Introduction to Biology for Veterinary Technicians: Key Terms

Comprehensive practice flashcards featuring essential veterinary biology, biochemistry, genetics, evolution, microbiology, and organ system terminology based directly on lecture notes.

Biological Hierarchy

A method of organizing living things based on emergent properties, from smallest to largest: atom → molecule → cell → tissue → organ → organism → population → ecosystem → biosphere

Emergent Properties

New properties that appear at each level of biological hierarchy due to increasing complexity

Deductive Reasoning

Using general principles or broad observations to predict specific outcomes or make specific conclusions

Inductive Reasoning

Taking specific observations and drawing broader conclusions or general principles from them

Scientific Method

An organized process for solving problems including: making observations, asking questions, forming hypotheses, making predictions, designing experiments, collecting data, and drawing conclusions

Systems Biology

The study of organisms and how they interact with their environment and other organisms, focusing on how changes in one part affect others

Primary Literature

Original research articles published by the scientists who carried out and verified the research; first-hand scientific reports

Secondary Literature

Articles that interpret, simplify, and summarize primary literature, such as review articles and clinical summaries

Tertiary Literature

General information sources like textbooks, blogs, and videos that distill information from both primary and secondary literature

Activation Energy

The minimum energy required for a chemical reaction to begin. Clinically, the energy barrier that enzymes lower to make biological reactions occur at body temperature.

Active Site

The specific region on an enzyme where substrate molecules bind and reactions occur. Clinically, the functional area that determines enzyme specificity and activity.

Covalent Bond

A chemical bond where atoms share electrons to achieve stability. Forms the backbone of most biological molecules including proteins, carbohydrates, and DNA.

Induced-Fit Model

A refined enzyme model showing that enzymes slightly change shape to better accommodate their substrates, like a flexible glove fitting a hand.

Lock-and-Key Model

A model describing enzyme specificity where enzymes and substrates fit together precisely, like a key fitting only one lock.

pH

A measure of hydrogen ion concentration ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral. Logarithmic scale.

Denaturation

The process of protein unfolding and losing its natural three-dimensional structure and function due to heat, pH changes, or chemicals.

Essential Amino Acids

Amino acids the body cannot synthesize and must obtain from food. Dogs need 10; cats need 11 including taurine from animal sources.

Fat-Soluble Vitamins

Vitamins A, D, E, and K that dissolve in fat and can be stored in body tissues and liver. Can accumulate to toxic levels unlike water-soluble vitamins.

Glycogen

Polysaccharide that stores energy in animal muscles and liver. Broken down to maintain blood glucose during fasting.

Kilocalorie

Unit of energy measurement used in nutrition; one kilocalorie equals 1,000 calories. Different macromolecules provide different energy amounts.

Triglyceride

Three fatty acids attached to glycerol; the main form of dietary fat and body fat storage.

Water-Soluble Vitamins

B vitamins and vitamin C that cannot be stored in the body; excess amounts are excreted in urine.

Adult Stem Cells

Undifferentiated cells found in mature tissues that can divide and become specific cell types within their tissue of origin. These multipotent cells serve as the body's repair system, maintaining and regenerating tissues throughout an animal's life.

ATP (Adenosine Triphosphate)

The universal energy currency of cells, a molecule that stores and releases energy for cellular work. ATP powers everything from muscle contractions to protein synthesis through its high-energy phosphate bonds.

Autophagy

The cellular housekeeping process where cells digest their own damaged components using lysosomes. This self-cleaning mechanism removes cellular debris and recycles useful materials to maintain cellular health.

Mesenchymal Stem Cells (MSCs)

Adult stem cells found in bone marrow and fat tissue that can differentiate into bone, cartilage, fat, and connective tissue cells. These multipotent cells are the most commonly used in veterinary regenerative medicine.

Active Transport

The movement of substances across cell membranes that requires cellular energy (ATP) to transport materials against their concentration gradient, like pumping water uphill.

Facilitated Diffusion

The passive transport of substances across cell membranes using specific transport proteins, but without requiring cellular energy expenditure.

Homeostasis

The body's ability to maintain stable internal conditions despite external changes, keeping temperature, pH, blood sugar, and other vital parameters within safe ranges.

Hypertonic Solution

A fluid with higher solute concentration than body cells, causing water to move out of cells and potentially causing cell shrinkage.

Hypotonic Solution

A fluid with lower solute concentration than body cells, causing water to move into cells and potentially causing dangerous cell swelling.

Sodium-Potassium Pump

An active transport system that uses cellular energy to maintain proper sodium and potassium concentrations essential for nerve and muscle function.

Taurine

An amino acid essential for feline heart function, vision, and reproduction that cats cannot synthesize adequately and must obtain from diet.

Aerobic Respiration

Cellular respiration that requires oxygen and produces 36-38 ATP molecules per glucose molecule. This efficient process supports sustained healing, normal organ function, and predictable recovery.

Anaerobic Respiration

Cellular respiration without oxygen, producing only 2 ATP molecules and lactic acid. This emergency backup system functions when blood flow is compromised.

Electron Transport Chain

Final stage of aerobic respiration in mitochondria that produces most ATP (about 34 molecules) using oxygen as the final electron acceptor.

Mitosis

Cell division producing two genetically identical diploid daughter cells for growth and repair of body tissues.

Mitotic Index

The percentage of cells actively dividing in a tissue at any given time, varies between tissue types.

Meiosis

Specialized cell division producing four genetically unique haploid gametes for reproduction through two sequential divisions.

Allele

Different versions of the same gene that create variations in traits, like having a gene for coat color that comes in "black" or "brown" versions. Each parent contributes one allele for every trait to their offspring.

Carrier

An animal with one copy of a recessive disease gene who looks normal but can pass the disease gene to offspring. Carriers don't show clinical signs, but are genetically important for breeding decisions.

Codominance

When both versions of a gene express themselves equally at the same time, creating a combined effect rather than one masking the other.

Law of Independent Assortment

Mendel's principle that genes for different traits are inherited separately from each other, creating endless combinations of characteristics in offspring.

Law of Segregation

Mendel's principle that each parent contributes only one gene copy for each trait to their offspring. Gene pairs separate during reproduction, then recombine in new ways.

Phenotype

The observable physical characteristics you can see or measure in an animal, like coat color, size, or behavior. Phenotype results from the interaction of genes with environment.

Antiparallel

DNA strands that run parallel but in opposite directions. The structural arrangement where one strand runs 5' to 3' while the complementary strand runs 3' to 5'.

DNA Polymerase

The enzyme that builds new DNA strands during replication by adding complementary nucleotides. Has proofreading ability to maintain genetic accuracy.

Helicase

The enzyme that unwinds DNA by breaking hydrogen bonds between base pairs. Creates access for DNA replication machinery.

Okazaki Fragments

Short DNA segments synthesized on the lagging strand during replication. Named after the scientists who discovered them.

Semi-Conservative Replication

DNA copying method where each new molecule contains one original and one new strand. Ensures genetic continuity.

Topoisomerase

Enzyme that relieves tension and prevents tangling as DNA unwinds during replication. Maintains DNA structure during copying.

Central Dogma

The fundamental principle describing how genetic information flows in living cells: DNA makes RNA, and RNA makes proteins. This one-way flow of information explains how genetic instructions become functional molecules.

Codon

A three-nucleotide sequence in mRNA that specifies which amino acid to add during protein synthesis or signals when to start or stop making proteins. Each codon is like a three-letter word in the genetic language.

Epigenetic Modifications

Chemical changes that affect gene activity without altering the DNA sequence itself. These modifications can be influenced by environment, diet, stress, and age, affecting which genes are turned on or off.

Frameshift Mutation

A genetic change caused by inserting or deleting nucleotides that shifts how the genetic code is read, usually resulting in completely non-functional proteins. Like skipping a letter in a sentence, it changes everything that follows.

Pharmacogenomics

The study of how genetic variations affect individual responses to medications. This field explains why the same drug dose can be effective in one animal but toxic or ineffective in another.

Transcription

The first step of gene expression where DNA information is copied into RNA in the cell nucleus. This process creates portable copies of genetic instructions that can be safely transported to protein-making sites.

Translation

The second step of gene expression where ribosomes read mRNA sequences and assemble amino acids into proteins. This process converts genetic language into functional molecules that perform cellular work.

Aneuploid

Having an abnormal number of chromosomes, either too many or too few compared to what's normal for that species. This creates an unbalanced genetic situation that usually causes health problems.

Barr Body

An inactivated X chromosome found in female cells. Since females have two X chromosomes, one gets randomly "turned off" in each cell during development.

Penetrance

The likelihood that a gene will actually cause observable symptoms in an animal that carries it. Complete penetrance means the gene always causes the condition.

Adaptive Radiation

When one ancestral species rapidly diversifies into many species, each adapted to different environments or jobs. The evolutionary process where organisms diversify rapidly from an ancestral species into multiple new forms to fill available ecological niches.

Allopatric Speciation

When populations become geographically separated and evolve into different species over time. Speciation that occurs when biological populations are geographically isolated from one another to an extent that prevents genetic interchange.

Analogous Structures

Body parts that have similar functions but evolved independently and have different internal structures, like bird wings and insect wings. Structures that are similar in function but not in evolutionary origin, arising through convergent evolution.

Homologous Structures

Body parts in different species that have the same basic structure because they share a common ancestor, even if they serve different functions now. Structures that are similar due to shared ancestry, regardless of their current function.

Binomial Nomenclature

Two-part scientific naming system using genus and species names, developed by Linnaeus (example: Canis familiaris for domestic dogs).

Taxonomic Levels

The eight hierarchical categories used to classify species: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Antibiotic Resistance

When bacteria develop the ability to survive exposure to antibiotics that would normally kill them or stop their growth

Biofilm

A thin film of bacteria that stick together on surfaces, embedded in a protective slimy matrix; simple definition: a protective slime layer that bacteria form

Gram-negative Bacteria

Bacteria with thin peptidoglycan that stains pink during Gram staining; simple definition: bacteria that turn pink in lab staining tests

Gram-positive Bacteria

Bacteria with thick peptidoglycan that stains purple during Gram staining; simple definition: bacteria that turn purple in lab staining tests

Koch's Postulates

Four principles linking specific microorganisms to specific diseases; simple definition: rules for proving what causes a disease

Zoonotic

Diseases transmissible from animals to humans; simple definition: infections that can spread from animals to people

Active Immunity

When an animal is exposed to an antigen and produces its own antibodies against it

Passive Immunity

When an animal receives ready-made antibodies from another source (like mother's milk); provides immediate but temporary protection

Major Histocompatibility Complex (MHC) / Dog Leukocyte Antigen (DLA)

Glycoproteins on the surface of cells that are unique to each individual; allows the immune system to distinguish self from foreign

Peristalsis

A pattern of muscle contractions creating wave motions that push food through the digestive tract

Action Potential

The electrical signal that travels down a neuron's axon when stimulated above threshold level; the basic unit of nerve communication

Nephrons

Functional units of the kidneys that filter blood and produce urine; dogs have ~400,000 per kidney, cats ~200,000

Resting Potential

The electrical charge difference across a neuron's membrane when not transmitting signals (approximately $-70\,\text{mV}$)