooth ER handles lipid production.

Cytoskeleton

Internal framework of the cell providing structure and aiding in movement; includes microfilaments and microtubules.

Prokaryote

Organism whose cells lack a nucleus and membrane-bound organelles (e.g., bacteria).

Eukaryote

Organism whose cells have a defined nucleus and membrane-bound organelles (e.g., plants, animals, fungi, protists).

Cell Theory

The idea that the cell is the basic unit of life; all organisms are made of cells; all cells come from pre-existing cells.

Cell Specialization

Cells develop specific structures and functions for tissues, organs, and organ systems.

Passive Transport

Movement of substances across the membrane without using cell energy (down the concentration gradient). Includes diffusion, osmosis, and facilitated diffusion.

Diffusion

Movement of molecules from an area of high concentration to low concentration across a membrane.

Osmosis

Diffusion of water across a semipermeable membrane from higher to lower water concentration.

Facilitated Diffusion

Movement of substances across a membrane via carrier proteins down a concentration gradient.

Active Transport

Movement of substances across a membrane that requires energy (ATP), often against the concentration gradient.

Endocytosis

Movement of large particles into the cell through vesicle formation.

Exocytosis

Movement of large particles out of the cell via vesicle fusion with the membrane.

Homeostasis

Maintenance of a stable internal environment in cells and organisms.

Negative Feedback

A control mechanism where the output reduces the original stimulus (e.g., glucose/insulin balance).

Positive Feedback

A control mechanism where the output enhances the original stimulus (e.g., blood clotting).

Cellular Respiration

Process of converting glucose into usable energy (ATP); glycolysis (anaerobic) → Krebs cycle and electron transport chain (aerobic).

Glycolysis

First stage of cellular respiration; glucose is split into pyruvate in the cytoplasm; produces a small amount of ATP and NADH; anaerobic.

Citric Acid Cycle (Krebs)

Second stage of cellular respiration; occurs in mitochondria; completes glucose oxidation; CO2 is released and NADH/FADH2 are produced.

Electron Transport Chain (ETC)

Final stage of cellular respiration; uses NADH and FADH2 to drive ATP production via oxidative phosphorylation.

Fermentation

Anaerobic energy production; lactate fermentation (muscle) or alcoholic fermentation (yeast) producing limited ATP.

Photosynthesis

Process by which plants convert light energy into chemical energy (glucose) using CO2 and water; releases O2.

ATP

Adenosine triphosphate; the energy currency of the cell; energy stored in and released from phosphate bonds.

ADP

Adenosine diphosphate; formed when ATP releases a phosphate and energy; can be recharged to ATP.

Enzyme

Protein that acts as a catalyst to speed up biochemical reactions; affected by pH, temperature, and concentration.

Substrate

Molecule that an enzyme acts upon at its active site.

DNA Replication

Process of producing an exact copy of DNA before cell division; semi-conservative.

Transcription

Synthesis of mRNA from a DNA template in the nucleus.

Translation

Synthesis of a protein from mRNA at the ribosome using tRNA to bring amino acids.

Gene

A basic unit of heredity that codes for a trait; located on chromosomes.

Allele

Variant form of a gene.

Genotype

Genetic makeup; the specific combination of alleles an organism has.

Phenotype

Observable traits of an organism resulting from the genotype and environment.

Homozygous

Two identical alleles for a gene (e.g., BB or bb).

Heterozygous

Two different alleles for a gene (e.g., Bb).

Dominant

Allele that is expressed when present; typically capitalized.

Recessive

Allele that is masked by a dominant allele; expressed only when both copies are present.

Punnett Square

A diagram used to predict the genotypes and phenotypes of offspring from a cross.

Pedigree

A family tree chart used to track the inheritance of traits across generations.

Karyotype

A visual representation of an organism’s chromosomes to study number and structure; reveals sex and abnormalities.

Test Cross

Cross between an individual with unknown genotype and a homozygous recessive individual to determine the unknown genotype.

Mutation

Change in the genetic code; may be spontaneous or induced; can be genetic variation or cause disease.

Genomics

Study of whole genomes, including gene structure, function, and interactions; used in biotechnology.

Human Genome Project

Large-scale project to map and understand all human genes and their functions.

Biotechnology

Use of living systems and organisms to develop or make products (e.g., recombinant DNA, insulin production).

Natural Selection

Darwin’s mechanism by which individuals with favorable traits survive and reproduce, passing traits to offspring.

Evolution

Change in the genetic makeup of populations over generations; can lead to new species (macroevolution) or changes within a species (microevolution).

Microevolution

Small-scale evolutionary changes within a population, often due to natural selection or genetic drift.

Macroevolution

Large-scale evolutionary changes that can lead to the formation of new species.

Speciation

Formation of new species through reproductive isolation and genetic divergence.

Fossil Record

Historically preserved remains or traces of organisms used to infer evolutionary history.

Embryology

Study of embryo development; similar embryonic stages suggest shared ancestry.

Taxonomy

Science of naming and classifying organisms based on relationships.

Binomial Nomenclature

Two-name naming system for species: genus and species (e.g., Homo sapiens).

Kingdoms

Six primary biological kingdoms: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia.

Dichotomous Key

A step-by-step tool that identifies organisms by choosing between two contrasting traits at each step.

Prokaryote vs Eukaryote

Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have a nucleus and organelles.

Virus

Non-living infectious agents made of nucleic acid enclosed in a protein coat; replicate only inside host cells; lytic and lysogenic cycles.

Lytic Cycle

Viral replication cycle that leads to host cell lysis and release of new viruses.

Lysogenic Cycle

Viral DNA integrates into the host genome and may replicate with it before entering the lytic cycle.

Immune System

Body’s defense against infection; includes barriers, innate responses, and adaptive immunity.

Antibiotic Resistance

Ability of bacteria to survive exposure to antibiotics; driven by mutations and gene transfer; a major public health concern.

Antibiotics

Drugs that target bacteria and treat bacterial infections; resistance threatens effectiveness.

Immunization

Stimulating immunity through vaccination (active) or receiving antibodies (passive).

Lymphatic System

Part of immune system; transports lymph, filters pathogens, and supports immune responses.

Carrying Capacity

Maximum population size that an environment can sustain indefinitely.

Food Chain

Sequence of organisms through which energy and nutrients flow, from producers to top consumers.

Food Web

Complex network of interconnected food chains showing all feeding relationships in a community.

Ecological Pyramid

Graphical representation of energy or matter transfer across trophic levels (energy, biomass, or numbers).

Symbiosis

Close and long-term biological interaction between two different species.

Mutualism

Symbiotic relationship where both species benefit.

Commensalism

Symbiotic relationship where one species benefits and the other is unaffected.

Parasitism

Symbiotic relationship where one species benefits at the expense of the other.

Biome

A large ecological area with distinct climate and communities (e.g., tundra, rainforest, desert, coral reef).

Succession

Gradual change in species composition of a community over time; primary occurs on barren land, secondary after disturbance.

Geotropism

Growth response to gravity; roots show positive geotropism, stems negative.

Phototropism

Growth response to light; helps plants optimize light capture.

Hydrotropism

Growth response to water gradients (roots grow toward water).

Thigmotropism

Growth response to touch (e.g., vines curling around supports).

Chemotropism

Growth response to chemical stimuli.