Cell Biology, Carbon Chemistry, Large Biological Molecules, and Water Flashcards

A complete set of vocabulary flashcards covering cell structure and organelles, carbon chemistry and functional groups, large biological macromolecules, and physical/chemical properties of water.

Light Microscope (LM)

A microscope that uses visible light passed through a specimen and glass lenses to magnify images up to about 1,000 times the actual size of a specimen.

Cell Fractionation

A cellular research technique where cells are broken up (homogenization) and spun in a centrifuge (differential centrifugation) to separate cellular components by size and density for individual study.

Prokaryotic Cell

A simple cell lacking a true nucleus and membrane-enclosed organelles, with its genetic material located in an unenclosed region called the nucleoid.

Eukaryotic Cell

A complex cell containing a double-membrane-enclosed nucleus housing its DNA, along with various membrane-bound organelles operating in compartmentalized functions.

Animal Cell

A generalized eukaryotic cell characterized by organelles such as lysosomes, peroxisomes, mitochondria, a complex endomembrane system, and a centrosome with centrioles, while lacking a cell wall or chloroplasts.

Plant Cell

A generalized eukaryotic cell characterized by a rigid outer cell wall made of cellulose, chloroplasts for photosynthesis, plasmodesmata, and a prominent central vacuole.

Nucleolus

A dense, nonmembranous structure located within the nucleus that functions as the site of ribosomal RNA (rRNA) synthesis and ribosome subunit assembly.

Chromatin

The cellular material consisting of DNA and associated proteins that condenses to form individual chromosomes during eukaryotic cell division.

Smooth Endoplasmic Reticulum (Smooth ER)

The region of the endoplasmic reticulum that lacks ribosomes; functions in lipid synthesis, drug and poison detoxification, carbohydrate metabolism, and calcium ion storage.

Rough Endoplasmic Reticulum (Rough ER)

The region of the endoplasmic reticulum studded with ribosomes; functions in synthesizing proteins (especially glycoproteins), packaging them into transport vesicles, and expanding cell membranes.

Golgi Apparatus

An organelle composed of stacks of flattened membranous sacs (cisternae) that modifies, manufactures, sorts, and packages ER products into transport vesicles for secretion or delivery.

Lysosome

A membranous sac of acidic hydrolases that functions as the primary recycling center of eukaryotic cells, digesting macromolecules, damaged organelles (autophagy), and engulfed food particles (phagocytosis).

Peroxisome

A single-membrane metabolic organelle containing oxidases and catalase that transfers hydrogen to oxygen to form hydrogen peroxide ($H_2O_2$), which is subsequently converted to water while detoxifying harmful compounds and breaking down fatty acids.

Endosymbiont Theory

The evolutionary theory stating that mitochondria and chloroplasts originated as independent prokaryotic cells that were engulfed by an ancestral eukaryotic host cell.

Microtubules

The thickest cytoskeletal fibers, constructed as hollow tubes made of tubulin, which maintain cell shape, guide organelle movement, separate chromosomes during division, and form cilia and flagella.

Microfilaments

The thinnest cytoskeletal elements, composed of twisted double chains of actin, which function in cell shape maintenance, muscle contraction, cytoplasmic streaming, and cell motility.

Intermediate Filaments

Fibrous protein cytoskeletal elements with intermediate diameters that provide permanent structural support, maintain cell shape, anchor organelles, and construct the nuclear lamina.

Plasmodesmata

Cytoplasmic channels passing through plant cell walls that connect the cytoplasms of adjacent cells, permitting passage of water, small solutes, and certain proteins or RNA.

Tight Junctions

Animal cell junctions where adjacent plasma membranes are pressed tightly together by specific proteins to form a continuous seal preventing extracellular fluid leakage.

Desmosomes

Anchoring cell junctions in animal tissues that fasten cells together into strong sheets, supported by intermediate filaments.

Gap Junctions

Communicating junctions in animal cells that provide cytoplasmic channels between neighboring cells for exchanging ions, sugars, and small molecules.

Hydrocarbons

Organic molecules composed exclusively of carbon and hydrogen atoms, which are nonpolar, hydrophobic, and store substantial chemical potential energy.

Structural Isomers

Isomers that have identical molecular formulas but differ in the covalent arrangement of their carbon skeletons and chemical bonds.

Cis-Trans Isomers

Isomers that differ in spatial arrangement around an inflexible double bond, where cis configuration has attached groups on the same side and trans has them on opposite sides.

Enantiomers

Isomers that are non-superimposable mirror images of one another due to an asymmetric carbon atom bonded to four different groups.

Adenosine Triphosphate (ATP)

An organic molecule consisting of adenosine attached to three phosphate groups, which stores potential energy and serves as the primary energy currency in cells.

Dehydration Reaction

A chemical reaction in which two monomers become covalently bonded to each other with the simultaneous elimination of a water molecule ($H_2O$).

Hydrolysis

A chemical process that breaks covalent bonds between monomers in a polymer through the addition of a water molecule ($H_2O$).

Glycosidic Linkage

A covalent bond formed between two monosaccharides through a dehydration reaction.

Starch

A storage polysaccharide in plants consisting entirely of glucose monomers linked together in unbranched (amylose) or branched (amylopectin) forms.

Glycogen

An extensively branched storage polysaccharide of glucose found in animal liver and muscle cells.

Cellulose

A structural polysaccharide composed of glucose monomers joined by $\beta$ glycosidic linkages, serving as the main structural component of plant cell walls.

Chitin

A structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi.

Peptide Bond

The covalent bond formed between the carboxyl group of one amino acid and the amino group of another via a dehydration reaction.

Primary Structure

The unique, linear sequence of amino acids in a polypeptide chain, encoded by genetic material.

Secondary Structure

The localized repetitive coiling (\text{\beta} pleated sheet or \text{\text{\textalpha}} helix) of a polypeptide chain stabilized by hydrogen bonds along the polypeptide backbone.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain formed by interactions among side chains (R groups), including ionic bonds, hydrogen bonds, hydrophobic interactions, van der Waals forces, and disulfide bridges.

Quaternary Structure

The overall functional protein structure that results from the aggregation of two or more individual polypeptide subunits.

Amino Acid Side Chains

Variable chemical groups (R groups) attached to the central carbon of amino acids that determine their nonpolar (hydrophobic), polar (hydrophilic), or charged (acidic/basic) properties.

Gene Expression

The process by which genetic information directs protein synthesis via transcription of DNA into messenger RNA (mRNA) in the nucleus, followed by mRNA translation into a polypeptide in the cytoplasm ($\text{DNA} \rightarrow \text{RNA} \rightarrow \text{protein}$).

Nucleotide

The monomer subunit of nucleic acids, consisting of a pentose sugar (ribose or deoxyribose), a nitrogenous base (purine or pyrimidine), and one or more phosphate groups.

Pyrimidines

A class of nitrogenous bases characterized by a single six-membered ring structure, comprising cytosine (C), thymine (T), and uracil (U).

Purines

A class of nitrogenous bases characterized by a six-membered ring fused to a five-membered ring, comprising adenine (A) and guanine (G).

Phosphodiester Bond

The covalent linkage joining the $3'$ hydroxyl group of one nucleotide pentose sugar to the $5'$ phosphate group of the adjacent nucleotide in a polynucleotide chain.

Triacylglycerol

A fat molecule formed by linking three fatty acids to one glycerol backbone through ester linkages via dehydration reactions.

Phospholipid

An amphipathic lipid made of two hydrophobic fatty acid tails attached to a glycerol molecule with a hydrophilic phosphate head group, forming biological membrane bilayers.

Steroids

Lipids characterized by a carbon skeleton consisting of four fused carbon rings, such as cholesterol and steroid hormones.

Cohesion

The binding together of like molecules, such as water molecules sticking together via hydrogen bonds to generate high surface tension and drive upward transport in plants.

Adhesion

The attraction between different types of substances, such as water adhering to plant cell walls to resist gravity during water transport.

Specific Heat

The amount of heat that must be absorbed or lost for $1\text{ g}$ of a substance to change its temperature by $1^\text{o}\text{C}$; water possesses an unusually high specific heat of $1\text{ cal/g}^\text{o}\text{C}$.

Evaporative Cooling

The phenomenon where the surface of a liquid cools down during evaporation because the molecules with the highest kinetic energy escape into the gas phase.

Hydration Shell

The organized sphere of water molecules that surrounds and isolates individual dissolved ions in an aqueous solution.

Molarity

A standard measure of solute concentration in aqueous solution, defined as the number of moles of solute per liter of solution.

pH

A logarithmic scale measuring hydrogen ion concentration in an aqueous solution, defined mathematically as $\text{pH} = -\text{log}[\text{H}^+]$.

Buffer

A chemical substance or system that resists drastic changes in pH by accepting hydrogen ions ($\text{H}^+$) when excess acid is present and donating hydrogen ions when depleted.

Ocean Acidification

The ongoing decrease in seawater pH caused by the absorption of excess atmospheric carbon dioxide ($\text{CO}_2$), which forms carbonic acid ($\text{H}_2\text{CO}_3$) and depletes carbonate ions ($\text{CO}_3^{2-}$) required by calcifying marine organisms.