• A type of nucleic acid that contains sugar (deoxyribose)
• Usually found in the cell nucleus and mitochondria
• Responsible for the storage and genetic information
• Is made up of four nitrogeneous bases
• Double stranded helix structure

• Purines
• Adenine (A)
• Guanine (G)
• Pyrimidines
• Cytosine (C)
• Thymine (T)
• Base Pairs
• Purine/Pyrimidine combinations
• A-T
• C-G

1. Messenger RNA (mRNA): Provides a template for protein synthesis depending on a codon sequence that is based on that of the complementary strand of DNA (cDNA).
2. Transfer RNA (tRNA): delivers these products into the cell. Recognizes and binds a specific amino acid, which it then transfers to organelles called ribosomes.
3. Ribosomal RNA (rRNA): Contributes to the formation of ribosomes along with nuclear ribosomal proteins.

Chromosomes in the nuclei of somatic cells go through a series of phases (prohpase, prometaphase, metaphase, anaphase, and telephase) resulting in the creation of daughter cells with the same chromosome number and genetic makeup as the original somatic cell.

• One cell produces four cells, each with half the number of chromosomes, known as gametocytes.
• This is the process that produces germ cells (sprem and ova)
• When sperm divide, four spermatids result
• When ove divide, three polar bodies and only one ovum are produced

• The study of the human genome, or the full DNA sequence.
• Reflects not just the study of single genes but the functions and interactions of all the genes in the genome, including interactions between genes and with genes and the environment.

The genetic makeup of an individual.  Not always apparent of visible.

A series of two or more different genes occupying the same location on a specific chromosome

• Huntington disease (HD)
• Marfan syndrome
• osteogenesis imperfecta

• Cystic fibrosis
• Tay-Sachs disease
• Thalassemia
• Sickle cell disease

• Hemophilia
• X-linked severe combined immunodeficiency (XSCID)
• "Bubble boy disease"

• Leigh syndrome.
• Manifestations of mitochondrial gene disorders usually occur in the first year of life and include hypotonia, spasticity, peripheral neuropathy, encephalopathy, ataxia, and vision and hearing loss
• Manifestations are variable because of the heteroplasmic features of these disorders.
• Mitochondrial genes are transmitted only through female or maternal lines.

refers to random distribution of mitochondria to daughter cells during embryonic cell division, leading to a variable distribution of mutant mitochondrial genes in tissues of an individual and between related individuals.

the combination of cells with the regular chromosome number and those with an altered number of chromosomes

• occurs when nondisjunction results in cells with one copy of a chromosome instead of two
• Defect is not compatible with life in autosomes
• Significatn physical and mental defects result in sex chromosomes
• Turner syndrome (females)

• The presence of three copies of a chromosome in a cell
• incompatible with life is a large chromosome is effected because they contain a great deal of genetic material
• Effected chromosome 21 results in Down syndrome

• occurs when a large segment of DNA breaks from one chromosome and reattaches to a different chromosome, often occurring during meiosis
• Balanced translocation doesnot affect the individual because he or she still retains the same amount of genetic material

• "Around the genome"
• caused by environmental and metabolic agents that stimulate chemical modifications of genes
• mostly include histone acetylation and DNA methylation
• Change the expression of the gene without causing genetic mutation
• are heritable with the potential to influence the health of future generations

• the mechanism that controls expression of genes based on parental origin
• An epigenetic phenomenon resulting in regulation of the expression of gene activity without alteration of genetic structure
• Usually the result of DNA methylation, preventing transcription of the gene
• Occurs when both maternal and paternal alleles are present, with only one allele expressed and the other allele inactive.
• Diseases inherited from the mother: myotonic muscular dystrophy (MMD); Fragile Xsyndrome (FXS)
• Diseases inherited from the father: Wilms tumor; osteosarcoma; bilateral retinoblastoma; embryonal rhabdomyosarcoma

• The embryologic period
• Weeks 3 through 8 of gestation
• organogenesis (development of organ systems) is occurring

• The group of diseases known to cause damage to the fetus if exposure occurs described by this acronym
• Toxoplasmosis
• Other (hepatitis)
• Rubella
• Cytomegalovirus
• Herpes

• Autosomal dominant genetic disorder caused by degeneration of the basal ganglia and cortical regions of the brain
• affects approximately 5 of 100,000 predominantly white males and females of northern European ancestry
• Caused by a defect in the huntington gene on chromosome 4
• Involuntary movements, cognitive impairment, and emotional disturbance
• Diagnosis is based on a complete family and personal medical history and physical examination
• Genetic testing can definitively diagnose HD
• Blood samples of bother the individual and close family member can precisely diagnose HD
• symptomatic individuals: CT, MRI, PET detect characterisitc brain anomalies associated with HD
• No cure exists

• Autosomal recessive disorder that affects red blood cells
• Hemoglobin A (HbA) is replaced by hemoglobin S (sickled)
• transmitted from parent to child
• Commonly found in individuals of African ancestry
• Is the result of a single gene mutation that follows Mendelian inheritance patterns
• Lab testing is used to diagnose
• Treatment is symptom specific

• Mitochondrial encephalomyopathy, lactic acidosis, and stroke
• significant cause of strokelike manifestations in individuals less than 45 years of age
• Life span: 20-40 years
• No gender or ethinc predilection
• Maternally inherited
• Diagnosis is based on family history and documentation of clinical manifestations, and it is confirmed with lab studies
• Biochemical analysis, and Muscle biopsy
• Treatment is focused on management of manifestations