Introduction to Cytogenetics – Comprehensive Vocabulary

A curated set of vocabulary flashcards covering key terms, structures, processes, and abnormalities introduced throughout the cytogenetics lecture series.

Cytogenetics

The branch of genetics that combines cytology and genetics to study heredity at the cellular (chromosomal) level.

Genetics

The science of heredity and variation in living organisms.

Human Genetics

Subspecialty that studies heredity specifically in humans.

Medical Genetics

Subspecialty that focuses on human genetic variation of medical relevance.

Hematology

Branch of clinical pathology that studies blood and blood-forming tissues.

Blood Bank

Clinical pathology discipline dealing with blood collection, storage, and transfusion.

Serology/Immunology

Field that examines antigen–antibody reactions.

Microbiology

Study of microorganisms such as bacteria, viruses, fungi, and parasites.

Clinical Microscopy

Analysis of urine, body fluids, parasites, and cells microscopically.

Clinical Chemistry

Chemical analysis of body fluids for diagnostic purposes.

Special Chemistry

Advanced chemical testing area that includes cytogenetics.

Cell

Basic functional unit of all living organisms.

Tissue

Group of similar cells performing a common function.

Epithelium

Tissue type that lines cavities and surfaces of structures.

Connective Tissue

Tissue that supports, binds, or separates other tissues and organs.

Muscle Tissue

Tissue specialized for contraction and movement.

Nervous Tissue

Tissue that transmits nerve impulses.

Organ

Structure composed of multiple tissue types performing a specific function.

Organ System

Group of organs working together to perform complex functions.

Plasma Membrane

Bilipid layer enclosing the cell, controlling substance movement and cell interactions.

Cytoplasm

Cellular region outside the nucleus containing organelles and cytosol.

Cytosol

Fluid portion of the cytoplasm in which organelles are suspended.

Cytoskeleton

Network of microtubules and filaments that maintains cell shape and enables movement.

Organelle

Metabolically active, membrane-bound structure performing specific cellular functions.

Inclusion

Intracellular accumulation of metabolites such as pigments or nutrients.

Ribosome

Organelle that synthesizes proteins by translating mRNA.

Rough Endoplasmic Reticulum (RER)

Membranous organelle studded with ribosomes; synthesizes and transports proteins.

Smooth Endoplasmic Reticulum (SER)

Organelle involved in lipid, steroid, and triglyceride synthesis and detoxification.

Golgi Apparatus

Organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery.

Lysosome

Acidic organelle containing hydrolytic enzymes for intracellular digestion.

Mitochondrion

Organelle with its own DNA responsible for ATP production via oxidative phosphorylation.

Centrosome

Microtubule-organizing center containing a pair of centrioles.

Centrioles

Cylindrical organelles (9 microtubule triplets) essential for spindle formation.

Nucleus

Largest organelle housing chromatin, nucleolus, and nucleoplasm.

Nucleolus

Non-membranous nuclear structure where rRNA is synthesized; hypertrophic in malignancy.

Chromatin

Complex of DNA and proteins forming chromosomes; exists as euchromatin or heterochromatin.

Euchromatin

Light-staining, transcriptionally active chromatin.

Heterochromatin

Dense, transcriptionally inactive chromatin located near the nuclear periphery.

Cell Cycle

Series of events that prepare a cell to divide into two daughter cells.

Interphase

Long cell-cycle phase (G1, S, G2) devoted to growth and DNA replication.

G1 Phase

Interphase stage of cell growth and synthesis of macromolecules needed for DNA duplication.

S Phase

Interphase stage during which DNA is replicated (chromosomes become double-stranded).

G2 Phase

Interphase stage preparing the cell for mitosis; tubulin synthesis occurs.

G0 Phase

Resting stage where highly differentiated cells exit the cell cycle, temporarily or permanently.

Mitosis

Process of nuclear (karyokinesis) and cytoplasmic (cytokinesis) division yielding two identical cells.

Prophase

First mitotic stage; chromatin condenses, nucleolus disappears, spindle begins to form.

Prometaphase

Mitotic stage when nuclear envelope disintegrates and kinetochore microtubules attach to chromosomes.

Metaphase

Mitotic stage where duplicated chromosomes align on the metaphase plate.

Anaphase

Mitotic stage when sister chromatids separate and move toward opposite poles.

Telophase

Final mitotic stage; nuclear envelopes reform, chromosomes decondense, cytokinesis completes.

Cytokinesis

Division of the cytoplasm forming two separate daughter cells.

Meiosis

Special cell division producing haploid gametes with genetic recombination.

Meiosis I

Reductional division that separates homologous chromosome pairs, halving chromosome number.

Meiosis II

Equatorial division resembling mitosis that separates sister chromatids.

Prophase I

Extended meiotic stage with sub-stages leptotene, zygotene, pachytene, diplotene, diakinesis.

Leptotene

Prophase I sub-stage where chromosomes begin to condense into thin threads.

Zygotene

Prophase I sub-stage where homologs pair (synapsis) via synaptonemal complex.

Pachytene

Prophase I sub-stage featuring crossing over and chiasmata formation.

Diplotene

Prophase I sub-stage where homologs separate slightly, revealing chiasmata.

Diakinesis

Final Prophase I sub-stage; chromosomes maximally condensed, nuclear envelope disappears.

Genotype

Genetic constitution (allele combination) of an individual.

Phenotype

Observable traits resulting from genotype and environment.

Allele

Alternative form of a gene located at the same locus on homologous chromosomes.

Gene

DNA segment encoding a functional product (protein or RNA).

Genome

Complete set of genetic material in an organism.

Gene Pool

All genes and their alleles present in a population.

Dominant Allele

Allele that masks expression of a recessive allele in heterozygotes.

Recessive Allele

Allele whose expression is masked in heterozygotes by a dominant allele.

Co-dominance

Inheritance pattern where both alleles are fully expressed (e.g., AB blood type).

Autosomal Gene

Gene located on one of the 22 pairs of non-sex chromosomes.

Autosomal Dominant Inheritance

Trait expressed in heterozygotes; only one mutant allele needed for phenotype.

Autosomal Recessive Inheritance

Trait expressed only when two mutant alleles are present.

X-Linked Dominant Inheritance

Mutant gene on X chromosome expressed in heterozygous females and hemizygous males; no male-to-male transmission.

X-Linked Recessive Inheritance

Mutation on X chromosome expressed mainly in males; females are usually carriers.

Mitochondrial Inheritance

Transmission of traits via mitochondrial DNA, passed almost exclusively from mother to all offspring.

Punnett Square

Grid used to predict genotypic and phenotypic ratios of offspring.

ABO Blood Group

System determined by A and B antigens on red cells and corresponding antibodies.

RNA

Single-stranded nucleic acid containing ribose and uracil; involved in gene expression.

DNA

Double-stranded helical molecule of deoxyribose nucleotides storing genetic information.

Nucleotide

Monomer of nucleic acids composed of a phosphate, pentose sugar, and nitrogenous base.

Purine

Double-ring nitrogenous base; adenine or guanine.

Pyrimidine

Single-ring nitrogenous base; cytosine, thymine, or uracil.

Complementary Base Pairing

Specific hydrogen bonding (A–T/U, G–C) between nucleotides in DNA/RNA.

Messenger RNA (mRNA)

RNA copy of a gene that carries coding information from nucleus to ribosome.

Transfer RNA (tRNA)

Cloverleaf RNA that delivers specific amino acids to ribosome; contains anticodon loop.

Ribosomal RNA (rRNA)

Structural and enzymatic component of ribosomes catalyzing protein synthesis.

Codon

Triplet of mRNA bases specifying one amino acid.

Anticodon

Complementary triplet on tRNA pairing with mRNA codon.

Start Codon

AUG sequence signaling initiation of translation (methionine).

Stop Codon

UAA, UAG, or UGA sequence signaling termination of translation.

Genetic Code

Universal correspondence between mRNA codons and amino acids.

DNA Replication

Semiconservative process copying entire DNA to produce identical double helices.

Replication Origin

Specific DNA sequence where replication begins.

Helicase

Enzyme that unwinds DNA helix at the replication fork.

RNA Primase

Enzyme that synthesizes short RNA primers to initiate DNA synthesis.

DNA Polymerase δ

Eukaryotic polymerase that synthesizes the leading strand 5'→3'.

DNA Polymerase ε

Polymerase that elongates lagging-strand fragments in eukaryotes.

Okazaki Fragment

Short DNA segment synthesized discontinuously on the lagging strand.

DNA Ligase

Enzyme that seals nicks in DNA backbone, joining Okazaki fragments.

Semiconservative Replication

Replication model where each daughter helix contains one old and one new strand.