AOS1 unit 1 (part 2) Flashcards
Q: What is the purpose of the cell cycle?
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A: The cell cycle ensures each daughter cell receives an accurate copy of DNA, enabling proper growth, development, repair, and reproduction.
Q: What are the major phases of the cell cycle?
A: Interphase and Mitotic (M) Phase.
Q: Which phase does a cell spend most of its time in?
interphase
Q: How do prokaryotic cells divide?
A: By binary fission, a process where a single cell duplicates its genetic material and splits into two identical daughter cells.
Q: What are the key differences between binary fission and mitosis?
A: Binary fission occurs in prokaryotes without spindle fibers, while mitosis occurs in eukaryotes with organized chromosomal segregation.
Q: What are the stages of mitosis?
A: Prophase, Metaphase, Anaphase, and Telophase and cytokinisis.
Q: How does cytokinesis differ in plant and animal cells?
A: In animal cells, a cleavage furrow forms; in plant cells, a cell plate forms.
Q: What are the three key cell cycle checkpoints?
A: G1 (cell size & DNA damage), G2 (DNA replication accuracy and cell growth), and M (metaphase: spindle fiber attachment).
Q: What happens if the G2 checkpoint fails?
A: Cells with damaged or unreplicated DNA may divide, leading to mutations or cancer.
Q: What is apoptosis?
A: A programmed cell death process that removes damaged or unnecessary cells.
Q: How can disruptions in apoptosis lead to cancer?
A: Failure of apoptosis allows abnormal cells to survive and proliferate uncontrollably.
Q: What is a carcinogen?
A: A substance that causes cancer by inducing mutations in cell cycle regulatory genes.
Q: What are stem cells?
A: Undifferentiated cells capable of self-renewal and differentiation into specialized cell types.
Q: What are the two main types of stem cells?
A: Embryonic stem cells (pluripotent) and adult stem cells (multipotent).
Q: What are the three germ layers and their associated tissues?
Endoderm: Lungs, liver, pancreas
Mesoderm: Bone, muscle, blood
Ectoderm: Skin, hair, nervous tissue
what is Proto-oncogenes
Proto-oncogenes stimulate cell division; when mutated become cancer causing oncogenes.
what is Tumour suppressor genes
Tumour suppressor genes prevent cancer by slowing down cell division
what is A carcinogen
A carcinogen is a cancer causing agent. Carcinogens may be chemical, physical or biological in nature.
what are the Risk factors for cell cycle disruption
-A weak immune system that is unable to detect and destroy cancer cells.
-Inheritance of an oncogene or missing / faulty tumour-suppressor gene.
-Environmental carcinogens may act as mutagens, damaging the DNA in proto-oncogenes and tumor suppressor genes.
what are the different mutagens?
physical mutagen: cause DNA damage through physical factors (x- rays, sun beds)
chemical mutagens: alter DNA structure by interfering with base pairing (smoking)
biological agent: viruses or organisms that alter DNA by inserting their genetic material into the host genome.
what is a totipotent, pluripotent, multipotent and unipotent stem cell.
totipotent- can become any cell type including pacental cells (fertilised)
pluripotent- can become almost any cell type
multipotent- can become a limited range of cell types
unipotent- can only become one specific cell type
