Term: Adaptor Protein
Definition: Proteins that facilitate interactions between other proteins by linking them together in cellular signaling pathways.

Term: Antiparallel Configuration of DNA
Definition: A structural arrangement in DNA where two strands run in opposite directions: one 5' to 3' and the other 3' to 5'.

Term: Autophosphorylation
Definition: A self-activation process where a kinase enzyme adds a phosphate group to itself, enhancing its function in signaling.

Term: Bacteriophages (Phages)
Definition: Viruses that specifically infect bacterial cells, using them to replicate.

Term: Cell Surface Receptors
Definition: Proteins located on the cell membrane that bind to external molecules, initiating intracellular responses.

Term: Chargaff's Rule
Definition: A principle that states DNA from any cell should have equal amounts of adenine and thymine, and cytosine and guanine.

Term: Chemically Gated Ion Channels
Definition: Ion channels that open in response to the binding of a specific chemical messenger.

Term: Clamp Loader
Definition: A protein complex that loads the sliding clamp onto DNA, facilitating DNA polymerase attachment during replication.

Term: Coactivators
Definition: Molecules that increase gene transcription by binding to transcription factors, enhancing their function.

Term: Conservative Model of DNA Replication
Definition: A proposed model where parental DNA remains intact and produces an entirely new copy during replication.

Term: Cyclic AMP (cAMP)
Definition: A secondary messenger involved in transmitting signals within cells, important in many biological processes.

Term: Cyclic Guanosine Monophosphate (cGMP)
Definition: A secondary messenger similar to cAMP, often involved in signaling pathways related to vision and vasodilation.

Term: Dephosphorylation
Definition: The removal of a phosphate group from a molecule, often regulating protein activity.

Term: Deoxyribose Sugar
Definition: A five-carbon sugar molecule found in DNA, lacking an oxygen atom at the 2' position.

Term: Direct Contact
Definition: A method of cell communication where cells are physically connected, allowing signal molecules to move directly between them.

Term: Dispersive Model of DNA Replication
Definition: A proposed model where new DNA strands are mixtures of old and new segments after replication.

Term: DNA Gyrase
Definition: An enzyme that relieves strain while double-stranded DNA is being unwound by helicase during replication.

Term: DNA Ligase
Definition: An enzyme that joins DNA fragments by forming phosphodiester bonds, essential in DNA replication and repair.

Term: DNA Polymerase
Definition: An enzyme responsible for synthesizing new DNA strands by adding nucleotides to a pre-existing strand.

Term: DNA Polymerase Delta (Pol δ)
Definition: A DNA polymerase enzyme that primarily synthesizes the lagging strand during DNA replication in eukaryotes.

Term: DNA Polymerase Epsilon (Pol ε)
Definition: An enzyme responsible for synthesizing the leading strand during DNA replication in eukaryotes.

Term: DNA Polymerase I (Pol I)
Definition: A DNA polymerase in prokaryotes that removes RNA primers and fills in nucleotides during DNA replication.

Term: DNA Polymerase II (Pol II)
Definition: A DNA repair enzyme in prokaryotes that also assists with the replication of damaged DNA.

Term: DNA Polymerase III (Pol III)
Definition: The primary enzyme responsible for DNA synthesis in prokaryotic organisms.

Term: DNA Primase
Definition: An enzyme that synthesizes RNA primers, initiating DNA synthesis.

Term: DNA Replication
Definition: The process by which a cell duplicates its DNA, producing two identical DNA molecules.

Term: Elongation
Definition: The phase in DNA replication where DNA polymerase extends the new DNA strand.

Term: Endocrine Signaling
Definition: A form of long-distance signaling where hormones are released into the bloodstream to reach distant cells.

Term: Endonuclease Activity
Definition: The ability of an enzyme to cleave the phosphodiester bond within a nucleotide chain.

Term: Enzymatic Receptors
Definition: Receptors that have enzymatic activity and catalyze reactions upon binding to a ligand.

Term: Excision Repair
Definition: A DNA repair mechanism that removes and replaces damaged DNA segments.

Term: Exonuclease Activity
Definition: The ability of enzymes to remove nucleotides from the ends of DNA or RNA chains.

Term: Initiation
Definition: The first step of DNA replication where enzymes unwind the DNA and prepare it for synthesis.

Term: Inositol Phosphates
Definition: A group of molecules that function as secondary messengers, relaying signals within cells.

Term: Intracellular Receptor
Definition: A receptor located inside the cell that binds to signaling molecules able to pass through the cell membrane.

Term: G-Coupled Receptors
Definition: A family of cell surface receptors that activate G proteins to transmit signals inside the cell.

Term: G Protein
Definition: A protein that binds to GTP and transmits signals from receptors on the cell surface to other cellular targets.

Term: Helicases
Definition: Enzymes that unwind the DNA double helix, essential for DNA replication and repair.

Term: Kinase Cascade
Definition: A series of protein kinases that sequentially activate each other to amplify cellular signals.

Term: Lagging Strand
Definition: The DNA strand synthesized discontinuously in small fragments (Okazaki fragments) during replication.

Term: Leading Strand
Definition: The DNA strand synthesized continuously in the direction of the replication fork.

Term: Ligand
Definition: A molecule that binds specifically to a receptor to trigger a biological response.

Term: Mismatch Repair (MMR)
Definition: A DNA repair mechanism that corrects errors introduced during DNA replication.

Term: Mitogen-Activated Protein (MAP) Kinases
Definition: Enzymes involved in a signaling pathway that regulate cellular responses to growth signals.

Term: Mutagens
Definition: Agents that cause genetic mutations by altering the DNA sequence.

Term: Nonspecific Repair
Definition: A DNA repair mechanism that addresses general types of damage without high specificity.

Term: Nitrogenous Base
Definition: A molecule in DNA or RNA, such as adenine, thymine, cytosine, guanine, or uracil, that encodes genetic information.

Term: Okazaki Fragments
Definition: Short DNA fragments synthesized on the lagging strand during DNA replication.

Term: Paracrine Signaling
Definition: A type of cell signaling where the signal only affects nearby cells in the local environment.

Term: Phosphatases
Definition: Enzymes that remove phosphate groups from proteins, often turning off signaling pathways.

Term: Phosphorylation
Definition: The addition of a phosphate group to a molecule, typically activating or deactivating proteins.

Term: Phosphodiester Bond
Definition: A bond that links nucleotides in DNA or RNA, connecting the phosphate group of one nucleotide to the sugar of another.

Term: Phosphate Group
Definition: A functional group found in nucleotides, ATP, and phospholipids, involved in energy transfer and signaling.

Term: Photorepair
Definition: A DNA repair mechanism that reverses UV-induced damage to DNA using light.

Term: Processivity
Definition: The ability of an enzyme, such as DNA polymerase, to continuously catalyze reactions without detaching.

Term: Proofreading
Definition: The function of DNA polymerases to detect and correct errors during DNA replication.

Term: Protein Kinase
Definition: An enzyme that adds phosphate groups to proteins, often activating them in signaling pathways.

Term: Purine
Definition: A double-ring nitrogenous base, including adenine and guanine, found in DNA and RNA.

Term: Pyrimidine
Definition: A single-ring nitrogenous base, including cytosine, thymine, and uracil, found in DNA and RNA.

Term: Ras Protein
Definition: A small G-protein that transmits signals for cell growth and differentiation.

Term: Receptor Protein
Definition: A protein on the cell surface or inside the cell that binds to ligands to initiate a cellular response.

Term: Receptor Tyrosine Kinases (RTKs)
Definition: A family of receptors that, when activated, add phosphate groups to tyrosine residues on proteins, triggering signaling pathways.

Term: Replication Fork
Definition: The Y-shaped structure formed during DNA replication where the double helix is unwound.

Term: Replicon
Definition: A region of DNA that replicates from a single origin of replication.

Term: Replisome
Definition: A complex of enzymes responsible for synthesizing DNA at the replication fork.

Term: Ribose Sugar
Definition: A five-carbon sugar found in RNA, differing from deoxyribose by having one more oxygen atom.

Term: RNA Primers
Definition: Short RNA sequences synthesized by primase to provide a starting point for DNA synthesis.

Term: Second Messengers
Definition: Molecules that relay signals from receptors on the cell surface to target molecules inside the cell.

Term: Semiconservative Model of DNA Replication
Definition: The correct model of DNA replication where each new DNA molecule has one original strand and one newly synthesized strand.

Term: Signal Amplification
Definition: A process where a single signal molecule triggers multiple downstream responses, enhancing the signal’s effect.

Term: Signal Transduction
Definition: The process of converting an external signal into a cellular response.

Term: Single-Strand-Binding Proteins
Definition: Proteins that bind to separated DNA strands during replication, stabilizing them to prevent re-annealing.

Term: Specific Repair
Definition: DNA repair mechanisms that target specific types of damage for precise correction.

Term: Steroid Hormone Receptors
Definition: Intracellular receptors that bind to steroid hormones, regulating gene expression upon activation.

Term: Supercoiling
Definition: The coiling of DNA beyond its usual double helix structure, helping to compact and organize DNA in cells.

Term: Synaptic Signaling
Definition: A form of cell communication occurring between nerve cells and target cells at synapses.

Term: Telomerase
Definition: An enzyme that extends telomeres, the protective caps at the ends of chromosomes.

Term: Telomeres
Definition: Repeating nucleotide sequences at chromosome ends, protecting DNA from degradation during replication.

Term: Termination
Definition: The final phase of DNA replication or transcription where synthesis is completed and machinery is disassembled.

Term: Topoisomerases
Definition: Enzymes that prevent supercoiling by cutting and rejoining DNA strands during replication.

Term: Transformation
Definition: The genetic alteration of a cell resulting from the direct uptake and incorporation of foreign DNA.

Term: Tyrosine Kinase
Definition: An enzyme that phosphorylates tyrosine residues on target proteins, often involved in signal transduction.