Biology of Ageing 1 Flashcards
Which cellular process is responsible for destroying old organelles and damaged macromolecules?
Autophagy is a catabolic process in eukaryotic cells that delivers cytoplasmic components and organelles to the lysosomes for digestion. Lysosomes are specialized organelles that break up macromolecules, allowing the cell to reuse the materials.
What organisms can undergo autophagy and why?
Most organisms can = prok and euk because it is an evolutionarily conserved survival mechanism
Define aggrephagy
The selective degradation of protein aggregates by macroautophagy is called aggrephagy
Define ferritinophagy
Ferritinophagy, a form of autophagy, is also an important part of ferroptosis, a type of regulated cell death resulting from abnormal iron metabolism involving the production of ROS
Ferritinophagy is a new autophagy process associated with ferroptosis in which the binding of nuclear receptor coactivator 4 (NCOA4) and ferritin in autophagosomes causes autophagic degradation
Define lysophagy
During lysophagy, a damaged lysosome is sensed and the site of membrane rupture is ubiquitinated, leading to the recruitment of autophagy receptors to the damaged site
Define reticulophagy
ER-phagy (reticulophagy) defines the degradation of portions of the endoplasmic reticulum (ER) within lysosomes or vacuoles
Define nucleophagy
Removal of damaged or non-essential nuclear material (such as nuclear lamina and DNA) from a cell through autophagy pathway is known as nucleophagy, a selective subtype of autophagy.
Define lipophagy
Lipophagy is defined as the autophagic degradation of intracellular lipid droplets
Define ribophagy
Define pexophagy
Peroxisomes are well characterized for their roles in ROS production and scavenging; however, it also appears that an increase in cellular oxidative stress can induce pexophagy.
Define mitophagy
Mitophagy is a specialized form of autophagy that regulates the turnover of damaged and dysfunctional mitochondria
Define xenophagy
xenophagy is defined as a type of selective macroautophagy/autophagy that is used for eliminating invading pathogens
Which of the following cellular components lacks an inherent repair mechanism?
mtDNA - RNA - proteins - DNA***
Only DNA has the ability to repair
What are the two theories of ageing?
Program theories of ageing = fundamental limitation
Damage theories of ageing = deterioration accumulation
What is the program theory of ageing?
Telomere attrition and stem cell exhuastion
Fundamental limitation = it is an irreversible process controlled by internal factors that we can only slow down the ageing process
What is the damage theory of ageing?
Mitochondrial dysfunction and chronic inflammation
Deterioration accumulation = it is a reversible process affected by external factors that can be rejuvenated when we remove the risk factors
What are the 12 hallmarks of ageing?
Dysbiosis/Chronica inflammation/Altered intercellular communication/Stem cell exhaustion
Deregualted nutrient-sensing/Mitochondrial dysfuction/cellular senescence
Genomic instability/Telomere attrition/Epigenetic alterations/Loss of proteostasis/Disabled macroautophagy
Which of the 12 hallmarks of ageing take place in the nuclei?
Genomic instability/Telomere attrition/Epigenetic alterations/Loss of proteostasis/Disabled macroautophagy
Which of the 12 hallmarks of ageing take place in the cytoplasm?
Deregualted nutrient-sensing/Mitochondrial dysfuction/cellular senescence
How do telomeres predict species life span?
The rate at which telomeres shorten predicts species life span
The faster telomeres shorten = the shorter the lifespan, this is regardless of initial length of telomeres
Name 3 techniques to measure telomere length
Southern blotting
Q-PCR»_space;> genome wise sequence
FISH = fluorescence in situ hybridization
Can we enhance telomere length to reverse ageing? ***
Cancer cells reactivate telomerase so they maintain telomere = allowing them to live longer and continuously replicate
What are the two outcomes of mitosis?
Proliferation and growth
Post-mitotic cells don’t proliferate, they grow in size
Name some post-mitotic cells
Neurones
Mature muscle cells
What are Jurkat cells?
Jurkat cells are an immortalized human T-lymphocyte cell line derived from acute T-cell leukemia.
Widely used in immunology, they model T-cell signaling, cytokine production, apoptosis, and cancer research.
They are suspension cells, expressing CD4, CD3, and the T-cell receptor (TCR), making them ideal for studying T-cell-related pathways.
Why do G2/M cells have a higher dye fluorescence in flow cytometry?
Because they have two copies of DNA
The dye used is small enough to infiltrate the cell membrane
What order do cyclins rise and fall in from G1 to M phase?
Cyclin D > E > A > B
What order do CDK bind cyclins in from G1 to M phase?
CDK4/D
CDK6/D
CDK2/E
CDK2/A
CDK1/A
CDK1/B
What does G1 check-point check?
Checks whether cell has enough energy and resources to replicate each chromosomes in the nucleus
What does G2 check-point check?
Checks whether replicated DNA is completed/not damaged AND whether proteins and organelles are properly duplicated
What does M check-point check?
Checks whether all chromosomes are lined up in center for segregation
How do the checkpoints halt the cell cycle?
Inhibit cyclin-CDK complexed via regulatory proteins
