Study of Life and Cellular Biology Flashcards

A complete set of vocabulary flashcards reviewing the scientific method, biomolecules, cell structures and organelles, transport mechanisms, and neuron action potentials.

Independent Variable

The variable that is intentionally manipulated in an experiment, plotted on the x-axis.

Dependent Variable

The variable that changes in response to the independent variable, plotted on the y-axis.

Controlled Variable

The constant conditions or baseline kept unchanged throughout an experiment.

Replicates

Multiple individual units or subjects tested within each independent variable group to ensure reliability.

Polar Molecule

A molecule, such as $\text{H}_2\text{O}$, with partial positive and partial negative regions that forms hydrogen bonds and dissolves charged or polarized substances.

Hypothesis

A proposed explanation and set of predictions in the scientific method that must be testable and falsifiable.

Observational Research

A scientific study conducted on existing situations with $0\%$ variable manipulation.

Controlled Experiment

A scientific study where variables are actively manipulated to observe relationships and test hypotheses.

Spurious Correlation

A mathematical relationship in which two or more events or variables are associated but not causally related.

Confounding Variable

An unconsidered variable that influences both the independent and dependent variables, potentially skewing experimental results.

Dehydration Synthesis

A polymerization reaction where monomers connect to form polymers with the release of a molecule of $\text{H}_2\text{O}$.

Hydrolysis

A reaction that breaks polymers into monomers through the addition of $\text{H}_2\text{O}$, where one part gains $\text{H}^+$ and another gains $\text{OH}^-$.

Monosaccharide

A simple sugar monomer with the formula structure $\text{C}_n\text{H}_{2n}\text{O}_n$ (containing $3$ to $7$ carbon atoms) that can form structural isomers.

Disaccharide

A carbohydrate consisting of two monosaccharides joined by a glycosidic bond formed via dehydration synthesis.

Polysaccharide

A long carbohydrate polymer made of many monosaccharides bonded together.

Lipid

A hydrophobic macromolecule consisting of glycerol and fatty acid chains (typically containing $4$ to $36$ carbon atoms).

Phospholipid Bilayer

A double layer of phospholipids forming the plasma membrane, with hydrophilic polar heads on the exterior and hydrophobic nonpolar tails in the interior.

Denaturation

The process in which environmental changes alter a protein's natural structure, causing it to lose its biological function.

Enzyme

A biological protein catalyst that speeds up chemical reactions by binding to specific substrates at its active site.

Primary Protein Structure

The unique linear sequence of amino acids linked together in a polypeptide chain.

Secondary Protein Structure

Local folding patterns, such as alpha-helices or beta-sheets, created by hydrogen bonding within a polypeptide chain.

Tertiary Protein Structure

The overall three-dimensional shape of a single polypeptide chain.

Quaternary Protein Structure

The protein structure resulting from the association of multiple polypeptide subunits.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid carrying genetic material held with histone proteins to form chromatin/chromosomes, composed of GCAT nucleotides.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid containing adenine, uracil, cytosine, and guanine that functions in cellular communication and protein synthesis.

Messenger RNA (mRNA)

The RNA molecule that carries transcribed genetic messages from DNA to ribosomes for translation.

Ribosomal RNA (rRNA)

The structural RNA component of ribosomes to which mRNA binds during protein synthesis.

Transfer RNA (tRNA)

The RNA type that transfers specific amino acids to the site of protein synthesis on the ribosome.

MicroRNA

A class of small non-coding RNA molecules that function in the regulation of gene expression.

Anabolic Process

A metabolic process that consumes energy to construct complex polymers from simpler monomeric units.

Catabolic Process

A metabolic process that releases energy by breaking down complex polymers into simpler monomers.

Starch and Glycogen

Storage polysaccharides with easily broken glucose bonds that serve as energy reserves in plant and animal cells.

Cellulose

A structural polysaccharide with difficult-to-break glucose bonds that forms the cell wall in plant cells.

Chitin

A structural polysaccharide that forms the tough exoskeleton of arthropods.

Cytosol

The fluid, water-based portion of the cytoplasm in which cellular organelles are suspended.

Cytoskeleton

A network of protein fibers in the cytoplasm providing structural support, cell shape, and movement direction.

Prokaryotic Cell

A unicellular organism lacking a membrane-bound nucleus or membrane-bound organelles, typically significantly smaller than eukaryotic cells.

Eukaryotic Cell

A cell containing a membrane-bound nucleus housing DNA and various specialized membrane-bound organelles.

Mitochondria

Membrane-bound organelles where cellular respiration takes place to synthesize cellular energy in the form of $\text{ATP}$.

Ribosome

A cellular structure composed of $\text{rRNA}$ and proteins that synthesizes proteins by linking amino acids.

Smooth Endoplasmic Reticulum

An organelle lacking ribosomes that synthesizes lipids and carbohydrates, detoxifies toxins, and stores calcium ions.

Golgi Apparatus

A membrane-bound organelle that further modifies, sorts, and tags proteins and lipids for transport to their final destinations.

Lysosome

An animal-cell-specific organelle containing digestive enzymes to break down and recycle cellular waste, threats, and dysfunctional organelles.

Chloroplast

A plant-cell-specific organelle possessing its own $\text{DNA}$ and ribosomes that carries out photosynthesis.

Vacuole

The largest organelle in plant cells that stores water and contracts or expands to regulate turgor pressure.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts originated as prokaryotic cells that were engulfed by ancestral eukaryotic cells.

Selective Permeability

The characteristic of plasma membranes allowing small, nonpolar hydrophobic molecules and gases to cross while restricting polar, large, or charged ions.

Passive Transport

The movement of molecules across a cell membrane from high to low concentration along their concentration gradient without requiring $\text{ATP}$.

Active Transport

The movement of molecules across a membrane against their concentration gradient (from low to high concentration) requiring cellular energy ($\text{ATP}$).

Simple Diffusion

A form of passive transport where unassisted particles move directly through the lipid bilayer down their concentration gradient.

Facilitated Diffusion

Passive transport of substances across a membrane down their gradient with the assistance of channel or carrier transport proteins.

Aquaporins

Specialized channel proteins that facilitate the rapid diffusion of water molecules across plasma membranes.

Osmosis

The diffusion of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Hypotonic Solution

A solution with a lower solute concentration than the inside of a cell, causing water to rush in, swelling the cell and potentially causing lysis.

Isotonic Solution

A solution with an equal solute concentration compared to the cell cytoplasm, resulting in net equal water movement across the membrane.

Hypertonic Solution

A solution with a higher solute concentration than the inside of a cell, causing water to leave the cell and leading to cellular shriveling.

Exocytosis

A bulk transport process in which vesicles fuse with the plasma membrane to release large amounts of waste or products outside the cell.

Endocytosis

A bulk transport process where cells engulf external substances by invaginating the plasma membrane to bring materials inside.

Dendrites

Branch-like extensions of a neuron that receive incoming chemical and electrical signals from other cells.

Myelin Sheath

An insulating layer formed around nerve axons that enables rapid saltatory conduction of electrical impulses between nodes of Ranvier.

Nodes of Ranvier

Unmyelinated gaps along a myelinated axon where voltage-gated ion channels regenerate the action potential during saltatory conduction.

Resting Potential

The electrical charge difference across a neuron membrane at rest (approximately $-70\,\text{mV}$), maintained actively by the $\text{Na}^+/\text{K}^+$ pump.

Depolarization

The phase of an action potential where voltage-gated $\text{Na}^+$ channels open, allowing $\text{Na}^+$ ions to rush inside, making the membrane potential more positive.

Repolarization

The phase of an action potential where $\text{Na}^+$ channels close and delayed $\text{K}^+$ channels open, allowing $\text{K}^+$ to exit and restore negative potential.

Astrocytes

Glial cells in the central nervous system that contact capillaries and neurons to provide nutrients, structural support for synapses, and block pathogens.

Satellite Glia

Glial cells that provide nutritional and structural support to neurons in the peripheral nervous system.

Microglia

Central nervous system glial cells that scavenge, ingest, and degrade dead cells and cellular debris.

Schwann Cells

Glial cells in the peripheral nervous system responsible for forming the myelin sheath around neuronal axons.

Neurogenesis

The process of forming new neurons, which continues into adulthood.

Fluid Mosaic Model

The structural model of cell membranes describing a dynamic bilayer of phospholipids with embedded proteins, glycoproteins, glycolipids, and cholesterol.

Cell Organelles Diagram

A visual comparison between animal cells (containing lysosomes) and plant cells (containing chloroplasts, cell walls, and large vacuoles).