aging Flashcards
resource allocating during developmental stages:
embryo to adult development
reproductive stage
maintenance
developmental progress is controlled and regulated by the amount of ___ available to an organism
when that is used up, ___ occurs
energy
when energy or resources are used up, senescence and eventually death occurs
aging vs. senescence
aging is ___ changes in an organism ___….
senescence describes a …
continuous, over time - time-related deterioration of the physiological functions necessary for survival & fertility
describes a final phase of life cycle of an organism (organized changes occurring b/w maturity & death)
what are the 2 mechanisms/theories of aging
1- unprogrammed senescence - aging
- wear & tear
- stress, ROS
- telomere shortening
2- programmed senescence
- whole organism level
- apoptosis
programmed senescence =
apoptosis, programmed cell death of specific tissues: webbing of bird feet
senescence changes gene expression & signaling pathways (3 things:)
cell division control
cell structure
metabolism - biologically active secreted molecules: proteinases, cytokines, growth factors
evolutionary selection on aging…some traits selected to optimize fitness in young organisms can have…
unselected bad effects in old organisms
what is good for u when u are young may be bad for u when u r old
aging occurs at multiple levels:
molecular
cellular
tissue
organ
organism
name 6 different causes of aging
1- stress: oxidative, hormones, DNA damage
2- mitochondrial genome damage
3- wear and tear
4- allocation of resources
5- genetic programs of aging (whole organism senescence)
6- telomere shortening
cause of aging: stress (ROS)
aging can result through general metabolism from by-products: ____
ROS: O2-, OH, H2O2
ROS oxidizes and damages membranes, proteins
mitochondria genome damage: ____ higher mutation rate in ___ than in nucleus, hots spots, higher ___ frequency than wild-type mitochondria
10-20x
mitochondria
replication
mitochondrial genome damage: mtDNA mutations lead to…
defects in energy production
production of ROS by faulty electron transport
induce apoptosis`
causes of wear and tear, DNA mutations can be _____
ROS, mutagens
DNA repair may slow ___…
aging
cells have multiple DNA repair systems
allocation of resources:
more investment in maintenance & less in reproduction results in an increase in life span (evolved balance)
balance of resources: theory that reduction of ___ and ___ can lead to a longer lifespan
non-maintenance and repair
nutrition also affects life span
___ is an environmental intervention that increase life span in flies & other species
calorie restriction
reduced recombination, longer life
__ gene which produces the ___ histone deacetylase protein —> ____ promotes longevity
SIR2
Sir2
Sir2-silenced chromatin
increased lifespan in diff genotypes, what organism is used as an example
C. elegans
increased lifespan for other organisms, ___
transgene Cu/Xn SOD catalase - ___% increase
transgene human SOD1 in adult motor neurons - ___% increase
methuselah- ___% increase
Drosophila
34%
40%
35%
telomeres are ___ found at ___, composed of ____ stimulus to this repeat from humans, ___
repetitive DNA sequences found at end of chromosomes composed of 6-8 bp repeats ‘5’ TTAGGG 3’
several different proteins are bound to telomere repeats forming a ____ that helps prevent…
telomere cap
the chromosome from being degraded by DNAses
telomeres & aging: caps on the ends of chromosomes get…
shorter each cell division - when telomeres get too short, cells stop dividing
___ extends telomeres and it permits separation of a ___ lineage and an ___ lineage
telomerase
mortal somatic cell lineage & immortal germ line lineage
