Mod 2 Patho Definition Sheet PDF

**Mod 2 term sheet: (Guyton chapter 3, McCance 4,5,6)** - **Cell differentiation:** changes in the physical and functional properties of the cell as they proliferate in the embryo to form diff body structures and organs - **Apoptosis:** programmed cell death - **Phagocytosis:** larg...

**Mod 2 term sheet: (Guyton chapter 3, McCance 4,5,6)** - **Cell differentiation:** changes in the physical and functional properties of the cell as they proliferate in the embryo to form diff body structures and organs - **Apoptosis:** programmed cell death - **Phagocytosis:** large molecules are engulfed by the plasma membrane and enter the cell so that they can isolated and destroyed by lysosomal enzyme - **cancer/ mutation** - **Proto-oncogenes:** normal genes that code for various proteins that control cell adhesion, growth, division - **Oncogenes:** mutated or excessively activated *proto-oncogenes.* Abnormally functioning- capable of causing cancer - **Antioncogenes:** *Tumor suppressor genes*- suppress the activation of specific oncogenes - **Chromosomes** - **Gametes:** sperm and egg. Haploid cells (1 member of each chromosome pair) **23 chromosomes** - **Germline:**a gene in a reproductive cell (egg or sperm) that is passed on to offspring - **Somatic:** includes all cells other than gametes- diploid cells ( one chromosome from mom and one from dad) **46 chromosomes** - **Histone:** Histones are vital proteins responsible for DNA packaging and provide structural support for chromosomes. DNA wraps around complexes of histone proteins, which helps give the chromosome a more compact shape. The histones are used as proteins for the DNA to be coiled around. - Mccance: proteins that facilitate the compaction of genomic DNA by coiling into the nucleus of a cell. - **Gene:** a specific segment of DNA that contains the instructions for making a particular protein - **Allele:** genes at a particular *locus* can have diff. Forms (composed of diff. Nucleotide sequences) - **Locus:** each gene occupies a position along a chromosome - **Polymorphic:** locus that has two or more alleles that each occurs with an appreciable frequency in a population - **Genotype:** composition of genes at a given locus - **Phenotype:** outward appearance of an individual (result of genotype and environment) - **Dominant:** allele whose effects are observable - **Recessive:** allele whose effects are hidden - **Carrier** - **Homologous:** when two alleles are identical (homo at that locus) - **Heterozygous:** when two alleles are not identical ( hetero at that locus) - **Polyploidy:** when a euploid cell has more than the diploid \# of chromosomes - **Triploidy::** a zygote that has three copies of each chromosome, rather than two (extra set of chromosomes) - Zygote: fertilized cell from male and female gamete - **Aneuploidy: a** cell that does not contain a multiple of 23 chromosomes - **Trisomy:** cell containing three copies of 1 chromosome ( 1 extra chromosome) - **Abnormalities of chromosome structure** - **Deletions** - **Cri du chat:** deletion short arm of chromosome 5 - **Duplications** - **Inversions:** two breaks take place on a chromosome, followed by the reinsertion of the missing fragment at its original site but in inverted order - **Translocations:** interchange of genetic material between nonhomologous chromosomes - **Robertsonian translocation:** long arms of two nonhomologous chromosomes fuse at the centromere, forming a single chromosome - **Reciprocal translocation** - **Fragile sites:** (breaks /gaps on chromosomes) - **Fragile x- syndrome** - **Down syndrome:** trisomy of chromosome 21 - **Turner syndrome:** (45, X) monosomy of X chromosome - **Klinefelter syndrome:** (47, XXY) XXY condition - **Transmission of genetic dx** - **Mendelian trait/gene:** traits caused by a single gene - **autosomal dominant** - **Penetrance:** % of individuals with a specific genotype who also exhibit the expected phenotype - **Expressivity:** extent of variation in phenotype associated with a particular genotype - **Obligate carrier:** those who have affected parents and affected children and, therefore, themselves must carry mutation - **Autosomal recessive** - **Consanguinity:** marriage between related individuals - **X-linked dominant** - **X-linked recessive** - **Relative risk (equation):** increased rate of the dx among individuals exposed to a risk factor/ incidence rate of the dx among individuals not exposed to a risk factor - **Multifactorial inheritance** - **Polygenic:** traits in which variation is thought to be caused by a combined effect of multiple genes - **Multifactorial trait:** when environmental factors are also believed to cause variation in the trait - **Recurrence risk** - **Threshold of liability:** refers to a hypothetical point on a continuous scale of genetic and environmental factors where, if an individual\'s combined liability exceeds that point, they will develop a particular disease or trait - **Twin studies** - **MZ:** monozygotic ( identical) - **DZ** Dizygotic (fraternal) - **Concordant:** if both members share a trait - **Discordant:** if both twins do not share a trait - **Epigenetics:** DNA sequence can produce dramatically diff. Phenotypes b/c of chemical modifications altering the expression of genes - **DNA methylation:** the attachment of a methyl group to a cytosine base followed by a guanine base in the DNA sequence - **Somatic mosaicism** - **Histone modification** - **Heterochromatic:** DNA is tightly bound into a condensed state and is not actively transcribed (dense methylation) - **Heterchromatin**: closed state, transcriptionally inactive - **Euchromatic:** rich in genes, open state and is genetically active - **Histone modifications** - **Acetylation**: Histone acetylation leads to relaxation of the chromatin and hence greater transcription. - **Methylation**: the modification of specific amino acids in a histone protein by adding one, two, or three methyl groups ( suppress the function of the gene) - **Non-coding RNAs** - **miRNAs**: a class of non-coding RNAs that play important roles in regulating gene expression. - **Oncomirs:** miRNAs regulate diverse signaling pathways, those that stimulate cancer development and progression are called oncomirs - **Genetic imprinting:** A process where one parent's allele is silenced, and the other is active - **Biallelic:** Both maternal and paternal alleles are active and expressed. - **Monoallelic:** Only one allele (from either the mother or the father) is active, while the other is silenced (imprinted). - **Imprinting:** The silencing of one allele of a gene due to epigenetic modifications - **Prader willi syndrome:** deletion of the long arm of chromosome 15, inherited from father ( short stature, obesity, hypogonadism) - **Angelman syndrome:** same deletion **(**deletion of the long arm of chromosome 15) inherited from mother (intellectual disability, seizures, ataxic gait) - **Beckwith-Wiedemann syndrome (**imprinting- two copies of a chromosome from mom and none from dad (uniparental disomy, chromosome 11) - **Tx of epigenetic dx** - **DNA methylating agents:** 5-azacytidine - **Histone deacetylase inhibitors** increase chromatic compaction- decreasing transcriptional activity