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Questions and Answers
What is a possible advantage of being larger in size as a predator?
What is the most important advantage of multicellularity?
What is a unique feature of some cells in our bodies?
What is the significance of controls on cell growth in development?
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What is the role of a specialised germline in multicellularity?
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What is the implication of multicellularity being lost as well as gained in phylogenetic analyses?
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What is the importance of an unbroken line of cell division from the origin of life?
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What is the primary reason why most cells in an organism cease to divide?
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What is the term used to describe cells that start to divide uncontrollably?
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What is the characteristic of most multicellular macro-organisms?
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What is the process by which intermediately multicellular organisms can come together?
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What is the result of natural selection between cells in an organism?
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What is the characteristic of unicellular organisms in relation to multicellular organisms?
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What is the primary reason why cancer occurs in multicellular organisms?
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What is the term used to describe the 'hallmarks of cancer'?
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What is the primary advantage of multicellularity, aside from increased size?
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What is a possible explanation for why multicellularity has been lost as well as gained in some lineages?
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What is the significance of some cells stopping division in our bodies?
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What is the primary reason why being larger in size can be advantageous for predators?
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What is the role of a germline in multicellularity?
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Why is it not necessary to have multiple cells to be large?
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What is the significance of an unbroken line of cell division from the origin of life?
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Why do most cells in an organism cease to divide?
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What happens when mutations break the control on cell division?
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What is a characteristic of intermediately multicellular organisms?
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What favors the cells that gain the 'hallmarks of cancer'?
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What is a result of cells behaving like unicellular organisms again?
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What is a characteristic of most multicellular macro-organisms?
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Why do germ cells have a chance to go forward to the next generation?
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What is the outcome of cells failing to respond to signals from the host organism?
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Study Notes
Multicellularity
- Multicellularity has been discovered independently by different lineages of plants, animals, slime moulds, etc.
- Phylogenetic analyses suggest that multicellularity has been lost as well as gained.
Advantages of Larger Size
- Protection: being larger means being safer from predators
- Attachment: being larger allows for better attachment to substrate
- Buffering: being larger provides a buffer against environmental changes
- Strength in numbers: being larger means being able to attack bigger prey or defend against predators
Importance of Specialisation
- Specialisation allows for efficiency in task allocation
- Specialised germline can be maintained to keep the genome as mutation-free as possible
Controls on Cell Growth
- Controls start in development and are an important part of it
- Cells can stop dividing and sometimes deliberately die, which is unprecedented for cells
- This control is not perfect and can be broken by mutations, leading to cancers
Multicellularity and Unicellularity
- There are organisms with lifestyles between unicellularity and multicellularity
- These organisms can come together by aggregation or by cells remaining associated with one another after cell division
Characteristics of Multicellular Macro-organisms
- Most are diploid
- Separate germline and soma very early in development
- Sexual and heterogametic, with separate sexes
Cancer
- Cancer occurs when a cell from a multicellular organism starts behaving like a unicellular organism again
- Natural selection between cells in the organism favours those cells that gain the 'hallmarks of cancer', leading to the organism's death in some cases
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Description
Explore the intricacies of cell division and its regulation. Learn how cells cooperate to form a whole organism, and what happens when this control is disrupted, leading to uncontrolled cell growth and cancer. Delve into the gray areas of multicellularity and its variations in different organisms.
