IBDP Bio - TOPIC 1 - Cell Biology Flashcards
What are the 3 key points of cell biology?
- Cells are the basic unit of life.
- New cells are formed from pre-existing cells.
- Cells and cell products make up all of the structures of living cells.
What are the functions of life?
Movement Reproduction Sensitivity Homeostasis Growth Respiration Excretion Nutrition
4 common features of all cells.
- Surrounded by a membrane
- Contain genetic material
- Chemical reaction occurring (catalysed by enzymes)
- Have their own energy release system for power.
Evidence of the cell theory
The cell theory can not be proven true or false.
What 3 cells fit in the cell theory even though they disapprove the cell theory?
- Giant Algae
- Striated muscle
- Multi nucleated fungi cell
What is different about the giant algae?
Can grow as big as 100mm in a single nucleated cell
What is different about the Striated muscle?
Very ling fibres and contain hundreds of nuclei.
What is different about the multi nucleated fungi cell?
Consists of a thread like structure called hyphae.
What are unicellular organisms?
Organisms consisting of only one cell and carry out all the functions of life.
Definition of metabolism of a cell.
Large numbers of chemical reactions occurring in the cytoplasm.
What is the rate of the reaction in a cell proportional to?
… to the volume of the cell.
What does the rate of which substances cross the membrane depend on?
… the surface area of the cell.
What happens if the ratio of the cell is too small?
- The substances will not enter the cell as quickly as they are required.
- Waste products will accumulate because they are produced more rapidly than they can be excreted.
- The cells may overheat.
2 Examples of a unicellular organism?
Paramecium & Chlam Domonas
How does the surface area to volume ratio work?
- The larger the cell the more the ratio decreases.
