Exam 2

Crick DNA –transcription–> RNA –translation–> protein

promoter: initiates expression 5’UTR: regulates gene expression open reading frame: RNA information (introns and axons)

functions in nucleus, migrates to ribsomes carries DNA sequence info to ribosomes

functions in cytoplasm provides linkage b/w mRNA and AAs, transfers AAs to ribosomes

functions in cytoplasm structural component of ribosomes

enzymes cut out introns exons spliced together to make mRNA more than 90% of pre-mRNA is destroyed (introns)

single gene can code for multiple proteins by mixing and matching exons

random chance events, DNA sequence

gametes, they can be passed onto offspring

exposure to toxins or radiation (mutagens) others lead to variations that are good for organism to adapt to environment

• Gene mutations: • Single gene • Substitution, stop, inversion, insertion, and deletion • Chromosomal mutations: • Abnormal chromosome structure (affects multiple genes) • Substitution, stop, inversion, insertion, deletion, and translocation

trisomy 21 (extra 21 chromosome) alters child’s phenotype - characteristic facial features, short stature usually some mental retardation

• Autosomal • single genes • multiple genes • Sex-linked • Chromosome abnormalities (eg down syndrome)

recessive: normally loss-of-function mutation dominant: normally gain-of-function mutation

caused by alleles on autosomes (chromosomes other than sex chromosomes) most are recessive (need two alleles) carriers ex (have 1 recessive) : CF, sickle cell dominant ex: huntingtons (only need 1 allele)

common Y-linked disorder: male infertility X-linked recessive disorders (most common in males): hemophilia, color blindness, muscular dystrophy, fragile-X syndrome

• Linkage analysis: • Data collected for family members • Good for rare disorders • Genome-wide association studies (GWAS) • Data colleced for unrelated individuals • Good for common diseases

dominant: affected parents have affected children

• x-linked dominant: • affected mother: either son or daughter can be affected • affected father: only can pass to daughter, but not son • x linked recessive: • female carrier: only son can be affected

single nucleotide polymorphyism: just one base changed at specific point microsatellite: series of bases repeated several times

synonymous: single nucleotide change does not change AA sequence missense: one AA change

alzheimers, autism, schizophrenia

best (a): C. elegans (worm), fruit fly, zebra fish also good (b): mice

best (a): C. elegans, fruit fly, zebra fish also good (b): mouse