Lecture 13/14- Genetics Flashcards Preview

HESP 632 - Medical Audiology > Lecture 13/14- Genetics > Flashcards

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What is Konigsmark's Classification of genetic hearing loss?

• No associated abnormalities
• External ear abnormalities
• Eye disease
• Musculoskeletal disease
• Integumentary system disease (Skin, hair, and nails)
• Renal disease (Kidney)
• Nervous system disease
• Metabolic and other abnormalities


What are the 2 universal principles of human genetics?

• Virtually all diseases (except some cases of trauma) have a genetic component
• There are no perfect human specimens – all of us carry a significant number of DNA glitches


What is a genome?

Complete set of genetic information
o Contains all of the biological information needed to build and maintain the organism
o Comprised of all of the organisms’ DNA
o Nuclear DNA
o Mitochondrial DNA (mtDNA)


What is an exome?

Protein coding portion of DNA
 Proteins are the output of the DNA

o Corresponds to mature RNA
o ~1% of total genome
o Composed of ~180,000 exons
o Mutations in exome harbor ~85% disease causing mutations


What is non-coding DNA?

o Intron- non-coding sections of a gene
o Important biologic functions


What are nucleotides?

Nitrogen containing base
 A and G are purines
 T and C are prymidines

Bound together through sugars and phosphate


How is DNA structured?

- Nucleotides
- DNA bases form pairs (A and T, C and G)
- Nucleotides strand forms a spiral (double helix)


What are amino acids?

Building blocks of proteins
o Amino acids are sequenced- linked to form proteins
o Order of amino acids dictates protein shape and function
o Proteins- critical roles in the body


What are antibodies?

Bind to foreign particles- protective function


What are enzymes?

Carry out almost all of the chemical reactions in cells


What are messengers?

Transmit signals to coordinate biological processes between cells, tissues, organs


What are structural components?

Provide structure and support for cells, allow movement


What are transport and storage?

Bind and carry atoms and small molecules within cells and throughout the body


What is a mutation?

Change in a gene’s biochemical makeup, change at the DNA level


What is a mutagen?

A substance that causes a mutation
o Examples: radiation, aflatoxin B (fungus on peanuts), cola, tea, coffee, food additives, cigarette smoke, etc.


What is a mutant?

An allele that differs from the wild type allele, altering the phenotype
o Wild type: normal variant of a gene


What is a spontaneous mutation?

A genetic change resulting from the mispairing of bases during replications


What is a mutational hot spot?

Most likely to happen when the nearby DNA is repetitive


What is a point mutation?

Involving a single nucleotide in the DNA molecule


What is a missense mutation?

Change in a codon so that it codes for a different amino acid


What is a nonsense mutation?

Changes a codon specifying an amino acid into a “stop” codon (UAA, UAG, UGA)- results in a shortened protein produce


What is a deletion and insertion?

Involving >1 nucleotide
o Codon deletions and inserts involving bases which are a multiple of 3 resulting in a “frame” mutation
o Expansion of a tri-nucleotide repeat


What is a frameshift mutation?

Additional or deletion of bases that are not a multiple of 3 with disruption of the reading frame of the protein


What are structural chromosomal abnormalities?

Telomeres: protects chromosome
• Will shorten with aging process
• Dysfunction is associated with some diseases

Centromere: involved in cell division and replication of cells

P arm (short arm)

Q arm (long arm)

Bands: specific address of a gene


What are the number of chromosomes?

46 chromosomes, 23 homologous pairs
• 22 pairs are autosomes (the same regardless of sex)
• 1 pair of sex chromosomes

Biologically female: XX

Biologically male: XY


What is aneuploidy?

One or more extra or missing chromosomes


What is a translocation?

Change of location.

- In genetics this typically refers to transfer of a segment of a chromosome to a new position, most often on another chromosome


What is a deletion?

Loss of genetic material, ranging from a single nucleotide to an entire pice of chromosome


What is an inversion?

Same genetic material, but it is flipped


What are characteristics of autosomal dominant traits?

• Only one copy of gene to product phenotype
• Chance of recurrence is ½
• Vertical family pattern
• Persons with the trait have a parent with the trait, unless they represent a new mutation
• If line broken, stays broken
• Male: female= 1:1