Control of Cell Division and Cell Growth Flashcards
(44 cards)
Organ and body size are determined by three fundamental processes:
- Cell growth
- Cell division
- Cell survival
The extracellular signal molecules that regulate cell growth, division, and survival are generally _____ , _____ , or _____ .
- Soluble secreted proteins
- Proteins bound to the surface of cells
- Components of the extracellular matrix
The extracellular signal molecules that regulate cell growth, division, and survival can be divided into three major classes:
- Mitogens
- Growth Factors
- Survival Factors
Stimulate cell division, primarily by triggering a wave of G1/S-Cdk activity that relieves intracellular negative controls that otherwise lock progress through the cell cycle.
Mitogens
Stimulate cell growth by promoting the synthesis of proteins and macromolecules and inhibiting their degradation.
Growth Factors
Promote cell survival by suppressing the form of apoptosis
Survival Factors
The rate of proliferation depends on the _______ .
The availability of nutrients in the environment
The cell of a multicellular organism divide only when the organism ______ .
Needs more cells
The first mitogens to be identified
Platelet-derived growth factor (PDGF)
Is prepared by removing the cells from blood without allowing clotting to occur
Plasma
Is prepared by allowing blood to clot and taking the cell-free liquid that remains
Serum
PDGF can stimulate many cell to divide including _____ , _____ , and _____ .
- Fibroblasts
- Smooth muscle cells
- Neuroglial cells
Stimulates division of epidermal cells, including epithelial and nonepithelial cells.
Epidermal Growth Factor
Inhibitory signal proteins that inhibits the proliferation of several cell types by blocking cell-cycle progression in G1.
Transforming growth factor β (TGBβ)
A state in which the cell-cycle control system is completely dismantled
Terminally differentiated G0 state
Most of the _____ and _____ _____ cells are in a terminally differentiated G0 state.
- Neurons
- Skeletal Muscle Cells
A monomeric GTPase that activates the mitogen-activated protein kinase (MAP kinase) cascade, leading to increased production of transcription regulatory proteins like Myc.
Ras
A signaling pathway activated by Ras
Mitogen-Activated Protein (MAP) Kinase Cascade
A transcription regulatory protein that promote cell-cycle entry by increasing the expression of genes encoding G1 cyclins, thereby increasing G1-Cdk activity.
Myc
Bind to specific DNA sequences in promoters of genes that encode for proteins required for S-phase entry.
E2F Proteins
Protein that inhibit the expression of E2F-dependent gene by binding to E2F in absence of mitogenic stimulation
Retinoblastoma Protein (Rb) Family
DNA damage can occur as a result of ______ , ______ , or ______ .
- Spontaneous chemical reactions in DNA
- Errors in DNA Replication
- Exposure to radiation or certain chemicals
The cell-cycle control system can detect DNA damage and arrest the cycle at either of two transitions:
- Start (prevents entry into S phase)
- G2/M Transition (prevents entry into mitosis)
Protein kinases that are phosphorylated by ATM and ATR in occurrence of DNA damage
Chk1 and Chk2
