week 10, chapters 9, 14

Adaptor Protein

Proteins that facilitate interactions between other proteins by linking them together in cellular signaling pathways.

Antiparallel Configuration of DNA

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

Autophosphorylation

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

Bacteriophages (Phages)

Viruses that specifically infect bacterial cells, using them to replicate.

Cell Surface Receptors

Proteins located on the cell membrane that bind to external molecules, initiating intracellular responses.

Chargaff's Rule

A principle that states DNA from any cell should have equal amounts of adenine and thymine, and cytosine and guanine.

Chemically Gated Ion Channels

Ion channels that open in response to the binding of a specific chemical messenger.

Clamp Loader

A protein complex that loads the sliding clamp onto DNA, facilitating DNA polymerase attachment during replication.

Coactivators

Molecules that increase gene transcription by binding to transcription factors, enhancing their function.

Conservative Model of DNA Replication

A proposed model where parental DNA remains intact and produces an entirely new copy during replication.

Cyclic AMP (cAMP)

A secondary messenger involved in transmitting signals within cells, important in many biological processes.

Cyclic Guanosine Monophosphate (cGMP)

A secondary messenger similar to cAMP, often involved in signaling pathways related to vision and vasodilation.

Dephosphorylation

The removal of a phosphate group from a molecule, often regulating protein activity.

Deoxyribose Sugar

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

Direct Contact

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

Dispersive Model of DNA Replication

A proposed model where new DNA strands are mixtures of old and new segments after replication.

DNA Gyrase

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

DNA Ligase

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

DNA Polymerase

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

DNA Polymerase Delta (Pol δ)

A DNA polymerase enzyme that primarily synthesizes the lagging strand during DNA replication in eukaryotes.

DNA Polymerase Epsilon (Pol ε)

An enzyme responsible for synthesizing the leading strand during DNA replication in eukaryotes.

DNA Polymerase I (Pol I)

A DNA polymerase in prokaryotes that removes RNA primers and fills in nucleotides during DNA replication.

DNA Polymerase II (Pol II)

A DNA repair enzyme in prokaryotes that also assists with the replication of damaged DNA.

DNA Polymerase III (Pol III)

The primary enzyme responsible for DNA synthesis in prokaryotic organisms.

DNA Primase

An enzyme that synthesizes RNA primers, initiating DNA synthesis.

DNA Replication

The process by which a cell duplicates its DNA, producing two identical DNA molecules.

Elongation

The phase in DNA replication where DNA polymerase extends the new DNA strand.

Endocrine Signaling

A form of long-distance signaling where hormones are released into the bloodstream to reach distant cells.

Endonuclease Activity

The ability of an enzyme to cleave the phosphodiester bond within a nucleotide chain.

Enzymatic Receptors

Receptors that have enzymatic activity and catalyze reactions upon binding to a ligand.

Excision Repair

A DNA repair mechanism that removes and replaces damaged DNA segments.

Exonuclease Activity

The ability of enzymes to remove nucleotides from the ends of DNA or RNA chains.

Initiation

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

Inositol Phosphates

A group of molecules that function as secondary messengers, relaying signals within cells.

Intracellular Receptor

A receptor located inside the cell that binds to signaling molecules able to pass through the cell membrane.

G-Coupled Receptors

A family of cell surface receptors that activate G proteins to transmit signals inside the cell.

G Protein

A protein that binds to GTP and transmits signals from receptors on the cell surface to other cellular targets.

Helicases

Enzymes that unwind the DNA double helix, essential for DNA replication and repair.

Kinase Cascade

A series of protein kinases that sequentially activate each other to amplify cellular signals.

Lagging Strand

The DNA strand synthesized discontinuously in small fragments (Okazaki fragments) during replication.

Leading Strand

The DNA strand synthesized continuously in the direction of the replication fork.

Ligand

A molecule that binds specifically to a receptor to trigger a biological response.

Mismatch Repair (MMR)

A DNA repair mechanism that corrects errors introduced during DNA replication.

Mitogen-Activated Protein (MAP) Kinases

Enzymes involved in a signaling pathway that regulate cellular responses to growth signals.

Mutagens

Agents that cause genetic mutations by altering the DNA sequence.

Nonspecific Repair

A DNA repair mechanism that addresses general types of damage without high specificity.

Nitrogenous Base

A molecule in DNA or RNA, such as adenine, thymine, cytosine, guanine, or uracil, that encodes genetic information.

Okazaki Fragments

Short DNA fragments synthesized on the lagging strand during DNA replication.

Paracrine Signaling

A type of cell signaling where the signal only affects nearby cells in the local environment.

Phosphatases

Enzymes that remove phosphate groups from proteins, often turning off signaling pathways.

Phosphorylation

The addition of a phosphate group to a molecule, typically activating or deactivating proteins.

Phosphodiester Bond

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

Phosphate Group

A functional group found in nucleotides, ATP, and phospholipids, involved in energy transfer and signaling.

Photorepair

A DNA repair mechanism that reverses UV-induced damage to DNA using light.

Processivity

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

Proofreading

The function of DNA polymerases to detect and correct errors during DNA replication.

Protein Kinase

An enzyme that adds phosphate groups to proteins, often activating them in signaling pathways.

Purine

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

Pyrimidine

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

Ras Protein

A small G-protein that transmits signals for cell growth and differentiation.

Receptor Protein

A protein on the cell surface or inside the cell that binds to ligands to initiate a cellular response.

Receptor Tyrosine Kinases (RTKs)

A family of receptors that, when activated, add phosphate groups to tyrosine residues on proteins, triggering signaling pathways.

Replication Fork

The Y-shaped structure formed during DNA replication where the double helix is unwound.

Replicon

A region of DNA that replicates from a single origin of replication.

Replisome

A complex of enzymes responsible for synthesizing DNA at the replication fork.

Ribose Sugar

A five-carbon sugar found in RNA, differing from deoxyribose by having one more oxygen atom.

RNA Primers

Short RNA sequences synthesized by primase to provide a starting point for DNA synthesis.

Second Messengers

Molecules that relay signals from receptors on the cell surface to target molecules inside the cell.

Semiconservative Model of DNA Replication

The correct model of DNA replication where each new DNA molecule has one original strand and one newly synthesized strand.

Signal Amplification

A process where a single signal molecule triggers multiple downstream responses, enhancing the signal’s effect.

Signal Transduction

The process of converting an external signal into a cellular response.

Single-Strand-Binding Proteins

Proteins that bind to separated DNA strands during replication, stabilizing them to prevent re-annealing.

Specific Repair

DNA repair mechanisms that target specific types of damage for precise correction.

Steroid Hormone Receptors

Intracellular receptors that bind to steroid hormones, regulating gene expression upon activation.

Supercoiling

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

Synaptic Signaling

A form of cell communication occurring between nerve cells and target cells at synapses.

Telomerase

An enzyme that extends telomeres, the protective caps at the ends of chromosomes.

Telomeres

Repeating nucleotide sequences at chromosome ends, protecting DNA from degradation during replication.

Termination

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

Topoisomerases

Enzymes that prevent supercoiling by cutting and rejoining DNA strands during replication.

Transformation

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

Tyrosine Kinase

An enzyme that phosphorylates tyrosine residues on target proteins, often involved in signal transduction.