Genetics and Chromosomal Abnormalities Overview

DNA

Deoxyribonucleic acid, genetic material of organisms.

RNA

Ribonucleic acid, involved in protein synthesis.

Nucleotide

Building block of DNA and RNA.

Phosphate

Component of DNA and RNA backbone.

Deoxyribose

5-carbon sugar in DNA structure.

Ribose

5-carbon sugar in RNA structure.

Pyrimidines

Single carbon-nitrogen ring bases in nucleic acids.

Purines

Double carbon-nitrogen ring bases in nucleic acids.

Cytosine

Pyrimidine base found in DNA and RNA.

Thymine

Pyrimidine base exclusive to DNA.

Guanine

Purine base found in DNA and RNA.

Adenine

Purine base found in DNA and RNA.

Base pairing

A-T and G-C interactions in DNA.

DNA polymerase

Enzyme facilitating DNA replication.

Mutation

Alteration in DNA sequence affecting gene function.

Point mutation

Alteration of one or few nucleotide base pairs.

Silent mutation

No consequence on protein function.

Missense mutation

Single amino acid change in protein.

Nonsense mutation

Introduces stop codon in protein synthesis.

Frameshift mutation

Insertion or deletion altering reading frame.

Transcription

Process of synthesizing mRNA from DNA.

Translation

Process of synthesizing proteins from mRNA.

tRNA

Transfer RNA carrying amino acids to ribosome.

Polypeptide

Chain of amino acids forming proteins.

Somatic cells

Diploid cells with 46 chromosomes.

Gametes

Haploid reproductive cells with 23 chromosomes.

Autosomes

Non-sex chromosomes, 22 pairs in humans.

Sex chromosomes

Determine biological sex, XX or XY.

Karyotype

Ordered display of an individual's chromosomes.

Chromosomal aberrations

Structural or numerical abnormalities in chromosomes.

Polyploidy

Multiple sets of chromosomes, e.g., triploidy.

Aneuploidy

Abnormal number of chromosomes due to nondisjunction.

Trisomy 21

Down syndrome, caused by an extra chromosome 21.

Partial trisomy

Extra portion of a chromosome present.

Chromosomal mosaics

Presence of two or more different cell lines.

Down syndrome prevalence

1 in 800 live births.

Down syndrome IQ range

Typically between 20 and 70.

Down syndrome features

Includes low nasal bridge and protruding tongue.

Down syndrome health risks

Includes congenital heart disease and respiratory infections.

Down syndrome life expectancy

Approximately 60 years.

Klinefelter syndrome

Condition in males with an extra X chromosome.

Klinefelter syndrome prevalence

1 in 1000 male births.

Klinefelter syndrome traits

Includes moderate mental impairment and gynecomastia.

Turner syndrome

Condition affecting females with a missing X chromosome.

Turner syndrome features

Includes short stature and webbed neck.

Genotype

Organism's specific genetic makeup.

Phenotype

Observable characteristics resulting from genotype.

Autosomal dominant inheritance

Trait appears in every generation.

Autosomal recessive inheritance

Trait often skips generations.

X-linked recessive inheritance

Trait more common in males than females.

Duchenne muscular dystrophy

Example of X-linked recessive condition.

Pedigree

Chart summarizing family relationships and genetic traits.

Sex-limited traits

Expressed only in one sex.

Sex-linked traits

Determined by genes on sex chromosomes.

Multifactorial inheritance

Influenced by multiple genes and environmental factors.

Cystic fibrosis

Example of autosomal recessive condition.

Huntington's disease

Example of autosomal dominant condition.

Sickle cell anemia

Another example of autosomal recessive condition.

Klinefelter syndrome variants

Includes XXY, XXXY, and mosaics.

Turner syndrome variants

Includes monosomy X and XXX.

Environmental factors

Influence trait expression in individuals.

Bell-shaped distribution

Common pattern for traits like height and IQ.

Huntington Disease

Autosomal dominant disorder with severe basal ganglia degeneration.

CAG repeat expansion

Genetic test for Huntington Disease diagnosis.

Chorea

Nonrepetitive muscular contractions in Huntington Disease.

Athetosis

Irregular, slow movements in distal extremities.

Ballism

Wild flinging of limbs due to neurological issues.

Down Syndrome

Caused by Trisomy 21, extra chromosome 21.

Nondisjunction

Failure of chromosomes to separate properly during meiosis.

Klinefelter's Syndrome

Males with extra X chromosome (XXY) leading to sterility.

Duchenne's muscular dystrophy

X-linked recessive disorder causing muscle degeneration.

DMD gene

Gene associated with Duchenne's muscular dystrophy.

Sickle Cell Anemia

Autosomal recessive disorder due to HBB gene mutation.

Vaso-occlusive crises

Pain episodes in Sickle Cell Anemia.

Turner Syndrome

Condition in females with a single X chromosome.

Cystic Fibrosis

Autosomal recessive disorder affecting chloride ion transport.

Sweat chloride test

Diagnostic test for Cystic Fibrosis.

IQ range in Down Syndrome

Typically between 20-70.

Life expectancy in Down Syndrome

Approximately 60 years.

Karyotyping

Chromosomal analysis for genetic disorders.

Muscle biopsy

Test showing dystrophin deficiency in Duchenne's.

Creatine kinase (CK)

Elevated levels indicate muscle damage.

Prenatal screening

Tests like nuchal translucency for Down Syndrome.

Emotional lability

Rapid mood changes in Huntington Disease.

Progressive cognitive dysfunction

Dementia-like symptoms in Huntington Disease.

Congenital heart disease

Common in individuals with Down Syndrome.

Webbing of neck

Physical feature associated with Turner Syndrome.

Gonadal streaks

Underdeveloped ovaries in Turner Syndrome.

Malnutrition

Result of pancreatic obstruction in Cystic Fibrosis.

Respiratory infections

Common complication in Cystic Fibrosis patients.