CH2 The cell cycle and cell growth, death and differentiation Flashcards
Covers 2.2.1 Cell replication in prokaryotes 2.2.2 Cell replication in eukaryotes 2.3.1 Regulation of the cell cycle 2.3.2 The cell cycle in action 2.3.3 Programmed cell death 2.3.4 When things go wrong: deviant cell behaviour 2.4.1 Differentiation and specialisation 2.4.2 Stem cells 2.4.3 Sources of stem cells 2.4.4 Somatic stem cells 2.4.5 Stems cells in medicine (30 cards)
What is reason for cell replication?
Growth, Repair and Procreation
What are the steps of binary fission?
Replication of chromosome DNA and cell elongation
Two circular chromosomes migrate to either side of the cells
Cell membrane pinches in two and a septum form which finally seperates them into two
What are the basic phases of the cell cycle in eukaryotes?
Interphase, Mitosis, Cytokinesis
What occurs in interphase?
Replication of DNA of parent cell
What occurs in mitosis?
Organisation of chromosomes, followed by their separation into two identical groups at different poles of the parent cell, leading to two identical nuclei
What occurs in cytokinesis?
Division of parent cell into two cells through the splitting of the membrane
What stages is interphase divided up into?
Gap 1 stage
Synthesis
Gap 2 stage
What are the stages of mitosis?
Prophase: Chromosomes gradually condense, becoming shorter and thicker
Metaphase: Double stranded chromosomes line up in the middle
Anaphase: Spindle fibers pull sister chromatids apart
Telophase: Nuclear membrane forms and chromosomes gradually decondense
What is a chromatin?
A mass of genetic material composed of DNA and proteins which condense to form chromosomes
What are centromeres?
The position where the chromatids are held together as chromosomes
What occurs in cytokinesis
Where the cytosol, and the organelles in the cytosol, distribute around the new nuclei and become enclosed within an entire plasma membrane
What does IPMATC mean?
Interphase: insivible/intermission
Prophase: plump
Metaphase: middle
Anaphase: apart
Telophase: two nuclei
Cytokinesis: cut/cleave/complete
Where do the three checkpoints of cell cycle regulation occur?
In G2, M, G1
What is the G1 checkpoint for?
To check that DNA is not damaged and is ready to be replicated
What is the M checkpoint for?
Occurs during mitosis to check the connection between the chromatids and the spindle fibers
What is the G2 checkpoint for?
To check the replicated DNA for completeness and lack of damage
What is p53?
Regulator of the cell cycle, therefore a tumor suppressor
What is the role of proto-oncogenes?
Genes contained in the DNA of a cell that lead to the production of proteins that initiate the cell cycle. These signals, of course, can be switched off, but this is not the only control in switching off the
cell cycle so that excessive production of cells does not occur.
What are oncogenes?
Mutated proto-oncogenes which lead to excess production of cells
What is apoptosis?
Programmed cell death
What are some reasons for apoptosis to occur?
Cells at the end of their natural life Dysfunctional, damaged or diseased cells
Excessive cells
What are the two mechanisms of apoptosis?
Extrinsic external signal outside the cell
Intrinsic: internal signal within the cell
What happens during apoptosis?
Cell shrinkage
Formation of blebs
Nucleas condensing
Formation of apoptoptic bodies
Phagocytosis
What is cell differentiation?
The process by which cells become specialized for a specific function
