Genes and Genetic Diseases

Flashcards covering key concepts related to genes, genetic diseases, mutations, chromosomal aberrations, Mendelian inheritance, and multifactorial disorders from the lecture notes.

What is the basic unit of inheritance composed of DNA?

Genes

What is the primary function of DNA?

Provides the code for all body proteins

What is the process where a DNA strand untwists, unzips, and acts as a template for new nucleotide addition?

DNA replication

What term refers to any inherited alteration of genetic material?

Mutation

What type of mutation occurs when one base pair is substituted for another, potentially changing the amino acid sequence?

Base pair substitution or missense mutation

What are agents like radiation and various chemicals that increase the frequency of genetic mutations called?

Mutogens

What is the synthesis of RNA from a DNA template?

Transcription

What is the synthesis of protein from an mRNA template?

Translation

How many chromosomes do normal body cells (somatic cells) contain, and what are these cells called?

46 chromosomes (23 pairs), called diploid cells

How many chromosomes do sperm or egg cells (gametes) contain, and what are these cells called?

23 chromosomes, called haploid cells

What are the first 22 pairs of chromosomes in males and females that do not include sex chromosomes called?

Autosomes

What is a karyotype?

The ordered display of chromosomes determined by length and centromere location

What is a cell that has an exact multiple of the haploid number of chromosomes?

Euploid cell

What is a euploid cell that has more than the diploid number of chromosomes?

Polyploid cell

What is the condition where a somatic cell does not contain a multiple of 23 chromosomes?

Aneuploidy

What is Trisomy 21 commonly known as, and what are some of its characteristic features?

Down syndrome; mental challenges, no nasal bridge, epicanthal folds, protruding tongue, flat and low set ears, short stature, and poor muscle tone.

Which sex chromosome aneuploidy results in females having only one X chromosome (45X)?

Turner syndrome

Which sex chromosome aneuploidy results in males with at least one Y and two X chromosomes (XXY)?

Klinefelter syndrome

What type of chromosomal structural aberration involves the loss of a DNA segment, such as seen in Cri du Chat syndrome?

Deletion

What type of chromosomal structural aberration involves the interchange of genetic material between non-homologous chromosomes?

Translocation

What is Fragile X syndrome, and what are some of its symptoms?

A condition caused by an elevated number of repeated DNA sequences on the long arm of an X chromosome, leading to mild to severe intellectual disability, speech delays, anxiety, hyperactivity, and distinct physical features like long ears and face.

In Mendelian inheritance, what is the specific location occupied by a gene on a chromosome called?

Locus

What is a term used to describe an individual's genetic composition at a given locus?

Genotype

What is the outward, observable appearance of an individual, resulting from their genotype and environment?

Phenotype

What type of inheritance pattern requires an individual to be homozygous for an abnormal allele to express the disease, and is often seen in children but not in parents?

Autosomal recessive inheritance

What is a pedigree?

A tool used to study genetic disorders within families, often starting with a proband.

What is the number of new cases of a disease reported during a specific period, divided by the number of individuals in the population?

Incidence rate

What research strategies are often used to estimate the relative influence of genes and environment on disease?

Twin studies and adoption studies

Neural tube defects are considered multifactorial congenital disorders. What causes them, and what factors contribute to their development?

Failure of the neural tube to close at the end of the fourth week of conception, caused by an interaction of genetic factors and environmental factors (e.g., viral exposure, dietary components, toxins, radiation).

What are the genetic factors commonly associated with increased risk of breast cancer?

Autosomal dominant forms linked to BRCA1 (chromosome 17) and BRCA2 (chromosome 13) genes.