apoptosis 10th oct Flashcards
what are the types of cell deaths that can occur
Necrosis
Apoptosis
Autophagy
Ferroptosis
Oncosis
Necroptosis
What is apoptosis
A mode of programmed cell death that occurs physiological conditions and the cells actively participated
What is cell necrosis
pathological cell death that occurs when cells are exposed to a physical or chemical insult
What is the key characteristics of cell necrosis
It is passive
It is pathological
Swelling and lysis occurs
Inflammation
Dissipates
Externally induced
What is the key characteristics of cell apoptosis
It is an active process
it is can be physiological or pathological
condensing and cross-linking occurs
the cells are phagocytosed
No inflammation occur
Internally or externally induced
What is the key characteristics of mitotic catastrophe
It is a passive process
It is pathological
Swelling and lysis occurs
the cells dissipates
Inflammation occurs
It is internally induced
Why do cells undergo apoptosis
For normal development
>Reabsorb tadpole tails during
To remove unwanted cells
>Infected with a virus
>Cells with DNA damage
>Cancer cells
What diseases can occur when there is inadequate apoptosis
Hyperplasia
>Cancer
>Autoimmune diseases
>restenosis
>Frequent infections
What occurs in extreme apoptosis
Tissue atrophy
>Neurodegenerative disease
>Cardiovascular diseases
>Haematologic diseases
>Other disorders
What are the steps of the intrinsic pathway
Cytochrome C —–> Caspases ——> Cell death
What are the steps of the extrinsic pathway
Death receptors —–> Caspases ——> Cell death
What signals are required for adequate elimination of apoptotic cells
Secreted ‘find me’
Exposed ‘eat-me’
Lacking ‘Don’t eat me’
What are the steps of ‘Eat-me’
Step 1: Tethering
Step 2: Tickling
What does (step 1) tethering involve
(phosphatidylserine (PtdSer) receptor) Tim4 on macrophages, tightly binds PtdSer on the apoptotic cell.
What does (step 2) tickling involve
Soluble proteins such as protein (S/Gas6 or MFG-E8 )bind PtdSer on apoptotic cells and activate their receptors(MerTK or Integrin) on phagocytes
leading to Rac1 activation and actin polymerization.
What are death receptors
The are member of the tumour necrosis factors (TNF) receptor superfamily
What does the death domain on the death receptors do
help transmit death signals for the cell’s surface to the intracellular signalling pathway
Explain the extrinsic pathway in detail
Trimeric TNFa binds to TNFR1.
Recruits Fas-associated death domain (FADD) and TRADD to TNFR1
Caspase-8 recruited to FADD which leads to the formation of death inducing signalling complex (DISC)
This activates Caspase 8 leading to apoptosis by activation caspases 3
What does Caspases stand for
Cysteinyl aspartate specific proteases
How many types of Caspases are there
14 different types
What are Caspases synthesised from
Inactive proenzymes called zymogens
How do inactive procaspases become active
Two of the procaspases are cleaved at two location then join together at the small subunit sections.
What are the steps of the intrinsic pathway for apoptosis
The process is activated stress
Lead to BAX and BAK inducing permeability in the mitochondria membrane
Multiple effector, SMAC and cytochrome C are released form the membrane pore to the intermembrane space
SMAC inhibits, inhibitors of apoptosis protein (IAP)
Cytochrome C activates Caspase 9
What prevents BAK or BAD from making increasing mitochondria permeability
Low levels of BH3
What are the characteristics of group 1 typical anti-psychotics
They are pronounced sedatives
Moderate antimuscarinic
Extrapyramidal side effects
What are the characteristics of group 2 typical anti-psychotics
Moderate sedatives
Fewer extra pyramidal side effects than group 1 or 3
What are the characteristics of group 3 typical anti-psychotics
Fewer sedative or anti- muscarinic side effects
More pronounced side effects than group 1 and 2
