Cells and control

• Mitosis is the process of cell division which creates two genetically identical diploid daughter cells.

  It is needed for growth, repair and reproduction.
• Stages of mitosis - Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokenesis.
• Interphase - chromosomes are Copied.
• Prophase - spindle fibres form and the nuclei membrane disapears.
• Metaphase - Chromosomes line up in the middle of the cell.
• Anaphase - Chromosomes are pulled apart by spindles and move to each end of the cell
• Telophase - The nuclei membrane reforms.
• Cytokinesis - The cytoplasm of the cell separates forming two new cells.
• If mitosis goes wrong, uncontrollable cell division can occur which causes a cancerous tumour to grow.
• A unicellular organism is made of just a single cell.

  Prokaryotes Are always unicellular.
• A multicellular organism is made of multiple different cells.

  Eukaryotes are normally multicellular.
• Stages of Animal growth - cell division by mitosis, cell differentiation which makes the specialised Cells.
• Stages of Plant growth - cell division by mitosis, cell elongation and cell differentiation which makes specialised cells.
• The brain is made up of a cerebral cortex, cerebellum, medulla oblongata and spinal cord.
• The cerebral cortex controls conscious thought, memory and language
• The cerebellum coordinates movement and balance
• The medulla oblongata regulates breathing rate and heartbeat
• The spinal cord is made of nerves and carries impulses between the brain and body.
• Our body reacts through a stimulus, receptor, neuron's, processor, effector and finally a response.
• A stimulus is what our body is sensitive to.
• Receptor cells are proteins which receive the signal from the surface.
• A sensory neuron is the cell that is activated by input from the environment which carries impulses.

  
• An interneuron connects the motor and sensory neurons.

  
• A motor neuron carry’s impulses away from the nervous system.

  
• A synapse is a gap between two neurons that allows impulses to pass through by diffusion.
• The processor is the brain.
• The effector is the muscle or gland that carries out the response to the stimulus.