aging Flashcards

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1
Q

resource allocating during developmental stages:

A

embryo to adult development
reproductive stage
maintenance

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2
Q

developmental progress is controlled and regulated by the amount of ___ available to an organism

when that is used up, ___ occurs

A

energy

when energy or resources are used up, senescence and eventually death occurs

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3
Q

aging vs. senescence

aging is ___ changes in an organism ___….
senescence describes a …

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)

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4
Q

what are the 2 mechanisms/theories of aging

A

1- unprogrammed senescence - aging
- wear & tear
- stress, ROS
- telomere shortening

2- programmed senescence
- whole organism level
- apoptosis

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5
Q

programmed senescence =

A

apoptosis, programmed cell death of specific tissues: webbing of bird feet

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6
Q

senescence changes gene expression & signaling pathways (3 things:)

A

cell division control

cell structure

metabolism - biologically active secreted molecules: proteinases, cytokines, growth factors

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7
Q

evolutionary selection on aging…some traits selected to optimize fitness in young organisms can have…

A

unselected bad effects in old organisms

what is good for u when u are young may be bad for u when u r old

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8
Q

aging occurs at multiple levels:

A

molecular
cellular
tissue
organ
organism

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9
Q

name 6 different causes of aging

A

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

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10
Q

cause of aging: stress (ROS)

aging can result through general metabolism from by-products: ____

A

ROS: O2-, OH, H2O2

ROS oxidizes and damages membranes, proteins

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11
Q

mitochondria genome damage: ____ higher mutation rate in ___ than in nucleus, hots spots, higher ___ frequency than wild-type mitochondria

A

10-20x
mitochondria
replication

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12
Q

mitochondrial genome damage: mtDNA mutations lead to…

A

defects in energy production
production of ROS by faulty electron transport
induce apoptosis`

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13
Q

causes of wear and tear, DNA mutations can be _____

A

ROS, mutagens

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14
Q

DNA repair may slow ___…

A

aging

cells have multiple DNA repair systems

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15
Q

allocation of resources:

A

more investment in maintenance & less in reproduction results in an increase in life span (evolved balance)

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16
Q

balance of resources: theory that reduction of ___ and ___ can lead to a longer lifespan

A

non-maintenance and repair

17
Q

nutrition also affects life span

___ is an environmental intervention that increase life span in flies & other species

A

calorie restriction

18
Q

reduced recombination, longer life

__ gene which produces the ___ histone deacetylase protein —> ____ promotes longevity

A

SIR2
Sir2
Sir2-silenced chromatin

19
Q

increased lifespan in diff genotypes, what organism is used as an example

A

C. elegans

20
Q

increased lifespan for other organisms, ___

transgene Cu/Xn SOD catalase - ___% increase

transgene human SOD1 in adult motor neurons - ___% increase

methuselah- ___% increase

A

Drosophila
34%
40%
35%

21
Q

telomeres are ___ found at ___, composed of ____ stimulus to this repeat from humans, ___

A

repetitive DNA sequences found at end of chromosomes composed of 6-8 bp repeats ‘5’ TTAGGG 3’

22
Q

several different proteins are bound to telomere repeats forming a ____ that helps prevent…

A

telomere cap
the chromosome from being degraded by DNAses

23
Q

telomeres & aging: caps on the ends of chromosomes get…

A

shorter each cell division - when telomeres get too short, cells stop dividing

24
Q

___ extends telomeres and it permits separation of a ___ lineage and an ___ lineage

A

telomerase
mortal somatic cell lineage & immortal germ line lineage

25
Q

telomere shortening is also a problem in cloning…

A

Dolly’s telomeres - analysis of her cells reveals that they were only 80% as long as in a normal one-year old sheep

nucleus that created Dolly had been deprived of telomerase