Cell cycle and cancer development

3805 dr shivkumar

What three processes control tissue homeostasis

cell growth, cell death and cell division are the three processes that control tissue homeostasis

what happens if any of the three process involved in the control of tissue homeostasis are dysregulated

Can cause cancer

what two phases are required for a complete cell cycle

the two phases required for a complete cell cycle are interphase and M phase (mitotic phase)

what are the different phases of interphase phase and describe their function

g1 phase where the cell grows in size synthesises mrna and proteins needed for dna replication as well as carrying out metabolic functions ,

g2 phase final phase of interphase , the cell grows and prepares for mitosis, it synthesises proteins for cell division and ensures that all dan has been accurately replicated without errors before entering through M phase and

S phase is where DNA replication occurs, each chromosome is replicated to produce two sister chromatids, this ensures that when the cell divides, each new cell gets a identical set of chromosomes are the different phases of interphase

what happens in g0 phase

where most quiescent cells (dormant cells) are, they carry out normal metabolic functions but do not progress through the cell cycle. and they can exit and enter g1 phase when they receive signals for growth and division such as growth factors or tissue damage

What happens in the mitotic phase?

Chromosomes which have been replicated into sister chromatids during the s phase of interphase, are aligned at the cells equator (metaphase plate) to ensure equal distribution of the daughter cells.

the nucleus divides by mitosis (prophase, metaphase,anaphase,telophase) this separates the sister chromarifs into 2 daughter cells.

Cytokinesis occurs while this happens or immediately after , this is the division of the cytoplasm resulting in the formation of two distinct daughter cells. each with its own nucleus and organelles.hyw

Why is this process regulated using checkpoints

cell cycle checkpoints are used to regulate the cell cycle and to. maintain homeostasis by preventing cell division when there is errors in dna , insufficient cell growth or damaged cells. this regulation ensures that only healthy cells proceed through the cycle, allowing for repair mechanisms to correct errors or, if necessary, trigger apoptosis.

what does each checkpoint detect for

g1 checks for dna damage , cell size to ensure its large enough to divide, nutritional status to assess if the cell has enough nutrients for DNA replication , growth signals to check if external signals for cell growth are present.

g2 checks that dna has been accurately replicated without errors , it ensures that no damage is in the DNA post replication and checks cells size to ensure the cell grew adequately for mitosis

m phase checks for chromosome alignment, ensures all the chromosomes are aligned on the metaphase plate, ensures spindle fibres are correctly attached to each chromosome to facilitate equal separation w

what happens if there are any issues detected at the checkpoints during the cell cycle

he clell cycle is is paused before any cells can progress to the next stage to allow for repairs and if the damage is irreparable the cell may undergo apoptosis to prevent the propagation of damaged DNA

What are the extracellular factors that regulate the cell cycle

mitogens - responsible for entry into the cell cycle

growth factors - signalling molecules that activate signalling pathways to increase cell mass

survival factors - siganlling factors that suppress apoptosis

what are the intracellular factors that regulate the cell cycle

cyclins and cdks - proteins important for entry and progression in the cell cycle

receptors eg. g coupled protein receptors , tyrosine kinase

downstream signalling pathways