Chemical and Cellular Levels of Organization

Comprehensive set of vocabulary flashcards covering chemical organization, inorganic and organic compounds, cellular structures, organelles, membrane transport, and cell division based on the provided lecture notes.

Matter

Anything that occupies space and has mass.

Elements

Pure substances that cannot be broken down into simpler substances by ordinary chemical means.

Major Elements in the Body

Oxygen ($\text{O}$), Carbon ($\text{C}$), Hydrogen ($\text{H}$), and Nitrogen ($\text{N}$), which make up about $96\%$ of total body mass.

Lesser Elements in the Body

Calcium ($\text{Ca}$), Phosphorus ($\text{P}$), Potassium ($\text{K}$), Sulfur ($\text{S}$), Sodium ($\text{Na}$), Chlorine ($\text{Cl}$), Magnesium ($\text{Mg}$), and Iron ($\text{Fe}$), which contribute to about $3.9\%$ of total body mass.

Trace Elements

Elements present in tiny amounts that are vital for body function, such as Iodine and Fluorine.

Atom

The smallest unit of an element that retains the chemical properties of that element.

Protons ($p^+$)

Positively charged subatomic particles located in the nucleus of an atom.

Neutrons ($n^0$)

Subatomic particles with no charge located in the nucleus of an atom.

Electrons ($e^-$)

Negatively charged subatomic particles that orbit the nucleus in electron shells.

Atomic Number

The number of protons in an atom's nucleus, which determines the identity of the element.

Mass Number

The total sum of protons and neutrons in an atom's nucleus.

Isotopes

Atoms of the same element that have different numbers of neutrons and thus different mass numbers.

Valence Shell

The outermost electron shell of an atom, which determines an atom's chemical reactivity.

Molecules

Two or more atoms held together by chemical bonds.

Compounds

Molecules containing at least two different elements.

Covalent Bonds

Chemical bonds formed when atoms share electrons.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally between atoms.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally, creating partial positive ($\delta^+$) and partial negative ($\delta^-$) charges.

Ionic Bonds

Chemical bonds formed when atoms transfer electrons, creating oppositely charged ions that attract each other.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Hydrogen Bond

A weak attraction between the partial positive charge on a hydrogen atom in one molecule and the partial negative charge on a more electronegative atom in another molecule or region; crucial for water properties and structural stability of DNA and proteins.

Reactants

Substances that enter into a chemical reaction.

Products

Substances produced by a chemical reaction.

Synthesis Reactions (Anabolic)

Chemical reactions where smaller molecules combine to form larger ones ($A + B \rightarrow AB$), requiring energy.

Decomposition Reactions (Catabolic)

Chemical reactions where larger molecules break down into smaller ones ($AB \rightarrow A + B$), releasing energy.

Exchange Reactions

Chemical reactions in which parts of the reacting molecules are swapped ($AB + CD \rightarrow AD + CB$).

Reversible Reactions

Chemical reactions that can proceed in both forward and reverse directions, indicated by $\rightleftharpoons$.

Activation Energy

The energy required to start a chemical reaction.

Catalysts

Substances that speed up chemical reactions without being consumed, such as enzymes in the body.

Water ($H_2O$)

The most abundant inorganic compound in the body, characterized by polarity, high heat capacity, high heat of vaporization, and lubricating qualities.

Salts

Ionic compounds that dissociate into their constituent ions when dissolved in water.

Electrolytes

Ions capable of conducting electrical current in solution, crucial for nerve and muscle function.

Acids

Proton donors that release hydrogen ions ($H^+$) in solution, lowering pH below $7$.

Bases

Proton acceptors that release hydroxide ions ($OH^-$) or accept $H^+$ in solution, raising pH above $7$.

pH Scale

A scale measuring hydrogen ion concentration from $0$ to $14$, where $7$ is neutral, values below $7$ are acidic, and values above $7$ are basic.

Buffers

Chemical systems that resist changes in pH by releasing or binding $H^+$, essential for maintaining homeostasis.

Carbohydrates

Organic compounds that serve as the primary energy source for the body, classified as monosaccharides, disaccharides, and polysaccharides.

Glucose

A simple sugar (monosaccharide) with the formula $C_6H_{12}O_6$ that serves as a primary cellular fuel.

Monosaccharides

Simple sugar monomers, including glucose, fructose, and galactose.

Disaccharides

Carbohydrates formed by two linked monosaccharides, such as sucrose, lactose, and maltose.

Polysaccharides

Long chains of linked monosaccharides, including glycogen in animals and starch and cellulose in plants.

Lipids

Hydrophobic organic compounds used for energy storage, insulation, and protection.

Triglycerides

Fats and oils composed of a glycerol molecule bonded to three fatty acids.

Phospholipids

Lipids containing a hydrophilic head and two hydrophobic tails that form the structural foundation of cell membranes.

Steroids

Lipids characterized by a distinctive ring structure, including cholesterol and steroid hormones like estrogen and testosterone.

Proteins

The most abundant organic molecules in the body, serving functions in structural support, enzyme catalysis, transport, defense, movement, and hormone signaling.

Amino Acids

The $20$ different monomer building blocks that link together to form proteins.

Peptide Bonds

Covalent bonds that link individual amino acids together into chains.

Primary Structure of Proteins

The specific linear sequence of amino acids in a polypeptide chain.

Secondary Structure of Proteins

Local folding patterns such as alpha-helices and beta-pleated sheets stabilized by hydrogen bonds.

Tertiary Structure of Proteins

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

Quaternary Structure of Proteins

The structural arrangement resulting from the combination of multiple polypeptide chains.

Denaturation

The loss of a protein's functional three-dimensional structure due to extreme heat or pH changes.

Nucleic Acids

Organic polymers that store and transmit genetic information, constructed from nucleotide monomers.

Nucleotides

Monomers of nucleic acids composed of a five-carbon sugar, a phosphate group, and a nitrogenous base.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid with deoxyribose sugar and bases Adenine ($\text{A}$), Guanine ($\text{G}$), Cytosine ($\text{C}$), and Thymine ($\text{T}$) that serves as the cell's genetic blueprint.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid with ribose sugar and bases Adenine ($\text{A}$), Guanine ($\text{G}$), Cytosine ($\text{C}$), and Uracil ($\text{U}$) involved in protein synthesis.

Adenosine Triphosphate (ATP)

The directly usable energy currency of the cell, releasing energy when a phosphate group is hydrolyzed to form ADP.

Fluid Mosaic Model

A structural model describing the cell membrane as a dynamic mosaic of phospholipids, cholesterol, proteins, and carbohydrates.

Integral Proteins

Membrane proteins embedded within the lipid bilayer, often forming channels or transporters.

Peripheral Proteins

Membrane proteins attached to the surface of the cell membrane.

Glycocalyx

A sugary coat on the outer cell membrane formed by glycoproteins and glycolipids that helps in cell-to-cell recognition and adhesion.

Cytosol

The gel-like fluid portion of the cytoplasm where many metabolic reactions occur.

Organelles

Specialized structures ('little organs') suspended in cytosol that perform specific cellular functions.

Inclusions

Stored nutrients and pigments in the cytoplasm, such as glycogen granules and fat droplets.

Nucleus

The cell's control center, containing DNA organized into chromosomes.

Nuclear Envelope

A double membrane with pores surrounding the nucleus that regulates transport in and out of the nucleus.

Nucleolus

A structure within the nucleus responsible for ribosome synthesis.

Mitochondria

The 'powerhouses' of the cell that produce ATP through aerobic respiration and contain their own DNA and ribosomes.

Ribosomes

Cellular structures that serve as sites of protein synthesis, floating free in the cytoplasm or bound to rough ER.

Rough Endoplasmic Reticulum (Rough ER)

A membrane network studded with ribosomes that synthesizes and modifies proteins.

Smooth Endoplasmic Reticulum (Smooth ER)

A membrane network lacking ribosomes that synthesizes lipids and detoxifies harmful substances.

Golgi Apparatus

The 'post office' organelle of the cell that modifies, sorts, and packages proteins and lipids for transport.

Lysosomes

The cell's 'recycling centers' containing digestive enzymes to break down waste materials, foreign substances, and worn-out organelles.

Peroxisomes

Organelles that break down fatty acids and amino acids while detoxifying substances, producing hydrogen peroxide as a byproduct.

Cytoskeleton

A network of protein filaments (microfilaments, intermediate filaments, microtubules) providing structural support and facilitating cell movement.

Cilia

Short, hair-like projections on the cell surface that move substances across the cell surface.

Flagella

A long, whip-like tail structure that propels an entire cell, such as sperm.

Microvilli

Finger-like projections of the cell membrane that increase surface area for absorption.

Tight Junctions

Impermeable intercellular seals that prevent substances from passing between adjacent cells.

Desmosomes

Intercellular anchoring junctions that act like 'spot welds' to hold cells together under mechanical stress.

Gap Junctions

Protein channels connecting adjacent cells that allow the direct passage of ions and small molecules.

Passive Transport

Movement of substances across the cell membrane without requiring cellular energy (ATP).

Diffusion

The passive movement of molecules from an area of high concentration to an area of low concentration.

Facilitated Diffusion

Passive diffusion of molecules across a membrane aided by membrane proteins.

Osmosis

The diffusion of water molecules across a selectively permeable membrane.

Isotonic Solution

A solution with the same solute concentration relative to a cell, causing no net movement of water.

Hypertonic Solution

A solution with a higher solute concentration relative to a cell, causing the cell to shrink.

Hypotonic Solution

A solution with a lower solute concentration relative to a cell, causing the cell to swell and potentially burst.

Active Transport

Movement of substances across a cell membrane against their concentration gradient using cellular energy (ATP).

Endocytosis

Vesicular transport process in which the cell engulfs external substances into a vesicle.

Phagocytosis

A form of endocytosis referred to as 'cell eating,' involving the uptake of solid particles.

Pinocytosis

A form of endocytosis referred to as 'cell drinking,' involving the uptake of liquids.

Exocytosis

Vesicular transport process by which substances are released outside the cell.

Mitosis

Nuclear division resulting in two genetically identical diploid daughter cells, progressing through prophase, metaphase, anaphase, and telophase.

Meiosis

Cell division process that produces four genetically different haploid cells (gametes: sperm and egg).

Interphase

The longest phase of the cell cycle, during which the cell grows and duplicates its DNA.

Cell Differentiation

The process by which a less specialized cell becomes more specialized.