Study Notes
The levels of organisation in biology include understanding how cells divide, grow, and differentiate, as well as how they coordinate and respond to stimuli.
- Mitosis — a process where a cell divides to form two genetically identical cells. Example: Mitosis is used for growth and repair in organisms.
- Stem Cells — unspecialised cells that can differentiate into specialised cells. Example: Embryonic stem cells can develop into any cell type.
- Central Nervous System (CNS) — consists of the brain and spinal cord, controlling body functions. Example: The CNS processes information from sensory neurons.
- Peripheral Nervous System (PNS) — connects the CNS to the rest of the body. Example: Sensory neurons in the PNS detect stimuli and send signals to the CNS.
- Reflex Arc — a pathway that controls an involuntary response to a stimulus. Example: Pulling your hand away from a hot object without thinking.
Exam Tips
Key Definitions to Remember
- Mitosis: cell division resulting in two identical cells
- Stem Cells: unspecialised cells with the potential to differentiate
- Central Nervous System: brain and spinal cord
- Peripheral Nervous System: nerves outside the CNS
Common Confusions
- Mitosis vs. Meiosis: Mitosis produces identical cells, while meiosis produces gametes
- CNS vs. PNS: CNS is the brain and spinal cord, PNS is all other nerves
Typical Exam Questions
- What is the first stage of mitosis? Answer: Prophase
- What is the term for when a cell divides? Answer: Cytokinesis
- Which neuron type is shown in a diagram? Answer: Motor neuron
What Examiners Usually Test
- Understanding of the stages of mitosis
- Differences between types of stem cells
- Functions of the CNS and PNS
- Pathway and function of a reflex arc