BIO282 Lecture Notes - Lecture 29: Cytotoxic T Cell, Cystine, Cell Membrane
Learning objectives:
In this topic/lecture you will learn about
• Apoptosis and how it is different from necrosis.
• The role of Ced proteins in apoptosis.
• What caspases are and how they are activated.
• Role of the Bad protein in apoptosis.
• How Bad is regulated.
• The process of programmed cell death is called apoptosis.
• It is an integral part of development in multi-cellular organisms.
o It is required for
• Maintenance of the size and shape of organs as new cells are added
• Removal of immature B lymphocytes that produce undesirable Ab’s.
o It provides protection against cancer
• p53, a tumor suppressor protein, induces apoptosis
• If not regulated properly, apoptosis causes a variety of diseases that include
o cancer,
o neurodegenerative diseases,
o multiple sclerosis and
o ischaemic stroke
Apoptosis
• It is distinct from uncontrolled cell death through necrosis
• The process of programmed cell death is called apoptosis.
• It is an integral part of development in multi-cellular organisms.
• Necrosis usually results in inflammation
• Fragmentation of DNA occurs ~2 hours after apoptosis is initiated in cells.
Characteristics of necrotic and apoptotic cell death.
Necrosis
Cell death due to injury
Inflammatory response
Apoptosis
Cell shrinkage
Marked condensation of chromosomes and
nucleosome fragmentation
Swelling of
mitochondria,
breakdown of plasma
membrane
Condensation of cytoplasm
protuberance of surface evident, Release of
membrane bound fragments with preserved
organelles,
Fragments removed by phagocytosis
Loss of ion transport,
DNA
degradation and cell
lysis
Document Summary
It is an integral part of development in multi-cellular organisms. It is required for: maintenance of the size and shape of organs as new cells are added, removal of immature b lymphocytes that produce undesirable ab"s. It provides protection against cancer: p53, a tumor suppressor protein, induces apoptosis. If not regulated properly, apoptosis causes a variety of diseases that include: cancer, neurodegenerative diseases, multiple sclerosis and ischaemic stroke. It is distinct from uncontrolled cell death through necrosis: the process of programmed cell death is called apoptosis. It is an integral part of development in multi-cellular organisms: necrosis usually results in inflammation, fragmentation of dna occurs ~2 hours after apoptosis is initiated in cells. Condensation of cytoplasm protuberance of surface evident, release of membrane bound fragments with preserved organelles, Identify the affected gene/protein product: by mutagenesis following two types of mutants were generated. Genes affected role: all cells survive ced-3, ced-4. Required for apoptosis: all cells die ced-9.
