Topic 2: Division, Differentiation and Death Flashcards
What are the phases of Interphase in the Cell Cycle?
G1, S Phase, G2
G1 checks for DNA damage, nutrients, and cell size; S Phase involves DNA replication; G2 ensures chromosomes are accurately replicated.
What occurs during the S Phase of the Cell Cycle?
DNA replication occurs, resulting in sister chromatids
Sister chromatids are identical copies of the same chromosome.
Definition of Sister Chromatids
identical copies of the same chromosome
State the number of chromosomes(N), amount of DNA (C) and whether sister chromatids are present in each stage of the mitotic cycle
prophase and metaphase: no. of chromosomes:2N=46, amount of DNA: 4C, sister chromosomes present
anaphase: no. of chromosomes: 4N=96, amount of DNA: 4C, no sister chromosomes are present
Telophase and Cytokinesis: no. of chromosomes:2N=46, amount of DNA: 2C, no sister chromosomes present
What is the purpose of the cell cycle regulation?
Ensure faithful replication, regulate cell growth, regulate cell division
These mechanisms are conserved in all eukaryotes and often linked to diseases like cancer.
What are CDKs and cyclins?
CDKs are enzymes; cyclins are proteins that activate CDKs
They play a crucial role in regulating the cell cycle.
What is Cell Differentiation?
The process in which a cell becomes specialized
Differentiation does not involve a change in DNA sequence.
What are stem cells?
Cells that can reproduce themselves indefinitely and are undifferentiated
Stem cells can become any cell type (pluripotent).
What does pluripotency refer to?
The capacity of cells to divide indefinitely and differentiate into different cell types
Pluripotent cells can renew themselves and give rise to various lineages.
What are Transit Amplifying Cells?
Cells that divide rapidly to amplify the number of cells
Their daughter cells will eventually become differentiated.
What is apoptosis?
The process of controlled cell death
It maintains homeostasis of cell number by balancing mitosis with cell death.
What are the steps in the cellular changes during apoptosis?
- Chromosomes condense into DNA fragments
- Cytoplasm condenses
- Cell breaks into membrane-bound fragments
- Fragments are engulfed by phagocytic cells
This prevents leakage of cellular contents and inflammation.
What distinguishes apoptosis from necrosis?
Apoptosis is regulated, ordered, and does not cause inflammation; necrosis is uncontrolled, disordered, and causes inflammation
Apoptosis is beneficial for development and error turnover, while necrosis occurs in response to injury.
What happens if apoptosis goes wrong?
Can lead to cancer or developmental disorders
Apoptosis is crucial for normal development and cellular turnover.
What are the characteristics of necrosis?
Induced by massive cellular injury, leads to cell membrane rupture and leakage of contents
This results in inflammation and damage to surrounding tissues.
Fill in the blank: The _______ phase is when cells are not actively dividing but remain metabolically active.
quiescent (G0) phase
Cells can enter this phase upon stimulation.
What are some examples of mature differentiated cells?
Nerve cells, muscle cells, skin cells
These cells do not divide.
What is the role of stem cell niches?
Necessary to replace differentiated cells
Found in most tissues to maintain cell populations.
