Genetics C1&2

Here are comprehensive flashcards for important terms and concepts from Chapters 1 and 2 of the textbook, designed for a Human Genetics class:

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### Chapter 1: Introduction

#### 1. Genetics

- Definition: The study of heredity and the variation of inherited characteristics.

- Key Point: Genetics explains how traits are passed from parents to offspring through genes.

#### 2. Genomics

- Definition: The study of the entire genome, including the interactions of genes with each other and the environment.

- Key Point: Genomics focuses on the structure, function, and mapping of genomes.

#### 3. Human Genome Project

- Definition: An international scientific research project that successfully mapped and sequenced the entire human genome.

- Key Point: Completed in 2003, it provided a reference sequence for human DNA, enabling advances in medicine and genetics.

#### 4. Medical Genetics

- Definition: A medical specialty that deals with the diagnosis and management of hereditary disorders.

- Key Point: Medical geneticists work with a team to evaluate, diagnose, and treat genetic conditions.

#### 5. Chromosome Disorders

- Definition: Disorders caused by changes in the number or structure of chromosomes.

- Key Point: Examples include Down syndrome (trisomy 21) and 22q11.2 deletion syndrome.

#### 6. Single-Gene Disorders

- Definition: Disorders caused by mutations in a single gene.

- Key Point: Examples include cystic fibrosis, Huntington disease, and Marfan syndrome.

#### 7. Multifactorial Disorders

- Definition: Disorders caused by a combination of genetic and environmental factors.

- Key Point: Examples include diabetes, heart disease, and some cancers.

#### 8. Variant of Uncertain Significance (VUS)

- Definition: A genetic change whose impact on health is not yet known.

- Key Point: VUS can complicate genetic testing and counseling.

#### 9. Penetrance

- Definition: The proportion of individuals with a specific genetic variant who exhibit the associated phenotype.

- Key Point: Incomplete penetrance means not all individuals with the variant show symptoms.

#### 10. Pleiotropy

- Definition: A single gene influencing multiple phenotypic traits.

- Key Point: Example: Marfan syndrome affects the skeleton, eyes, and cardiovascular system.

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### Chapter 2: Introduction to the Human Genome

#### 1. Human Genome

- Definition: The complete set of DNA in a human, including all genes and non-coding sequences.

- Key Point: The human genome contains approximately 20,000-25,000 protein-coding genes.

#### 2. Chromosome

- Definition: A structure composed of DNA and proteins that carries genetic information.

- Key Point: Humans have 46 chromosomes (23 pairs) in each somatic cell.

#### 3. Karyotype

- Definition: The number and appearance of chromosomes in the nucleus of a eukaryotic cell.

- Key Point: Used to detect chromosomal abnormalities.

#### 4. Autosomes

- Definition: Chromosomes that are not sex chromosomes.

- Key Point: Humans have 22 pairs of autosomes.

#### 5. Sex Chromosomes

- Definition: Chromosomes that determine an individual's sex.

- Key Point: Females have two X chromosomes (XX), and males have one X and one Y chromosome (XY).

#### 6. Mitochondrial DNA (mtDNA)

- Definition: DNA located in the mitochondria, inherited maternally.

- Key Point: Encodes 37 genes involved in energy production.

#### 7. DNA Structure

- Definition: A double helix composed of nucleotides (A, T, C, G).

- Key Point: The sequence of bases encodes genetic information.

#### 8. Nucleosome

- Definition: The basic unit of DNA packaging in eukaryotes, consisting of DNA wrapped around histone proteins.

- Key Point: Nucleosomes help condense DNA into chromatin.

#### 9. Histones

- Definition: Proteins that help package DNA into nucleosomes.

- Key Point: Histone modifications can regulate gene expression.

#### 10. Mitosis

- Definition: Cell division that results in two identical daughter cells.

- Key Point: Essential for growth, repair, and asexual reproduction.

#### 11. Meiosis

- Definition: Cell division that produces gametes (sperm and egg) with half the chromosome number.

- Key Point: Involves two rounds of division (meiosis I and II) and results in genetic diversity.

#### 12. Crossing Over

- Definition: The exchange of genetic material between homologous chromosomes during meiosis.

- Key Point: Increases genetic diversity by creating new combinations of alleles.

#### 13. Gametogenesis

- Definition: The process of forming gametes (sperm and egg) through meiosis.

- Key Point: Spermatogenesis occurs in males, and oogenesis occurs in females.

#### 14. Spermatogenesis

- Definition: The process of sperm production in males.

- Key Point: Begins at puberty and produces millions of sperm daily.

#### 15. Oogenesis

- Definition: The process of egg production in females.

- Key Point: Begins during fetal development, with eggs arrested in prophase I until ovulation.

#### 16. Fertilization

- Definition: The fusion of sperm and egg to form a zygote.

- Key Point: Restores the diploid chromosome number (46 in humans).

#### 17. Zygote

- Definition: The diploid cell formed by the fusion of sperm and egg.

- Key Point: The first cell of a new organism.

#### 18. Telomeres

- Definition: Repetitive DNA sequences at the ends of chromosomes that protect them from degradation.

- Key Point: Telomeres shorten with age and are associated with cellular aging.

#### 19. Centromere

- Definition: The region of a chromosome where sister chromatids are joined and where spindle fibers attach during cell division.

- Key Point: Essential for proper chromosome segregation.

#### 20. Allele

- Definition: Different versions of a gene that can exist at a specific locus.

- Key Point: Example: The gene for eye color may have alleles for blue, brown, or green eyes.

#### 21. Genotype

- Definition: The genetic makeup of an organism.

- Key Point: Determines the potential traits an organism can have.

#### 22. Phenotype

- Definition: The observable characteristics of an organism, resulting from the interaction of genotype and environment.

- Key Point: Example: Eye color, height, and blood type.

#### 23. Homologous Chromosomes

- Definition: Chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location.

- Key Point: Carry the same genes but may have different alleles.

#### 24. Haploid

- Definition: A cell with one set of chromosomes (n).

- Key Point: Gametes are haploid (23 chromosomes in humans).

#### 25. Diploid

- Definition: A cell with two sets of chromosomes (2n).

- Key Point: Somatic cells are diploid (46 chromosomes in humans).

#### 26. Recombination

- Definition: The process by which DNA is exchanged between homologous chromosomes during meiosis.

- Key Point: Increases genetic diversity in offspring.

#### 27. Nondisjunction

- Definition: The failure of chromosomes to separate properly during cell division.

- Key Point: Can result in aneuploidy (e.g., Down syndrome).

#### 28. Aneuploidy

- Definition: The presence of an abnormal number of chromosomes in a cell.

- Key Point: Example: Trisomy 21 (Down syndrome).

#### 29. Gene

- Definition: A unit of heredity that is transferred from parent to offspring and determines some characteristic of the offspring.

- Key Point: Composed of DNA and located on chromosomes.

#### 30. Exome

- Definition: The part of the genome that codes for proteins.

- Key Point: Makes up less than 2% of the human genome but contains most disease-causing mutations.

#### 31. Repetitive DNA

- Definition: Sequences of DNA that are repeated multiple times in the genome.

- Key Point: Includes satellite DNA, Alu elements, and LINEs.

#### 32. Alu Elements

- Definition: A type of repetitive DNA sequence found in the human genome.

- Key Point: Alu elements can cause mutations if they insert into genes.

#### 33. LINEs (Long Interspersed Nuclear Elements)

- Definition: A type of repetitive DNA sequence that can move around the genome.

- Key Point: LINEs can cause mutations and contribute to genetic diversity.

#### 34. Segmental Duplications

- Definition: Large blocks of DNA that are duplicated in the genome.

- Key Point: Can lead to genomic rearrangements and disease.

#### 35. Genetic Variation

- Definition: Differences in DNA sequences among individuals.

- Key Point: Includes single nucleotide polymorphisms (SNPs), insertions, deletions, and copy number variations.

#### 36. SNP (Single Nucleotide Polymorphism)

- Definition: A variation at a single position in a DNA sequence among individuals.

- Key Point: SNPs are the most common type of genetic variation.

#### 37. Copy Number Variation (CNV)

- Definition: A type of genetic variation where the number of copies of a particular gene or DNA segment varies among individuals.

- Key Point: CNVs can contribute to disease susceptibility.

#### 38. Telomere Syndromes

- Definition: Disorders caused by defects in telomere maintenance.

- Key Point: Associated with premature aging and organ failure.

#### 39. Cytogenetics

- Definition: The study of chromosomes and their role in heredity.

- Key Point: Used to diagnose chromosomal abnormalities.

#### 40. Chromatin

- Definition: The complex of DNA and proteins that makes up chromosomes.

- Key Point: Can be condensed (heterochromatin) or relaxed (euchromatin).

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These flashcards cover the key terms and concepts from Chapters 1 and 2, providing a solid foundation for understanding human genetics.