Genetics and Cytogenetics Lecture

Comprehensive vocabulary flashcards covering historical foundations, cytogenetics branches, cell biology, Mendelian and non-Mendelian genetics, molecular genetics and key laboratory techniques.

Pangenesis

Hippocrates’ early idea that tiny particles from all body parts gather in reproductive organs and pass traits to offspring.

Chromosome Theory of Inheritance

Sutton and Boveri’s proposal that genes are located on chromosomes, explaining Mendel’s laws at the cellular level.

Transforming Principle

Substance discovered by Griffith (1928) and shown by Avery, MacLeod & McCarty (1944) to be DNA, capable of transferring genetic information.

Human Genome Project

1990–2003 international effort that mapped all human genes, revolutionizing modern genetics and disease research.

Classical Cytogenetics

Branch that studies chromosomes by light microscopy using karyotyping, G-banding and basic stains.

Molecular Cytogenetics

Field combining molecular biology with cytogenetics; employs FISH, CGH and array CGH to analyze DNA on chromosomes.

Clinical Cytogenetics

Application of cytogenetic techniques to diagnose chromosomal abnormalities in prenatal testing, cancer, infertility, etc.

Cancer Cytogenetics

Study focused on chromosomal changes in tumors, such as translocations, deletions and amplifications.

Cytogenetics

The study of chromosomes, their structure, function and role in disease.

Chromosome

DNA-protein thread-like structure that carries genetic information.

Gene

A segment of DNA that encodes a functional product, usually a protein.

Karyotype

Ordered visual profile of an individual’s chromosomes showing number, size and shape.

Genome

The complete set of genetic material in an organism.

Mutation

A change in the DNA sequence that can alter gene function.

Aneuploidy

Presence of an abnormal chromosome number in a cell.

Translocation

Chromosomal abnormality in which a segment moves from one chromosome to another.

Cell

Basic structural and functional unit of all living organisms.

Prokaryotic Cell

Cell without a true nucleus; exemplified by bacteria.

Eukaryotic Cell

Cell with a true nucleus and membrane-bound organelles; e.g., human cell.

Nucleus

Organelle that houses DNA and controls cellular activities.

Mitochondria

Organelle that produces cellular energy (ATP).

Ribosome

Organelle where protein synthesis occurs.

Endoplasmic Reticulum

Membranous network; rough ER synthesizes proteins, smooth ER produces lipids and detoxifies.

Golgi Apparatus

Organelle that modifies, packages and distributes proteins.

Lysosome

Organelle containing digestive enzymes for cellular waste breakdown.

Centrioles

Cylindrical organelles that help organize the spindle during cell division.

Plasma Membrane

Phospholipid bilayer that regulates substance entry and exit from the cell.

Sister Chromatid

One of two identical DNA copies joined at a centromere after replication.

Centromere

Constricted chromosomal region where sister chromatids are joined.

Autosomes

The 22 pairs of non-sex chromosomes in humans.

Sex Chromosomes

Chromosome pair determining sex (XX female, XY male).

Diploid

Cell with two sets of chromosomes (2n = 46 in humans).

Haploid

Cell with one set of chromosomes (n = 23 in human gametes).

Mitosis

Somatic cell division producing two identical diploid daughter cells.

Cytokinesis

Division of the cytoplasm following nuclear division.

Meiosis

Germ-cell division producing four non-identical haploid gametes; promotes genetic diversity.

Law of Segregation

Mendelian principle stating alleles separate during gamete formation so each gamete carries one allele per gene.

Law of Independent Assortment

Mendelian principle that genes on different chromosomes assort independently during gamete formation.

Law of Dominance

Mendelian concept where one allele masks the expression of another in heterozygotes.

Allele

Alternative form of a gene (e.g., A or a).

Genotype

Genetic makeup of an organism (e.g., AA, Aa, aa).

Phenotype

Observable traits resulting from genotype and environment.

Homozygous

Having two identical alleles for a gene (AA or aa).

Heterozygous

Having two different alleles for a gene (Aa).

Monohybrid Cross

Genetic cross analyzing inheritance of one trait with two alleles.

Dihybrid Cross

Genetic cross following two traits, yielding the classic 9:3:3:1 phenotypic ratio.

Punnett Square

Grid diagram used to predict offspring genotypes and phenotypes.

Test Cross

Cross of an individual showing a dominant phenotype with a homozygous recessive to reveal the unknown genotype.

Pure Line

True-breeding organisms homozygous for a trait through repeated self-fertilization.

Filial Generation

Offspring generations in genetics; F1 is first, F2 is second, etc.

Incomplete Dominance

Inheritance where the heterozygote shows a blended intermediate phenotype.

Codominance

Inheritance where both alleles are fully expressed in the heterozygote.

Multiple Alleles

More than two allele forms exist for a gene in a population (e.g., ABO blood group).

Sex-Linked Trait

Trait determined by a gene on the X or Y chromosome.

Mitochondrial Inheritance

Transmission of genes solely through the maternal mitochondria.

DNA

Deoxyribonucleic acid; double-helix molecule storing hereditary information.

Nucleotide

DNA or RNA building block composed of sugar, phosphate and nitrogenous base.

Double Helix

Twisted-ladder structure of DNA described by Watson and Crick.

RNA

Ribonucleic acid; single-stranded molecule involved in protein synthesis.

mRNA

Messenger RNA; carries genetic code from DNA to ribosomes.

tRNA

Transfer RNA; brings amino acids to ribosomes during translation.

rRNA

Ribosomal RNA; structural and catalytic component of ribosomes.

Transcription

Process of synthesizing RNA from a DNA template.

Translation

Process of decoding mRNA to assemble amino acids into a protein.

PCR

Polymerase Chain Reaction; amplifies specific DNA sequences in vitro.

Gel Electrophoresis

Technique that separates DNA fragments by size through a gel matrix.

DNA Sequencing

Determining the exact order of nucleotides in DNA.

RT-PCR

Reverse Transcription PCR; converts RNA to DNA then amplifies it for analysis.

Down Syndrome

Trisomy 21; genetic disorder with an extra chromosome 21.

Turner Syndrome

45,X chromosomal condition in females characterized by monosomy X.

Klinefelter Syndrome

47,XXY chromosomal condition in males with an extra X chromosome.

Patau Syndrome

Trisomy 13; severe congenital disorder caused by an extra chromosome 13.

Edwards Syndrome

Trisomy 18; genetic disorder with an extra chromosome 18.