Molecular Genetics, Cell Cycle Regulation, and Biotechnology

Comprehensive vocabulary flashcards covering prokaryotic and eukaryotic gene regulation, cell cycle control mechanisms, cancer genetics, and modern biotechnology tools including PCR, cloning, and CRISPR.

Gene Expression

The entire set of processes that results in using the information stored in a gene to synthesize a functional product.

Coding Strand

The non-template strand of DNA that has the same nucleotide sequence as the synthesized mRNA (with thymine instead of uracil).

Structural Sequences

Regions of a gene containing information that codes for amino acids or nucleotides in the final protein or RNA product.

Regulatory Sequences

DNA sequences containing information that controls the rate of transcription or other aspects of gene expression.

Operon

A group of genes with a common function that fall under the control of common regulatory sequences in bacteria.

Promoter

A specific DNA sequence where RNA polymerase binds to initiate transcription of a gene.

Operator

A regulatory DNA sequence within an operon where an activator or repressor protein binds to regulate transcription.

Transcription Factors

Proteins coded by regulatory genes that control and regulate gene expression.

Activator

A transcription factor that induces transcription by making it easier for RNA polymerase to bind to the promoter.

Enhancer

A regulatory DNA site involved in positive control where activator proteins bind to induce transcription.

Repressor

A transcription factor that inhibits transcription by binding to DNA and making it harder or impossible for RNA polymerase to bind.

Silencer

A regulatory DNA sequence involved in negative control where repressor proteins bind to inhibit transcription.

lac Operon

An operon in E. coli consisting of a series of genes that break down lactose when lactose is present and glucose is low.

Chromatin

A diffuse complex of DNA and packaging proteins present in the nucleus when eukaryotic cells are not actively dividing.

Histone

Proteins with positively charged tails that pack and organize negatively charged DNA molecules.

Nucleosome

A structural unit of eukaryotic chromatin consisting of a length of DNA coiled around a core of $8$ histone proteins.

Exon

A expressed coding region of a eukaryotic gene that remains in mRNA and codes for amino acids.

Intron

A non-expressed genetic sequence inside a eukaryotic gene that is spliced out of the pre-mRNA transcript before translation.

Spliceosome

A molecular complex of RNA and proteins that removes introns and splices exons together during eukaryotic mRNA processing.

Alternative Splicing

A post-transcriptional process where different combinations of exons and introns are spliced, allowing a single gene to produce multiple distinct protein isoforms.

Competitive Inhibitor

A regulatory molecule that competes directly with an enzyme's substrate for binding at the active site.

Noncompetitive Inhibitor

A molecule that binds to an enzyme at a site other than the active site, inducing a conformational change that renders the enzyme inactive.

Feedback Inhibition

A cellular control mechanism in which the end product of a metabolic pathway acts as an inhibitor of an enzyme earlier in that pathway.

Kinase

An enzyme that catalyzes the transfer of a phosphate group from ATP to a specific target protein to alter its shape and activity.

Cell Cycle

The regular sequence of growth, DNA duplication, and division that eukaryotic cells undergo.

Interphase

The phase of the cell cycle during which the cell grows, replicates its DNA, and prepares for division, consisting of G1, S, and G2 phases.

G0 Phase

A non-dividing, metabolically active resting state of the cell cycle entered by cells that do not pass the G1 checkpoint.

Mitosis

The mitotic phase process in which the nucleus and replicated chromosomes divide and distribute equally between two daughter nuclei.

Cytokinesis

The division of the cytoplasm following mitosis to form two separate daughter cells.

Anchorage Dependence

The requirement that a cell must be attached to a solid substratum or surface in order to divide.

Density-Dependent Inhibition

A phenomenon in which crowded cells stop dividing once an optimal monolayer density is achieved.

Vascular Endothelial Growth Factor (VEGF)

A growth factor protein in mammals that stimulates the formation of new blood vessels during fetal development and wound healing.

Cell Cycle Control System

A cyclically operating set of molecules in the cell that triggers and coordinates key events through hard-stop checkpoints (G1, G2, and M).

Proto-Oncogene

A normal gene coding for proteins that stimulate healthy cell growth, division, and survival (analogous to a car's gas pedal).

Tumor Suppressor Gene

A gene coding for proteins that inhibit cell division, repair damaged DNA, or promote apoptosis (analogous to a car's brakes).

Oncogene

A mutated, overactive, or abnormally expressed proto-oncogene that causes uncontrolled cell proliferation.

Apoptosis

A programmed pathway of cellular self-destruction triggered by severe DNA damage or cellular abnormalities.

Benign Tumor

A noncancerous mass of abnormal cells that remains confined to its original site and does not invade surrounding tissue or spread.

Malignant Tumor

An abnormal cancerous mass of cells capable of invading surrounding tissues and disseminating to distant body sites.

Metastasis

The spread of malignant cancer cells beyond their primary site to establish secondary tumors in distant tissues.

Carcinoma

A major category of cancer that originates in epithelial tissues, including skin and the lining of organs.

Sarcoma

A category of cancer that originates in supportive and connective tissues, such as bone and muscle.

HeLa Cells

A continuously dividing, immortal cell line established in $1951$ from cervical cancer tissue taken from Henrietta Lacks.

Differentiation

The process by which an unspecialized cell becomes specialized in structure and function through differential gene expression.

Totipotent

Describing a cell that has the potential to differentiate into any cell type and give rise to an entire complete organism.

Regeneration

The biological process of regrowth and restoration of lost or damaged tissues and body parts, such as lizard tails or starfish arms.

Nuclear Transplantation

A cloning method where the nucleus of an unfertilized egg or zygote is replaced with a diploid nucleus from a differentiated somatic body cell.

Gene Cloning

The insertion of a foreign target DNA fragment into a plasmid vector using restriction enzymes and ligase to produce multiple copies inside host bacteria.

Insulin

A pancreatic hormone that regulates blood glucose levels by promoting glucose uptake into somatic cells and glycogen storage in the liver.

CRISPR Immune System

A prokaryotic adaptive defense system where bacteria integrate snippets of invading viral DNA into genomic spacer arrays to recognize future infections.

Cas9

A bacterial endonuclease enzyme guided by RNA that cleaves double-stranded DNA matching a target sequence for gene editing.

Gene Knockout

A genetic engineering technique in which a specific target gene is rendered completely inoperative or disabled.

p53

A tumor suppressor gene that prevents tumor development; knocking it out in mice leads to significantly premature tumor onset.

Bioengineering

The deliberate alteration and manipulation of an organism's genetic material to achieve desired functional traits.

Genetically Modified Organism (GMO)

An organism whose genetic material has been artificially altered using recombinant DNA technology or gene editing.

DNA Amplification

The molecular process of generating millions of identical copies of a specific target DNA segment from a minute starting sample.

Polymerase Chain Reaction (PCR)

An in vitro thermocyclic method used to rapidly amplify target DNA sequences through repeated cycles of denaturation, primer annealing, and extension.

Gel Electrophoresis

A technique used to separate charged macromolecules, such as DNA fragments, based on their molecular size and charge as they migrate through a gel matrix.

Short Tandem Repeat (STR)

A tandem sequence of $2$ to $6$ base pairs in DNA that repeats multiple consecutive times, varying in length between individuals.

STR Analysis

A forensic DNA profiling method that examines and compares the repeat lengths at polymorphic STR loci between individuals using PCR and gel electrophoresis.

CODIS

The Combined DNA Index System; an FBI-maintained database of STR profiles used in criminal investigations across $20$ core loci.

Genetic Ancestry Testing

The analysis of unique single-nucleotide variants across the genome to infer the likely geographic origins of an individual's recent ancestors based on population frequencies.