Modern Genetics Exam 2 - Gordon College

organelle heredity

DNA contained in mitochondria/chloroplasts determines certain phenotypic characteristics of the offspring

Infectious Heredity

resulting from symbiotics/parasitic association of a microorganism

maternal effect

nuclear gene products are stored in the egg and then transmitted to offspring from the female parent in the cytoplasm of the ovule

chlamydomonas

model system for studying organelle heredity: it has a single large chloroplast that exhibits a uniparental inheritance pattern

Neurospora (Mitochondrial mutation)

imparied mitochondrial funciton and is due to absence of several cytochrome proteins needed for electron transport

Saccharomyces cerevisiae (Mitochondrial mutation)

small size of colonies, deficiency in cellular respiration, and mitochondria perfoms adnormal electron transport

Segregational petites

are yeast mutants that exhibit a deficiency in mitochondrial function due to segregational loss of mitochondrial DNA during cell division.

natural petites

demonstrate cytoplasmic transmission, lack mtDNA, inherited from both parental cells

endosymbiotic theory

mitochondria and chloroplasts arose independenly from free-living bacteria that possess the abilities now attribute to these organelles - aerobic respiration and photosynthesis

Nuclear genes are encoded by

DNA and RNA polymerase, Initiation and elongation factors, ribosomal proteins, and aminoacyl tRNA synthetases

mtDNA are susceptible to mutations because

they lack efficient DNA repair mechanisms and are exposed to reactive oxygen species produced during cellular respiration.

heteroplasmy

Variation in the genetic content of organelles within a cell. A zygote inherits many organelles through the egg, and mutations in a few may be diluted by normal, functional mitochondria. As a result, adult cells have a mix of normal and mutated organelles.

human disorder to mtDNA

deficiency in bioenergetic function of organelle and mutation in one+ mitochondrial gene

mtDNA disorders

MERRF (myoclonic epilepsy and ragged-red fiber disease), LHON (Leber’s hereditary optic neuropathy), KSS (Kearns-Sayre syndrome)