Final Exam Flashcards
Unregulated cell division leads to what?
Cancer
Abnormal cell growth is controlled by what genes?
Protooncogenes and tumor suppressor genes
Proteins form these genes control cell growth and differntiation. If mutated they become known as oncogenes.
Protooncogenes
These genes control unregulated progression through the cell cycle. Loss of function of these genes predisposes cells to cancer.
Tumor suppressor genes
What are the two theories of cancer?
Clonal evolution model and the stem cell theory
This theory of cancer believes that a tumor develops from a single mutated cell and that every mutated cell has the potential to develop another tumor.
Clonal evolution model
What is the stepwise process of cancer development?
Initiation, Promotion, Progression, and Metastasis
Self sufficient growth signals, ignoring of anti-growth signals, evasion of apoptosis, limitless replication potential, angiogenesis, reprogramming of energy metabolism, evasion of immune destruction, and metastasis are all considered to be what?
The Hallmarks of Cancer
This process is due to injury or disease. Cells increase in size and lyse. Intracellular contents are inflammatory.
Necrosis
During this process cells shrink in size, plasma membrane buds off (blebs), phosphatidylserine moves from the inner to outer leaflet, mitochondria release cytochrome c, chromatin in the nucleus condenses and cells are finally engulfed by the macrophages. Another name for this is programmed cell death
Apoptosis
This is a specialized white blood cell that engulfs foreign invaders and cells that are no longer needed.
Macrophages
Macrophages bind to ____ on the apoptotic cell, internalizing and degrading the cell, preventing ____
Phosphatidylserine, Inflammation
This state occurs when the number of cells is relatively constant due to cell replication and cell death.
Homeostasis
Apoptosis is internally initiated by the insertion of what protein into the mitochondrial membrane?
Bax
After binding of Bax to the mitochondrial membrane within the cell this molecule triggers apoptosome complex in the cytoplasm, which leads to a caspase cascade to destroy protein and DNA.
Cytochrome C
Apoptosis is externally initiated by what?
Death receptors
In the initiation of apoptosis by an external signal, ____ ligand binds to its respective death receptor, thereby recruiting ____. The recruiting of these domains activate procaspase ___ to caspase ___.
Fas, Fas-associated death domain (FADD), 8, 8.
These three components make up the death inducing signaling complex when apoptosis is initiated by an external signal?
Fas receptor, FADD, and caspase 8.
These are proteases that mainly function during apoptosis.
Caspases
Which caspases are initiator caspases?
Caspases 2, 8, 9, and 10
Which caspases are effector caspases?
Caspases 3, 6, and 7
What proteins compose the prosurvival (antiapoptotic) proteins?
Members of Bcl-2 family (the BAD proteins)
What proteins compose the prodeath (apoptotic) proteins?
Bak and Bax proteins
What are some neurodegenerative diseases in which apoptosis is no longer working?
- Schizophrenia (altered neuronal apoptosis)
- Dementia and Alzheimer’s (localized apoptosis)
What are some hallmarks of aging?
Genomic instability, telomere attrition, epigenetic alterations, loss of protein homeostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intracellular communication
This is a hallmark of aging and is characterized by an accumulation of DNA damage throughout life, loss of DNA repair mechanisms, and damage to the nuclear lamina.
Genomic instability
This is a hallmark of aging and is characterized by a lack of telomerase and special shelterin proteins hide telomere damage from repair mechanisms.
Telomere attrition
This is a hallmark of aging and is characterized by histone modifications (methylation), DNA modifications, Chromatin remodeling, and transcriptional alterations.
Epigenetic alterations
This is a hallmark of aging and is characterized by a decreased synthesis of chaperone proteins in aging and protein degradation.
Loss of protein homeostasis
This is a hallmark of aging and is characterized by anabolic pathways, slower replication, and sirtuins signal nutrient scarcity and promote cell survival and catabolism.
Deregulated nutrient sensing
This is a hallmark of aging and is characterized by the production of reactive oxygen species (ROS), a lower efficiency in ATP generation, and mitohormesis, which is the activation of defense mechanisms by toxins attacking mitochondria.
Mitochondrial dysfunction
This is a hallmark of aging and is characterized by a decrease in hematopoiesis and a decrease in the cell cycle due to more DNA damage and overexpression of INK4A (cyclin inhibitor)
Stem cell exhaustion
This is a hallmark of aging and is characterized by an increase in inflammation. Enhanced activation of NF-kB, senescent cells produce more inflammatory cytokines, less SIRT1.
Altered intracellular communication
This is a cell state characterized by a lack of replication. These cells do not re-enter the growth cycle, but are still metabolically active.
Senescence
Where is senescence beneficial? Detrimental?
It is beneficial for tumor suppression, but detrimental during aging
What are some causes of cellular senescence?
Telomere shortening, reactive oxygen species (ROS), and oncogene/tumor suppressor genes
What are some traits of cells in senescence?
Growth arrest, apoptotic resistance, change in gene expression, chromatin modifications, and senescence-associated beta-galactosidase
A decreased expression of cyclins and transcription factors and active cyclin-dependent kinase inhibitors p21 and p16 result in what type of cell cycle for senescent cells?
A irreversible cell cycle
Chromatin modifications in senescent cells result in more of this type of chromatin?
Heterochromatin
Sirtuins can both induce and inhibit what process?
Senescence
This is mainly produced in mitochondria from oxidative phosphorylation, can damage DNA in mitochondria, and the most common one is superoxide.
Reactive oxygen species
Senescent cells produce high levels of what two things?
Inflammatory cytokines and matrix metalloproteinases (MMPs)
This ion creates conditions of electropositivity outside of the cell and electronegativity inside the cell. It is primarily concentrated inside of nerves.
Potassium
This ion is concentrated outside of the nerve. Diffusion of it inside of the cell creates a membrane potential of +61mV.
Sodium
The membrane of a nerve is 100 times more permeable to what ion?
Potassium
A nerve in the resting state is known as what?
Polarized
This process is characterized by a nerve’s membrane becoming permeable to Na+. There is a large influx of Na into the cell.
Depolarization
This process is characterized by a nerve’s sodium channels closing and potassium channels opening. There is an efflux of K+.
Repolarization
The nerve action potential utilizes what type of channels?
Voltage-gated sodium and potassium channels.
Voltage-gated channels have three components what are they?
- Activation gate: opens when the membrane potential changes
- Selectivity filter: selects for a particular ion
- Inactivation gate: found on sodium channels (located on the interior of the cell)
When do the sodium channels open?
When the membrane potential of a nerve is less negative (-70 to -50mV)
When do the sodium channels close?
Close due to the membrane potential becoming less negative
When do the potassium channels open?
They open as the membrane becomes less negative and when the sodium channels close
When do the potassium channels close?
When resting membrane potential is reached
What type of channels are calcium channels in terms of an action potential?
They are slow channels that provide a sustained depolarization