Topic 1 Flashcards
Define Energy source
An energy source is available that can be trapped and utilised by an organism for metabolic processes that maintain its living state
Define liquid water
Liquid water is available to allow biochemical reactions to occur and to dissolve chemicals and transport them both within cells and to and from cells
Define chemical building blocks
Chemical building blocks are available for use by an organism in cellular repair growth and reproduction
Define stable environmental conditions
Stable environmental conditions exist within the range of tolerance of an organisms such as pressure temperature light intensity Ph and salinity so that they can maintain their living state
What is the cell theory
All organisms are made up of cells and products of cells
All cells are derived from pre existing cells
All cells contain genetic information that is used as instruction for growth functioning and development
The cell is the smallest structural organisational and functional unit of all living things in which the chemical reactions of life take place
What is the surface area to volume ratio
The surface area to volume ration is obtained by dividing the objects surface area by its volume.
As cells increase in size through an increase in cytoplasm both their surfaces and volumes increase but not at the same rate. The internal volume of cells expands at a greater rate than the areas of their plasma membranes.
What is the relationship between sa and v of a cell
As the size of the cell increases the sa to v ratio decreases
How does the sa to v ratio affect cells
The rate at which nutrients enter and wastes leave the cell is inversely proportional to the cell size. The larger the cell the slower the rate of movement of nutrient into and wastes out of the cell
Why are cells limited to small sizes
Beyond a given cell size the two way exchange of materials across the plasma membrane cannot occur fast enough to sustain the volume of the cell contents
It is reasonable to suggest that cells are limited to small sizes so that their surface areas are large enough to meet their needs
How do cells adapt to have favourable sa to v
Cells divide into smaller cells with favourable sa to v ratios
Evolve different shapes and folding to maintain efficiency of diffusion eg. Micro villus have extensive folding to increase SA
muscle cells are long
What disadvantage would organisms with low SA to V ratios have living in extreme conditions
Low sa to v slower
Name the four conditions that must be met for life to exist
Energy source
Liquid water
Chemical building blocks
Stable environmental condition
