Tài liệu, ebook Sinh Học

Prediction Individual genome sequence can be used to determine chance of developing a particular disease Blood fingerprints will allow early detection and stratification of disease types New prevention strategies Better understanding of networks will lead to more effective therapeutic agents and drugs to prevent disease Personalization Apply ...

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Evolutionary battle at the molecular level between the AIDS virus and cells of the immune system After viral infection, virus-specific immune response ensues that can destroy the pathogen HIV has a high mutation rate and is able to diversity and amplify itself via selection Speed of viral evolution is faster than the immune response Effective t...

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Heritability quantifies the potential for selection A trait with high heritability has a large potential for evolution Selection differential = S Difference between value for this trait in the parents and value for this trait in the entire population (breeding and non-breeding) Response to selection = R The amount of change in the mean value ...

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Cells must obtain information about their positions relative to other cells Ligand expressed by one cell binds to a receptor expressed on the surface of another cell Juxtracrine signaling – ligand is membrane-bound and interacts with a receptor on an adjacent cell Paracrine signaling – ligand is secreted and mediates long- range (e.g. hormones) ...

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Cancer is a disease of genes Multiple cancer phenotypes arise from mutations in genes that regulate cell growth and division Environmental chemicals increase mutation rates and increase chances of cancer Cancer has a different inheritance pattern than other genetic disorders Inherited mutations can predispose to cancer, but the mutations causin...

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Ubiquitination – covalent attachment of ubiquitin to other proteins targets those proteins for degradation by the proteosome Cascades of phosphorylation and dephosphorylation Transmission of signals across the cell membrane to the nucleus (discussed more in Chapter 17) Sensitization – tissues exposed to hormones for long periods of time lose abi...

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Initiation – core RNA polymerase plus sigma (σ) factor Core has four subunits: two alpha (α), one beta (β), one beta prime (β') DNA is unwound and polymerization begins Elongation – core RNA polymerase without σ factor Continues until RNA polymerase recognizes termination signal Termination – two kinds in bacteria Rho-dependent – Rho (ρ) pro...

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Oxidative phosphorylation system in the mitochondria generates free radicals, which can damage DNA Accumulation of mtDNA mutations over time may result in age-related decline in oxidative phosphorylation Evidence in support of role of mtDNA and aging: Percentage of heart tissue with a mitochondrial deletion increases with age Brain cells of peo...

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Incidence of abnormal phenotypes caused by aberrant chromosome organization or number is 0.004% Half of spontaneously aborted fetuses have chromosome abnormalities Incidence of abnormal phenotypes caused by single-gene mutations is 0.010%

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Specialized chromatin in central core of centromere marks this region for attachment of kinetochore proteins Central core of each centromere: Composed of unique chromatin that does not recombine and is not transcribed Surrounded by regions of heterochromatin interspersed with euchromatin Histone variant CENP-A is present in central core of all...

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