Molecules of Biology and General Biology Comprehensive Flashcards

Comprehensive vocabulary flashcards generated directly from the biology review lecture transcript, systematically covering biomolecules, cell biology, genetics, respiration, photosynthesis, taxonomy, plant physiology, evolution, ecology, human anatomy, and animal behavior.

Isotopes

Atoms of the same element that have different numbers of neutrons but the same number of protons and electrons.

Specific Heat

The amount of heat required to raise the temperature of $1\,g$ of a substance by $1\,^{\circ}\text{C}$.

Adhesion

The clinging of one substance to another, such as water clinging to the vascular walls of plant roots and stems.

Cohesion

The sticking together of particles of the same substance, which creates surface tension and allows continuous upward flow of water in plants.

Dehydration Synthesis

The chemical process of joining two simple molecules together following the removal of a water molecule ($H_2O$).

Hydrolysis

The breakdown of a complex molecule into simpler units by the addition of water, functioning as the reverse of dehydration synthesis.

Saturated Fats

Dietary lipids mainly from animal sources that contain only single bonds in their hydrocarbon chains, making them solid at room temperature.

Unsaturated Fats

Dietary lipids extracted from plants that contain at least one double bond in their hydrocarbon chains and remain liquid at room temperature.

Activation Energy

The minimum amount of energy needed to begin a chemical reaction, which biological catalysts (enzymes) lower to speed up reactions.

Induced Fit Model

The model of enzyme mechanism stating that substrate binding to the active site induces the enzyme to slightly alter its shape for a tighter fit.

pH

A measure of the acidity or alkalinity of a solution, calculated as the negative logarithm of the hydrogen ion concentration in moles per liter.

Buffer

A biological substance, such as the bicarbonate ion ($\text{HCO}_3^-$), that resists changes in pH by absorbing excess hydrogen ions or donating hydrogen ions.

Prion

An infectious misfolded protein normally found in mammal brains that causes other normal proteins to misfold similarly, leading to diseases like mad cow disease.

Prokaryotic Cell

A unicellular cell lacking a nucleus and membrane-bound organelles, containing smaller ribosomes and a circular chromosome.

Eukaryotic Cell

A cell containing a true nucleus enclosed by a double membrane, linear chromosomes, and membrane-bound organelles.

Selective Permeability

The property of the plasma membrane that allows it to regulate the passage of specific substances into and out of the cell regardless of charge or concentration.

Nucleolus

A prominent non-membrane-bound region inside the nucleus where ribosomal RNA (rRNA) and ribosome subunits are synthesized.

Lysosome

A membrane-bound sac containing hydrolytic digestive enzymes responsible for intracellular digestion, breaking down worn-out organelles, and programmed cell death (apoptosis).

Mitochondrion

A double-membrane organelle containing its own DNA and ribosomes that serves as the site of aerobic cellular respiration and ATP synthesis.

Endosymbiosis Theory

The evolutionary theory proposing that eukaryotic organelles like mitochondria and chloroplasts originated as free-living prokaryotes that lived symbiotically inside host cells.

Plasmolysis

The shrinking of a cell's cytoplasm away from its membrane or cell wall due to water loss when placed in a hypertonic solution.

Phagocytosis

A form of active endocytosis in which a cell extends pseudopods to enclose and engulf large particles or microorganisms into a vacuole.

Mitosis

A division of the nucleus in somatic cells that yields two genetically identical daughter cells maintaining the original chromosome number ($2n$).

Meiosis

A two-stage cell division in germ cells that reduces the chromosome count by half ($2n \rightarrow n$), producing four genetically distinct haploid gametes.

Crossing Over

The exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis, introducing genetic variation.

Allele

One of two or more alternative versions or variants of a specific gene inherited from parents.

Genotype

The underlying genetic composition or combination of alleles of an individual organism.

Phenotype

The physical appearance or observable external characteristics expressed by an organism's genotype.

Law of Segregation

Mendel's first law stating that allele pairs separate during gamete formation, ensuring each gamete carries only one allele for each gene.

Law of Independent Assortment

Mendel's law stating that alleles for different traits on non-homologous chromosomes segregate independently of one another during gamete formation.

Test Cross

A genetic cross between an individual showing a dominant phenotype but unknown genotype ($B\_$) and a homozygous recessive individual ($bb$) to determine the unknown genotype.

Incomplete Dominance

A pattern of inheritance where neither allele is completely dominant, producing an intermediate, blended phenotype in heterozygous individuals.

Codominance

A genetic pattern where two different alleles of a gene are fully and simultaneously expressed in the phenotype of a heterozygote.

Sex-Linked Genes

Genes located on sex chromosomes (typically the X chromosome) that exhibit distinct inheritance frequency patterns between males and females.

Linked Genes

Genes located close together on the same chromosome that tend to be inherited together during gamete formation.

Telomeres

Repetitive non-coding nucleotide sequences located at the ends of linear chromosomes that protect essential genetic information from being lost during replication.

Transcription

The synthesis of an mRNA molecule from a DNA gene template catalyzed by RNA polymerase inside the nucleus.

Translation

The ribosome-mediated process in which an mRNA nucleotide sequence is decoded into a specific amino acid sequence to construct a polypeptide chain.

Operon

A functional unit of bacterial DNA containing structural genes and regulatory elements (promoter and operator) that control collective gene expression.

Missense Mutation

A point substitution mutation in which a single base change converts a codon to code for a different amino acid.

Nonsense Mutation

A point mutation that converts an amino acid-coding codon into a premature stop codon, terminating translation early.

Nondisjunction

An error during meiotic anaphase where homologous chromosomes or sister chromatids fail to separate properly, causing aneuploidy.

Gel Electrophoresis

A laboratory technique using an electric current to separate charged DNA fragments through an agarose gel matrix according to their size.

Polymerase Chain Reaction (PCR)

An in vitro technique used to rapidly amplify and generate billions of copies of a targeted DNA segment.

Glycolysis

The anaerobic metabolic breakdown of one glucose molecule ($C_6H_{12}O_6$) into two pyruvate molecules in the cytoplasm, producing a net gain of $2\,\text{ATP}$.

Chemiosmosis

The movement of protons across a membrane down their electrochemical gradient to drive the synthesis of ATP by ATP synthase.

Calvin Cycle

The light-independent pathway of photosynthesis occurring in the stroma, where carbon dioxide is fixed into sugar molecules using ATP and NADPH.

Binomial Nomenclature

The system of naming species introduced by Carolus Linnaeus using a two-part scientific name comprising the capitalized genus and lowercase species.

Extremophiles

Microorganisms belonging to Domain Archaea that live in extreme environments, including methanogens, halophiles, and thermophiles.

Cnidocytes

Specialized stinging cells unique to Phylum Cnidaria that contain barbed, venomous organelle structures called nematocysts.

Hermaphrodite

An organism possessing both functional male (testis) and female (ovary) reproductive structures.

Bacteriophage

A specialized virus that infects and replicates exclusively within bacterial cells.

Retrovirus

An RNA virus that utilizes the enzyme reverse transcriptase to synthesize a DNA copy of its viral genome to integrate into the host genome.

Xylem

Vascular plant tissue made of dead cells (tracheids and vessel elements) that conducts water and minerals upward from roots to leaves without energy consumption.

Phloem

Living vascular plant tissue (sieve tube elements and companion cells) that transports organic nutrients like sugars throughout the plant by translocation.

Stomata

Microscopic pores on leaf surfaces regulated by guard cells that permit gas exchange ($CO_2$ and $O_2$) and control water loss through transpiration.

Double Fertilization

An angiosperm reproductive process where one sperm nucleus fertilizes the egg ($2n$ zygote) and another fuses with two polar nuclei ($3n$ endosperm).

Phototropism

Plant growth movement in response to light, directed by the accumulation of auxin hormones on the shaded side of shoots and roots.

Bottleneck Effect

A severe reduction in population size and gene pool diversity resulting from a random catastrophic event or natural disaster.

Founder Effect

A form of genetic drift occurring when a small founding population colonizes a new habitat, establishing gene frequencies different from the original population.

Homologous Structures

Anatomical parts in different species that share common evolutionary and structural origins despite having different functions, demonstrating divergent evolution.

Analogous Structures

Anatomical traits in distinct species that perform similar functions but evolved independently without common ancestral origin, demonstrating convergent evolution.

Hardy-Weinberg Equilibrium

A model stating that allele and genotype frequencies in a large, isolated, randomly mating population remain constant over generations without evolutionary forces.

Carrying Capacity

The maximum population size of a species that a specific environment can sustainably support based on available limiting resources.

r-Strategists

Species that reproduce rapidly in uncrowded habitats, producing large quantities of small offspring with minimal parental investment.

K-Strategists

Species that optimize population density around carrying capacity, producing few, large offspring with extensive parental care.

Batesian Mimicry

An evolutionary defense mechanism in which a harmless, edible organism mimics the conspicuous warning coloration of a toxic or dangerous species.

Mullerian Mimicry

An evolutionary convergence where two or more unpalatable or poisonous species share similar warning coloration patterns.

Biological Magnification

The process by which non-degradable toxic substances accumulate in increasingly higher concentrations at successive trophic levels of a food web.

Primary Succession

Ecological succession starting in a completely barren environment devoid of intact soil, initiated by pioneer organisms like lichens on bare rock.

Eutrophication

An ecological process where nutrient runoff stimulates algal blooms, blocking light and causing severe oxygen depletion as decomposers break down dead organic matter.

Parthenogenesis

An asexual reproductive process where an unfertilized egg develops into a complete, viable offspring.

Peristalsis

Rhythmic waves of involuntary smooth muscle contractions that move material sequentially along the alimentary canal.

Villi

Microscopic finger-like projections along the inner lining of the small intestine that maximize surface area for nutrient absorption into blood capillaries and lacteals.

Alveoli

Microscopic, thin-walled, moist air sacs in lungs where gas exchange ($O_2$ and $CO_2$) occurs by simple diffusion with surrounding capillaries.

Erythrocytes

Biconcave red blood cells lacking a nucleus that contain hemoglobin to transport oxygen from lungs to body tissues.

Nephron

The functional microscopic unit of the kidney consisting of the glomerulus, Bowman's capsule, tubules, and loop of Henle that filters blood to form urine.

Antidiuretic Hormone (ADH)

A hormone released by the posterior pituitary that promotes water reabsorption in renal collecting tubules to decrease urine output and regulate blood pressure.

Vasodilation

The widening of dermal blood vessels to increase blood flow near the skin surface, promoting evaporative and radiant heat loss during thermoregulation.

Homeostasis

The maintenance of a dynamic, stable internal physiological environment within an organism despite fluctuating external conditions.

Reflex Arc

An automatic, rapid neural reflex circuit consisting of a receptor, sensory neuron, interneuron, motor neuron, and effector organ.

Action Potential

A self-propagating wave of voltage reversal along an axon caused by sequential opening of voltage-gated sodium and potassium channels.

Sarcomere

The basic functional contractile unit of striated muscle cells composed of organized overlapping actin and myosin filaments.

Histamine

An inflammatory chemical released by damaged tissues that induces vasodilation and increased capillary permeability during a second-line immune response.

Active Immunity

Long-term immune protection acquired when an individual's immune system produces its own memory B/T cells and antibodies in response to antigen exposure or vaccination.

Fixed Action Pattern (FAP)

An innate, unlearned sequence of behaviors initiated by a specific external sign stimulus that continues to completion once triggered.

Habituation

A simple form of learned behavior where an animal decreases or ceases its response to a harmless, repeated stimulus over time.

Altruism

An unselfish social behavior that reduces an individual animal's personal reproductive fitness while increasing the fitness and survival of related group members.