PMCY 4600 key words

Cell theory

The cell theory states that all living organisms are composed of one or more cells, the cell is the basic structural and functional unit of life, and all cells arise from pre-existing cells.

Cell structure

Cell structure refers to the organization and arrangement of cellular components, including the plasma membrane, cytoplasm, nucleus, and organelles, each of which performs specific functions necessary for cell survival and activity

Mosaic Model of the plasma membrane

describes the plasma membrane as a flexible phospholipid bilayer with embedded proteins, carbohydrates, and cholesterol that move laterally, giving the membrane both fluidity and a mosaic-like appearance.

DNA structure

has a double-helix structure composed of two antiparallel strands of nucleotides held together by hydrogen bonds between complementary base pairs (adenine–thymine and guanine–cytosine), with a sugar-phosphate backbone on the outside.

Structure and properties of membrane proteins

Membrane proteins are embedded in or associated with the lipid bilayer and may be integral (transmembrane) or peripheral. They have hydrophobic regions that interact with lipids and hydrophilic regions that face aqueous environments, enabling functions such as transport, signaling, and enzymatic activity.

membrane potential

the electrical charge difference across a cell membrane, created by unequal distribution of ions (such as Na⁺, K⁺, and Cl⁻), and is essential for processes like nerve impulse transmission and muscle contraction.

membrane function

functions as a selectively permeable barrier that regulates the movement of substances in and out of the cell, maintains cellular integrity, enables communication, and supports cell signaling and recognition.

phospholipids and glycolipids

Phospholipids are amphipathic molecules with a hydrophilic phosphate head and hydrophobic fatty acid tails that form the structural basis of cell membranes. Glycolipids are lipids with attached carbohydrate chains that play roles in cell recognition and membrane stability.

mRNA structure

a single-stranded nucleic acid molecule composed of codons that carry genetic information from DNA to ribosomes. In eukaryotes, it includes a 5′ cap, a coding region, and a 3′ poly-A tail for stability and translation efficiency.

protein kinase

an enzyme that catalyzes the transfer of a phosphate group from ATP to a specific protein, thereby altering the protein’s activity, location, or function in cell signaling pathways.

cell organelle

a specialized structure within a cell, often membrane-bound, that performs a specific function, such as energy production, protein synthesis, or waste processing.

Ribosomes

non-membrane-bound organelles composed of rRNA and proteins that serve as the site of protein synthesis by translating mRNA into polypeptide chains.

Rough and smooth endoplasmic reticulum

The rough ER is a membrane network studded with ribosomes and is responsible for the synthesis and initial modification of proteins destined for secretion or membranes. The smooth ER lacks ribosomes and functions in lipid synthesis, detoxification, and calcium storage.

Golgi apparatus

a stack of flattened membrane sacs that modifies, sorts, and packages proteins and lipids received from the endoplasmic reticulum for transport to their final destinations.

Endocytosis

the process by which a cell takes substances into itself by enclosing them in membrane-bound vesicles formed from the plasma membrane

peroxisome

a membrane-bound organelle that contains enzymes involved in fatty acid oxidation and the detoxification of harmful substances through reactions that produce and break down hydrogen peroxide.

Cytoskeleton

a dynamic network of protein filaments that provides structural support, maintains cell shape, enables intracellular transport, and facilitates cell movement and division.

Microtubules

hollow cylindrical structures made of tubulin that form part of the cytoskeleton and are involved in cell shape maintenance, vesicle transport, chromosome movement, and mitotic spindle formation.Mic

Microfilaments

thin cytoskeletal fibers composed primarily of actin that support cell shape, enable muscle contraction, and play a role in cell motility and cytokinesis.

Centrosome

a microtubule-organizing center located near the nucleus that contains a pair of centrioles and plays a key role in spindle formation during cell division.

Nucleus

a membrane-bound organelle that houses the cell’s DNA and serves as the control center for gene expression, DNA replication, and cell cycle regulation.

exosome

a small extracellular vesicle released by cells that carries proteins, lipids, and nucleic acids, playing a role in intercellular communication and signaling.

nuclear envelope

a double-membrane structure that surrounds the nucleus, separating nuclear contents from the cytoplasm and containing nuclear pores that regulate molecular transport.

chromatin

the complex of DNA and histone proteins that packages genetic material within the nucleus and regulates gene expression.

Gene

a specific sequence of DNA that contains the instructions for synthesizing a functional product, usually a protein or RNA molecule.

Cell cycle

the ordered series of events by which a cell grows, replicates its DNA, and divides into two daughter cells.

interphase

the phase of the cell cycle during which the cell grows, performs normal functions, and replicates its DNA, consisting of G₁, S, and G₂ phases.

cytokines

small signaling proteins released by cells, especially immune cells, that regulate immunity, inflammation, and cell communication.

chromosome

a condensed structure of chromatin that becomes visible during cell division and ensures accurate distribution of genetic material to daughter cells.

signal transduction

the process by which a cell converts an external signal, such as ligand binding to a receptor, into a specific intracellular response through a series of molecular events.

Life span of a cell

the length of time a cell remains viable and functional before undergoing division, senescence, or programmed death, and it varies depending on cell type and physiological conditions.

Apoptosis

a regulated, energy-dependent process of programmed cell death characterized by cell shrinkage, DNA fragmentation, and membrane blebbing, without triggering inflammation.

programmed cell death

a genetically controlled process by which cells are eliminated in a precise and orderly manner during development, tissue maintenance, or disease prevention; apoptosis is its primary form.

Exons and introns

the coding sequences of a gene that remain in mature mRNA and are translated into protein, while introns are non-coding sequences that are removed during RNA splicing.

Epigenetics

refers to heritable changes in gene expression that do not involve alterations in the DNA sequence, often mediated by DNA methylation, histone modification, or non-coding RNAs.

Gene expression regulation

the control of when, where, and how much a gene is transcribed and translated, allowing cells to respond to internal and external signals.

Transduction

the process by which an external signal is transmitted into a cell, typically through receptor activation and intracellular signaling pathways that lead to a cellular response.

Plasmid Vector

a small, circular DNA molecule used in genetic engineering to transfer foreign genes into a host cell for cloning or expression.

Biotechnology

the application of biological systems, organisms, or molecules to develop products and technologies for medical, agricultural, pharmaceutical, or industrial purposes.

Translation

the process by which ribosomes synthesize proteins by decoding the genetic information carried by mRNA into a specific amino acid sequence.

MicroRNA

a small non-coding RNA molecule that regulates gene expression by binding to target mRNA, leading to translational repression or mRNA degradation.

proteasome

are large protein complexes that degrade damaged, misfolded, or unneeded proteins tagged with ubiquitin, helping maintain cellular protein homeostasis.

Extracellular communication

the process by which cells communicate with one another through signaling molecules such as hormones, neurotransmitters, or cytokines.

Membrane junction

a specialized structure that connects adjacent cells or links cells to the extracellular matrix, facilitating adhesion, communication, or transport (e.g., tight junctions, gap junctions).

Monoclonal antibody

a laboratory-produced antibody derived from a single B-cell clone that binds specifically to one epitope on an antigen and is widely used in diagnostics and therapy.

Hybridoma

a fused cell created by combining an antibody-producing B lymphocyte with a myeloma (cancer) cell, resulting in an immortal cell line capable of producing a single type of monoclonal antibody.

Tight junction

a type of cell–cell junction that seals adjacent epithelial cells together, preventing the passage of substances between cells and maintaining cell polarity.

membrane transporter

a transmembrane protein that facilitates the movement of specific molecules or ions across the cell membrane, either passively or using energy.

Ion channel

a transmembrane protein that forms a pore in the membrane, allowing selective and rapid movement of ions down their electrochemical gradient.

osmolarity

a measure of the total concentration of solute particles in a solution, expressed as osmoles per liter, and determines the direction of water movement across membranes.

isotonic control

has the same osmolarity as the cell’s cytoplasm, resulting in no net movement of water into or out of the cell.

Receptor-mediated endocytosis

a selective form of endocytosis in which specific ligands bind to cell-surface receptors and are internalized in vesicles.

Transfection

the deliberate introduction of foreign nucleic acids (DNA or RNA) into eukaryotic cells to study gene function or produce proteins.

Differentiation

the process by which unspecialized cells become specialized in structure and function through changes in gene expression.

Autophagy

a regulated cellular process in which cells degrade and recycle their own components through lysosomal pathways to maintain cellular homeostasis.

Rationale design-based drug development process (rational drug design)

a systematic approach to drug development that uses knowledge of biological targets, molecular structure, and mechanisms of action to design and optimize therapeutic agents.

PCR (polymerase chain reaction)

a laboratory technique used to amplify specific DNA sequences exponentially through repeated cycles of denaturation, annealing, and extension.

Southern blotting

a technique used to detect specific DNA sequences by transferring DNA fragments from a gel onto a membrane and probing with a labeled DNA probe.

Western blotting

a technique used to detect specific proteins by separating them by size, transferring them to a membrane, and using antibodies for identification.

immunity

the ability of the body to recognize, respond to, and defend against foreign substances such as pathogens through innate and adaptive immune mechanisms.

Adaptive immunity

a specific, acquired immune response that develops after exposure to an antigen and involves B cells and T cells, providing immunological memory.

DNA sequencing

the process of determining the exact order of nucleotides (A, T, C, G) in a DNA molecule.

Protein sequencing

the determination of the amino acid sequence of a protein, which reveals its structure and function.

ELISA (enzyme-linked immunosorbent assay)

a laboratory technique used to detect and quantify antigens or antibodies using enzyme-linked antibodies that produce a measurable signal.

Human genome project

an international research initiative that successfully mapped and sequenced the entire human genome, identifying all human genes.

immunostaining

a technique that uses labeled antibodies to detect and visualize specific proteins or antigens in cells or tissues.

ultracentrifugation

a high-speed centrifugation technique used to separate cellular components or macromolecules based on size, shape, and density.

Cell cycle checkpoint

a regulatory point at which the cell assesses whether conditions are suitable to proceed to the next phase of the cell cycle, ensuring DNA integrity and proper division.

Vaccine

a biological preparation that stimulates the immune system to develop protective immunity against a specific pathogen without causing disease.

stem cells

undifferentiated cells capable of self-renewal and differentiation into specialized cell types.

CAR-T cells

genetically engineered T lymphocytes that express chimeric antigen receptors (CARs) enabling them to recognize and kill specific cancer cells.

NK cells (natural killer cells)

innate immune lymphocytes that destroy virus-infected or cancerous cells without prior sensitization.

Genome editing

the targeted modification of an organism’s DNA using technologies such as CRISPR-Cas9 to add, remove, or alter genetic sequences.

Mutation

a permanent change in the DNA sequence that may alter gene function and can be inherited or acquired.

Transgenic animal

an organism that has been genetically engineered to carry and express foreign DNA introduced into its genome.

Gene knockout animal

a genetically engineered organism in which a specific gene has been completely inactivated to study its function.

Genetic engineering

the deliberate modification of an organism’s DNA using biotechnology techniques to alter gene expression or introduce new traits.

Drug development process

the series of steps used to bring a new drug to market, including target identification, lead discovery and optimization, preclinical testing, clinical trials, and regulatory approval.

Chemotherapy

the use of cytotoxic drugs to treat cancer by killing or inhibiting the growth of rapidly dividing cells.

immunotherapy

a treatment approach that enhances or modulates the body’s immune system to fight diseases such as cancer or infections.

Gene cloning

the process of making multiple copies of a specific gene by inserting it into a vector and propagating it in a host cell.

viral vectors

genetically modified viruses used to deliver genetic material into cells for gene therapy or research purposes.

mRNA vaccine

uses messenger RNA to instruct cells to produce a specific antigen, stimulating an immune response without using a live pathogen.

Regenerative medicine

a field focused on repairing, replacing, or regenerating damaged tissues or organs using stem cells, biomaterials, or biological molecules.

Central dogma of molecular biology

describes the flow of genetic information in cells: DNA is transcribed into RNA, which is translated into protein.

Chromatography

a laboratory technique used to separate and analyze mixtures based on differential interactions between a stationary phase and a mobile phase.T

Transcription

the process by which RNA polymerase synthesizes RNA from a DNA template.

Lymphocytes

are white blood cells, including B cells, T cells, and NK cells, that play key roles in immune responses.eutn

neutrophil

a type of white blood cell that is part of the innate immune system and is one of the first responders to infection, specializing in phagocytosis.

Nucleosome

the basic structural unit of chromatin, consisting of a segment of DNA wrapped around a core of histone proteins.

Microarray

a laboratory tool that allows simultaneous analysis of the expression of thousands of genes by hybridizing DNA or RNA samples to probes fixed on a solid surface.

Lead compounds

are chemical substances identified during drug discovery that show desirable biological activity and serve as starting points for drug optimization.

Carcinogenesis

the multistep process by which normal cells transform into cancer cells due to genetic and epigenetic alterations.

Genetic toxicity (genotoxicity)

refers to the ability of a substance to damage DNA or chromosomes, potentially leading to mutations or cancer.

Preclinical study

involves laboratory and animal testing of a drug candidate to evaluate its safety, efficacy, pharmacokinetics, and toxicity before human trials.

Clinical studies

research studies conducted in humans to evaluate the safety, efficacy, dosage, and side effects of a medical intervention, conducted in phases (I–IV).

Herbal medicine

the use of plant-derived substances for the prevention or treatment of diseases, based on traditional practices or scientific evidence.

E. coli

a gram-negative bacterium commonly found in the human intestine and widely used as a host organism in molecular biology and biotechnology.

In vitro and in vivo

In vitro refers to experiments conducted outside a living organism (e.g., in test tubes or cell cultures), while in vivo refers to studies performed within a living organism.

Pharmaceutics

the branch of pharmaceutical science concerned with the formulation, manufacturing, and delivery of drugs to ensure safety, stability, and effectiveness.