L3 Cell Cycle Flashcards
Understand the process and regulation of cell growth and division in context of the cell cycle, including mitosis and how this affects organismal health and development
All cells derive from a…
Pre-existing cell 😉
In eukaryotes somatic cell division occurs via mitosis. This produces…
Genetically identical daughter cells
Prokaryotes divide by…
Binary Fission
Rather than a distinct phase, prokaryotes replicate…
Throughout interphase
FtsZ protein in prokaryotes is homologous to ? in eukaryotes
Actin
The Eukaryotic Cell Cycle has 4 distinct phases
G1, S, G2 and Mitosis
Mitosis can be divided into 5 steps, followed by cytokinesis
- Prophase
- Prometaphase (late prophase)
- Metaphase
- Anaphase
- Telophase
G1
Main growth (cellular contents, bar chromosomes, duplicate) and ✅checkpoint
S
DNA (and associated protein) synthesis, chromosomes duplicate
G2
Further growth and additional ‘double-check’ ✅
Checkpoints are regulated by (3)…
Specific growth factors,
External factors and Kinases
Kinases are phosphorylating enzymes which signal the cell is ready to proceed with the cell cycle, when the correct…
type of cyclin is present (G1, G1/S, S, M)
Regulation of the cell cycle is important because (2)…
it allows detection and repair of genetic damage and prevents uncontrolled cell division
Phase G0 (G-zero) is known as…
Quiescence ⏸
Without the right signals cells proceed to either…
G0, or programmed cell death ☠️
Terminally differentiated cells stop at which phase of the cell cycle?
G0 (G-zero)
The cell cycle varies greatly in length. This is mostly due to the time spent in… ⏱
G1/G0 phases
Important Growth Factors (GF) (3)…
- PDGF (Platelet-derived)
- FGF (Fibroblast)
- EGF (Epidermal)
🙅♀️No growth factors? Cell cycle moves to …
G0 phase
Apoptosis is characterised by (4)…
- Nuclear condensation and fragmentation
- Blebbing of membrane, triggering phagocytosis
- Subsequent recycling of cell contents
Necrosis is accidental cell death💀. After nuclear swelling and lysis, cell contents is released into the tissues, which is messy and can cause…
an inflammatory response 🤒
Apoptosis can be activated physiologically in order to achieve (2)…
- Remodelling of tissues during embryonic development (‘sculpting’)
- Homeostasis of cell numbers ⚖️
Apoptosis can be activated by pathogens, such as by viral toxins, or the bodies own immune system…
by cytotoxic-T cells or heat shock
The p53 gene is known as…
“The Guardian of the Genome” 👼
When switched on, the tutor suppressor gene p53 promotes…
apoptosis
Complete the cascade following detection of DNA damage:
- DNA damage
- ?
- G1 checkpoint ?
- ?
- ? Leak
- ? 9, 3 & 7
- Apoptosis
- p53 activated 🔆
- progression blocked 🛑
- mitochondrial membrane ruptures
- cytochrome leak 💦
- release of Caspase 9, 3 & 7
Both cell ? and ? are required for normal tissue development and maintenance.
Growth & death
