AOS1: The cell cycle and cell growth, death and differentiation Flashcards
* binary fission in prokaryotic cells
What method do prokaryotes divide by? List the process.
3 marks
Involves growth and development, maintenance and repair, and reproduction
DESC
1. DNA replication
2. elongation
3. septum formation
4. cell division
* the eukaryotic cell cycle + characteristics of sub-phases of mitosis
What does the eukaryotic cell cycle involve?
List the phases
- Interphase-cellular growth and duplication of chromosomes
- Mitosis-separation of sister chromosomes and formation of two new nuclei
- Cytokinesis-division of cytoplasm and formation of two daughter cells
* the eukaryotic cell cycle + characteristics of sub-phases of mitosis
Characteristics of interphase and prophase
Interphase: longest stage, preparation for replication and growth by synthesising proteins and organelles G1 and G2 phase, and replicating DNA in S phase.
Prophase: spindles fibres appear, chromosomes condense, nuclear membrane breakdown
Characteristics of metaphase and anaphase
Metaphase: Spindle fibres attach to chromosomes, chromosomes align at the equator
Anaphase: Centromeres divide, contraction of spindle fibres, sister chromatids separate to the opposite poles
Characteristics of telophase and cytokinesis
Telophase: nuclear membrane reforms, chromosomes decondense, spindle fibres disappear
Cytokinesis: cytoplasm divides, parent cell splits into two genetically identical daughter cells
cytokinesis in plant and animal cells
What is difference is there for cytokinesis in plant vs animal cells?
Cell plate forms
Cleavage furrow forms
* apoptosis as a regulated process of programmed cell death
Apoptosis and its uses.
-(aka programmed cell death) controlled death of cells in the body
-remove malfunctioning, damaged or unnecessary cells by initiating apoptosis
What are the steps of apoptosis?
- Activation of caspases-mitochondria detects internal DNA damage and releases cytochrome c
- Digestion of cell contents-caspases CLEAVES proteins which breakdown of organelles
- Cell shrinks- NUCLEUS shrinks as intracellular material is broken down
- Membrane blebbing and breakage- apoptotic bodies break away
How does apoptosis get activated? Explain the pathways.
4 marks
Mitochondrial:
Mitochondria detect internal cell damage
–>releases cytochrome c –>binds with cytosolic proteins and forms an APOPTOSOME–> activates caspase enzymes
Death receptor-death signalling molecules bind to death receptor proteins–>activates caspase enzymes
* disruption to the regulation of the cell cycle
What disruptions and how are they caused in the regulation of the cell cycle?
Failure to initiate apoptosis
Malfunctioning of checkpoints during the cell cycle.
Disruptions:
-cell cycle disrupted or insufficient, damaged cells replicate exponentially
OR
-failure to initiate apoptosis at checkpoints of mitosis
-malfunctioning death receptor proteins, leading to an inability for death signalling molecules to initiate apoptosis = reduced rate of apoptosis.
malfunctions in apoptosis that may result in deviant cell behaviour
What happens when apoptosis malfunctions?
Malfunctions in apoptosis leads to cancer
cancer and the characteristics of cancer cells
What are the two types of cancer?
Malignant and benign cancer.
cancer and the characteristics of cancer cells
Name the characteristics of cancer cells. Explain each one.
4 marks
- Self-sufficient: do not need chemical signals to replicate cells
- Antigrowth deactivation: disabling mechanisms to continue replicating
- Increased survival: Apoptosis does not function properly, and replicative immortality
- Blood supply formation: form new blood vessels for nutrients and oxygen
cancer and the characteristics of cancer cells
Name the characteristics for malignant cancer cells.
Malignant cells
1. Tissue invasion/Metastasis: travel via the lymphatic system to other parts of the body/tissue
Metastasis: the migration of tumour cells from the primary tumour site to distant parts of the body
* properties of stem cells
Properties of Stem Cells
that allow for differentiation, specialisation, renewal of cells
- Self-renewal: produce a copy of themself and a differentiated cell
- Potency: capability to differentiated cells
