1306 Biology Vocab

Adaptation

A characteristic or trait that enhances an organism’s ability to survive and reproduce in a specific environment.

Alimentary canal

The continuous, tube-like digestive tract extending from the mouth to the anus, through which food is processed and nutrients are absorbed.

Apical membrane

The surface of an epithelial cell facing the lumen or external environment, involved in nutrient and substance exchange.

Basolateral membrane

The sides of an epithelial cell that face away from the lumen and are in contact with the bloodstream or connective tissue.

Cholecystokinin (CCK)

A hormone released by the small intestine that stimulates the digestion of fats and proteins by promoting bile and pancreatic enzyme secretion.

Co-transport

The simultaneous transport of two substances across a membrane in the same direction by a single transporter protein.

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

Digestion

The chemical and mechanical breakdown of food into smaller molecules that can be absorbed and utilized by the body.

Duodenum

The first section of the small intestine where most chemical digestion occurs.

Epithelium

A layer of cells that covers body surfaces or lines internal cavities, often involved in protection, absorption, or secretion.

Facilitated diffusion

The passive movement of molecules across a membrane via a specific carrier or channel protein.

Gastrin

A hormone produced by the stomach that stimulates the secretion of gastric acid for digestion.

Gastrovascular cavity

A simple digestive cavity in certain animals (e.g., cnidarians) that functions in both digestion and circulation.

Helicobacter pylori

A bacterium that can infect the stomach lining and is a common cause of ulcers.

Hydrolysis

A chemical reaction that breaks bonds in molecules by the addition of water, often involved in digestion.

Hyperosmotic

A solution with a higher concentration of solutes compared to another solution, leading to water moving into the hyperosmotic solution.

Hypoosmotic

A solution with a lower concentration of solutes compared to another solution, leading to water moving out of the hypoosmotic solution.

Ileum

The final section of the small intestine, primarily responsible for absorbing vitamin B12, bile salts, and remaining nutrients.

Ingestion

The act of taking food or other substances into the body via the mouth.

Integral/transmembrane protein

A protein that spans the entire membrane of a cell, involved in transporting substances or cell signaling.

Isosmotic

Two solutions having the same osmotic pressure, with no net movement of water between them.

Jejunum

The middle section of the small intestine where most nutrient absorption occurs.

Lipid

A group of hydrophobic organic molecules, including fats, oils, and phospholipids, that store energy and form cell membranes.

Microvilli

Tiny, finger-like projections on the surface of epithelial cells that increase surface area for absorption.

Osmosis

The movement of water across a semi-permeable membrane from a region of low solute concentration to high solute concentration.

Pepsin

An enzyme produced in the stomach that breaks down proteins into smaller peptides.

Peristalsis

The rhythmic contractions of smooth muscles in the alimentary canal that move food through the digestive tract.

Phagocytosis

The process by which a cell engulfs large particles or microorganisms to digest them.

Saturated fatty acid

A type of fatty acid with no double bonds between carbon atoms, usually solid at room temperature.

Secretin

A hormone released by the small intestine that stimulates the pancreas to release bicarbonate to neutralize stomach acid.

Selective permeability

The ability of a cell membrane to allow certain molecules to pass while blocking others.

Tight junction

A connection between neighboring epithelial cells that forms a barrier to prevent the leakage of substances between cells.

Unsaturated fatty acid

A fatty acid with one or more double bonds between carbon atoms, usually liquid at room temperature.

Villi

Finger-like projections lining the small intestine that increase surface area for nutrient absorption.

Channel protein

A protein that forms a pore in the cell membrane, allowing specific molecules or ions to pass through by diffusion.

Carrier protein

A membrane protein that binds and transports specific substances across the cell membrane.

Cholesterol

A lipid molecule that stabilizes cell membranes and is a precursor for steroid hormones.

Dehydration

The loss of water from the body or from a molecule, often resulting in reduced physiological function.

Ester linkage

The bond formed between a glycerol molecule and fatty acids during the formation of fats (triglycerides).

Osmolarity

The concentration of solute particles in a solution, influencing the movement of water.

Phospholipid

A lipid with a hydrophilic phosphate head and hydrophobic fatty acid tails, forming the bilayer of cell membranes.

Prokaryote

A simple, unicellular organism without a membrane-bound nucleus, such as bacteria.

Eukaryote

An organism made up of cells that have a membrane-bound nucleus and organelles, including animals, plants, fungi, and protists.

Plasmid

A small, circular DNA molecule in bacteria that can replicate independently and often carries genes for antibiotic resistance.

Endocytosis

The process by which cells engulf extracellular material into vesicles to bring it inside the cell.

Peptide bond

The covalent bond formed between two amino acids during protein synthesis.

Primary structure

The linear sequence of amino acids in a protein, determined by the gene encoding it.

Secondary structure

The local folding of a protein into alpha-helices or beta-sheets stabilized by hydrogen bonds.

Tertiary structure

The overall three-dimensional shape of a protein formed by interactions between side chains (R-groups) of amino acids.

Nucleotide

The building block of nucleic acids (DNA and RNA), consisting of a sugar, phosphate group, and nitrogenous base.

Phosphodiester bond

The covalent bond that links nucleotides together in the sugar-phosphate backbone of nucleic acids.

Microfilaments

Thin protein fibers, primarily made of actin, that provide structural support and enable movement in cells.

Microtubules

Hollow tubes made of tubulin proteins that provide structural support and are involved in cell division and transport.

Intermediate filaments

Rope-like protein fibers that provide mechanical support to cells and maintain their shape.

Lysosomes

Membrane-bound organelles containing enzymes that break down waste materials and cellular debris.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for transport or secretion.

Endoplasmic reticulum (ER)

A network of membranes involved in protein and lipid synthesis, with rough ER having ribosomes and smooth ER lacking them.

Exocytosis

The process by which cells release substances (e.g., proteins, neurotransmitters) to the extracellular environment through vesicles.