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Carbon Backbone
Carbon forms four covalent bonds due to its electron configuration, allowing for diverse organic molecules.
Covalent Bonds
Strong bonds where atoms share electrons.
Ionic Bonds
Bonds formed when one atom donates an electron to another.
Hydrogen Bonds
Weak bonds between partially charged hydrogen and electronegative atoms (e.g., between water molecules).
Polarity
Unequal sharing of electrons in covalent bonds, resulting in partial charges.
Cohesion
Water molecules stick to each other.
Adhesion
Water molecules stick to other substances.
Surface Tension
Resistance of water surface due to hydrogen bonding.
High Specific Heat
Water requires more energy to change temperature due to hydrogen bonding.
Solvent Properties
Water dissolves polar and charged substances (hydrophilic) but not nonpolar substances (hydrophobic).
Dehydration Synthesis
Forms covalent bonds by removing water, linking monomers into polymers.
Hydrolysis
Breaks covalent bonds by adding water, splitting polymers into monomers.
Monomer (Carbohydrates)
Monosaccharides (e.g., glucose, fructose).
Polymer (Carbohydrates)
Polysaccharides (e.g., starch, cellulose, glycogen).
Glycosidic Bonds
Covalent bonds joining monosaccharides.
Function (Carbohydrates)
Energy storage and structural support.
Simple vs. Complex Carbohydrates
Simple sugars spike blood sugar; complex carbohydrates release energy slowly.
Types (Lipids)
Triglycerides, phospholipids, steroids.
Monomer (Lipids)
Glycerol and fatty acids.
Saturated Fats
No C=C bonds; solid at room temperature.
Unsaturated Fats
At least one C=C bond; liquid at room temperature.
Phospholipids
Amphipathic molecules forming cell membranes (hydrophilic head, hydrophobic tails).
Function (Lipids)
Energy storage, insulation, cell membrane structure.
Monomer (Proteins)
Amino acids.
Primary Structure
Linear sequence of amino acids joined by peptide bonds.
Secondary Structure
Alpha helices and beta sheets formed by hydrogen bonds.
Tertiary Structure
3D folding driven by R-group interactions (hydrophobic, hydrophilic, ionic, disulfide bonds).
Quaternary Structure
Multiple polypeptide chains forming functional proteins (e.g., hemoglobin).
Disulfide Bonds
Strong covalent bonds between cysteine R-groups, increasing stability.
Function (Proteins)
Enzymes, structural support, transport, signaling.
Monomer (Nucleic Acids)
Nucleotides (phosphate group, five-carbon sugar, nitrogenous base).
Polymers (Nucleic Acids)
DNA and RNA.
Phosphodiester Bonds
Covalent bonds between nucleotides.
DNA Structure
Double helix, antiparallel strands (5' to 3' and 3' to 5'), complementary base pairing (A-T with 2 hydrogen bonds, G-C with 3 hydrogen bonds).
RNA Structure
Single-stranded, uracil replaces thymine.
Function (Nucleic Acids)
DNA stores genetic info; RNA transmits genetic info for protein synthesis.
Hydrophilic R-Groups
Face outward to interact with aqueous environments.
Hydrophobic R-Groups
Fold inward to avoid water.
Impact of Mutations
Changes in primary structure can disrupt protein function.
GC Content
Higher GC content leads to higher Tm due to stronger triple hydrogen bonds.
Denaturation
High temperatures or chemical agents can disrupt hydrogen bonds in DNA.
Cell Theory
States that all living organisms are composed of cells, all cells come from preexisting cells, and the cell is the fundamental unit of life.
Prokaryotic Cell
A type of cell lacking membrane-bound organelles, including a nucleus, found in organisms such as bacteria and archaea.
Eukaryotic Cell
A type of cell with membrane-bound organelles, including a nucleus, found in plants, animals, fungi, and protists.
Cytoplasm
The jelly-like substance within a cell that contains the cytosol and organelles.
Plasma Membrane
A selectively permeable phospholipid bilayer that encloses the cell and regulates the movement of substances in and out.
Organelle
A specialized subunit within a eukaryotic cell that has a specific function and is usually membrane-bound.
Nucleus
The organelle in eukaryotic cells that houses DNA and is surrounded by the nuclear envelope.
Ribosome
A cellular structure responsible for protein synthesis, found in both prokaryotic and eukaryotic cells.
Mitochondria
The organelle where cellular respiration occurs, producing ATP for the cell.
Chloroplast
The organelle in plant and algae cells where photosynthesis occurs, producing sugars and oxygen.
Endoplasmic Reticulum (ER)
A network of membranes within eukaryotic cells involved in protein (rough ER) and lipid (smooth ER) synthesis.
Golgi Apparatus
An organelle that modifies, sorts, and packages proteins and lipids for secretion or use within the cell.
Lysosome
A vesicle containing enzymes that break down macromolecules and recycle cellular components.
Vacuole
A storage organelle in cells, especially prominent in plant cells, where it helps maintain turgor pressure.
Phospholipid Bilayer
A two-layered arrangement of phospholipids that forms the cell membrane, with hydrophilic heads facing outward and hydrophobic tails facing inward.
Fluid Mosaic Model
Describes the cell membrane as a flexible, dynamic structure with embedded proteins, cholesterol, and carbohydrates.
Selective Permeability
A property of the plasma membrane that allows some substances to pass through while blocking others.
Simple Diffusion
The movement of small, nonpolar molecules across the cell membrane without assistance or energy.
Facilitated Diffusion
The passive transport of molecules across the cell membrane through specific transport proteins.
Active Transport
The movement of molecules across the cell membrane against their concentration gradient, requiring energy (ATP).
Osmosis
The diffusion of water molecules across a selectively permeable membrane from high to low water concentration.
Na+/K+ Pump
A membrane protein that uses ATP to pump sodium out and potassium into the cell, maintaining membrane potential.
ATP (Adenosine Triphosphate)
The primary energy carrier in cells, produced through cellular respiration in mitochondria.
Endosymbiotic Theory
The theory that certain organelles, such as mitochondria and chloroplasts, evolved from free-living prokaryotic cells engulfed by ancestral eukaryotic cells.
Surface Area-to-Volume Ratio
Explains why cells are small; a larger ratio allows for efficient transport of materials.
Compartmentalization
The organization of eukaryotic cells into membrane-bound organelles to allow specialized functions to occur independently.
Homeostasis
The maintenance of a stable internal environment within a cell or organism despite external changes.
Concentration Gradient
The difference in the concentration of a substance between two regions.
Membrane Potential
The voltage difference across a cell membrane due to the differential distribution of ions.
Signal Transduction Pathway
A sequence of molecular events and chemical reactions that lead to a cellular response to a signal.
Water Potential (ψ)
The measure of the potential energy of water in a system, influenced by solute concentration and pressure.
Tonicity
The relative concentration of solutes in two solutions separated by a membrane, determining the direction of water movement (hypertonic, hypotonic, isotonic).
Aquaporins
Specialized channel proteins in the cell membrane that facilitate the rapid movement of water.
Microvilli
Tiny, finger-like projections on the surface of certain cells (like enterocytes) that increase surface area for absorption.
Villi
Finger-like projections lining the small intestine that maximize surface area for nutrient absorption.
Turgor Pressure
The pressure exerted by water inside the cell against the cell wall, maintaining structural integrity in plant cells.
Cristae
The folded inner membrane of mitochondria, which increases surface area for ATP production.
Cytoskeleton
A network of protein fibers (microfilaments, microtubules, and intermediate filaments) that maintain cell shape, assist in cell movement, and support intracellular transport.
Cell Junctions
Structures that connect cells to one another (e.g., tight junctions, gap junctions, and desmosomes) and allow communication or structural support in multicellular organisms.
Extracellular Matrix (ECM)
A collection of proteins (e.g., collagen) and polysaccharides outside animal cells that provide structural and support to cells.
Peroxisome
A small organelle that contains enzymes for breaking down fatty acids and detoxifying harmful substances like hydrogen peroxide.
Cilia and Flagella
Hair-like structures on the cell surface that assist in cell movement or the movement of substances along the cell surface.
Gap Junctions
Channels that allow ions and molecules to flow directly between neighboring cells, enabling communication.
Plasmodesmata
Channels in plant cell walls that enable transport and communication between plant cells.
Integral and Peripheral Proteins
Membrane proteins that either span the membrane (integral) or are attached to its surface (peripheral), playing roles in transport, signaling, or structural support.
Endocytosis
A process by which cells engulf substances into vesicles for internalization (e.g., phagocytosis and pinocytosis).
Exocytosis
The process of vesicles fusing with the plasma membrane to secrete materials out of the cell.
Golgi Vesicles
Small vesicles that bud from the Golgi apparatus and transport modified proteins and lipids.
Enzyme
A protein that catalyzes chemical reactions by lowering activation energy.
Active Site
The specific region on an enzyme where the substrate binds.
Substrate
The reactant that an enzyme acts upon.
Enzyme-Substrate Complex
A temporary molecule formed when the enzyme binds to the substrate.
Activation Energy
The energy required to initiate a chemical reaction.
Catalysis
The acceleration of a chemical reaction by an enzyme.
Lock-and-Key Model
Active site and substrate have specific complementary shapes.
Induced-Fit Model
Enzyme changes shape slightly to better fit the substrate.
Temperature and pH
Optimal conditions where the enzyme functions best; extremes cause denaturation.
Denaturation
Loss of enzyme structure due to environmental changes, resulting in loss of function.
Competitive Inhibitor
Binds to the active site, blocking the substrate.
